The UK government’s advisory Committee on Climate Change (CCC) has had another look at biomass, following on from its earlier study, and thinks it could play a vital role in UK emission reduction, as can biomass energy with carbon capture and storage (BECCS) in many scenarios. In the new report the CCC says that “using biomass with CCS to store carbon and produce a useful energy service is likely to deliver more abatement than most other potential end-uses. Based on our current expectations of BECCS costs and technical performance, we conclude that biomass available for use in the energy system (i.e. after wood in construction opportunities have been satisfied) should be used with BECCS applications to the maximum extent possible”. So, it’s BECCS all the way, offering carbon negativity, a view partly shared by the IPCC in its recent climate review.
However, the CCC notes that “the use of BECCS is currently not incentivised by policy mechanisms intended to drive emissions reductions (e.g. Contracts for Difference and the EU Emissions Trading System)” and says “we would not expect BECCS to be deployed at scale immediately”. Nevertheless, it suggests that “the availability of incentives would encourage those making decisions now to factor it in (e.g. locating a biomass facility near to where CO2 infrastructure may be developed). The government should examine how BECCS can be incentivised with changes to existing policy mechanisms and/or new mechanisms.”
No need for BECCS?
Given that there are issues with BECCS (and CCS generally), this “full ahead” proposal is a little surprising. CCS is still unproven on any significant scale, with there being uncertainty about the cost, capture rates and the viability of long term CO2 storage. However, the CCC says “our central estimate of future BECCS capture rates is 90% (meaning that 90% of the carbon in the biomass feedstock is captured and stored)”. But it also says that “BECCS can still deliver greater emissions savings than non-BECCS energy uses even at much lower rates of CO2 capture. Consequently, BECCS applications may make sense even with CO2 capture rates as low as 40%, below which the other bioenergy applications (e.g. aviation biofuel production) start to be preferred”. That, it says, “broadly supports our off-model analysis that shows (under our central assumptions) BECCS providing around twice as much GHG [greenhouse gas] abatement as the next best uses without CCS (e.g. production of aviation biofuel)”.
Which wood?
Where is all this biomass going to come from? CCC says that “by 2050 up to 1.7 million oven-dried tonnes of high-quality sawn wood suitable for construction and up to 27 million oven-dried tonnes of sustainably-produced biomass from forestry and agricultural residues and energy crops could be produced in the UK. Combined with imports enabled by strong sustainability governance, this would support an expansion of the use of wood in construction and mean that bioenergy could meet between 5% and 15% of the UK’s energy demand in 2050 (compared to around 7% today).”
It suggests that UK-sourced biomass could supply 5–10% of energy by 2050, the lower end of that range being just from organic wastes (after removal of anything that can be recycled or reused), the upper end needing over 1 million hectares of land for energy crops — around 7% of current farm land. And also more tree planting and more timber for use in construction, which is a form of carbon sequestration. Alternatively, or maybe additionally, tripling biomass imports could push the energy supplied up to 15%.
Given that there are issues with BECCS (and CCS generally), this “full ahead” proposal is a little surprising.
Dave Elliott
However, the CCC is clearly worried about some of the implications of imports. It wants better sustainability regulations and says “imports should only have a role if future efforts to develop this sustainability framework are successful (improved monitoring and transparency, closing gaps) and the UK can have confidence that all imports are both low-carbon and sustainable. This does not imply that the current imports are by definition unsustainable – instead, it recognises some ongoing uncertainty, public controversy and scope for improvement in the rules, particularly if scaling up imports”.
It is certainly true that the use of forest wood is controversial, unlike the use of farm and food wastes, converted to biogas via anaerobic digestion (AD), with multiple possible uses. Nevertheless, whatever the source and use, CCC evidently sees BECCS as best. Indeed, it says that “in many scenarios where the use of BECCS is excluded, as much if not more bioenergy feedstock is required to achieve the emissions reductions necessary to meet the same climate outcome. This is because biomass cannot be used as efficiently (in terms of emissions mitigation) as when BECCS is available”. But it does also say that “if substantial improvements in energy efficiency, shifts in diet, rapid electrification and low population growth” are possible, then “the use of large amounts of bioenergy without CCS may also be avoidable”.
Future worries
Some of that seems to be a sop to some on the “deeper green” end of the spectrum e.g. the CCC says that diet changes would help free up land (e.g. from meat growing), making it all easier. True enough. However, it’s not just deep greens who worry about biomass use and look to alternatives. As I noted in an earlier post, a study by Vivid Economics/ Imperial College London, for the US NRDC, claimed that deep decarbonisation of the UK power system was possible with renewables like wind and solar by 2030, without reliance on “expensive and controversial” biomass or CCS. Or indeed nuclear.
The CCC’s scenarios include all of those to varying degrees. Given the problems facing the use of forest-derived wood (recently critically reviewed again), it is easy to see why BECCS, using other types of biomass and wastes, might be talked up. Similarly, given the problems facing nuclear (for example with the recent demise of Toshiba’s Nugen project), it’s easy to see why fossil CCS might be talked up. But that too is looking pretty shaky. There is very little CCS included in the most recent BEIS scenario — just 1 GW by 2035. Instead most of the residual focus in this field is on Carbon Capture and Utilisation (CCU), since that avoids the problem of underground storage and offers potentially valuable synfuel products.
However, as POST, the Parliamentary Office of Science and Technology, has noted in a new briefing, CCU only has a “relatively small” direct CO2 mitigation potential, since the synfuels made would be burnt, releasing CO2 again. POST, perhaps a little optimistically, nevertheless adds “CCU could develop an early-stage market for wider CO2 capture technologies. This would help to develop capture carbon and storage (CCS), which is widely accepted to be a likely and substantial component of future mitigation efforts at the global level.” The government maybe has this in mind in its shift from using the label “CCS” to the use of “Carbon Capture, Utilisation and Storage” (CCUS), with some funding promised. CCU certainly make sense for some industrial applications.
For the moment, however, while CCU may potentially be a viable commercial option, full CCS may never be viable on a large scale. And by implication, that means the prospects of BECCS offering large-scale carbon negativity is in fact illusory, or at least uncertain. But POST, and it seems CCC, still seem wedded to CCS. So, evidently, is the government, with a fossil gas CCS project planned for Scotland “in the mid 2020s”. More immediately, there is a small prototype BECCS project underway at Drax, although with no carbon storage as yet. Time was when some saw BECCS as riding on the coat tails of CCS. Now if anything it might be the other way around, though it’s all rather uncertain: there may be better options.
BECCS may nevertheless have a place, along with other renewable energy options, including directly used biomass, as well as carbon sequestration via improved land/soil management. However, quite apart from the land-use issues, can we really look to large-scale storage of CO2 as a central way ahead for biomass? And do we really want to give fossil fuels a new lease of life with CCS? Why not just push renewables and efficiency harder? Starting by unblocking onshore wind.
