New report hopes to bring clarity to biomass debate
Burning biomass – often from wood – is a key pillar of the government’s renewable energy strategy, but there are questions over whether more biomass means higher emissions. A joint government and industry initiative launched yesterday sets out to clarify biomass’s role in the UK’s drive to meet its energy needs while cutting carbon.
The initiative is coordinated by Carbon Connect which brings together MPs, peers and industry. The group’s report will aim to outline “the role of renewables and how they tie into security of supply”, according to former energy minister and Carbon Connect co-chair Charles Hendry. Here’s a few key issues it will need to address.
Biomass emissions controversy
The government must reduce greenhouse gas emissions by 80 per cent by 2050 by law.
It’s hard to know whether biomass will help the UK cut carbon, however. Biomass generation can be carbon negative, in theory. But it depends on what kind of biomass is used and where it comes from.
Biomass is at the core of the Department of Energy and Climate Change’s strategy to deliver a “secure and cost-effective supply of low carbon energy”. DECC proposes getting up to 11 per cent of the UK’s total primary energy demand from biomass by 2020.
DECC is developing a new calculator to work out what ramping up biomass burning could do to emissions. And it looks like it could push emissions up unless carefully judged. Early results showed biomass generation may produce more emissions than burning coal in five out of the calculator’s twelve scenarios.
The new report will need to carefully assess what the government’s plans mean for the UK’s emissions goals.
Whole trees or cuttings
A key issue is deciding precisely what gets burned. A lot of biomass is wood, but emissions vary depending on what type of wood gets burned.
Burning whole trees rather than cuttings – such as sawdust, bark and thinnings – emits more carbon dioxide and means less is absorbed by young trees which replace more mature wood stock.
The UK could be burning somewhere between 15 million and 25 million tonnes of wood for energy in 2017. That means harvesting and burning somewhere between two and a half to five times the UK’s 2011 wood harvest.
The bioenergy industry says it will be able to rely on waste products from the forestry industry. But green groups dispute this, saying there simply won’t be enough wood from these sources, and biomass power stations will end up burning whole trees instead.
A lot of the wood is expected to be imported. Industry group, Back Biomass, previously told us 120 million tonnes of wood could be “sustainably” harvested in parts of North America. That poses problems for emissions, too, however – as transporting the wood to the UK would mean more emissions.
A key task for the new report will be to clarify where the government expects to get the wood from, what type it will be, and how it might affect the UK’s emissions.
Biomass in industry
Policymakers and industry are also debating whether biomass should be used to power homes or put to other uses.
The government’s climate change advisors, the Committee on Climate Change (CCC), says the most desirable use for biomass is in construction and industrial heat production – not electricity generation, as the graphic below shows. It says wood could replace carbon intensive materials like coal and cement in construction. It could also be burned as a heat source in industrial processes.
Image - CCC biomass (note)Source: Committee on Climate Change, Bioenergy Review
When it comes to power generation, the CCC says biomass should only play a role if carbon capture and storage (CCS) technology becomes viable on a large scale soon. Without CCS, more biomass will be needed to meet the government’s emissions reduction targets than can sustainably sourced, according to the report. It says:
“without CCS, there does not appear to be a longer term role in large scale power generation [for biomass], given available alternative low-carbon technologies.”
The CCC describes the UK’s bioenergy stock as a “scarce resource”, and the report will have to carefully consider how best to use it.
Next steps
The final report is due out in mid-July. We look forward to seeing if banging the heads of government and industry together produces workable solutions to these difficult issues.