Bioenergy is expected to play a crucial long-term role in reducing the UK’s greenhouse gas (GHG) emissions. As well as helping to mitigate climate change, bioenergy provides a cost-effective and more controllable energy supply relative to other renewables technologies and has the potential to reduce the UK’s reliance on imported fossil fuels.
However, GHG savings from bioenergy vary widely because they are offset by the fossil energy used for cultivation, harvesting, processing and transportation of biomass feedstocks. In addition, major direct and indirect land use change, particularly deforestation and draining of peat bogs, can completely negate any emissions savings, as well as cause damage to biodiversity and other ecosystem resources.
Moreover, the level of bioenergy accessible to the UK may be scarce, particularly with regards to imports. There is limited land available to produce biomass feedstocks, either domestically and internationally, and strong competition for land in the form of food production. There are also competing uses for biomass, not only for reducing emissions but as an alternative source of material for construction, plastics and industrial chemicals. Soubts have been expressed that the UK could source the required quantities of bioenergy sustainably, particularly if international energy demand increases beyond current projections.
In addition, there are near-term pressures on the use of bioenergy to help meet the Renewable Energy Directive, which requires the UK to meet 15 per cent of its final energy consumption and 10 per cent of the energy used in transport from renewables by 2020.
Taking these concerns into account, the Committee on Climate Change recently undertook a review of bioenergy to assess how it might best be used to support the UK in building a low-carbon economy. It concluded that a 10 per cent share of bioenergy in total primary energy would be required to meet the UK’s 2050 emissions target, compared with the current share of 2 per cent.
Working jointly with the Department of Energy and Climate Change (Decc), the Committee on Climate Change engaged specialist consultancy Redpoint Energy to lead the development of a single standardised optimisation model. This helped to harmonise the range of disparate information on bioenergy and competing fossil and low carbon alternatives in a common framework.
Although numerous studies have been conducted, they have tended either to focus on bioenergy use within an individual sector, or look at the energy system as a whole without sufficient detail of bioenergy to understand all of the possible trade-offs. Conversely, the Committee on Climate Change’s approach has been to identify the most appropriate use of each bioenergy technology across the energy mix while considering how to meet both the greenhouse gas and renewables targets, as well as including the impact of bioenergy life cycle emissions and competing non-energy uses. It was then able to construct a hierarchy of appropriate uses of bioenergy and, in particular, consider how this was affected by uncertainty around different levels of sustainable bioenergy resource, particularly imports and the impact of the availability
of key technologies such as carbon capture and storage (CCS).
The key conclusions are that bioenergy for industrial heat and non-energy uses in construction are highly desirable, whereas liquid biofuels for surface transport and power generation – without CCS – are generally undesirable. This is because liquid biofuels offer a less cost-effective way to reduce emissions across the system as a whole, when considering both bioenergy and other low-carbon alternatives.
There were also a number of uses whose desirability depends on the availability of CCS technology. In conjunction with CCS, the use of bioenergy would effectively help to generate additional GHG emissions reductions, by capturing carbon from the atmosphere during growth of the feedstock and also preventing its re-release during combustion or conversion. Bioenergy with CCS could then be applied at various points throughout the energy system, including in the production of power, heat and hydrogen or liquid biofuels. The Committee on Climate Change’s Bioenergy Review reiterated the urgency of demonstrating CCS at commercial scale.
The modelling work has allowed the committee to distil clear and robust conclusions from a complex system that are valuable both in terms of short-term policy thinking, particularly around the European Union’s targets and how best to meet these, as well as long-term planning to 2050.
In particular, it highlights that the nearer-term renewables targets are potentially diverting bioenergy resources away from more appropriate longer-term uses via a combination of locking in infrastructure that becomes less appropriate in the long term and not using the scarce bioenergy resource as cost-effectively as possible in the medium term. This raises questions over the viability of potentially more transitional roles for bioenergy, such as surface transport or new dedicated power generation, if CCS does not prove feasible or if the infrastructure cannot be cost-effectively adapted to produce aviation or maritime fuels.
Consideration must be given to how the near and mid-term UK policy framework incentivises real-world deployment of bioenergy relative to the idealised view from the optimisation modelling. For example, at a micro-level the Committee on Climate Change review highlighted that Decc’s current Renewables Obligation banding consultation is proposing higher incentives for dedicated new biomass power generation – without CCS – than for enhanced co-firing/conversion of the existing stock, which from the committee’s analysis is likely to be a more cost-effective way of contributing to renewables targets.
At a macro level, wider consideration will need to be given to the impact on bioenergy use from separate incentive schemes targeted at different parts of the UK energy system, such as the new Renewable Heat Incentive or existing Renewable Transport Fuel Obligation. This will also need to include the significant impact of the proposed mechanisms under the government’s Electricity Market Reforms, such as carbon price support, or contracts for difference for low-carbon technologies.
Finally, adding yet another layer of complexity is the consideration that will now also need to be given to how to prioritise bioenergy for desirable non-energy uses against competing energy-based alternatives, as well as how bioenergy – not just for power generation – should be treated by the overarching UK/EU policy framework when used in combination with CCS.
Understanding the multiple roles of bioenergy demonstrates how it is becoming increasingly difficult to study the energy system and associated policy implications only at a sectoral level. While it inevitably complicates any analysis, considering the impacts more holistically is ultimately necessary to help ensure the UK’s targets are met as efficiently as possible.
James Greenleaf is a managing consultant at Redpoint Energy
This article first appeared in Utility Week’s print edition of 30 March 2012.
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