Ross Clark Ross Clark

The farce of Drax’s wood pellets

Drax power station in Selby (Photo by Christopher Furlong/Getty Images)

When is the government going to stop pretending that chopping down trees in North American forests and shipping them across the Atlantic to burn them in UK power stations is a zero-carbon form of energy? The environmental-friendliness of Drax power station in North Yorkshire has been called into question yet again this week after BBC Panaroma investigation reported that some of the woodchips being burned there have allegedly been sourced from established ‘old growth’ forests in Canada rather than recent plantations. Drax has not commented on those specific allegations, but the investigation has thrown the issue back into the spotlight. How and where the wood is sourced has a dramatic difference on the overall calculations of carbon emissions from biomass burning – quite apart from the environmental issues involved with chopping down established forests.

But wherever the wood comes from, the whole business of counting biomass burning – which accounted for 11 per cent of Britain’s electricity generation in 2022 – as zero carbon is deeply flawed. It isn’t just Britain which is doing this – in 2022 the European Parliament voted to carry on doing the same.

Burning wood does, of course, release carbon dioxide. In fact, unit of energy for unit of energy, it emits more greenhouse gases than does burning coal. A paper published in the journal Science in 2020 estimated that the effective emissions from generating a gigajoule of electrical energy from wood are 117kg of carbon dioxide equivalent. The corresponding figure for anthracite – one of the cleaner forms of coal – is 103kg and for gas it is 67kg. Yet the UK and EU continue to insist on counting biomass as a zero-carbon fuel on the grounds that the wood has only recently been grown, and will be replanted – thereby claiming that the process as a whole is carbon neutral. 

There are two obvious things wrong with this. First, while it will take a few minutes to burn a tree in the boiler of a power station it will take several decades to regrow the tree. Moreover, it ignores the emissions involved in the forestry, as well as the processing and the transport of the wood pellets. A study by Chatham House in 2021 estimated that Drax emitted the equivalent of 12,795 kilotonnes of carbon dioxide in 2022 directly in the burning of wood pellets, plus a further 1,699 kilotonnes in the production of the wood pellets.

Here is how silly it gets: plant a tree in Britain and it counts towards carbon credits – removing carbon from the air – but cut down a tree in the US and it doesn’t count for anything. It goes on the US’ carbon budget, rather than Britain’s. It is a piece of creative carbon accounting which has helped the UK government to claim that it is the first country to halve its carbon emissions on 1990 levels.

I have a better idea. Rather than transporting wood from North American trees all the way to Britain, why not tip them out in the Mid Atlantic, where they will sink to the anaerobic depths, locking in the carbon they extracted from the air while they grew. Then, instead of burning the wood, we burn gas in our power stations. Given that – as per the figures above – gas emits less CO2 per unit of energy, that would reduce global carbon emissions (even if it raised Britain’s official, bogus total). Moreover, it would reduce particulate pollution because gas burns cleaner than wood. 

Alternatively, we could just leave the trees alone where they are growing in North America, perhaps collecting the dead wood and burying that in anaerobic conditions. That would do the planet a big favour compared with what we are doing at Drax.