Future supplies of bioenergy feedstock ‘highly uncertain’

The long-term availability of bioenergy supplies in the UK is “highly uncertain” and requires fresh analysis to establish whether feedstocks can continue being imported out to 2050.

National Grid Electricity System Operator (ESO) gave the warning in a new report examining several of the key uncertainties identified in its Future Energy Scenarios for 2019.

The ESO said bioenergy offers multiple benefits, including high energy density, the potential to generate negative emissions and suitability for industrial processes that would otherwise be difficult to electrify. However, it cautioned: “This critical resource is nuanced and has interactions right across society.”

The production of crops for bioenergy can create competition for land and water that might otherwise be used for food production or reforestation. It is a finite resource and the more used in one sector or country means kess available for another.

The value of bioenergy as a source of negative emissions also depends on how much they are needed: “Deeper understanding of the potential scale, opportunities and impacts of deploying bioenergy across the whole system is required”, the report warned.

One of the main issues highlighted by the ESO is that although imported feedstock is critical to some pathways for reaching net emissions by 2050, the “underlying assumptions for this are not well understood or tested.”

“Primary research on feedstock availability is limited and quickly becoming outdated and a lack of policy incentives add to this uncertainty,” the report explained.

Domestic production could be raised, although care would need to be taken to ensure this increase is sustainable across all sectors of the economy. Waste will continue to be available as a feedstock – but at what scale is unclear.

The ESO said there no consensus on what the best use for bioenergy would be: “More fundamentally, there is currently no shared view on how to assess the ‘best’ use of biomass across competing options.

“Some stakeholders have stated a position in this area and factors to consider could include where no decarbonisation alternatives exist, where the greatest amount of carbon can be displaced or captured, and what the counterfactual of any other uses of the biomass might be.

“This has implications for the coherence of future policy or market measures for biomass use.”

The ESO said “primary, up to date research” is needed to “explore the drivers of feedstock availability over time, with a particular focus on how imports of international biomass feedstocks might change to 2050.” This analysis should explore both “physical and policy factors”.

It said the government and industry must work together to establish a “best use hierarchy” for bioenergy: “This would then inform future planning, policy decisions, market design, and innovation, with review points over time.”

The body additionally called for a common definition of “net zero across the whole system” to ensure decisions are made on “consistent foundations”, and clear carbon accounting standards that cover the supply chain and beyond: “For bioenergy imports, consideration needs to be given not only to whether a country implements a regulation, but also how well this is enforced and audited, ideally by a third party.”

The report also examined the topic of peak electricity demand for heating, highlighting another gap in knowledge over the performance of air-source heat pumps in British homes.

As they generate heat at a lower rate than gas boilers, heat pumps are better suited to well-insulated homes that can store up energy over time.

However, consumers are unable to assess whether their home is suitable for a heat pump as “their performance across the diverse range of UK housing stock, thermal efficiency ratings and climates is not well understood”.

Consumers need to be able to understand if significant investments in energy efficiency would be worthwhile, allowing them to heat their homes with just a heat pump, or whether they would be better off going for a hydrogen boiler or hybrid heating system.

The report said this evidence is also needed to ensure there is sufficient generation and network capacity to meet peak demand. It noted that the ability of households to shift to demand to off-peak times will be dependent on the amount of storage available, both within the homes themselves and devices such as hot water tanks and thermal batteries.

It also cautioned that consumers preferences around heat are “relatively untested” and “important in confirming the parameters of the decarbonised heating challenge”.

The ESO said its Future Energy Scenarios for 2020 will be partly based around the “level of societal change”, enabling them to explore “the potential trade-off between consumer and system changes required for different future heating approaches”.

Frank Gordon, head of policy at the Association for Renewable Energy and Clean Technology (REA), said they “broadly agree” with the report’s recommendations but added it could “go further in highlighting that the UK already has a well-established bioenergy feedstock supply chain that can be substantially increased in line with the Committee on Climate Change’s recommendations on land use.”

He continued: “If we are going to capitalise on the carbon reduction benefits bioenergy has to offer, we need to focus on feedstock availability in the context of market dynamics, where demand for bioenergy drives sustainable production, rather than always assuming its limited availability. This will in turn grow the UK bioeconomy, create green jobs and support critical sectors such as farmers, foresters and landowners.”