Geraint Evans explores 'how can Life Cycle Assessment inform bioenergy choices?'

Geraint Evans Programme Manager

Over the last decade, our research into accelerating low carbon technologies has consistently shown that bioenergy is one of the largest and most versatile sources of renewable energy in the UK, with the potential to provide around 10 per cent of the country’s energy needs, including heat, power and fuels, by 2050

Our Energy System Modelling Environment (ESME) which seeks to plot the least cost pathways to UK climate targets, shows that the value of bioenergy increases when it is combined with carbon capture and storage technology where it can deliver net negative emissions into the wider energy system, providing a credit against the emissions from other sectors. Our analysis also suggests it would cost the UK up to an additional £200 bn to meet its 2050 carbon targets if we fail to increase the current level of bioenergy production.

However, as an industry that is still in its infancy, it is critical that we asses all bioenergy production chains and quantify the impacts of any such increase in bioenergy production. For this we use Life Cycle Assessment (LCA), an established technique that can be used to quantify the impacts of the life cycle of a product or service on resources or the environment. LCAs help us to understand exactly what emissions are associated with producing bioenergy, which is important if we are to truly establish genuine carbon savings. To do this, though, it is important that LCA’s are carefully designed and structured.

Several different methodologies can be used in LCAs and our Carbon Life Cycle Assessment Evidence Analysis project, led by North Energy Associates Ltd and working with Forest Research and the bioenergy consultants NNFCC, assessed the strengths and weaknesses associated with applying these methodologies to different supply chains. The project brought together and reviewed data and information from existing studies, to create a collection of the most reliable data that can be used in LCAs, and produce carbon balance calculations which are comparable across different bioenergy feedstocks.

We felt this research was important to understand the impact of bioenergy production chains on the whole energy system. LCAs help us to quantify emissions both with current bioenergy practices (typically using an attributional LCA) or with a change in the level of bioenergy production (often using a consequential LCA approach). Where these systems are well understood, they can provide useful insights about the dominant sources of emissions within a supply chain which can then be targeted for reduction, for example, through efficiency improvements or technological change. For LCAs which compare a bioenergy system to several different scenarios, or counterfactuals, it can highlight the circumstances under which an increase in bioenergy production could deliver genuine emissions reductions.

We did find that there remains uncertainty, perhaps because of empirical knowledge gaps or lack of understanding of the bioenergy system. This can lead to wide variations in the results of an LCA. This, then, is a prompt for developing further evidence. Progress has been made in filling these knowledge gaps but priority areas for further research include mapping the impact of producing bioenergy feedstocks on wider farming or forest systems in geographical areas where this is not well understood. There are also empirical data gaps, particularly relating to the emissions resulting from biomass storage, where further research could improve best practice guidelines.

We have contracted the Energy Systems Catapult to produce a short perspective report on the project, its methodologies and some of its conclusions – How can Life Cycle Assessment inform bioenergy choices