The transport industry is one of the fastest growing industries with the sector playing a significant role in negative impact on global warming and pollution through the emission of greenhouse gases. Aviation in particular, has enjoyed growth especially in the few decades. New airlines and aircraft manufacturers are coming up with different innovations and technologies to ensure they make the best possible environmentally friendly aircraft. The new main area of focus has been on how to come up with fuel that will reduce the greenhouse gas-emissions. The stakeholders in the same effort include developed nations like the United States, United Kingdom, Russia, France, Germany, and Canada among others. Energy providers as well as jet fuel suppliers are also making efforts to conserve the environment. The purpose of this thesis is to explore the area of biofuel in aviation by looking into various stakeholders involved in the efforts of the transition from fossil fuel to biofuel. The conclusion of this thesis is that biofuels are viable options in the aviation industries since there have been positive results in the tests made. 

This study analyzes different options for solar panel installations for four apartment buildings owned by Eksta Bostads AB and are located in Åsa, Kungsbacka. The objective of this thesis is to find an installation suitable for the properties and the area, The aspects to be examined is the economic aspect, the environmental impact, and solutions for storage options for surplus excess electricity produced.

To achieve this, various components of a solar panel are examined to decide different sizes and storage possibilities. This is dimensioned using a programme called Polysun to obtain realistic production and self-consumption rates. Economic calculations are then made for the different options to assess the profits. The result of this gives a variety of combinations that show both production and self-consumption, as well as the investment cost and profit for the installations.

Simultaneously,   emissions, aesthetics and improvements for the installation are investigated. After all aspects have been explored and calculated, an installation is chosen that is most suitable for the properties. The installation deemed most suitable is one with 45 solar panels (19,8 kWp) and a lithium-ion battery with a capacity of 20 kWh. The investment cost for the facility is 313 784 SEK, and it produces between 18 000 – 19 000 kWh per year depending on the house. The self-consumption rate for the installation ranges between 70,9% and 73,2% depending in the house. This installation can return a profit of 155 420 SEK after 25 years at the lowest estimated discount rate but can also result in a loss of 42 451 SEK after 25 years at the highest discount rate used.

The role of liquid biofuels in transportation to minimize the effects of climate change is  evident and has led to a number of studies on finding effective solutions to replace fossil fuels. Liquid biofuels are especially important for heavy duty transports as the effective ‘green’ alternatives are not as many compared to light duty vehicles; for which for e.g. electrification is an option. This thesis presents a comparison study of 8 liquid biofuels with a total of 13 different fuel pathways for use in road freight transports; both current and potential future fuels are assessed in terms of their environmental effects, fuel properties and compatibility with the heavy duty vehicle engines (see Table 10, page 36). Furthermore, a case study is performed to assess the practicality of the results of the study.  Hydro-treated vegetable oil, Bio Dimethyl ether, Liquefied Bio Methane/ ED95 are identified as fuels with considerable potential in the shorter term. Algal biofuel and Biomass to liquid (BTL) fuels from synthesis gas, if realized commercially would be a breakthrough for biofuels in overall transportation sector. However, life cycle analysis has to be performed for the different fuel pathways to completely understand the various impacting factors.

Solar photovoltaic industry is a hot research field, massive attempts are going on all over the world to increase its productivity in different ways. One of the challenges for solar cells is the light spectrum mismatch losses, which referred to the part of solar spectrum that cannot be utilized to electricity by the conventional cells.

Two ways have been suggested to overcome solar spectrum mismatch losses, the first is multi layered cells (tandem cells) with a different light behavior for each layer, and the second is spectrum conversion which is this researches subject.

Spectral modification or conversion in solar cells industry has been studied and different lab scale models have been introduced. According to nanoscale journal, such technology may be the base of the next generation solar cells, mentioning specifically the use of luminescence down conversion and up conversion techniques to control the light spectrum on the solar cell, these endeavors targets to produce solar cells that is not subjugated to Shockley-Queisser maximum efficiency limit of 31%.

This research aims to draw a map of various ideas introduced to incorporate similar technologies in solar cell products, beside further suggestion to enhance its technical behavior and to push the commercialization of the technology forward. This is expected to reveal clear image about technology’s future development map for the upcoming studies, and to create a motivation for further studies towards a commercial production scale.

The proposed commercialized model will result in enhancing the maximum theoretical efficiency limit to 48% if all spectral mismatch loses have been eliminated. Quantum energy level diagrams have been illustrated to describe each model’s performance under a theoretical light spectrum.

The supply of energy is a key factor in modern societies. As the old fossil sources for energy are dwindling, conflicts arise between competing nations and regions. Fossil energy sources also contribute to the pollution of the environment and emission of greenhouse gases.

With renewable energy sources many of these drawbacks with fossil fuels can be eliminated as the energy will be readily available for all without cost or environmental impact.

Combining the renewable energy sources will be very effective, particularly in commercial areas where lake of electricity is high. The cost of combining onshore wind and solar power plant is affordable. Furthermore there is no power failure or load shedding situation at any times. When it is manufactured in a large scale, cost of this integrated natural resources power generation system is affordable. Moreover there is no power failure or load shedding situation at any times. Therefore, it is the most reliable renewable power or electricity resources with less spending and highly effective production. ref [1].

The thesis work would take planning of offshore renewable plant (Lillgrund) with considering the resources of renewable power. The study would take in account combining the Lillgrund wind farm with solar system and take close look into the advantage and disadvantage of combining the renewable resources together and figure out if such station can work in proper way and provide sufficient power production. The study would take in account the effect of each resource on other resource, also calculations would be done.

The study site is Lillgrund in south of Sweden. The Lillgrund wind farm is the most important offshore wind power plant installed in Sweden with a total capacity of 110 MW, corresponding to 48 turbines. ref [2].

Efficiency of a ground source heat pump with thermal capacity of 6 kW determined in two differentlocations in Sweden. In the north side with low average temperature which could go down to -10 ᵒCand in the south side, with low average temperature with +2 ᵒC. The heat pump has refrigerantR407c, which could be connected to both, ground source heat feeding methods the horizontal, andthe vertical model. The heat pump give heat for both space heating and domestic hot watercompared the micro CHP which has thermal capacity of 12.5 kW and electrical capacity of 4.4 kW. Ithas IC engine which means the engine has internal combustion work. It also works with two kinds offuel, natural gas and propane MOZ 92; the energy and exergy of the fuel in micro CHP feeding thethermal process by heat. That heat used for space heating and domestic hot water after going outthe process for the cooling which keep the heat in storage tank and it heat the liquid to the gas to beused in the turbine to produce the electricity. The two locations in the north and south of Swedenwill influence the thermal operation and that influence power used for compressor for heat pumpand somehow the pump in the micro CHP. The study shows that the different in exergy and energyefficiency between these two heat technologies by located them in the locations. Higher efficiencyof the micro CHP which give the advantage of use Micro CHP some technology give the benefit byusing the fuel for producing the heating and electricity , the benefit which give the customer manybenefit shows in the study. That’s comparing with the heat pump which is large use in Sweden. Inthis paper will introduce Micro CHP as heating technology which has been used in the rest of Europecould be used in Sweden for future heating technology with electricity producing, shall change thecostumer from energy consumption costumer to producing costumer.

City of Malmö has ambitions for the district Hyllie to become a demonstrative area ofsustainable urban development. As a part of this the following report aims to investigate the potential in using noise barriers combined with photovoltaics along Annetorpsvägen to generate solar electricity. To quantify the losses that shadows from buildings along the roadmight cause, a 3D-model of the area was constructed in SketchUp. This digital model made it possible to simulate shadows and how they change over the year. A reference model of a photovoltaic noise barrier (PVNB) was constructed and used to find the dates on which the solar cells are shadowed depending on building heights and positioning of the barrier.

The results show that two lengths with a total distance of 400 meters is appropriate for applying photovoltaic noise barriers. Along distance A, a PVNB with a total capacity of 19 kWp is expected to generate 18 000 kWh per year assuming realistic shadowing, which equals 6% losses compared to production without shadows. The PVNB along distance B with installed capacity of 37 kWp has no considerable problems with shadowing and is expected to generate 37 500 kWh per year. This gives a total production of 56 500 kWh per year.

The combined investment costs (excluding costs for the actual noise barrier) for both power plants are assumed to be approximately one million SEK. Expected economical outcome is a negative capital value after 25 years, although a change of critical factors such as investment aid, investment cost, electricity prices and cost of capital may result in a more positive outcome. Production losses from shadowing and dirt seem to have a minimal effect on the outcome

Despite uncertainty in the economical outcome, realizing the project would have several other positive effects such as reduction of carbon dioxide emissions and a positive impact on the public view of renewable energy.

The cosmic “Dark Ages” is the cosmic era between the epochs of recombination of cosmic microwave background and the formation of the first stars. The only signal from this epoch is from neutral hydrogen, which could represent one of the richest data sets in cosmology. In order to extract this data, NASA/JPL has proposed a rover mission to the farside of the moon to deploy several radio arrays. Here the arrays would gather data undisturbed by human interference. This thesis examines the possibility of using photovoltaic and electric batteries as an energy solution for a rover on the moon. The requirement for such a system to survive on the moon is discussed in a literature study. A proof of concept simulation using a Simulink model has also been done. The thesis concludes that a rover can deploy the radio array using solar energy. It would be able to hibernate through the night using radioisotope heating. It would need to wait for its batteries to charge before each night.

This degree thesis investigates the possibilities of producing food inside a container at Svalbard, using renewable energy and energy storage. The idea was to be able to place the container at remote places without the need of being connected to the grid. We chose Svalbard, where it is cold and the sun is shining 24 hours a day at summertime. In the winter the opposite occurs and the sun is absent from the sky.

The work is divided into theoretical studies and results based on different calculations. Such as economical evaluations (LCOE), and simulations using the computer programs Matlab and PVsyst. We have investigated if solar power and wind power is suitable as energy sources. Options for storage were batteries, grid and hydrogen storage. Different cases with Photovoltaics- and wind power plants, with batteries or grid, were compared against each other. It is not possible to use the grid as storage. This resulted in different sizing of our cases, with no excess energy production. The result showed that a 5 kWp photvoltaic plant with dual axis tracking system, was the most profitable. The Pay off would be 14 years and the total profit 63 453 SEK. If it will become possible in the future to use the grid at Svalbard as storage, it will open up opportunites for bigger systems. This will lead to higher profit than with smaller ones. Our results show that it is now most profitable with solar power.

For many of us, electricity is a natural and necessary source, making it easier to go about our everyday life. Imagine having to collect firewood, for several hours a day, to be able to carry out such a simple task as preparing a meal. For many people, especially in developing countries, everyday life looks just like that, but it does not have to. In line with the increasing demand of sustainability, new technologies now turn their focus to the almost inexhaustible source of energy, namely the sun.

The energy that is being received every day in the form of solar radiation, corresponds to about 8000 times more energy than what is being consumed on the planet, throughout anentire year. With today's technology, there is now a possibility to farm parts of this energy, to be used as a more sustainable alternative. 

Sunfurias product uses a technology that, with the help of solar collectors, saves solar energy in a heat storage, enabling cooking at any time.

For the solar collectors to be as efficient as possible, they need to rotate following the movement of the sun throughout the day. Today, this is done by using an advanced tracking device, which in turn makes the entire product significantly more expensive. Which also affects the sales volume, especially in the developing countries.

The SunTrack project has been carried out in collaboration with Sunfuria AB to solve the need for a more affordable product, by developing a cost-effective alternative to the current solar tracking system.

The possibility of the modal shift to public transport and active mobility while considering transport electrification and fuel efficiency improvement has yet to be adequately investigated. This paper explores transition pathways toward an environmentally sustainable road passenger transportation system in the province of British Columbia (BC), Canada. MESSAGE, as a bottom-up energy systems optimization model, is used to find the cost-optimal fuel and technology mix in the transport and power sector. Multiple scenarios mainly assess the influence of modal shift and electric vehicle (EV) diffusion on greenhouse gas emissions by 2050. Besides, the effects of scenarios on the power sector configuration are examined. The results show that BC would not achieve the 80% emissions reduction target in the Climate Change Accountability Act unless by a radical expansion of transport electrification. The target could be met by a minimum diffusion of 70% EVs in the total car stock as well as 35% public transport contribution in total passenger kilometers. The findings also indicate that fully electrified light-duty vehicles coupled with active transport would lead to almost a zero-emission level. Nevertheless, 100% electrification would impose an extra 5.6 TWh burden on the power supply system relative to the business-as-usual scenario. © 2023 The Authors. Published by Elsevier Ltd

Power-to-heat solutions like heat pumps and electric boilers are foreseen to be possible future tools to stabilise international power markets with high proportions of variable power supply. Temporary low cost electricity can be used for heat generation at times with high availability of wind and solar power through substitution of ordinary heat supply, hence contributing to increased energy system sustainability. Power-to-heat installations in district heating systems are competitive due to low specific investment and installation costs for large electric boilers, heat pumps, and heat storages. Several large-scale heat pumps were installed in Swedish district heating systems during the 1980s, since a national electricity surplus from new nuclear power existed for some years. The aim of this paper is to summarise the accumulated operation experiences from these large Swedish heat pumps to support and facilitate planning of future power-to-heat solutions with heat pumps in district heating systems. Gained experiences consider; installed capacities, capacity utilisation, heat sources used, refrigerant replacements, refrigerant leakages, and wear of mechanical components. The major conclusion is that many of the large thirty-year-old heat pumps are still in operation, but with reduced capacity utilisation due to internal competition from waste and biomass cogeneration plants in the district heating systems.

Maintained balance between supply and demand is a fundamental prerequisite for proper operation of electric power grids. For this end, power systems rely on accessibility to various balancing technologies and solutions by which fluctuations in supply and demand can be promptly met. In this paper, balancing approaches in the case of surplus electricity supply, due to long-term, seasonal, or short-term causes, are discussed on the basis mainly of compiled experiences from the Swedish national power grid. In Sweden, a structural long-term electricity surplus was created in the 1980s when several new nuclear plants were commissioned and built. One of four explicit domestic power-to-heat solutions initiated to maximize the utilization of this surplus electricity, as export capacities were limited, was the introduction of large scale electric boilers and compressor heat pumps in district heating systems. In retrospective, this solution not only satisfied the primary objective by providing additional electricity demand to balance the power grid, but represents today – from an energy systems perspective – a contemporary example of increased system flexibility by the attainment of higher integration levels between power and heat sectors. As European power supply will be reshaped to include higher proportions of fluctuating supply technologies (e.g. wind and solar), causing occasional but recurring short-term electricity surpluses, the unique Swedish experiences may provide valuable input in the development of rational responses to future balancing challenges. The main conclusions from this study are that district heating systems can add additional balancing capabilities to power systems, if equipped with electrical heat supply technologies, hereby contributing to higher energy system flexibility. Consequently, district heating systems also have a discrete but key role in the continued integration of renewable intermittent power supply technologies in the future European energy system.

This paper presents an assessment of the excess heat recovery potential from EU metro stations. The assessment is a sub-study on low temperature recovery opportunities, explored in the H2020 ReUseHeat project, and consists of spatial mapping of 1994 underground stations with quantitative estimates of sensible and latent heat, monthly and annually, attainable in rejected platform ventilation exhaust air. Being a low-temperature source, the assessment conceptually anticipates recovery of attainable heat with compressor heat pumps to facilitate the temperature increase necessary for utilisation in district heating systems. Further, the paper explores the influence on useful excess heat volumes from low-temperature heat recoveries when distributed at different temperature levels. The findings, which distinguishes available (resource) and accessible (useful) excess heat potentials, indicate an annual total EU28 available potential of ~21 PJ, characterised by a certain degree of seasonal temporality, and corresponding accessible potentials of ~40 PJ per year at 3^rd generation distribution, and of ~31 PJ at anticipated 4^th generation conditions. Despite lower accessible volumes, utilisation in 4^th generation systems are naturally more energy efficient, since relatively less electricity is used in the recovery process, but also more cost-effective, since heat pumps, at lower temperatures, can be operated at capacities closer to design conditions and with less annual deviations.

Most of the world’s electricity is being generated through conventional sources of energy like coal and nuclear. People are realizing the dire effect of using these fuels, and the amount of CO2 being released into the environment. Therefore, in recent year there has been a shift in emphasis towards cleaner ways of generating electricity. One such recent trend is solar photovoltaics (PV), which has seen rapid growth over the years. This ever-increasing trend of adopting PV system allows consumers to be producers or “Prosumers”. Due to the irregular production capability of solar PV, the need for an energy storage system like a battery bank is on the rise as well. This report evaluates how solar PV can be used in combination with a battery bank to supply the annual electricity demand for a household with little to no support from the grid. The building is assumed to be located in Bangalore, India. The energy demand for the household is estimated based on the requirements of a basic Indian house standard. The size and configuration of each component have been done with regards to the total load demand. Furthermore, the cost of the whole system is estimated in order to evaluate the feasibility of the grid-tied system from an economic perspective. The results show that a PV system consisting of four 270W solar panels, a battery bank of eight150Ah lead-acid batteries and a 48V 4kW inverter is required to meet the annual energy demand of the house. The results show that from a technical standpoint, the above-mentioned technology is feasible. The results from the economic evaluation show that the localized cost of energy(LCOE) for the system is ₹6.01/kWh or € 0.078/kWh or 0.84SEK/kWh and the payback time for the given system is 16.19 years. On the bright side, there are new technological advancements in the PV field every day, which could mean that an energy system of this type can be an achievable and practical alternative.

Most of the world’s electricity is being generated through conventional sources of energy like coal and nuclear. People are realizing the dire effect of using these fuels, and the amount of CO₂ being released into the environment. Therefore, in recent year there has been a shift in emphasis towards cleaner ways of generating electricity. One such recent trend is solar photovoltaics (PV), which has seen rapid growth over the years. This ever-increasing trend of adopting PV system allows consumers to be producers or “Prosumers”. Due to the irregular production capability of solar PV, the need for an energy storage system like a battery bank is on the rise as well.

This report evaluates how solar PV can be used in combination with a battery bank to supply the annual electricity demand for a household with little to no support from the grid. The building is assumed to be located in Bangalore, India. The energy demand for the household is estimated based on the requirements of a basic Indian house standard. The size and configuration of each component have been done with regards to the total load demand. Furthermore, the cost of the whole system is estimated in order to evaluate the feasibility of the grid-tied system from an economic perspective.

The results show that a PV system consisting of four 270W solar panels, a battery bank of eight 150Ah lead-acid batteries and a 48V 4kW inverter is required to meet the annual energy demand of the house. The results show that from a technical standpoint, the above-mentioned technology is feasible. The results from the economic evaluation show that the localized cost of energy (LCOE) for the system is ₹6.01/kWh or € 0.078/kWh or 0.84SEK/kWh and the payback time for the given system is 16.19 years. On the bright side, there are new technological advancements in the PV field every day, which could mean that an energy system of this type can be an achievable and practical alternative.

In Sweden, a great deal of energy is used for residential and commercial heating. To fulfill the ever increasingly need for heat, new heating plants is built to complement the district heating system. At the same time there is unused energy in industry, which produces heat as an unwanted byproduct.

This report evaluates the possibility to use this byproduct to supply energy to a district heating system and store it in seasonal heat storage. When the heat demand increases during the cold season of the year, the seasonal heat storage contributes with heat energy.

The idea is to replace parts of the heating plants in Halmstad with heat storage and waste heat. The aim is to exclude usage of all fossil fuels. This report will also evaluate the economical prerequisites and environmental benefits in replacing biofuels.

A steelworks company, Höganäs Halmstadverken, is situated in Halmstad. This industry could contribute with surplus heat, which is calculated in this report.

With help of calculations and simulations in Microsoft Excel, a system with adequate heat storage method and surplus heat from local industry is formed. This system is optimized concerning economic and environmental matters.

The results reveal that Halmstad's conditions are favorable to integrate pit heat storage and there is potential to deliver waste heat from Höganäs Halmstadverken steelworks. Sizes of seasonal heat storage is optimized to 200 000 m³ for replacing fossil fuels respectively 550 000 m³ for replacing fossil fuels and biofuels. Waste heat effect is calculated to 15 MW.

The economical calculations results in an annual profit up to 8 million SEK with a payoff equal to 8 years. The environmental benefits consisting of reduced greenhouse gases are calculated to 4 800 tons carbon dioxide equivalents annually.

 The main objective of this paper is to develop a readiness index model that can serve as an analytical tool for exploring the achievements of electrification of transportation systems. We have applied this readiness index model to evaluate the readiness positioning of China, Norway, and Sweden towards transport electrification. We have chosen these three countries as they represent diversity among countries that are in the process of adopting electrified transport system solutions. Our developed readiness index model has four key dimensions, technological readiness, political readiness, societal readiness, and economic readiness. The embeddedness of all four dimensions in one model provides a multi-perspective way of analyzing and evaluating the readiness levels of countries moving towards transforming the transportation system. Therefore, we named the model a“multidimensional readiness index.”

Our main conclusions are that the political processes and political decisiveness involved are the most important factors followed by the societal needs and economic ability, with the current technology available as the fourth. Without the participation of dedicated and determined political decision-makers being involved, the other three factors are challenging to obtain. Political decision-makers need to facilitate the use of economic means to support the transformation in the society and affected industries to balance the initial economic disadvantages of the electrically-powered systems until they pass the cost disadvantage turning point. The development of the relevant technology is no longer a great barrier as it was at the beginning of this transformation, about 20 years ago. The technology for electrically powered transportation systems and devices is widely available now, although it is continuously evolving and being improved. Associated industries cannot be expected to initiate, finance, take the risk, and take the lead in this global societal transformation without clear and strong political support.

Based on our multidimensional readiness index analysis, China is being positioned as the leading country in the world in the electrification of its transportation systems. This is mainly so because of the strong technology advancements, control of the entire value chain of research, development (R&D), and manufacturing of EVs, strong government decisiveness, and execution power in developing and implementing favorable electric vehicle (EV) policies. The willingness of China’s public sector to take the lead and their citizen’s support to adopt clean technology are additional factors facilitating this advancement. Norway has rapidly become one of the newcomers in electrification with large numbers of registered electric vehicles, despite lacking manufacturing industries of electric vehicles. Sweden is a rapidly developing country in the electrification of transport, with three vehicle manufacturers introducing EVs in 2021. The government has been committed to building demonstration sites for electric roads systems for more than ten years. Sweden is also working on establishing battery manufacturing facilities dedicated to the needs of electrified transportation equipment and systems. 

The electric road system is an emerging concept in this modern era. The advancement of technology has made it possible to give this concept a real shape (electric road system). However, the energy provided to the electric roads is still produced by non-renewable energy sources, which are completely unhealthy and harmful for society. Furthermore, the traditional grid is not suited to integrate with decentralized/localized energy generation and distribution systems. It is an ineffectual and environmentally extravagant system. Therefore, the preliminary contribution of this research is to introduce a decentralized/localized energy generation system based on renewable energy sources and energy distribution to electric roads through the emerging technology of microgrid and smart grid systems, which have the capability to integrate with renewable energy sources easily. Thus, producing electricity with renewable energy sources is environmentally friendly, less expensive, and available without charges. However, each source of energy has some environmental impacts and cost differences. A brief description of the environmental and cost impact of renewable energy sources (wind, solar) is also presented. 

Hybridparks combines two or more energy sources. In this thesis in partnership with Arise AB case studies have been conducted in combined photovoltaic power in their existing windparks. Wind and photovoltaic have productionpatterns that compelemts the other. Which in turn gives a more stable production. 

Four windparks was chosen to be studied and tested as hybridparks: Fröslida, Häradsbo, Råbelöv och Idhult. 

The size of the hybridpark was based on an earlier study from Arise. One conclusion from that study was that it is possible to install photovoltaics with 2/3 of the installed windpower. 

The photovoltaic plant was simulated in the program Polysun. Polysun can make simulations and give insight on the possible photovoltaic yield. The data from the simulation was combined with the windpower yield data from Arise to analyse how the hybridpark would function. 

Energy storage with lithium batteries have been calculated and tested in Excel. The results show the impact the energy storage have on production and delivery to the grid. A simple control scheme with on/off method with a schedule gave the best results in a daily battery cycle. 

The energy sources seldom overlap and with a controlled energy storage it is possible to deliver power to the grid during power lacking periods such as winter.   

The current heat use refers normally to the average heat use in a country or a sector during the course of a year. But it is also important to be aware of the distribution of high to low use when estimating the potential for reducing total heat use.Energy statistical data published in the annual report from Statistics Sweden have been supplemented by a deeper analysis of distribution of heat use and systematic causes regarding high heat use.The aim of this paper is to explain the variation in heat use with respect to construction year, degree days and energy efficiency measures.In the Swedish energy efficiency debate, many voices refer to systematic causes for high heat use. However, the results from this study do not support this opinion, since the use distribution mostly comes from individual causes. The most important implication of the study results is that systematic policy measures will have a low impact on the total national energy efficiency.

With the adoption of the EU Climate Law in 2021, the EU has set itself a binding target to achieve climate neutrality by 2050 and to reduce greenhouse gas emissions by 55 percent compared to 1990 levels by 2030. To support the increased ambition, the EU Commission adopted proposals for revising the key directives and regulations addressing energy efficiency, renewable energies and greenhouse gas emissions in the Fit for 55 package.

The heating and cooling (H&C) sector plays a key role for reaching the EU energy and climate targets. H&C accounts for about 50 percent of the final energy consumption in the EU, and the sector is largely based on fossil fuels. In 2021, the share of renewable energies in H&C reached 23%. The decarbonisation of heating and cooling is addressed across several directives and regulations at EU level.

The aim of this study is to support the analytical basis for the development and implementation of policies to ensure a seamless pathway to the full decarbonisation of the heating and cooling sector by 2050 in buildings and industry.

Currently, the electric vehicles (EV) have been considered as the future trend in the automotive industry. Among the countries’ motivations for this are: reducing the dependence on oil and its derivatives, promoting more efficient energy use and causing lower environmental impacts, especially those related to the emission of greenhouse gases (GHG). Hybrid and Electric vehicles do not represent a recent technological invention; however these vehicles account to a marginal contribution in the vehicle history since 30’s decade. Moreover, it is worth to note that EV is not released from environmental impacts, mainly through its production phase. In this paper, we expect to contribute with information about the characteristics of EV’s environmental performance in comparison with conventional vehicles powered by internal combustion engine, analyzing which are their advantages and disadvantages, the environmental impacts caused through all the life cycle and how this technology could contribute to mitigate the climate change. In addition, it is also discussed the impacts of the electric and hybrid vehicles expansion on the final energy demand. In   

There is great potential to apply energy recovery from municipal wastewater treatment plants (WWTP) to achieve better energy efficiency and greenhouse gas emissions abatement. However, in most of the wastewater treatment plants that produce biogas through sludge digestion, there is no thermal energy recovery or electricity generation, and the biogas is flared and wasted, particularly in developing countries. This paper discusses the recent technological advances related to biogas recovery from wastewater treatment besides identifying research gaps and local conditions, which affect implementation. Techniques for enhancement of biogas production such as co-digestion and microalgae systems for energy recovery were reviewed in terms of performance and context for application. This paper provides an assessment of how local conditions promote or hinder biogas recovery from WWTP in megacities of developing countries. The lack of government subsidies and a biogas market that is not well developed and regulated hinder biogas recovery implementation in the studied megacities. Infrastructure and electricity prices are also discussed. Strategies to promote energy recovery are recommended based on successful examples of energy self-sufficient WWTP. The findings may not only support planning on energy recovery but also guide technological development and research on this topic, aligned with the sustainable development goals.

As the high mobility nature of the vehicles results in frequent leaving and joining the transportation network, real-time data must be collected and shared in a timely manner. In such a transportation network, malicious vehicles can disrupt services and create serious issues, such as deadlocks and accidents. The blockchain is a technology that ensures traceability, consistency, and security in transportation networks. In this study, we integrated edge computing and blockchain technology to improve the optimal utilization of resources, especially in terms of computing, communication, security, and storage. We propose a novel, edge-integrated, blockchain-based vehicle platoon security scheme. For the vehicle platoon, we developed the security architecture, implemented smart contracts for practical network scenarios in NS-3, and integrated them with the SUMO TraCI API. We exhaustively simulated all the scenarios and analyzed the communication performance metrics, such as throughput, delay, and jitter, and the security performance metrics, such as mean squared error, communication, and computational cost. The performance results demonstrate that the developed scheme can solve security-related issues more effectively and efficiently in smart cities. © IEEE

Six different strategies have recently been proposed for the European Union (EU) energy system in the European Commission’s report, Energy Roadmap 2050. The objective for these strategies is to identify how the EU can reach its target of an 80% reduction in annual greenhouse gas emissions in 2050 compared to 1990 levels. None of these scenarios involve the large-scale implementation of district heating, but instead they focus on the electrification of the heating sector (primarily using heat pumps) and/or the large-scale implementation of electricity and heat savings. In this paper, the potential for district heating in the EU between now and 2050 is identified, based on extensive and detailed mapping of the EU heat demand and various supply options. Subsequently, a new ‘district heating plus heat savings’ scenario is technically and economically assessed from an energy systems perspective. The results indicate that with district heating, the EU energy system will be able to achieve the same reductions in primary energy supply and carbon dioxide emissions as the existing alternatives proposed. However, with district heating, these goals can be achieved at a lower cost, with heating and cooling costs reduced by approximately 15%. © 2013 Elsevier Ltd.

Many strategies have already been proposed for the decarbonisation of the EU energy system by the year 2050. These typically focus on the expansion of renewable energy in the electricity sector and subsequently, electrifying both the heat and transport sectors as much as possible. In these strategies, the role of district heating has never been fully explored system, nor have the benefits of district heating been quantified at the EU level. This study combines the mapping of local heat demands and local heat supplies across the EU27. Using this local knowledge, new district heating potentials are identified and then, the EU27 energy system is modelled to investigate the impact of district heating. The results indicate that a combination of heat savings, district heating in urban areas, and individual heat pumps in rural areas will enable the EU27 to reach its greenhouse gas emissions targets by 2050, but at a cheaper price than a scenario which focuses primarily on the implementation of heat savings.

More than half of the world population live in urban settlements which are responsible for a large share of energy consumption and, consequently, carbon emissions. The transition towards a more sustainable urban environment requires a change in paradigm in terms of how we design and manage our cities. Urban areas require innovative technologies and strategies to reduce energy consumption and carbon emissions, and to be included in comprehensive plans encompassing all technical, social and economic dimensions which characterise cities. This involves the transformation of urban contexts, with a focus on local and urban-level mitigation measures, such as the construction of positive energy buildings, deployment of renewable energy, promotion of a sustainable mobility, creation of resilient urban infrastructure, implementation of circular economy and recycling practices, etc. The present article provides a perspective on the sustainable energy transition in cities, focusing on the building and transportation sectors. Furthermore, insights on supporting mechanisms and innovative management strategies are presented. © 2023 by the authors.

The challenges facing low voltage grids are rising as an increasing number of domestic houses transition from fossil fueled heating to electricity based heating. Several environmental goals and visions have the same transition from fossil based power to electricity based power in mind for the transportation sector. One of the most important tools for this transformation is widely regarded to be the electric vehicle. With the demands of the electric vehicle pressuring the power grid, several questions arise regarding the growth of the electric vehicle market and what repercussions it may have on the grid. This paper focuses on a typical low voltage grid in southern Sweden and what effects a growing electric vehicle market may have on it. Through computer-assisted simulations based on several future scenarios regarding the EV market, this paper finds that few modifications and reinforcements are needed on this particular grid within the next 10 to 15 years. After this timeframe the voltage drop becomes a serious concern and should be addressed.

This work aims at showing the potential of waste and renewable heat recovery in Italy through detailed mapping of these sources. The ambition of this analysis is to highlight the areas with important heat recovery potential and to show how the matching with suitable heat demand would allow its exploitation through district heating expansion. The importance of waste heat and renewable heat potentially recoverable to reduce primary energy consumption in the civil sector is widely recognized. Nevertheless, these potential is widely unexploited in Italy. The processes and energy sources have been analysed in terms of geographical location, quantification of available heat and recovery costs with a special focus on temperature levels. The main distinction between low temperature and high temperature heat sources has been applied in order to identify the heat recovery characteristics and the consequent additional costs for temperature upgrades. The inputs of the analysis performed in this work come from national database, which has allowed obtaining more detailed and wider results with respect to international existing studies on the same subject. Two different approaches have been used to map potential heat: one to identify and quantify existing waste heat recovery and one to assess and estimate energy coming from potential new plants. The analysed sources belonging to the first category are industrial processes, waste to energy plants, waste water treatment plants and datacentres, while biomass, geothermal energy and electrolysis plants estimation belong to the second one. Results shows that the national available waste and renewable heat amount to 270 TWh which is an important outcome in comparison with a national heat demand for the residential and tertiary sector of 400 TWh. Out of this results, according to a nuts 3 regional aggregation of heat demand, 95 TWh could be recovered in DH. The reduction from theoretical potential of 270 TWh to 95 TWh is due to geographical matching of heat demand and available waste heat and on some hypothesis related to the diffusion of DH. This work shows the huge unexpressed potential of waste heat reutilisation in Italy and how the mapping of recoverable heat and not only its quantification is essential to properly estimate the utilization potential.

This work aims at showing the unexploited potential of waste and renewable heat in Italy through detailed mapping of these sources. The ambition is to highlight the areas with an important heat recovery potential that could be exploited through DH expansion. The recoverable heat sources have been analysed in terms of geographical location, and recovery aspects with a special focus on temperature levels and technological implications for temperature upgrades. The methodology presented in this work addresses not only the theoretical potential of waste heat and renewable heat use in DH, but also several technical aspects to get a result as closer as possible to the realistic potential at national level. Two different approaches have been used to map potential heat: one to quantify existing waste heat recovery from industrial processes, waste to energy plants, wastewater treatment plants and one to estimate the energy coming from potential new plants based on biomass, geothermal energy and solar thermal. Results shows that for a total heat demand for the civil sector of 329 TWh, out of which 114 TWh come out being suitable for a DH connection, the national available waste and renewable heat that could be integrated in DH amounts to 156 TWh. These results show the significant unexpressed potential of waste heat use in Italy and how its mapping is essential to properly estimate the utilization potential. This work has been commissioned by AIRU, Italian DH association. Copyright © 2021 Elsevier Ltd.

The evaluation of the district heating network investment costs requires the knowledge of its topology. However, when assessing district heating potential, the topology is not known a priori and a simulation is required. One method for modelling future heat networks involves the use of Minimum Spanning Tree, from the graph theory. In this work, the MST is used together with real networks lengths to elaborate an updated equation describing the effective width in correlation with the number of building ratio instead of plot ratio. The reason motivating the use of simulated networks lies in the goal of analysing sparse areas where there’s a general lack of data. In this study, the census cells vertexes and local roads layout are used as inputs for the application of the MST in order to simulate DH network layouts in areas where DH is not present. The method has been validated by running simulations in areas where DH is already present, allowing the comparison of the respective lengths. The validation shows a variable but systematic overestimation of the simulated lengths. The study of the error has brought to the definition of a correlation between accuracy of results and the share of buildings with centralized heating systems suitable for DH connection. The updated version of the effective width confirms the exponential tendency and gives higher results for Italian cities then for Scandinavian ones, showing an important impact of the city structure in the curve. The city of Milano is finally used as a case study to show the effects of using the updated effective width curve.

Biomass gasification with subsequent synthesis to liquid or gaseous biofuels generates heat possible to use in district heating (DH) systems. The purpose here is to estimate the heat sink capacity of DH systems in the individual EU nations and assess the possibilities for biomass-gasification-based co-generation of synthetic biofuels for transportation and heat (CBH) for DH systems in the EU countries. The possibilities are assessed (i) assuming different levels of competiveness relative to other heat supply options of CBH corresponding to the EU target for renewable energy for transportation for 2020 and (ii) assuming that the potential expansion of the DH systems by 2020 is met with CBH. In general, the size of the DH heat sinks represented by the existing national aggregated DH systems can accommodate CBH at a scale that is significant compared to the 2020 renewable transportation target. The possibilities for CBH also depend on its cost-competitiveness compared to, e.g., fossil-fuel-based CHP. The possible expansion of the DH systems by 2020 represents an important opportunity for CBH and is also influenced by the potential increase in the use of other heat supply options, such as, industrial waste heat, waste incineration, and CHP. © 2009 Elsevier Ltd. All rights reserved.

The access to ideal heating and power techniques has always been highly thought after.This is mainly due to the development in housing architecture and the cold nature of certain regions which has led to an increase in popularity of the heating market and modernised heating technologies. The current DH systems make use of CHP plants for thegeneration of power and electricity. These CHP plants for the most part, are powered through biomass and during winter periods the demand for heating is highly increased.The biggest issue with relying on biomass solely is the constant need to burn wasteproducts which not only results in increasing the demand for consuming in more waste,but also results in producing remains (by-products) that cannot be broken down further and hence might require the utilization of land-space (landfills) for their disposal. Solar modules on the other hand, have gained increased popularity in the recent age. This is mainly due their extremely high flexible ability in converting solar irradiance intoelectrical and thermal energies. This study will try to provide a comprehensive study intothe utilization of a hybrid solar system that combines a standard PV module with a flat-plate collector through estimating the energy demands for a simple housing within Sweden and China. This will be the main aim of the study, however the possibilities of integrating this hybrid solar system alongside current DH systems will mostly be discussed in the first sections to proof the possibility of executing such a system. The theoretical work carried out will only include simulations of having just separate,standalone PV and flat-plate collector modules. However, designing a hybrid solar and DH system will not be the major focus of this study. The results at the end of the report,concluded that the electrical production for the Swedish case were noticeably higher thanthat of the Chinese case in spite of maintaining the same load values through both cases and higher solar irradiation for the Chinese case. Due to PVsyst simulation constraints,the results show that the investment cost of the Swedish PV (electrical component) module was about 3.6 times greater than that of the Chinese which could possibly mean that the Swedish case has a bigger PV module area than the Chinese case in order to meetel ectricity demand monthly. However, when it came to the thermal energy production, it was possible to assume different collectors cases and hence an area of 7m2 was chosen for the Swedish perspective while an area of 4m2 has been considered for the Chinese case. The thermal useful energy values where then compared with heating demands for both of the cases. Finally, the thesis concluded that there was no requirement for having an integrated DH network within the standalone houses, having small electricity and heat demand and hence, it might be more beneficial to have an integrated DH and solar system within more densely populated housing areas.

The behavior of a district heating (DH) substation has a social and operational context. The social context comes from its general usage pattern and personal requirements of building inhabitants. The operational context comes from its configuration settings which considers both the weather conditions and social requirements. The parameter estimating thermal energy demand response with respect to change in outdoor temperature conditions along with the strength of the relationship between these variables are two important measures of operational efficiency of a substation. In practice, they can be estimated using a regression model where the slope parameter measures the average response and R2 measures the strength of the relationship. These measures are also important from a monitoring perspective. However, factors related to the social context of a building and the presence of unexplained outliers can make the estimation of these measures a challenging task. Social context of a data point in DH, in many cases appears as an outlier. Data efficiency is also required if these measures are to be estimated in a timely manner. Under these circumstances, methods that can isolate and reduce the effect of outliers in a principled and data efficient manner are required. We therefore propose to use Huber regression, a robust method based on M-estimator type loss function. This method can not only identify possible outliers present in the data of each substation but also reduce their effect on the estimated slope parameter. Moreover, substations that are comparable according to certain criteria, for instance, those with almost identical energy demand levels, should have relatively similar slopes. This provides an opportunity to observe deviating substations under the assumption that comparable substations should show homogeneity in their behavior. Furthermore, the slope parameter can be compared across time to observe if the dynamics of a substation has changed. Our analysis shows that Huber regression in combination with ordinary least squares can provide reliable estimates on the operational efficiency of DH substations. © 2018 The Authors. Published by Elsevier Ltd.

Introduction: The global demand for renewable energy is expected to grow annually due to rising electricity consumption and economic and regulatory incentives. Efficient consumption and management of electricity consumption can support this trend (shifting from fossil resources to renewable resources) and benefit companies economically by reducing peak loads, reducing subscription costs, and protecting companies' power systems and networks. For effective and efficient electricity management that can help reduce peak electricity demand, resulting in lower demand charges and further reducing operational costs, it is necessary to understand the amount of electricity consumption and its influencing factors. Seasonal and daily variations and social behaviors influence changes in electricity consumption. Electric load variation management is essential for electricity consumers to control costs related to maximum load capacity and building electrical network equipment protection. This research presents an assessment method for describing daily electric load variations. It is applied to electricity consumption systems, but the technique is generic and can be applied to all activities where daily variations occur.Purpose: This thesis aims to show when and why peak load occurs in an office building and also to provide methods to improve the efficiency of electricity consumption during peak load.Method: This method implemented parameters like temperature, electricity consumption, and hours. It assessed a year's hourly electricity consumption in an office building to understand how load changes daily, weekly, and monthly. The case study was the AirSon office building. Data-driven from the efergy online portal was based on the hourly consumption every year.Results: The results show that the outdoor temperature, working hours, and consumption behavior can affect the overall electricity consumption and peak loads. Efficient building strategies are crucial for reducing peak loads by smartly controlling indoor temperature and managing electricity demand. The analysis offers insights into office building electricity consumption patterns and recommends strategies such as prioritizing car charging, optimizing the heat pump's operation of the HVAC system, improving the electricity management system, and using energy storage systems to reduce peak load.Discussion: The findings from this analysis carry implications for electricity consumption. It can provide some insights for reducing electricity consumption and enhancing efficiency in office buildings and similar facilities and also prioritization and rescheduling car chargers. In conclusion, it has interpreted and discussed the various electricity-saving strategies and their potential impact on electricity management.

The economical sustainability of DH compared to individual heating systems depends on the cost of producing heat, transporting and distributing it. Assessing economically sustainable potential of district heating DH thus requires the ability to combine this costs, detecting the relative distance of sources and demands and the density of demand, comparing it to the alternative solution. In this work we present an open model, based on the Oemof modelling framework, which is able to take into account the possibility of connecting sources and demands on national scale level with a high spatial resolution. The model considers the investment and operating costs of production and distribution of heat in competition with the individual heating systems costs specific to each area. The end result is the most economically viable heat supply configuration, identifying the demand shares where the most cost-effective solutions are individual systems or DH and its composition in terms of energy sources. The model is part of the method used for the assessment of district heating potential in Italy. The latter is based on GIS maps of both energy demand, waste and renewable heat sources. Of the 114 TWh of potential demand for DH, 38 TWh are those that the optimisation suggests could be economically served by DH. The composition is mostly waste heat, 22 TWh, geothermal heat, 11 TWh and a minority of solar thermal, 2 TWh with 3 TWH of natural gas CHP back up.

Facilities of energy-intensive industries including those for the production of steel, cement, paper, glass, chemicals and others are spread across Europe. The combination of high flue gas temperatures, continuous operation and highly concentrated point sources make the excess heat from such industrial plants a very attractive source for district heating. Despite this, excess heat sources from industry are currently only rarely exploited and major potentials are being wasted. Here, we aim to contribute by providing the most detailed, comprehensive assessment of the excess heat potentials available for Europe. More specifically, we aim to analyse the available excess heat from heavy industry in Europe and assess its suitability for use in district heating systems. Our approach uses GIS-based mapping of 1608 industrial sites in Europe combined with a process-specific assessment of their excess heat potential. The heat sources are then matched with data on heat demand density and existing as well as potential district heating networks. The scope of this analysis covers the major industrial excess heat sources (large heavy industry facilities) and the most important excess heat streams: flue gases. Our results show a total potential of 425 PJ of excess heat available at a temperature of 95°C, with 960 PJ available at a lower temperature (25°C). This equals about 4% and 9% of total industrial final energy demand in 2015, respectively. Matching this potential with a GIS analysis of heat demand densities and current district heating systems reveals that 151 PJ of excess heat could be used within a 10km range at a temperature of 95°C, which is compatible with most existing district heating systems. As district heat today has a total final energy consumption of 1,945 PJ, this means that about 8% of district heating in the EU28 could be supplied by excess heat sources from energy-intensive industries.

The cooling demand increases in Sweden despite the cold climate, which could cause the increase of district cooling. District cooling is a centralized cooling system with multiple benefits such as safer operations, reduced failures and removal of rumbling that will otherwise occur in local cooling systems. That’s why the absorption chiller is becoming more and more interesting to incorporate indistrict heating.The purpose of this report is to give the company Öresundskraft the technical and economic conditions for absorption cooling in Helsingborg. The main goal with the report have been to investigate: which temperature from the district heating system will be used for the absorptions chiller, how the coefficient of performance affects the conditions of absorption chiller, different dimensions for absorption chiller, different placement options for absorption chiller, if the existing cool water storage tank can be used in the future, is it profitable to invest in an absorption plant. The main goal questions have been answered through interviews, compilation and calculation of data, examination of research literature and other literature. Conclusions the authors were able to find is that the absorption chiller should be sized to 2,2 MW and it should be placed on Västhamnsverket. Under the conditions that there was access to cheap heat and only operating during the summer the result to invest in an absorption plant was profitable.

Current temperature levels in European district heating networks are still too high with respect to future conditions as customer heat demands decrease and new possible heat source options emerge. A considerable reduction of temperature levels can be accomplished by eliminating current faults in substations and customer heating systems. These faults do not receive proper attention today, because neither substations nor customer heating systems are centrally supervised. The focus of this paper has been to identify these faults by annual series of hourly meter readings obtained from automatic meter reading systems at 135 substations in two Swedish district heating systems. Based on threshold methods, various faults were identified in 74% of the substations. The identified faults were divided into three different fault groups: Unsuitable heat load pattern, low average annual temperature difference, and poor substation control. The most important conclusion from this early study of big data volumes is that automatic meter reading systems can provide proactive fault detection by continuous commissioning of district heating substations in the future. A complete reduction of current faults corresponds to approximately half the required reduction of the current temperature levels in the effort toward future low-temperature district heating networks. (C) 2015 The Authors. Published by Elsevier Ltd.

The context for this chapter is the current use and typical applications of thermal energy storages within contemporary district heating and cooling systems in the Nordic countries. Examples include a new assessment method, distributed heat storages, and hourly, daily, weekly, and seasonal heat and cold storages. Specific sizes have been estimated for 209 heat storages and 9 cold storages.

On planet Earth, fossil fuels are the most important sources of energy. However, these resources are limited and being depleted dramatically throughout last decades. Finding feasible substitutes of these resources is an essential duty for humanity. Fortunately, Mother Nature is providing us a number of good solutions for this crucial threat against our planet. Solar irradiance, wind blowing, oceanic and maritime waves are natural resources of energy that are capable of completely covering the annual consumption of all inhabitants on the Earth. In this research a set of components including “Northern Power NPS 100-24” wind generators, “Kyocera KD 145 SX-UFU” PV arrays, “Gildemeister 10kW-40kWh Cellcube” battery bank and HOMER bi-directional converter system were considered and successfully applied on HOMER tool and Particle Swarm Optimization (PSO) method. The main design goals of the presented hybrid system are to use 100% renewable energy resources in the commercial sector, where all power is produced in the immediate vicinity of the business place, adding strong advertising values to the setup. In order to supply hourly required load for a grocery store   (1000 ) in Malmö city with 115 kW peak load and 2002 kWh/d with maximum 0.1% unmet, the system was optimized to achieve minimum Levelized Cost of Energy (LCOE) and the lowest Net Present Cost (NPC). The HOMER simulation for quantitative analysis, along with a Particle Swarm Optimization (PSO) solution method is proposed and the results are compared. The results show that an optimized hybrid system with 3.12  LCOE, and power production of 28.5% by PV arrays and 71.5% by wind generators, is the best practice for this case study. 

The ambition of the Swedish government is rapidly concentrating on the development of the

renewable energy systems especially on wind energy, bio energy and solar energy. It has been

observed on the growth of the production of electricity and heat from these three mentioned renewable

energy systems. But, relatively in Sweden the share of production of electricity obtained from PV is

quite smaller than the other two. The PV electricity production in Sweden comprises in a large scale

of mainly the grid connected distributed PV systems and with a small number of installed solar parks.

The aim of this paper is to analyze the viability of installing mid -size PV solar parks in Sweden and

to simulate the effect of the proposed project in the village’s (Åled is the village where the proposed

site is located) and the country’s electricity production. This study includes designing, simulation and

financial analysis of different grid connected centralized mid -size capacities of PV solar parks of 250

kWp,500 kWp,1MWp and 2MWp. They are all fixed ground mounted systems. Moreover, it also

discusses the main reasons that hinders decision makers, the PV complications that are connected to

the grid, Sweden’s energy regulations particularly the emission regulation and the financial policies

of PV. Also, study visit, telephone and email contacts have supplemented it.

This study was done with the collaboration of Nyedal Solenergi, in which the proposed site was

owned by the company and this paper will be a future guide for the investment of the mid-size PV

solar park. According to the study a discussion has been made with the grid supplier (EON) in that

area on the investment on one of the designed projects which are presented in this paper.

The results of the study show that the effect of the proposed systems on the production of electricity

in the village of Åled was between 2.68 – 21.4 % and the impact on the country’s PV electricity

production was 0.2 – 1.58 %. And, the possibility of installing mid-size PV solar parks generally in

Sweden particularly in the proposed site is possible and economically it is viable but not profitable

for system capacities less than 1 MW. As the IRR found for all capacities is greater than the estimated

WACC, hence each proposed capacity has the possibility of paying back all its investment costs in

about 23 years. So, the profitability is very low in case of the 250 kWp and 500 kWp but for the others

they have about 7-8 years of profitability. A sensitivity analysis also has shown the impact of initial

investment costs, O & M costs and electricity export rate on the IRR, NPV and equity payback. The

initial investment cost and electricity export rate were seen with high effect on the IRR, NPV and

equity payback. The LCOE calculated was higher than the average electricity spot price (300

SEK/MWh) for 250 kWp and 500 kWp but lower for the other two capacities. The overall impact for

the financial analysis was due to the decreasing of module prices, the rules that changes every year

on electricity subsidies for renewables, tax reductions and rapid decreasing of electricity spot prices.

In the future if the price of modules continues decreasing, spot price increases, more modification of

the subsidy and introduction of new PV technologies integrated with other sources of energy is done

then such projects could be more profitable.

Different energy and exergy concepts and methods are presented and applied to a Swedish pulp and paper mill. Flow diagrams show that the exergy content is mostly much less than the energy content of the flows. The largest exergy losses appear in the boilers. Heating processes are highly exergy inefficient. A limited Life Cycle Exergy Analysis (LCEA) shows that the exergy output amounts to over 3 times the spent exergy as non-sustainable resources. By replacing the present use of non-sustainable resources, mostly fuel oil, the mill could move towards a truly sustainable process. Copyright © 2005 John Wiley & Sons, Ltd.

About three quarters of the total final energy consumption is in the form of electricity and district heat and 49 TWh of district heat was used in Sweden in 2015. The energy supply and user demands vary and do not always match. The electricity production depends on the available energy resource that often is renewable, such as wind, solar and hydro power. The heat demand strongly depends on outdoor temperature and the weather conditions. Electricity and thermal storages are needed in order to reduce the losses from the lack of match between production and consumption. The cost of energy examined by others shows that electricity storage is about 100 times more expensive than thermal storage. However, in this study cost of exergy is only 20 times more for electricity than thermal. This study views electricity and district heat from source to end use and analyze the cost of exergy with storage. With a surplus of electricity the most efficient and cheapest way is to use electricity storage, such as battery or hydro storage on the purpose of electricity usage. The advantage of thermal storage depends strongly on the purpose of use, e.g. if it is for heating purposes. Heat pump is a method to convert electricity to district heat with 56% exergy efficiency. This paper will analyze different cases in order to give a more detailed discussion. Further studies of more cases are needed in the future.

The recent growth of the Chinese district heating sector has been very high. No other country in the world can show the same growth rate during the last decades. The heated building area increased six times between 1995 and 2008. China has also enjoyed strong growth of scientific articles and papers about district heating in recent years. One third of all international scientific journal articles and conference papers about district heating came from Chinese scientists during 2010–2012, while Swedish scientists accounted for one quarter according to the Scopus scientific search engine. It is important to identify the Chinese district heating research to judge the potential for future collaborative research on district heating systems between Sweden/Europe and China. The 205 international publications on district heating by Chinese scientists published until 2013 have been mapped and summarised with respect to demand, supply, technology, market and environment. More diversified heat supply with renewable source was grasping the Chinese interest, since many new systems have been established, having more degrees of freedom when choosing various heat supply and technology options. The Chinese district heating systems were compared with sustainable district heating solutions in Sweden. Both countries would benefit from future research cooperation. © 2015 Elsevier Ltd.

Exergy concept is applied on district heating systems with different network temperature levels in their distribution networks. These district heating systems use a combination of renewables and heat recovery from other primary processes. The aim is to show simplicity and value of using exergy concept when comparing current and future temperature levels. Both the traditional exergy factor and the novel exergy utilisation rate are used in these analyses. Exergy utilisation rate expresses the ratio between the exergy delivered to customer heating systems and the exergy content in heat supply input to the distribution network. The analyses are performed on four different generations of district heating technologies, two national groups of district heating systems in Denmark and Sweden for revealing variations among systems, and two municipal systems for revealing variations within systems. The main conclusions are simplifications can be introduced in order to analyse the network temperature levels, current exergy factors reveal that current temperature levels can be reduced, and that almost two thirds of the exergy content in heat supply input are lost in the heat distribution chain. These conclusion will be vital input in developing the future fourth generation of district heating systems using both renewables and heat recovery. © 2015 Elsevier Ltd.

District heating has been available in Sweden since the 1950s and used more than half of the total energy use in dwelling and no-residential premises in 2013. Energy and exergy efficient conversion and energy resources are key factors to reduce the environmental impact. It is important to understand energy and exergy flows from both the supply and demand sides. The exergy method is also a useful tool for exploring the goal of more efficient energy-resource use. Sankey diagrams together with energy and exergy analyses are presented to help policy/decision makers and others to better understand energy and exergy flows from primary energy resource to end use. The results show the most efficient heating method in current district heating systems, and the use of renewable energy resources in Sweden. It is exergy inefficient to use fossil fuels to generate low quality heat. However, renewable energies, such as geothermal and solar heating with relative low quality, make it more exergy efficient. Currently, about 90% of the energy sources in the Swedish district heating sector have an origin from non-fossil fuels. Combined heat and power is an efficient simultaneous generator of electricity and heat as well as heat pump with considering electricity production. Higher temperature distribution networks give more distribution losses, especially in exergy content. An outlook for future efficient district heating systems is also presented.

District heating has been available in Sweden since the 1950s and used more than half of the total energy use in dwelling and no-residential premises in 2013. Energy and exergy efficient conversion and energy resources are key factors to reduce the environmental impact. It is important to understand energy and exergy flows from both the supply and demand sides. The exergy method is also a useful tool for exploring the goal of more efficient energy-resource use. Sankey diagrams together with energy and exergy analyses are presented to help policy/decision makers and others to better understand energy and exergy flows from primary energy resource to end use. The results show the most efficient heating method in current district heating systems, and the use of renewable energy resources in Sweden. It is exergy inefficient to use fossil fuels to generate low quality heat. However, renewable energies, such as geothermal and solar heating with relative low quality, make it more exergy efficient. Currently, about 90% of the energy sources in the Swedish district heating sector have an origin from non-fossil fuels. Combined heat and power is an efficient simultaneous generator of electricity and heat as well as heat pump with considering electricity production. Higher temperature distribution networks give more distribution losses, especially in exergy content. An outlook for future efficient district heating systems is also presented.