The use of biomass to produce fuels or electricity should be heavily restricted — and two to three times smaller than the IEA suggests — in order to prevent bioenergy demand harming the fight against climate change, according to a major report by think-tank Energy Transitions Commission (ETC).
This is because plant material naturally sequesters carbon as it grows, so burning it to produce energy — whether as biofuels or in power plants — can be counterproductive and not the carbon-neutral solution that proponents often claim, says the study, Bioresources Within a Net-Zero Emissions Economy: Making a Sustainable Approach Possible.
Biomass should also not be used for energy if it competes with food production, triggers deforestation or negatively impacts biodiversity and ecosystem health, says the global private-sector coalition.
As ETC commissioner Manish Bapna, the interim CEO of the World Resources Institute, points out: “The world has a fixed quantity of land, while demand for food, fibre, carbon storage [ie, offsetting] and biodiversity continues to grow. We can’t have an ‘all of the above’ strategy; there are real trade-offs in play, requiring informed decisions.”
Bioenergy sources should therefore be limited to agricultural and forestry waste and residues, and fast-growing non-food energy crops such as miscanthus or jatropha that are grown on degraded or marginal lands, says the ETC.
Mature trees should not be cut down for energy purposes, while existing government mandates for the use of plant-based ethanol and biodiesel blends in petrol and diesel are counterproductive and should be phased out, the report adds.
“Truly sustainable biomass is limited in volume, so its use must be restricted to priority sectors where alternative decarbonisation options don't exist. The good news is that clean electrification and hydrogen provide a cheaper solution,” says ETC chairman Lord Adair Turner, who previously headed the UK’s Financial Services Authority and, prior to that, the country’s main business lobby group, the Confederation of British Industry (CBI).
“If you build a little too much offshore wind in the North Sea, the negative costs of that are going to be trivial, there’s sort of almost no regrets possible about just going out and putting as much solar and wind in the world as you possibly can. With biomass, if you do too much, you can actually do harm,” he tells Recharge.
Best use cases
The study points out that “most current applications of bioenergy — in particular in road transport and bulk power generation — will be uneconomic versus electricity or hydrogen in the coming years”.
Bioenergy might be cost-competitive in the short term for shipping, seasonal power balancing, some residential heating, and some industrial heat, the report says. “But its use in these sectors should still be tightly limited, and initially higher-cost electricity-based options, where the energy can be provided through renewables, should be favoured to keep total [biomass] demand within sustainable supply constraints and accelerate cost reduction of the electricity-based options,” it explains.
Aviation, however, is one sector “where biofuels should play a major transitional role and may be a significant use of biomass even in the long-term, as the alternative option (power-to-liquid) [ie, synthetic fuels derived from green hydrogen with captured CO2] may not reach cost-competitiveness and scale fast enough to achieve necessary emission reductions”, the document adds.
‘IEA too bullish on biomass’
While the International Energy Agency’s (IEA) recent Net Zero by 2050 roadmap report stated that 102 exajoules (EJ) of energy should come from biomass annually by 2050, the ETC study says a “prudent” figure would be 30-50 EJ.
The ETC argues that the IEA is being over-optimistic about the amount of agricultural residues and municipal & industrial waste that could be cost-effectively harvested for bioenergy, and also how much biomass could be sustainably supplied from dedicated land.
The IEA also uses less strict sustainability criteria than the ETC, “particularly relating to the percentage of residues that must be left on the ground to maintain soil quality”, while the former also includes 5 EJ from traditional firewood, which the ETC does not include.
The ETC report breaks down its “prudent” 30-50 EJ figure as 5-10 EJ annually from non-food crops grown on dedicated land; 10-20 EJ from forestry residues, such as tree roots and “thinning” — ie, removing small trees to allow bigger ones to grow; 5-12 EJ from agricultural residues such as corn husks; 6-9 EJ from municipal and industrial wastes; and 0-1 EJ a year from seaweed and algae (which the IEA did not consider).
The report adds that these figures could be much higher with improved collection of organic waste, commercial development of seaweed for energy usage, and large-scale switching of pastureland to energy crops, which would require a massive change in consumer demand for meat.
The inherent problems of biomass for energy
Plants naturally store carbon as they grow, so if plant matter is burned, that same amount of carbon is theoretically released into the atmosphere, resulting in a carbon-neutral cycle. But in reality, that is not true.
First of all, removing plants can also remove CO2 stored in the soil. secondly, energy is required to harvest and collect the biomaterial (eg, using petrol-driven tractors or chainsaws), then to process it (eg, turning sawdust from timber mills into wood pellets or converting sugar cane to biofuel), and then transported it to its destination (usually using fossil-fuelled trucks or ships).
All this could be reduced to close to zero by using electric equipment powered by renewable energy, but in the short term, wind and solar and green hydrogen are likely to be a lot closer to zero-carbon, says the ETC.
Biomass power without carbon capture and storage (CCS) does not make sense from a climate or economic perspective, as wind and solar energy is considerably cheaper to produce. Even using biomass in peaker plants to provide grid balancing services would not be competitive with battery-based services, says the ETC.
“Only if coupled with CCS, and with a carbon price to remunerate carbon removal, can biomass be cost-competitive with renewable generation for bulk power generation,” the report concludes.
Lord Turner tells Recharge that due to the supply-chain emissions and the fact that CCS can only capture roughly 90% of emissions, a bioenergy with CCS (BECCS) plant — such as Drax’s planned 2.6GW facility in northern England — is more likely to have an overall carbon footprint of minus 20%, rather than minus 100% if all the carbon originally stored in the plant matter were captured and stored.
Still, the BECCS process would result in removing carbon from the atmosphere, while also producing renewable energy — if the biomass source is sustainably managed.
But there is a danger that companies will exaggerate how much carbon they are saving, which means that some sort of verification process will be needed.
Enforcing sustainability standards
Calculating the carbon balance from a biomass source requires an understanding of the amount of CO2 stored in the plant material and its soil, the emissions from the supply chain, and the size and efficiency of the CCS equipment being used.
So measuring the net carbon impact — and therefore the potential carbon price — from bioenergy production is far from simple.
“This is so complicated that a central planner can’t sit down and do this,” Lord Turner tells Recharge, adding that an economy-wide carbon price is needed to drive decarbonisation.
“You have to combine that [carbon pricing] approach with incredibly tight sustainability standards to [ensure] we are not going to pull down any existing forests; that we are always going to return enough residues to the soil to maintain soil quality; that we are only going to take this stuff from forest areas where the total area under forestation and the total carbon store is either stable or increasing, not decreasing.
“This will always be a complicated area. It will always be an area where you are worried that things are escaping from your control mechanism, that people are getting round it.
“So in that environment, build as much wind and solar as you can, and crucially, where there are alternatives, always favour those alternatives. So on road transport, pivot your policy to support electric batteries and hydrogen, because you're much more confident that those are sustainable. Whereas whenever you're using biofuels, there’s a danger that — however tight your regulation is — something nasty is occurring somewhere.”
He adds that this regulation could be voluntary or overseen on a national or, preferably, an international basis.
“If somebody is operating in a place where they're aren't tight national standards, we should encourage them to ally with trusted NGOs [non-governmental organisations] who can be trusted to impose tight standards, define the standards, agree with other people, publish their standards. That’s all good stuff, but it’s never going to be as good as regulated national standards.
“It would be lovely to have international standards, but it may be difficult to get that quickly or quick enough. So I think there has to be a major role for national standards, applying both to biomass produced in your country and biomass imported into your country.”
Four priorities for industry and government
The ETC report sets four key priorities for industry and government to implement to ensure that the world’s bioenergy is sustainable.
These are: 1) Defining and enforcing clear sustainability standards for biomass supply. This involves adopting comprehensive and specific biomass sourcing standards, banning conversion of preserved natural ecosystems to commercial biomass exploitation; creating mechanisms to allow transparency and traceability of biomass supply chains; and improved data analysis and monitoring to inform land use policies.
2) Pursuing opportunities to further increase sustainable supply: improving waste collection; innovations in seaweed-for-energy production; encouraging massive dietary change and technological developments to reduce land needed for animal meat and food production.
3) Creating the conditions for a prioritised use of bioresources: use of carbon pricing to allocate scare, sustainable supply, alongside policies to discourage suboptimal and encourage priority uses; developing explicit national and local strategies taking into account local land-use.
4) Supporting key technologies enabling efficient, sustainable supply and use of bioresources, including improving efficiency of existing land use and increasing waste collection while targeting funding towards emerging bioenergy and biomaterial technologies.