Europe wastes about the same amount of heat in energy conversion and inefficient end-use patterns as it actually makes use of. The answer, according to Sabine Froning and Norela Constantinescu, is to make much greater use of sustainable sources of heat from electricity generation, industry, biomass and, eventually, geothermal sources to fuel district heating and cooling systems.

Europe wastes more heat than it uses. Looking at the European energy balance for 2003 (Figure 1), it is remarkable to see where in fact the energy is going. Around half is wasted or evaporated to the atmosphere. Is this acceptable while Europe suffers under rising energy prices and is subject to increasing energy dependency and environmental damage? Should we carry on with business as usual? Should energy companies act? Should policymakers act?


Figure 1. European energy balance, 2003; total primary energy supply = 81.1 EJ
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As yet, the heating and cooling markets have received little attention and positive engagement from energy analysts and policymakers. For many, it comes as a surprise that the largest slice of the ‘primary energy cake’ is used for heating – though cooling seems to be catching up. Whereas in the past electricity peak loads occurred in winter, demand for powering air conditioning is frequently peaking in increasingly hotter summers (and not only during the latest heat waves).

District heating and cooling grids make it possible to optimize and combine a large spectrum of ‘free’ energy inputs. Such inputs include surplus heat from electricity production based on conventional or renewable fuels, from waste incineration and/or from industrial processes as well as different forms of renewable heat (such as geothermal, heat/cold from deep sea or lake water).

HEAT DEMANDS AND MARKETS

For its analysis of the heat market, the ECOHEATCOOL project used a demand-side approach, offering a different perspective to more frequent supply-side assessment. As electricity contributes to the heat balance of buildings, the total heat demands in the target area were estimated based on the sum of net heat and electricity end-use. A top-down analysis, with the information and results crosschecked by the project partners, was carried out. The five main findings from the assessment of heat demands/markets are summarized below.

International heat statistics must be improved

International Energy Agency (IEA) and Eurostat databases were used as information sources. Comparison of national and/or Euroheat & Power statistics showed that national information about district heating (DH) is not always transferred properly to international statistics.


CHP plant connected to the district heating network of Ferrara, northern Italy. Europe is only using 15% of its CHP potential for district heat
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For example, the amount of district heating delivered in Germany, France and Italy is not reported properly to Eurostat. As a result, the heat deliveries in the target area are substantially underestimated by approximately a quarter (the DH sector in the three countries accounts for 120 TWh out of a total of approximately 550 TWh). In addition, there are differences in the use of definitions and reporting procedures when it comes to data collection at a European level.

The resulting misinterpretations are carried forward in energy modelling exercises, with the potential for wrong conclusions and the development of inappropriate tools for implementing targeted policies.

Heat dominates energy end-use

The project showed once more that heat dominates the total end-use and represents approximately 55% of total energy use.

Despite its share of the total heat demand, domestic hot water consumption remains an unknown factor. A detailed assessment of this parameter at both national and European levels would contribute to a better understanding of the heat market.

Natural gas and electricity supply dominate heat use

The use of natural gas and electricity for heat (accounting for 66%) dominates in the industrial, residential and service sectors, while district heating represents only 6% of the total heat market.

European energy balance

An energy balance shows that Europe wastes more heat in transforming energy than it consumes. In 2003, the total primary energy supply was 81.1 exajoules (1 EJ = 1018 J), but the final energy consumption was only 57.3 EJ. This means that the total heat losses in the energy transformation sector are in the same order of magnitude as the net final heat demands (Figure 1). Thus, Europe has huge heat losses to retrieve.

The main conclusion from this simple energy balance analysis is that the huge total heat losses correspond to more than half the total energy supply. A future European energy system must reduce these losses in order to increase energy efficiency, reduce carbon dioxide emissions and increase security of supply.

The heat sector in general and the district heat sector in particular could contribute to meeting these objectives by recycling existing heat losses in the energy system to satisfy local heat demands within the European heat market.

Heat costs

In 2003, the total financial burden from the net heat and electricity use for all end-users in the European countries – including national taxes but excluding value added tax (VAT) – was 3.7% of the gross domestic product (GDP).

Total net heat and electricity costs amounted to €120 billion for the industrial sector and €270 billion for the residential, service and agricultural sectors, corresponding to 1.1% and 2.6% respectively of the total GDP.

When looking at the heat costs as share of the national GDP, this fraction is higher in central and eastern Europe than in the 15 older Member States (EU-15), showing that heat is relatively more expensive in the newer Member States and the Accession Countries than in western Europe.

COOLING DEMANDS

The estimate of cooling demands was based on three main elements:

  • European Cooling Index (developed within the ECOHEATCOOL project)
  • buildings statistics
  • specific cooling demands analysis.

The most striking picture is of the accelerated growth of cooling demands in the 32 European countries studied. This is largely because space cooling demands are increasing rapidly in most European countries as a result of higher availability and increasing ability of customers to pay.

Although the demand in 2000 was only 150 TWh (corresponding to a saturation rate of 14%), space cooling demand in 2020 is forecast to be 2.4 EJ, with a saturation rate of 60% in the service sector and 40% in the residential sector.

About 100 district cooling systems currently exist in high-density European city centres and commercial areas. Most of them are located in France, Sweden, Germany and Italy. The current market share for district cooling is almost 2%, corresponding to district cold deliveries of about 9 PJ/year. A district cooling market share of 25% would give district cold deliveries of 0.6 EJ/year.

Furthermore, the cooling demands assessment showed that, for the same geographical location, the actual specific cooling demand can vary considerably in terms of energy per square metre. This variation is due mainly to large variations in technical solutions, design guidelines and operational strategies. Nevertheless, specific cooling demands are higher in the service sector than in the residential sector. In the Nordic countries, the dimensions of public and office buildings are normally set to give specific cooling demands of 30-60 W/m2, while retail areas are dimensioned for to give a specific cooling demand of 50-80 W/m2. In southern Europe, specific cooling demands are approximately 20% higher.

In addition, there is a large variation in the full load hours. For the same geographical location, a wide variation is registered in the load curve of the cooling demands for different types of customers – especially in the public and service sectors. The load curve shows that a large proportion of the total cooling demand is due to non-climatic factors. Duration times are usually within between 1100 and 1300 equivalent full load hours per year in northern European countries and 50% higher in southern ones.

The lack of reliable and aggregated information is even more striking for the cooling sector. The ECOHEATCOOL analysis assessed changes in electricity consumption patterns over the last decade. This exercise revealed that, in general, there is an upward shift in national electricity consumption. Moreover, this shift is very pronounced from April to August, for example, in Italy and Spain. This is assumed to be connected to the increase in cooling needs.

In order to tackle the increasing demand for cooling and its impact on electricity systems, there is a need to improve our understanding of how electricity demand is driven by consumer needs and the changes in consumption patterns.

Improved data on electricity consumption in buildings are also needed.

BENCHMARKS FOR RESOURCE EFFICIENCY IN HEATING AND COOLING

Energy policy analyses traditionally distinguish between demand and supply sides. Although useful for modelling purposes, this approach (or similarly, a focus on a single energy source or use) often results in sub-optimal and inefficient use of resources.

The development of intelligent energy solutions should aim at reducing end-use consumption, using more efficient technologies at all levels and increasing the use of renewables (optimally combined and assessed in terms of their resource efficiency). In this way the fossil primary energy consumption will be reduced.

Only an assessment covering the whole supply chain from conversion to delivery will give a realistic picture of resource efficiency. An approach based on primary resource factors (PRFs) enables a comprehensive assessment of the resource efficiency of all heating and cooling options. PRFs express the ratio between the non-regenerative energy input and final energy used; the lower the PRF of a technology (in operation), the greater its contribution to reducing the use of fossil primary energy.

The ECOHEATCOOL project developed a method (WP3) to assess the performance of individual district heating and cooling systems using PRFs. Based on IEA energy balances, the average PRF was calculated for all district heating systems in the 32 European countries studied. The result is a value of 0.82, which should be compared to values of 2.5 for electric heating (reflecting an average conversion efficiency of 40%), 1.3 for gas boilers and 0.9 for an average heat pump.

National examples for district heating PRF values illustrate differences in the proportion of recovered heat – from combined heat and power (CHP) – and renewables in the district heating systems (Table 1). At the same time, these values can serve as indicators for potential improvements. Figure 2 shows examples of the PRFs of specific district heating systems around Europe.

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Figure 2. Primary resource factors (PRFs) for selected European district heating systems
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POSSIBILITIES WITH MORE DISTRICT HEATING

The ECOHEATCOOL project assessed the role and the present situation of the district heating sector in Europe, paying special attention to how the systems are fulfilling the fundamental concept of district heating.

Recovering energy instead of wasting it

With approximately 5000 schemes in the 32 European countries, district heating delivers almost 10% (2 EJ) of the heat consumed in the region and accounts for 6% of the final end-use of net electricity and heat. Most of the district heating deliveries are within the EU-25; two thirds appear in the EU-15 and one third in the 10 new Member States (NMS10). But since much more people live in the EU-15, the relative use of district heating (DH/capita) is 50% higher in the NMS10.

The fundamental idea of district heating is to use local fuel or heat resources that would otherwise be wasted to satisfy local customer heat demand using a heat distribution network of pipes as a local market place. This idea contains the three obligatory elements of a competitive district heating system:

  • suitable cheap heat source
  • demand from the heat market
  • pipework as a connection between demands and sources.

These three elements must all be local in order to obtain the short length of pipework necessary to minimize the capital investment in the distribution network. Suitable heat demands are space heating and production of domestic hot water in residential, public and commercial buildings. District heating is also suitable for low-temperature industrial heat demands.

The combined effect of the use of renewable energies (RES) and recovered heat (CHP, surplus heat, large heat pumps) highlights how well the national district heating sector fulfils the fundamental idea of district heating (i.e. the use of energy that would otherwise be wasted or of fuels difficult to handle).

The average recovery factor is approximately 80%, with differences among the countries. These figures are higher in the EU-15 than in the NMS10 and ACC4 (Figure 3).


Figure 3. Share of renewable and recovered heat used for district heating in selected European countries, 2003
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The ECOHEATCOOL project also looked at the position and possibilities that exist for district heating by taking into account the demand-side and supply-side perspectives. The latter identifies five strategic heat source options for district heating, with enormous potential to reduce Europe’s consumption of fossil fuels (Table 2). Figure 4 compares the volumes of the five sources (CHP, waste incineration, surplus heat, geothermal heat and combustible renewables) with the current volumes of district heat generated.

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Figure 4. Five available district heat sources and corresponding heat flows during 2003 in EJ/year for the target area of 32 countries
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The possibility of doubling the district heat deliveries made in 2003 was assessed in the light of international concerns, national growth rates over the past 10 years and national/regional conditions (expansion factors). In this case, the district heating share in the final heat and electricity demand is assumed to increase from 6% to 12%. This corresponds to increased deliveries of 4.7% per year until 2020. The benefits are clear:

Higher energy efficiency will reduce primary energy supply by 2.6% (of 2003 figures) or 2.1 EJ, or 50.7 million tonnes of oil equivalent (Mtoe)/year – equal to the primary energy supply of Sweden. Higher security of supply will reduce the import dependency by 4.5 EJ (105.4 Mtoe)/year – equal to the primary energy supply of Poland.

Carbon dioxide emissions will be reduced by 404 million tonnes/year, corresponding to 9.3% of current emissions – equalling current emissions of France from fuel combustion.

HOW TO GET THERE?

The ECOHEATCOOL project identified 10 priorities (Table 3) that will ensure that the significant potential of district heating and cooling (DHC) in Europe can be utilized to improve resource efficiency.

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Sabine Froning is Managing Director and Norela Constantinescu a Project Officer at Euroheat & Power, Brussels, Belgium. e-mail: sabine.froning@euroheat.org
norela.constantinescu@euroheat.org

For more information about the ECOHEATCOOL project go to www.ecoheatcool.org

ECOHEATCOOL

The ECOHEATCOOL project was launched at the beginning of 2005 by Euroheat & Power, in co-operation with 13 partners across Europe and support from the Intelligent Energy Europe programme, to obtain a comprehensive overview of the heating and cooling markets in Europe.

The project covered 32 countries including the then 25 Member States of the European Union (EU-25), the Accession Countries at that period (ACC4: Bulgaria, Romania, Croatia and Turkey) and three European Free Trade Association (EFTA) countries (EFTA3: Iceland, Norway and Switzerland). It concluded at the end of 2006. The project’s aims were to:

  • assess the heating and cooling markets in Europe
  • identify opportunities for more district heating and district cooling in Europe
  • provide recommendations for policymakers
  • develop a tool for assessing the efficiency of district heating and cooling systems.

The six project reports can be downloaded from the project website (www.ecoheatcool.org).