Last week, a group of respected scientists wrote to the Guardian to argue that using wood to generate electricity in place of coal is not a solution to climate change. Their critique pointed to a “carbon debt” arising from the years between using a tree for fuel and new one growing. They gave the impression that forests are being cleared wholesale to be shovelled into power stations. Reality on the ground is, however, somewhat different.

I found this out when earlier this year I went to the USA as an advisor to Drax, a power company in the UK that is seeking to accelerate the phase out of coal by using a biomass instead. On my travels I had many vivid reminders as to how forests are more than collections of individual trees. In the case of the US South, from where much of the wood being used in the UK comes from, I saw vast expanses of production woodlands being harvested for a range of products.

I learned that the demand for wood has over recent decades been the main reason why the quantity of wood those forests hold has about doubled. Those managed ecosystems are taking carbon out of the atmosphere, while supplying various industries including, lumber, paper and bioenergy. I saw how, at the level of the landscape, there is no carbon debt.

And it is important to know which wood is being made into wood pellets to generate electricity here. Much of the wood produced by these forests is low grade thinnings taken out as part of the process of growing higher grade lumber. These, along with branches and sawmill waste, are the principle sources of materials being made into wood pellets to displace coal.

Of course it might be argued that solar and wind are better, but when it’s dark or calm these intermittent renewable sources need to be complemented with sources that can be turned up and down at a moment’s notice. Hydropower and tidal sources can do this but in the UK context have limited potential. Nuclear is another low carbon alternative but is inflexible and if anything is an alternative to wind and solar, rather than a complement to them.

A decade ago when I was campaigning for the new laws that eventually became the UK Climate Change Act, I pressed for the urgent slashing of greenhouse gas emissions. Since then we’ve made good progress on renewables deployment, helping to bring about the UK’s first day without coal power since we’ve had electricity – a landmark reached in April this year.

Such progress is possible not just because of ambitious determination but also because campaigners have been pragmatic. We showed ministers that it was not just necessary to slash emissions, but also doable. That is why some of us called for conversion of the UK’s biggest power station, Drax, from coal to biomass.

There are many questions about biomass (and indeed all energy choices), but in the case of biomass I fear that some advocates have gone from questions to opposition rather too quickly. I stand by the policy I backed a decade ago and would encourage a discussion that seeks to make biomass as a good as it can be, rather than to stop it.

• Tony Juniper is an environmentalist, writer and co-founder of the sustainability advisory group Robertsbridge. In that capacity, he has been advising Drax on sustainability issues.

