The competitiveness of present and future district heating systems can be at risk when residential and service sector heat demands are expected to decrease in the future. In this study, the future competitiveness of district heating has been examined by an in depth analysis of the distribution capital cost at various city characteristics, city sizes, and heat demands. Hereby, this study explores an important market condition often neglected or badly recognised in traditional comparisons between centralised and decentralised heat supply.

By a new theoretical approach, the traditional and empirical expression for linear heat density is transformed into an analytical expression that allows modelling of future distribution capital cost levels also in areas where no district heating exists today. The independent variables in this new analytical expression are population density, specific building space, specific heat demand and effective width.

Model input data has primarily been collected from national and European statistical sources on heat use, city populations, city districts and residential living areas. Study objects were 83 cities in Belgium, Germany, France, and the Netherlands. The average heat market share for district heat within these cities was 21 % during 2006.

The main conclusion is that the future estimated capital costs for district heat distribution in the study cities are rather low, since the cities are very dense. At the current situation, a market share of 60 % can be reached with a marginal distribution capital cost of only 2.1 €/GJ, corresponding to an average distribution capital cost of 1.6 €/GJ. The most favourable conditions appear in large cities and in inner city areas. In the future, there is a lower risk for reduced competitiveness due to reduced heat demands in these areas, since the increased distribution capital cost is low compared to the typical prices of district heat and competing heat supply. However, district heating will lose competitiveness in low heat density areas. Hence, reduced heat demands in high heat density areas are not a general barrier for district heating in the future. © 2010 Elsevier Ltd.

One key concept when assessing network investment cost levels for district heating systems is the linear heat density. In contrast to a traditional way of expressing this quantity entirely on the basis of empirical data, a recently developed analytical approach has made it possible to estimate linear heat densities on the basis of demographic data categories. A vital complementing quantity in this analytical approach is the concept of effective width.

Effective width describes the relationship between a given land area and the length of the district heating pipe network within this area. When modelling distribution capital cost levels by use of land area values for plot ratio calculations, there is a potential bias of overestimating distribution capital cost levels in low dense park city areas (e < 0.3). Since these areas often include land area sections without any housing, avoiding overestimations of network investment costs demand some kind of corrective mechanism.

By use of calculated effective width values, a compensating effect at low plot ratio levels is achieved, and, hence, renders lower anticipated distribution capital cost levels in low dense park city areas.

Increased recovery of excess heat from thermal power generation and industrial processes has great potential to reduce primary energy demands in EU27. In this study, current excess heat utilisation levels by means of district heat distribution are assessed and expressed by concepts such as recovery efficiency, heat recovery rate, and heat utilisation rate. For two chosen excess heat activities, current average EU27 heat recovery levels are compared to currently best Member State practices, whereby future potentials of European excess heat recovery and utilisation are estimated. The principle of sequential energy supply is elaborated to capture the conceptual idea of excess heat recovery in district heating systems as a structural and organisational energy efficiency measure. The general conditions discussed concerning expansion of heat recovery into district heating systems include infrastructure investments in district heating networks, collaboration agreements, maintained value chains, policy support, world market energy prices, allocation of synergy benefits, and local initiatives. The main conclusion from this study is that a future fourfold increase of current EU27 excess heat utilisation by means of district heat distribution to residential and service sectors is conceived as plausible if applying best Member State practice. This estimation is higher than the threefold increase with respect to direct feasible distribution costs estimated by the same authors in a previous study. Hence, no direct barriers appear with respect to available heat sources or feasible distribution costs for expansion of district heating within EU27. © 2012 Elsevier Ltd.

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.

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 study presents a methodology to assess annual excess heat volumes from fuel combustion activities in energy and industry sector facilities based on carbon dioxide emission data. The aim is to determine regional balances of excess heat relative heat demands for all third level administrative regions in the European Union (EU) and to identify strategic regions suitable for large-scale implementation of district heating. The approach is motivated since the efficiency of current supply structures to meet building heat demands, mainly characterised by direct use of primary energy sources, is low and improvable. District heating is conceived as an urban supply side energy efficiency measure employable to enhance energy system efficiency by increased excess heat recoveries; hereby reducing primary energy demands by fuel substitution. However, the importance of heat has long been underestimated in EU decarbonisation strategies and local heat synergies have often been overlooked in energy models used for such scenarios. Study results indicate that 46% of all excess heat in EU27, corresponding to 31% of total building heat demands, is located within identified strategic regions. Still, a realisation of these rich opportunities will require higher recognition of the heat sector in future EU energy policy. © 2014 Elsevier Ltd.