Every month or so there seems to be another “new” article stating that cutting down trees and burning them for bioenergy is bad. The latest instalment of this long running story was in the Guardian yesterday and signed by 15 academics from across Europe.
Many people will read this article, look at the roll of honour at the bottom of the page and as a result conclude that it’s completely black and white – bioenergy is bad.
However, there are just as many counter arguments and probably more academics who come to a different conclusion. As a Director of the Wood Heat Association I am frequently trying to fight back against the doomsday scenarios offered by the anti-bioenergy lobby. Of course our arguments don’t generally make headlines and because they come from a trade body are frequently criticised in the form of “you would say that wouldn’t you”.
In the last 24 hours I was privileged to be part of a great deal of email discussion about the Guardian article amongst academics and conservationists. So rather than give my own response to the article I’ve decided to collate some of the responses from this cohort. Here they are:
Dr Jeremy Woods, Senior Lecturer in Bioenergy Imperial College London
“What is really striking to me is the divergence between the potential counterfactuals and with the empirical evidence base pointing in the opposite direction to ones implicitly and explicitly used in the more negative assessments of bioenergy futures. Crop land may actually be contracting and forests are expanding in many countries. Deforestation in Brazil is not coupled to bioenergy…
Whilst it would be naive and complacent to simply assume that the land use and crop (and forestry) yield trends will continue into the future, at least through 2050 to 2100, it is equally and possibly more damaging to assume that they won’t and then base long term policy development on this assumption. We can be too afraid of the shadows.
Ultimately, the long term share of global energy provision derived from bioenergy does not need to be set in stone now and certainly does not all need to arise from land use expansion. However, unless substantive markets are signalled over the next few years and to persist over a 20 to 30 year time horizon we can be certain that our children will be stood looking back wondering why the bioenergy potential was not properly assessed and all those possible co-benefits missed. That would be more than a pity!”
Tony Juniper CBE writer, sustainability advisor and environmentalist
“Part of the argument against woody biomass for power relies on a counter factual wherein the forests are left alone to accumulate biomass. I was in California last year and heard from foresters how the drop in demand for wood had led to the forests not being managed for harvest, leading to concerns about worsening fire risk. This year a lot of it has gone up in smoke, perhaps raising questions as to the wisdom of some ‘leave the forests alone’ scenarios.”
“One thing that is striking about the now highly polarised debate about biomass for power is how the forest side of the equation has become increasingly divorced from the realities of electricity policy. Wind and solar must grow rapidly if we are to implement the Paris accord, but both of those intermittent technologies need to be complemented by sources of power that can be turned up and down at a moment’s notice. The alternatives to biomass are either limited in their potential (such as hydro and tidal), need to phased out (coal and gas) or are basically an alternative to wind and solar (nuclear). Some blithely say that batteries are the way forward, but do that in the absence of any economically (and therefore politically) viable assessment. Battery storage is at present about 200 times more expensive per megawatt than biomass and it seems unlikely that in a policy climate where sustainable energy is under attack on cost grounds that this can possibly work at the scale of a national grid. Under these circumstances it seems odd that campaigners have chosen strategies to basically close down biomass rather than to make it as good as it can be, for carbon, wildlife, energy security and jobs. Should there be success in ending policies for sustainable biomass, and if there is a massive scaling up in battery storage, how long will it be before we see the first campaigns to stop that, because of the human rights, pollution and wildlife impacts arising from the mining of lithium, copper and other minerals needed to make it happen?”
Dr Astley Hastings, Senior Research Fellow, University of Aberdeen
“If you limit bioenergy burn to the net primary production (NPP) of the world it is C neutral, if you exceed this then you are increasing emissions. So they are right in interpreting an extreme case but wrong as it can be manged to this limit. Unfortunately publishing in the Guardian slants the argument to “all bioenergy is bad”, which is frankly wrong and misleading.”
(Note: net primary production or the net carbon per hectare absorbed from the atmosphere by biota in a year. It includes all carbon absorbed by photosynthesis minus carbon released to the atmosphere by plant and soil respiration. It is basically the biomass carbon grown in a year per hectare.)
“And another aspect of this… Both the 2 degree and the 1.5 degree objectives agreed at the Paris accord will rely on negative emissions.. These largely depends on the technology of Bioenergy Carbon Capture and Storage. (BECCS). Without substantial amounts of biomass production this will not work. As I said before as long and the NPP limit is not exceeded then biomass fuel on its own without CCS is largely carbon neutral.”
“To quote from our newly-published bioenergy chapter (Scurlock et al.) in Peake, S. Renewable Energy (OUP, Oxford):
- Net annual production of terrestrial biomass = 130 billion dry tonnes/year
- Rate of energy storage by land biomass = 2400 EJ/year (76 TW)
- Rate of global primary energy consumption (2015) = 567 EJ/year (15.9 TW)
“…the amount fixed annually as chemical energy in biomass is…equivalent to between four and five times the world’s total primary energy consumption.”
“…the utilisation of plant biomass for energy should add no more carbon dioxide to the atmosphere than would have been formed in any case by natural processes as long as consumption does not exceed the natural level of production, estimated over appropriate temporal and spatial scales. Such assumptions about carbon budgets and accounting methods have been challenged by claims that, while ultimately renewable, the production of many biomass biofuel crop feedstocks (especially wood fuels from forest timber) would take decades to replace the carbon released in their combustion – and that such a ‘carbon deficit’ does not fit the urgent timescale for mitigating climate change.
However, in a well-managed system of forestry rotation, every tonne of biomass that is harvested and burnt will be balanced by a tonne of new biomass that is growing somewhere else nearby. If the rate of harvest is at least equalled by the rate of regrowth, when averaged over the whole supply region and measured on a timescale appropriate to forestry practice (e.g. 1–5 years), the carbon deficit may be non-existent or even reversed. Suitable data may be available from national forest inventories to assess whether overall standing biomass stocks are indeed static or increasing across a region.”
Professor Nilay Shah, Head of Department of Chemical Engineering, Imperial College London
“It’s almost as if we just imagined the pulp and paper industries of the last >100 years; according to the logic that you sometimes see there is no way they could still exist and their hinterland should look like Easter Island…”
Dr Andrew Welfle, Senior researcher, University of Manchester Tyndall Centre for Climate Change
“The problem with bioenergy is that it is highly complex and as a result there can be much variation in the performances of different bioenergy pathways – any bad calculated performances being jumped on and highlighted as reasons not to pursue bioenergy.”
“Any counterfactuals used that assume that forests would alternatively have continued to grow locking up carbon will obviously demonstrate large net CO2 being taken from the atmosphere, which will look highly attractive compared to any scenario where large net CO2 is released to the atmosphere through bioenergy. However if you stretch out the timeline, there is a point where forests mature and the uptake of CO2 will slow and then reach an equilibrium as trees start to die and decay – at this point forests stop being the continual sinks of CO2 as eluded by much anti-bioenergy reporting”.
If forests are well managed through regular thinning and successive harvest rotations, the overall forest system may be kept in a phase where the maximum rates of CO2 taken up from the atmosphere are maintained (during the early life phases of trees). If the harvested resource from these well managed forests is also used for bioenergy, much life cycle assessment analyses such as that undertaken by the UK Supergen Bioenergy Hub highlight highly favourable GHG performances of forestry bioenergy.”
If you’ve read all the way through this blog and would like to find out more about why bioenergy is a key part of future energy mix then I suggest you download the excellent document “A graphic introduction to Bioenergy” produced by the Supergen Bioenergy Hub.
If you only have one minute to spare why not watch the Wood Heat Association & UK Pellet Council’s video on woodfuel sustainability.