„Coal-fired power plants, also known as power stations, provide over 42% of global electricity supply. At the same time, these plants account for over 28% of global carbon dioxide (CO2) emissions. This report responds to a request to the IEA from G8 leaders in their Plan of Action on climate change, clean energy and sustainable development, issued alongside the G8 Gleneagles Summit communique in July 2005. The G8 requested a review and assessment of information on the energy efficiency of coal-fired power generation.
This report reviews the methods used to calculate and express coal-fired power plant efficiency and CO2 emissions, and proposes a means to reconcile differences between these methods so that comparisons can be made on a common basis. With a clearer understanding of power plant efficiency and how to benchmark this performance measure, policy makers would be in a better position to encourage improvements in power plant performance.
An essential part of sound policy development is the rigorous analysis of information which should be internally consistent and verifiable. Reliable power plant operating information is not easy to obtain, whether for an individual unit or for a number of units comprising a power plant, particularly efficiency-related information such as coal quality, coal consumption and electricity output.
It is therefore proposed that an international database of operating information for units at coal-fired power plants should be established for the purposes of determining, monitoring, reporting, comparing and projecting coal-fired power plant efficiencies and specific CO2 emissions on an annual basis. Such a database of individual units could be maintained by the IEA through its Energy Statistics Division or by the IEA Clean Coal Centre Implementing Agreement as an extension of its existing CoalPower5 database of world coal-fired power plants.
At present, there is no common standard for collecting and compiling coal-fired power plant efficiency or CO2 emissions data; many different bases and assumptions are used around the world. Defining a common methodology to rationalise efficiency reporting is not a practical proposition. Instead, approximate corrections are proposed, requiring only limited information that can be collected even where the detailed bases of the original calculations are not known. Average figures, reported for periods of a month or more, will be inherently more reliable, reflecting the actual efficiency achieved more accurately than design values, performance guarantees or results from short-term tests under ideal conditions.
The corrected data can then be compared with one another and to reference data sets reflecting best practices. CO2 capture and storage, once adopted, will impact significantly on the efficiency of both existing and future plants. At the current state of technology, units retrofitted with CO2 capture would suffer a decrease in efficiency of up to 12 percentage points, and consume perhaps 20% to 30% more fuel per unit of electricity supplied. While a concept of what constitutes “capture-ready” exists for new power plants, it may not be economic or technically viable to retrofit existing plants with CO2 capture, especially at smaller inefficient units. Refurbishments will often be necessary to improve efficiency at existing plants before CO2 capture retrofit can be contemplated.
Policy makers must reflect on what steps are now needed to improve the overall efficiency of power generation from coal. This report presents the tools for analysis and makes recommendations on how to use these tools to compare performance. This will allow poorly performing plants to be identified, wherever they are located. The costs and benefits of refurbishing, upgrading or replacing these plants can be estimated as the first stage in developing new policies that would encourage greater efficiency. The prize is large; some estimates suggest that 1.7 GtCO2 could be saved annually. However, securing this reward would demand a major realignment of national energy and environmental policies, a realignment that may be less politically acceptable than allowing old, inefficient coal-fired power plants to continue running, in the hope that they will eventually fade away. Given that there currently appears to be no prospect of meeting global electricity demand without coal, governments must implement policies that respond more proactively to the growing use of coal, rather than wishing it away. Monitoring the efficiency of power plants and targeting those that perform poorly would be an important step in that direction.”