Sustainability and Whole Systems

Theme Leader: Prof Peter Taylor
Interdisciplinary Studies Leader: Prof William Gale

It is likely that most PhD projects will focus on some aspects of this theme even where most of the work is covered by other themes. Areas that broadly overlap other themes include the Life Cycle Analysis, supply chain optimisation, effects of bioenergy inclusion in power networks, land-use issues, economics and policy.

Whole Systems relates to cities, including district heating. Bioenergy could potentially play a significant role in providing power and heat for communities both large and small. The efficiency and effectiveness of bioenergy for existing energy users will depend on factors including the fuel supply, cost, storage and quality, the technology delivering the energy service, the skills and capacity of the technology supply chain, and the skills and capacity of the energy user. These factors are likely to show spatial variation. Bioenergy (particularly biomass) systems are often framed as community energy schemes, notably in rural areas where forestry plays a role in land management. Urban areas will provide different opportunities for bioenergy because of higher dwelling density and one of the challenges of decarbonising the UK power system is how best to integrate large quantities of variable renewable energy sources while maintaining system security. Bioenergy could be an attractive solution to providing the necessary system flexibility as it is a renewable energy source with the properties of fossil fuel. However, there are many areas of the energy system where the fossil-fuel like characteristics of bioenergetics are attractive, notably transport. Yet sustainable sources of biomass are limited and so there needs to be a focus on using it in the most effective way. Land use issues are also explored in this area and the Food vs Fuel debate is vitally important to consideration of bioenergy systems.

Life Cycle Analysis, Energy Flows and Supply Chain Issues explore the effect of using bioenergy, e.g. whether there are negative impacts that outweigh the advantages and the benefit compared with the existing situation. Underpinning much of process engineering is the issue of energy balance or energy flows. Many processes within the Feedstocks, Processing and Safety and Conversion themes look at conversion of material (biomass) to other states e.g. gases, volatile liquids as a practical consideration as a way of improving efficiency. However, a consideration of the energy cost of the process is paramount and should be the first item considered in a full Life Cycle Analysis. How does the energy input compared to the output differ when a change is made to a process and how do different processes compare?

Socio and Techno-Economics looks at the growing of bioenergy crops, e.g. miscanthus or short rotation coppice, involves multiple agricultural processes, including tillage, mewing, application of agro-chemicals etc. There are pollution and waste issues related to these practices. Solutions are usually technological, which undermines the potential of utilizing ecosystem processes to help or replace some of these needs. Carbon Capture and Storage is another area with complex interactions requiring understanding of techno-economic systems.

Policy explores how bioenergy can play an important role in helping the world meet its future energy requirements in a sustainable, secure and affordable way. However, many of the fuels and technologies associated with bioenergy supply and use are not yet commercially available. This is true for many renewables, but in most cases there are clear emerging routes to exploitation of a limited number of candidate technologies. The situation for bioenergy is very different with a diverse range of exploitation routes. An effective innovation system is therefore needed at all stages from the push of basic research funding to the pull of deployment support to ensure that bioenergy realises its long-term potential.