The role of fossil fuel plant in flexible power generation was the title of the Advanced Power Generation Technologies Forum annual workshop held in London over two days this week. Given the workshop’s strong focus on meeting the UK’s energy challenges, the choice of theme was a timely response to increasing concern over how to manage the increasing amounts of intermittent renewable capacity planned for the country. Following the recent release of the APGTF’s detailed technology strategy for CCS, this long-standing focus of the workshop was also well represented, as well as an emphasis on biomass for the second day.
A range of speakers representing academia, utilities, and manufacturers, all stressed the need for some mechanism of valuing flexibility in power generation for future energy supply. With massive increases in wind power capacity planned in meeting the UK’s renewable energy targets, the grid will begin to see unprecedented levels of variability in power supply, potentially leading to unacceptable wastage of expensive energy and highly volatile electricity prices. In addition to improved energy storage options and interconnectivity with Europe, significant increases in capacity of highly flexible CCGT (or even OCGT) plant will be essential for adjusting this supply to meet real demand. However, with coal currently priced well below gas, these gas-fired plants are actually being mothballed in the UK and abroad. Modelling by researchers at Imperial College suggested that the true value of such flexible plant could more than double the plant cost, but with flexibility provision absent from the UK’s energy market reforms, such investment remains highly unfavourable. Besides these policy gaps, technical issues will also need addressing in order to optimise gas plant flexibility and achieve faster start-ups; identified as the main limiting factor as opposed to ramp rates.
Despite this strong emphasis on the need for more gas capacity, the ongoing importance of coal in the energy mix was not forgotten, with several speakers looking at how much flexibility could be achieved by a CCS plant. The lengthy process chain of capture, transport, and storage makes for a complex problem, but the Energy Technology Institute has recently produced a software package for modelling the whole process. CO2 compression was identified as the potential weak link in the chain for rapid load changes, as the compressors used have limited response times, although running several in parallel would be one costly solution. Potential problems at the storage end such as minimum flow rates were also raised, but long pipelines can even out rapid changes and capture plant clusters would also be beneficial. An update on the White Rose project was a reminder that CCS may become a reality in the UK within the next decade, whilst a talk from Tees Valley Unlimited on the need for CCS to decarbonise this heavily industrialised region highlighted that there are still worthy projects like this that have missed out on the government’s CCS funding. It is often ignored that CCS remains the only means of decarbonising the hugely polluting industrial sector.
Thursday’s biomass talks featured the Clean Coal Centre’s own Debo Adams speaking on sustainability in biomass cofiring. The thorny issue of accounting for emissions resulting from direct and indirect land use change was raised by Debo and in talks throughout the day although, as someone pointed out, fossil fuels seem to escape the same stringent analysis of upstream emissions. In my relatively brief time in clean coal circles, I’ve noticed that a question on accounting for negative emissions from biomass is pretty much obligatory after any talk on CCS. Hopefully a lot of this curiosity was cleared up by Jasmin Kemper’s presentation on the IEAGHG’s extensive work on bioCCS, which has quantified the negative emissions achievable from a range of bioenergy routes and reviewed which emissions trading schemes reward negative emissions.
The APGTF workshop always seems to create a lot of discussion during and after the sessions, and with good representation from the major UK energy players, it does justice to its name as a great forum for tackling issues in fossil fuel generation. Although there was a strong feeling that providing for future flexibility of power supply has not been given sufficient attention, hopefully the workshop went some way towards bringing the oversight to the fore.