The Global Sustainable Electricity Partnership, consisting of 11 of the world’s biggest electricity generators from Russia to North and South America to Africa, Asia and Europe, noted in a new report that the reality remains that coal-fired plants still account for 40% of global electricity generation in many countries.
They also see the likelihood of India importing coal if its domestic needs continue to increase, which every forecaster sees happening.
Improving the thermal efficiency of existing coal-fired generation units (which is 33% on average), is therefore the key, the group says, while developing and deploying innovative coal plant technologies will also be critical to reducing carbon emissions.
This, the group says, is because “coal will remain a major primary energy source of new electric power generation in many countries, notably Asia, over the next decades”
Their analysis, made clear this week in the their report Powering innovation for a sustainable future, backed up the analysis of the International Energy Agency’s report also issued this week which said Southeast Asia would be at the heart of saving the seaborne thermal coal market.
While this claim was rubbished by anti-coal activists who said the IEA wasn’t looking at the “reality” of the bigger picture, the aforementioned electricity generators said in their report that the process of phasing out less thermally efficient, older, smaller coal-fired generating units had already started, particularly in industrialised countries.
While activists may use this to point to a wider trend against coal, the electricity generators group said they are merely being replaced by high efficiency low emissions (HELE) technology which the World Coal Association championed last year in its Platform for Accelerating Coal Efficiency policy document which outlined the HELE’s usefulness in a low-carbon future.
For example, sub-critical coal-fired plants are being retired in Europe and the US due to market forces and/or environmental regulations, which the electricity generator group said was leaving relatively newer, more thermally efficient supercritical plants in operation.
“In this respect, innovative and cost-effective mothballing processes are a priority in regions like Europe,” the group said.
“Large pulverised coal plants are becoming the technological standard, with efficiencies of around 40%.
“Circulating fluidised bed combustion is for now mostly a niche technology, which has high flexibility in terms of fuel and can use – besides poor quality coal – industrial waste and biomass at medium-sized facilities.”
Innovation
This is where research and development comes in, and thus far the bulk of it has focused on improving thermal efficiency.
The group said ultra-supercritical coal-fired plants, which first appeared in the mid-1990s, operate at very high temperatures and pressures (typically 600C and 300 bar) to generate power at about 42% efficiency and higher.
Recent improvements to components can drive efficiency up to 46%.
The group said that going beyond this level to advanced ultra-supercritical systems involves increased R&D and use of high-nickel alloys capable of withstanding even higher temperatures and pressures (700C and 350 bar).
“The ultimate goal is for advanced ultra-supercritical units to generate power at thermal efficiencies upwards of 50%,” the group said.
Integrated gasification combined-cycle (IGCC) plants represent another avenue for innovation.
IGCC plants use a gasifier to convert coal (or other carbon-based energy sources) to synthesis gas (syngas), which then drives a CCGT.
The electricity generators said that, at demonstration phase, this technology can generate power at 42% efficiency, achieving thermal efficiencies of up to 50% as gasifier and turbine technologies continually evolve and improve.
“Such technologies would result in coal plants 50% more efficient than the existing fleet, thus emitting around one third less CO2 per kWh,” the group said.
“With certain modifications, pulverised coal power plants can utilise fuel with a 10% to 15% biomass blend, enabling a proportionate decrease in carbon footprint.”
However, amid all this, the group said additional demonstrations to determine performance, operational and economic impacts are also needed.
“The need for a robust and sustainable biomass supply chain, both in terms of resources and logistics, is a significant factor for the successful development and widespread deployment of this type of technology,” the group said.
