With several decades to go before low carbon and renewable energy sources are in any position to replace fossil fuels, the Institution of Chemical Engineers (IChemE) is urging greater innovation in the design of coal-fired power plants to improve efficiency and reduce greenhouse gas emissions.
Coal provides around 40 per cent of the world’s energy and has been the fastest growing global energy source for over a decade. However, the existing 2,300 coal-fired power plants currently generate around 43 per cent of global CO2 emissions, and this will increase with over a thousand new coal-fired power plants planned for development in around 60 countries.
Despite the growth in renewable energy and natural gas, coal will continue to be the dominant source of electricity through to 2050, especially in countries like China and India. With low carbon, renewable energies not expected to replace fossil fuels by 2075, the Institution of Chemical Engineers (IChemE) is urging more research into mitigating the impact of coal on climate change.
IChemE president, professor Geoff Maitland, says, “We need to be realistic. The global transition to renewable energies will take time, but, eventually, it will solve many of the challenges of climate change. But there is still a major job to do now to mitigate electricity generation from burning fossil fuels. Although the Obama administration in the US is currently waging a war on coal, globally there are still plans for a 50 per cent increase in the number of coal-fired power plants suggesting things will get worse before they get better – we need to limit this damage as much as possible.
“Effective carbon capture and storage will be an important and essential step and must be implemented on a large scale much more rapidly than it is at the moment. Also, more investment in research is needed to improve the efficiency of coal-fired plants to lessen emissions.”
Some of the most interesting power plant design research is looking at waste heat recovery systems, in particular flue gas waste heat.
Up to fourth fifths of a boiler’s thermal loss is simply emitted into the environment – equivalent to up to eight per cent of a coal-fired power plant’s energy input. Making better use of this waste heat continues to be a major opportunity to improve efficiency and reduce the amount of coal used.
New research from China shows that changes in plant design and using flue gas waste heat differently has the ability to nearly double the power output from conventional waste heat recovery systems to around 11 MWe. There are financial benefits too with potential energy savings of up to US$2.6 million per year.
Maitland says, “Some of the research coming out of major coal consuming countries like China, US and Germany is helping to improve plant design bit by bit. Over the next few decades, this steady flow of improvements could aggregate to produce significant benefits.”
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