Biomass FAQs

Does burning biomass emit more harmful greenhouse gases than coal?

No. The greenhouse gas saving relative to coal at Drax last year was over 80%. When it comes to carbon emissions and sequestration it is important to recognise that biomass is part of a closed cycle, with exchanges between carbon pools in the atmosphere and biosphere. These exchanges have been taking place for millennia. A growing forest uses carbon from the atmosphere. With fossil fuels the situation is radically different. When fossil fuels are burnt carbon which has been stored for millions of years and which would otherwise have remained in the earth’s crust is released into the atmosphere producing a net increase in atmospheric carbon. It is this net increase which puts pressure on the otherwise closed carbon cycle’s ability to absorb the carbon and leads to the greenhouse gas effect we are seeking to avoid.

If a tree burns in seconds but a replacement tree takes years to re-grow to the same size there must be a ‘carbon debt’ until the new tree has reached the size of the tree it replaced? 

An assessment of the carbon stock of a forest has to look at the landscape, not at a single tree, because for every plot or stand of trees which is removed there will be many other plots at different stages of growth.  Provided the rate at which carbon is absorbed by the forest as a whole equals or exceeds the rate at which it is being removed there is no net release of carbon. Healthy demand for wood stimulates supply and ensures forests remain as forests. That is why forest cover in the US is growing year on year and has been growing for each of the last 50 years.

It is a requirement of Drax’s independently monitored sustainability policy that our sourcing of pellets does not lead to a net increase in carbon levels. This status is found to be true at a landscape level, at state level, across the south east US and across the US as a whole.

Do Drax’s suppliers ‘clear cut’ bottomland forests in order to manufacture wood pellets?

Absolutely not, doing so would not be sustainable and it would be terrible economics. Large, straight trees are substantially more valuable when used as saw logs for construction or furniture. Foresters manage their land to maximise the number of these most valuable trees and harvest when the maximum number of trees have reached their maximum value.

At the time of harvest there are inevitably some trees which do not meet the market standard. They may be diseased, misshapen or have a rotten core. Some parts of the highest value trees, such as the offcuts, branches and tops are not suitable for saw logs and these residues are also used as biomass. In the past these ‘sub-standard’ trees and residues were often left to rot or burnt on site – it is material like this which is not destined for any other market which is suitable for use as biomass. The US Department for Energy estimates that 93 million tons of such residues and thinnings are left to rot or burnt in forests every single year.

It is clear that some of your suppliers have whole trees or at least very large trees from bottomland forests on their stock piles. Are these destined to become pellets and how does that square with your claims?

For the reasons explained above it is likely that some quite large trees and bits of trees will be processed into biomass pellets. More typically the feedstock is residues, thinnings and other types of wood which would otherwise be left unused on the forest floor or burnt after other forestry operations have taken the valuable wood they need.   

An economically rational system will ensure high-grade, high-value forest produce is separated out and sent to industries such as furniture making and construction. The lowest grade fibres, such as twigs, bark, thinnings and sawdust are sent to the bioenergy sector.  

The proposed £105 per MWh of support looks more expensive than wind and nuclear, is sustainable biomass a cost effective renewable fuel?

Sustainable biomass is one of the most cost effective low carbon technologies available. It is incorrect to claim £105/MWh makes it more expensive than onshore and even nuclear power. Support for biomass conversion ends in 2027 whereas the price onshore wind generators will get is guaranteed until 2030 and the subsidy paid to nuclear operators will be paid for 35 years – this means that while the price paid per MWh may be slightly lower the government will pay that price for longer, in the case of nuclear new build nearly three times longer. Independent work carried out for DECC shows that the costs of meeting our 2050 decarbonisation target would be £44bn higher without sustainable biomass.

Moreover these £ per MWh ‘strike prices’ do not include the cost of connecting new build assets to the grid, of maintaining those new connections or even the cost of keeping power stations standing idle when the wind doesn’t blow. Importantly, under the contracts for difference (CfD) regime if the electricity price goes above the strike price electricity generators actually have to pay back the difference. In this way the CfD provides good protection against rising prices for consumers.

Is the extraction of biomass tightly regulated? 

Yes, our suppliers are independently audited against Drax’s own robust sustainability policy which covers a range of issues including protection of biodiversity and ensuring no net carbon release from forests and soil. In addition to that the UK has its own robust sustainability criteria, which makes government support contingent on independently verifiable greenhouse gas emissions throughout the supply chain.

At a federal level in the US, forestry is regulated by the Clean Water Act, Clean Air Act, Endangered Species Act, Migratory Bird Treaty Act, Coastal Zone Management Act and the Lacey Act. At State level, it is regulated by a range of water quality management regimes, established industry best practices, wetlands protections and zoning and landscaping ordinances.

How can it possibly make sense to ship wood pellets up to 3,800 miles to generate electricity when there are other alternatives available?

The economies of scale are a tremendous advantage as we are able to ship our biomass in vessels as large as 50,000 tonnes capacity. We measure the carbon footprint of every step in the supply chain so we know exactly how much carbon is emitted during harvest, processing and transport. Even when this entire life cycle is taken into account savings relative to coal are over 80%.

There is no magic alternative to biomass. Other scalable low carbon renewables in the UK are intermittent (sun or wind dependent) and cannot be relied upon to respond to changes in demand when needed. Other renewables are important, but on their own they cannot meet our electricity needs.