Meeting future energy demand through greater use of Combined Heat and Power is the only way

In the "roadmap for heat" report, energy scientists from Imperial College London and the University of Surrey highlighted challenges in the current all-electric approach to decarbonisation of the UK energy system and outlined what they claimed to be a more efficient approach of utilising waste heat from power generation.

In order to achieve a decarbonised energy system in line with the UK's legally binding targets for an 80% reduction in greenhouse gas emissions by 2050, the government has undertaken to produce route maps. In the report, Dr Rob Gross and Professor Matt Leach claim a key implication of this has been the provision of energy through the electricity network, which has become known as the "all-electric future".

According to the scientists, an all electric system by 2050 would mean a 29% increase in electricity production and an increase in renewable energy such as wind power and hydropower by around six times over on today's levels.

The report notes that to deliver this transformation of the energy system, there would be a number of challenges to overcome, including the need for rapid and sustained progress across all low carbon electricity supply options within a tightly constrained timeframe and problems with intermittent and inflexible generation.

Other issues highlighted with delivering an all electric future are the need for investment in additional electricity transmission capacity and in the distribution grid, as well as the installation of smart metering to allow for the management of electricity demand data.

Integrated approach

In order to combat these challenges, the report's authors claim that a more heat-focused approach to energy supply which makes greater use of CHP and district heating, and to a lesser extent biomass, would help mitigate many of the more demanding aspects of the all electric scenario.

The approach proposed in the report assumes that large scale CHP facilities have been built in 21 locations with Carbon Capture and Storage (CCS) fitted and that District Heat Networks (DHNs) have been constructed, delivering heat from additional CHP plants to population centres and representing 14% of heat demand in the domestic sector.

While the report notes that this scenario would create its own challenges - including the disruption to streets and domestic properties of building and connecting DHNs to people's homes - the authors claim it offers the following benefits (as compared to an ‘all-electric' scenario):

• Energy losses from power generation reduced by 8 MTOE (million tonnes of oil equivalent), equivalent to almost half the final energy demand from households in 2050;
• A more flexible energy system overall, with reduced peaks in electricity demand and greater capacity to store surplus electricity in the form of heat;
• A 13% reduction in electricity demand as compared to the benchmark ‘all-electric' approach;
• A reduction in the new investment required in electricity networks;
• A 33%reduction in the demand for coal fired generation by displacing the need to build four to seven coal fired power stations;
• A reduction in overall energy losses from power generation of 30%;
• Greater diversity in heat supply - including waste heat and bioenergy sources.

Speaking at the launch of the report, Graham Meeks, director of the CHPA, said: "Diversity is the key to maintaining affordability and security of our energy supplies as we transition to a low-carbon economy.

"The report highlights the enormous risks we face in focusing on electricity to meet our demands for energy services. But it also demonstrates that more robust, dynamic and efficient pathways are open to us, recovering the waste heat from power generation, to create a more integrated and resilient energy system."

Imperial scientist and one of the authors of the report, Dr Rob Gross, explained: "No route to 80% carbon reduction is without challenges. But it seems clear that improvements can be made to the ‘all- electric' approach we are currently pursuing.

"The integrated scenario we have identified offers a potentially extremely valuable contribution to efforts to green our energy system."

Welcomed

Welcoming the report, head of climate change at environmental group WWF, Keith Allott, said: "A revolution in energy efficiency and the creation of smarter grids powered by renewable energy sources could put us on the pathway to a zero-carbon economy. But we need to think carefully about what that would mean for meeting the country's needs for heat.

"A strong focus on energy efficiency is the low-risk, low-cost solution, and combined heat and power and district heating networks have a central role to play in delivering this. If the UK intends to meet its carbon targets, there simply isn't room for ruling out these options."

Janine Freeman, head of Public Affairs at National Grid added that as operator of both the UK gas and electricity transmission systems, the National Grid shares the view that the UK should explore the alternatives for providing low carbon heat.