EN19 Efficiency of conventional thermal electricity and heat production
Assessment made on 01 Nov 2008
ClassificationEnergy (Primary theme)
DPSIR: Driving force
- ENER 019
Policy issue: How rapidly is energy efficiency increasing?
The efficiency of both electricity, and combined electricity and heat production from conventional thermal power plants improved steadily between 1990 and 2005. This was due to the closure of old inefficient plants, improvements in existing technologies and the installation of new, more efficient technologies, often combined with a switch from coal power plants to more efficient combined cycle gas-turbines. This trend is expected to continue in the future. However, the rapid growth in fossil-fuel based electricity production outweighs some of the environmental benefits of the efficiency improvements.
The indicator shows the efficiency of electricity and heat production from conventional thermal plants. A distinction is made between public (i.e. main activity producers) thermal plants and autoproducers. Public thermal plants mainly produce electricity (and heat) for public use. Autoproducers produce electricity (and heat) for private use, for instance in industrial processes. The efficiency of electricity and heat production is an important factor since losses at production account for a substantial part of the primary energy consumption. Higher efficiency of production therefore results in substantial reductions in primary energy consumption.
In the "Energy Policy for Europe" (COM(2007)2) and the "Action Plan for Energy Efficiency" (COM(2006)545), the European Commission sets targets for a 20% reduction of energy-use in Europe in 2020. One of the priority actions (#3) of the Action Plan focuses on more efficiency in power generation. Following this action the Commission will by 2008 develop minimum efficiency requirements for new electricity, heating and cooling capacity lower than 20 MW. Furthermore it considers such requirements for larger units.
The average energy efficiency of conventional thermal electricity and heat production in the EU-27 improved over the period 1990-2005 by 3.3 percentage points to 47.0 %. For most countries efficiency improved, but for three countries there was a net decrease in efficiency (Poland, France and Sweden). The decrease of efficiency in these countries is not part of a continuing trend, but due to annual fluctuations.
For public thermal power plants the average efficiency increased in most countries over the period 1990- 2005, resulting in a net efficiency of 46.6% by 2005. For autoproducers the average efficiency also increased in most countries over the period 1990-2005, resulting in a net efficiency of 49.1% by 2005. The higher efficiency for autoproducers is largely explained by the fact that the installations of autoproducers are often designed or dimensioned more suitable for the electricity and heat demand on a location.
For both public thermal plants and autoproducers, this energy efficiency improvement has been due to a combination of factors including the closure of old inefficient plants, improvements in existing technologies, installation of new, more efficient technologies, often combined with a switch to fuels with a better generating efficiency, such as from coal power plants to high-efficiency combined cycle gas-turbines. Environmental regulation has also been important in encouraging improvements and fuel switching towards more efficient fuels. However, the main factor in the choice of new electricity production plant during the period 1990-2005 was economic, as the costs of electricity produced from gas-fired plants have generally been less than for coal or oil fired plants, which has led to gas being the more desirable fuel for new plants.
The growth in the use of combined cycle gas turbine plants (CCGT) has been an important factor in the improving efficiency seen in the pre-2004 EU-15 Member States. CCGT plants can achieve conversion efficiencies in the order of 60%, with the prospect of even higher efficiencies in future plants. However, continued improvements have also been made in conventional coal generation with plant capable of efficiencies in the range 40-45%, and further advances that may allow this to exceed 50% (IEA, 2005).
CHP provides a large potential for increasing efficiency of electricity-production and reduction of emissions of CO2. Meeting the indicative EU-15 target of doubling the share of CHP in gross electricity production from 1994 to 2010 could lead to avoided CO2 emissions of over 65 Mt CO2/year by 2010. The potential at refineries in the Dutch port or Rotterdam equals app. 5 Mt CO2/year (see EN20).
Although overall improvements in electricity generation efficiency have been seen over the period 1990 to 2005, a marginal stagnation in the late 1990s and a decline in efficiency has been observed in 2002. This has been due primarily to an increased utilisation of existing lower efficiency coal plant (see EN-27 for more details). In the following years the efficiency increased due to an increasing share of gas.
It should also be noted that positive impacts on the environment overall, due to reduced emissions, from increased efficiency in electricity production may be offset by the high rate of increase in electricity consumption, which is growing at an average rate of 1.7 % per year (see EN18), especially considering that over half of this electricity (53.6 % in 2005) is produced from coal, gas and oil (see EN27)1. There is also a potential tension between environmental legislation (for example the Large Combustion Plant Directive 2001/80/EC) requiring the reduction of other air pollutants such as SO2, whereby retrofitting flue-gas desulphurisation technology incurs an energy penalty thus reducing overall efficiency. However, future coal technologies such as IGCC (Integrated Gasification Combined Cycle) can operate at higher efficiencies and also allow the sulphur, nitrogen compounds and particles to be removed prior to combustion (OECD, 2005).
At the beginning of the 1990s, the electricity sectors of the new EU Member States were characterised by low efficiencies of production mainly due to obsolete plant technology. However, in the second half of the 1990s investments were made to improve the performance of existing plants. Another significant trend was a switch from coal to gas in new and reconstructed fossil fuelled heat and power plants. This also contributed to an increase in generating efficiency due to the higher efficiency of gas combined cycle technologies. The growth in the use of gas has been supported by environmental regulation, government support (as high-efficiency electricity production from gas is seen as a low-pollution option) and programmes to finance enlargement of the gas networks.
The greatest efficiency improvements in both electricity and electricity and heat production occurred in Luxembourg (construction of a new CCGT) and in Cyprus (new more efficient plant). Significant decreases in the efficiency of electricity production were seen in the Czech Republic between 1990 and 2005, but closer examination of the trend shows a sharp fall in efficiencies in the early 1990s during the period of economic collapse due to low utilisation of plants, followed by relatively constant efficiencies in more recent years.
Efficiencies of fossil-fired electricity and heat production in different countries have been compared in a recent study (Ecofys, 2007). It appears that efficiencies in European countries (France, UK, Ireland, Nordic countries and Germany) are higher than the world-wide average. When the worldwide average is set at 100%, efficiencies in India and China are typically 15 - 19 % lower than those in the investigated European countries. The efficiencies in the USA are 1% below the average level.
The trend in increasing efficiency is expected to continue into the future, as new more efficient technologies are introduced, in particular with the increased market penetration of combined cycle gas turbine technologies, and following the closure of older less efficient plants.
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