I haven’t investigated this issue before, and my general uninformed view as I begin this post is that producing fuel somehow from plants when we’re already having problems with over-use of land, and maintaining biodiversity, seems like a solution which will likely cause further problems downstream.

This general view I’ve found well expressed in an article published in The Guardian and on the World Resources Institute website in late January 2015, nearly seven years ago now. Were the authors correct then, and has anything changed since?

The 2015 article argues for solar energy as a more efficient use of sunlight, which, essentially is what bioenergy also uses. However, there are problems with getting energy generated from the sun, in, say, the Sahara Desert, to regions of high demand in Europe. And there may be ways of harnessing bioenergy without excessive land use. An article published in Nature Sustainability at the beginning of this year (2021) suggests, in its abstract, that:

growing perennial grasses on recently abandoned cropland is a near-term strategy for gradual bioenergy deployment with reduced risks for food security and the environment

The full article is behind a pay-wall, and I’m poor and cheap, but the authors appear to be arguing that a fair amount of bioenergy potential, measured in exajoules (that’s a ginormous number of joules) can be tapped from abandoned cropland, and from increasing areas of potential cropland, without affecting biodiversity or utilising essential water resources.

None of this suggests that bioenergy has major potential for an immediate future that looks increasingly dire. Saul Griffith, an Australian scientist, inventor and entrepreneur, spoke on the Climate One podcast (Electrify Everything, Oct 29 2021) about the situation.

There’ll be some geothermal; there’ll be some biofuels for some applications; there’ll be some hydroelectricity. But wind and solar are now proven to be the cheapest generators of electricity in the world.

The International Energy Agency (IEA) has an article from earlier this year about bioenergy, land, and the net-zero-emissions-by-2050 target. This is a new area for me, so I was interested in the quoted fact that, currently, some 40% of bioenergy supply (about 25 exajoules) is from solid biomass (wood, and waste materials). This is a traditional use, mostly for cooking, ‘which is inefficient, often linked to deforestation, and whose pollution was responsible for 2.5 million premature deaths in 2020’. The aim is to reduce this type of fuel to zero by 2030 – which does sound optimistic.

The plan, or hope, is to transfer to and control a sustainable bioenergy supply as part of a transformed energy economy. This energy, IEA reckons, will be divided into solid bioenergy, biogas, liquid biofuels and bioenergy with carbon capture and storage. We’re talking 2050 here, and the IEA article writes about it in the present tense (a bit weird – for example ‘by 2050 almost half of liquid biofuel use is for aviation’). It projects that around 5% of our energy generation will come from bio, and that it will be ‘an important source of low-emissions flexibility to complement variable generation from solar PV and wind’. It will also be used in the paper and cement industries, to meet high temperature heat requirements not easily electrified, and in the early future to 2030 it will be used to replace ‘dirty’ biomass – for example, improved stoves. The IEA also appears to be talking up carbon capture and storage (CCS, or BECCS if you unite it with bioenergy), that somewhat vague technology which has yet to prove itself. I’ll have to write about that in future, to comprehend the process and to see if any progress has been made.

The IEA projects that the 2050 bioenergy supply (that 5% of total) will amount to around 100 exajoules. In its optimistic scenario, 60% of this supply will come from ‘sustainable waste streams’ which don’t require land use, compared to 20% currently. The idea appears to be that we will have come much closer to solving the current waste problem – from plastics to clothing  and various recyclables. Sorting and utilising will presumably be much more efficient, perhaps using advanced AI. There is also much talk of ‘advanced’ biofuels, presumably more efficient and energy dense. 

The controversial issue of utilising food crops and land for bioenergy is addressed, with a scenario that involves increased usage up to 2030, then gradually reducing to zero by 2050. Short-rotation woody crops (which are generally more productive of bioenergy) on marginal lands will largely replace them.

This emphasis on reclaimed land for bioenergy-producing short-rotation woodland makes me wonder about something outside of the IEA’s purview – the other life that such woodland might sustain, or not, as the case may be. What sort of birdlife, for example, would be attracted to such human-designed forests? A forest without birdlife would be an empty place indeed, but how would any bird fit into this human scenario? The IEA’s narrow focus thus becomes problematic when biodiversity issues are raised, but intercommunication on these issues should allow such woodland to be sustainable from a biodiversity perspective. 

 Another interesting usage in this IEA projection is the term ‘advanced’ . There will be ‘advanced’ biofuels by 2050, as well as ‘advanced’ short-rotation woody crops, and other such advances. In some respects, this is a reasonable assumption, but unforeseen consequences are unseen, after all. Still, the IEA are intent on collaboration with other stakeholders, including presumably spokespeople for those without a voice, such as all non-human species. Quite a large and varied sector. 

An article on ResearchGate from two years ago, ‘The Future of Bioenergy”, argues that land-intensive bioenergy may have uses in the short-term but is not a viable long-term option, due largely to the promise of other technologies. It quotes an earlier IEA study that finds that bioenergy has become an increasingly significant part of the current energy mix, a situation that’s likely to pertain for some time, but not so much for the long term. It also questions the viability of BECCS, which was promoted in an earlier IPCC paper. The problem with bioenergy, it seems, is that it may not be, and is unlikely to be, as green as its proven alternatives. There are, of course, major problems in applying green energy to aviation and to some heavy industries, and some current methods of biofuel production are hardly less harmful than those for conventional fuels. Land use is also an issue fraught with unforeseeables. But of course, researchers will continue their research, and new breakthroughs are always possible. Something to keep an eye on.

References

https://www.nature.com/articles/s41893-020-00680-5

https://www.climateone.org/audio/electrify-everything

https://www.iea.org/articles/what-does-net-zero-emissions-by-2050-mean-for-bioenergy-and-land-use

https://www.researchgate.net/publication/336740381_The_Future_of_Bioenergy