Integrated Infrastructure for Sustainable Thermal Energy Provision (IN-STEP)

Since the turn of the century there has been a reduction in UK energy independence. While this trend has recently started to reverse, there is still a pressing need to further increase energy independence, as well as continue reduction in total consumption, and work towards becoming a carbon free energy nation. The Climate Change Act 2008 mandates the UK government to reduce carbon dioxide emissions by at least 80% (based on 1990 levels) by 2050. In total, domestic, commercial and industrial heat provision in the UK accounts for around one third of all greenhouse gas emissions and 40% of energy consumption. Hence tackling heating (and cooling) for all buildings is essential for addressing the energy problem.

One energy efficiency solution which must play a future role in both demand reduction and decarbonisation is ground thermal energy storage. Such systems typically comprise some form of ground heat exchanger connected to a heat pump and a low temperature building heating delivery system (and/or higher temperature cooling delivery system). Traditional schemes use special purpose drilled boreholes as the ground heat exchanger, but since the 1980's building foundations developed as ground heat exchanger have also been used. Foundation ground heat exchangers are now becoming more common place, but there remains significant opportunities to use other underground structures for heat transfer and storage, thus contributing to the delivery of sustainable heating and cooling for overlying buildings. Retaining walls, tunnels and water/waste water pipes can all potentially be used as so called energy geostructures, where they exchange and store heat as well as performing their original structural function.

However, despite a number of trials, most of these energy geostructures are a long way from routine adoption. Rigorous assessment of both their energy potential and how they are constructed is lacking. There are no routine design guides or standards and where schemes have been, or are being developed, they usually involve expensive and complicated analyses typically conducted in collaboration with a university partner. There are challenges in terms of energy assessment and further barriers to adoption in the requirement for adjacent consumers of the supplied energy. There is also a need for a heat/cool distribution network to reach the consumers which may not be currently in place. This proposal will tackle the challenges relating to routine implementation of energy geostructures, including design, construction and heat/cool delivery. This will encourage future adoption and help the development of the UK ground energy market.

The research proposed covers a number of different aspects of the construction industry, as well as energy distribution. Therefore there are a number of different groups who will benefit from the research outputs. Beneficiaries include:

Infrastructure Clients have the opportunity to improve their own energy efficiency where the heating and/or cooling sourced from their buried infrastructure can be used for their own adjacent assets. Alternatively they can sell the resulting thermal energy, either directly or indirectly. An example of the latter is Crossrail who use the energy potential as a selling point for associated over station developments (OSDs).

Civil & Mechanical Engineering Contractors and Designers who build and maintain buried infrastructure will be able to offer new services around characterisation and design of thermal energy storage. They will be able to apply the design methods, tools and protocols provided; advise clients and work effectively down the supply change with specialist suppliers.

Specialist Geothermal Suppliers can strengthen their skills and broaden their business offerings. Their core business will become a lower risk solution with new guidance and hence this will also assist with market expansion for this type of supplier, often SMEs.

District Heating Providers (including local authorities) will have access to new sources of heat or cool. Currently the district heating market in the UK is underdeveloped. However, heating networks linked to low carbon sources is a key step in the move to decarbonising heating. Hence the results of this research can offer a boost to district heating development.

Government, government agencies, regional metropolitan authorities are all committed to renewable energy and carbon emission reduction targets. The research outputs will contribute to reducing the risk of implementing an important source of low carbon renewable heat.

The general public and society at large will all benefit from decarbonisation of heat as emissions are reduced and climate change impacts are therefore minimised. In the long term they will also benefit from affordable heat as mainstreaming of currently novel technologies will reduce costs.

Academic Beneficiaries. They will all benefit from the availability of datasets, models and analysis methods that can be applied in their own work, plus insights that will move forward the field of endeavour.