By Dave Elliott
There is a lot going on in the bioenergy field in the UK, with the government keen on biomass conversion of large old coal fired plants like the 4GW Drax plant in Yorkshire. That’s based on importing wood pellets from North America, something most greens are opposed too (see my last post), especially if it uses whole trees, as some allege: https://www.foe.co.uk/sites/default/files/downloads/felled-fuel-46611.pdf
However while the DRAX project is going ahead, with support under the new Contracts for a Difference system, as is the 420MW RWE Lynemouth project in Northumberland, the 2GW Eggborough project has been sidelined from support from the first round of CfD, and last year RES closed the Tilbury biomass conversion plant, which used imported wood pellets. There had been a fire there. So there are evidently operational and economic limits to this approach.
In any case, some say it is far better to build new smaller more efficient purpose-designed units using local biomass sources and so avoid importing wood pellets from North America. For example, Renewable Energy Generation is planning an 18MW bio-power plant at Whitemoor Business Park near Selby, Yorkshire, using recycled waste cooking oil. It’s expected to cost £6.3m and become operational late 2014. But that’s small, reflecting amongst other things local shortages of waste bio-material. It’s the same for big municipal waste combustors: they may have to truck in waste from far away to get economies of scale, and of course most greens, concerned about toxic emissions, oppose mass burn projects, using general waste, although gasification plants are sometimes said to be cleaner: http://www.gasification.org/page_1.asp?a=87 But there are limits.
There also seem to be limits to the support available for new dedicated biomass projects. RES has now abandonedplans for a new £300m 100MW dedicated biomass power in Northumberland at North Blyth. RES said a key partner had pulled out ‘due to ongoing uncertainty in UK energy policy’ and accused ministers of ‘inconsistent support for dedicated biomass energy’. It suggested that biomass has ‘been increasingly marginalised by the U.K. government in a series of policy developments over the last two years, including the introduction of a cap on dedicated biomass under the Renewables Obligation (RO).’ RES says the cap ‘represents a radical downsizing in government ambition for the technology from a target of 4,000 MW in 2011 to a cap of 400 MW in 2013, long after the industry had invested significant sums in developing projects on the back of DECC ambitions’.
It certainly does not look good. E.ON had already scrapped its 150MW Portbury Dock project in Bristol, saying that ‘under the current regulatory and policy framework’ the project ‘was not a priority investment for E.ON’, while RWE’s 65MW Stallingborough project in Lincolnshire has been put on hold. And Forth Energy has pulled out of 3 projects in Scotland, including wood-burning biomass plants in Grangemouth and Rosyth. In fact, according to Process Engineering, as of March this year, only two projects, totaling 73.5MW generating capacity, have been approved by the Department of Energy and Climate Change to receive RO support within the 400MW RO cap: Eco2’s 42.5MW North Lincs project and E.ON’s 31MW Blackburn Meadows scheme. http://processengineering.theengineer.co.uk/home/comment/a-biomass-mess-again/1018184.article
However it’s not all bad news. Renewable Energy World noted that Biomass with CHP, i.e. biomass-fired combined heat and power plants, were continuing to attract investment, given that they still qualify for significant government support, including the £60m 8.32 MWe Helius Energy plant in Rothes, Speyside, Scotland, using by-products from nearby malt whisky distilleries to produce renewable energy and an animal feed protein supplement; the RWE Innogy UK Markinch 65MW Biomass CHP plant in Fife, feeding steam to a paper mill; and Estover Energy’s £65 m biomass-fired CHP plant at Sandwich, Kent, generating 11-15 MWe and 8-12 MWth, using locally sourced low-grade wood. In addition, Kedco plc, is developing a12 MW Enfield Biomass CHP project in north London. The first interim round of the CfD has also supported a large 299MW biomass CHP plant at Middlesbrough on Teeside. www.renewableenergyworld.com/rea/news/article/2014/03/uk-bioenergy-are-dedicated-biomass-plants-a-bust?cmpid=WNL-Friday-March14-2014
Mid-scale Biomass CHP projects do make a lot of sense if there are fuel sources nearby, and local loads for the heat. Support for CHP has been somewhat convoluted: was it heat or power? Was the heat (which would otherwise have been wasted) from fossil CHP in effect virtual green power? At present, medium and small-scale biomass heat and/or power projects can get support under the Renewable Heat Initiative, with a domestic version now opening up, after some delay, but there are still debates about the RHI eligibility criteria and the level of support.
Anaerobic digestion of municipal domestic and food wastes, and of agricultural wastes, is also often seen as a good local option, with biogas production, perhaps 20TWh per annum, making a significant potential contribution to power and heat supply, possibly feeding into the gas grid. Indeed it’s been claimed that if we went for a large programme of anaerobic digestion, it could provide 10% of the domestic gas supply. However there have been some disputes about the support system being offered for AD, with the Feed In Tariff level being cut back. AD offers many opportunities for farmers at a range of scales, so unsurprisingly the NFU has objected to the cut. For example see http://www.nfus.org.uk/news/2014/march/tariffs-not-fit-purpose
Although there are many good projects around the UK, and DEFRA’s grants have helped, progress on AD is rather limited compared to the huge potential for heat and/or power production. This seems tragic. As detailed in a new Routledge book, ‘Bioenergy Production by Anaerobic Digestion’ edited by Nicholas Korres et al, biogas can replace natural gas for heating or electricity generation, or even for use in vehicles, or be used as a feed stock to make other fuels. The substrates used can include any non-woody materials, including grass and maize silage, seaweeds, municipal and industrial wastes. Cost effectiveness has been an issue, but the authors show that recent advances have made smaller-scale systems more viable through a greater understanding of optimising bacterial metabolism and productivity. http://www.routledge.com/books/search/author/john_ah_benzie/
Finally there are the liquid biofuels, for use in vehicles. The UK initially had ambitions to get to a 5% biofuel mix by volume by 2010, but this was downgraded, first pushing it back four years to 2014 and then reducing it to 4.75%. And even that now seem unlikely to be met. The Department for Transport has reported that the level of biofuel in the overall fuel mix for 2012/13 stood at 3%, whereas the target for the period was 4.5%. http://www.businessgreen.com/bg/analysis/2327297/uk-biofuels-sector-flat-lining-industry-warns
Biofuels of course open up a big debate, with global implications and strongly conflicting views. Energy crops allegedly replace food crops and can lead to significant social and environmental damage. There is hope that second generation non-food crops can avoid some of this, using marginal land, and that more advanced options can have higher calorific values- some first generation biofuels need more energy to produce than they yield. The EU has in the past been very supportative of biofuels, but is now imposing caps on some types, so progress may slow. For a short partisan NGO overview see: www.opendemocracy.net/ross-heard/great-biofuel-greenwash
Overall then a mixed set of results, in part due to government reluctance to offer support, but also reflecting economic, social and environmental constraints- including land use and biodiversity issues. Some of these limits may be reduced or avoided by using biomass wastes, and, longer term, extra value could be obtained from biomass combustion for heat and/or power production if it was linked to Carbon Capture and Storage, making it net carbon negative. But there is some way to go before the UK could hope to obtain what the Tyndall Centre for Climate Change say might be possible- obtaining 44% of UK energy from biomass by 2050. www.sciencedirect.com/science/article/pii/S0301421513012093