Greater reliance on electricity a risk to low-carbon strategy

London – Using more electricity to heat buildings and power cars increases our dependence on the electricity system and risks undermining the Government’s ability to meet stringent 80% cuts in CO2 emissions by 2050, warns a new report by leading energy scientists at Imperial College London and the University of Surrey.

Calling for a more integrated approach to energy supply, the study proposes that ’waste’ heat from power generation could meet a significant share of our demand for energy, providing a more efficient, flexible and resilient energy system. Starting to develop this system today, it argues, could reduce the anticipated stresses on the electricity system.

To this end, heat storage can be used to help manage the intermittent output of some renewables and reduce growth in peak demand that has potential to place real strain on the electricity system in 2050, said the report, which was commissioned by the Combined Heat and Power Association (CHPA).

Most scenarios for a 2050 energy system - including those used to develop the UK Government’s Low Carbon Transition Plan - anticipate that electricity will increasingly be used to meet energy needs for transport and heating. The report outlines that such a transition could result in a doubling of peak electricity demand. Realising this ’all-electric’ scenario is in turn dependent on a number of critical outcomes, all which must be met to achieve carbon abatement targets.

These include:

- Investment in new, low-carbon power stations at unprecedented growth rates

- Expansion of electricity network capacity to meet higher system peak demand

- Insulation to a very high standard of much of the UK building stock, and significant change in consumer behaviour

The report finds that any route to a low carbon future brings major challenges. A system that makes greater use of combined heat and power (CHP) and district heating (DH) can however mitigate many of the more demanding aspects of the ’all-electric’ approach. Used in combination with biomass and carbon capture and storage (CCS) technology for fossil fuels, CHP and DH infrastructure have a key role to play up to 2050 and beyond.

The integrated approach proposed in the report, assumes an energy system where CHP and DH, used in combination with a decarbonised electricity grid, delivering the following benefits (as compared to a leading ’all-electric’ scenario):

- Energy losses from power generation reduced by 8 MTOE, equivalent to almost half the final energy demand from households in 20506

- A more flexible energy system overall, with reduced peaks in electricity demand and greater capacity to store surplus electricity in the form of heat

- Reduced electricity demand - a 13% reduction as compared to the benchmark ’all-electric’ approach

- A reduction in the new investment required in electricity networks

- A reduction in the demand for coal fired generation by 33% (saving 13 MTOE), displacing the need to build 4 to 7 coal fired power stations, each equivalent in size to the some of the largest plant of this type currently operating in the UK today

- Lower primary energy consumption - a 5% cut, reducing dependence on imported fossil fuels

- A reduction in overall energy losses from power generation of 30%

- Greater diversity in heat supply - including waste heat and bioenergy sources

This integrated scenario, therefore, offers energy savings and other benefits, helping improve prospects for meeting our targets. Findings however illustrate the need for government to adopt a broader focus in policy formulation around decarbonisation. These, and other highlights of the report, promise to spark debate on the direction and focus of current policy. The Government is expected to publish its own work on a roadmap to 2050 in the coming weeks.

Speaking at the launch of the report, Graham Meeks, director of the CHPA commented: “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, said: “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.”

Janine Freeman, head of Public Affairs at National Grid said: “As operator of both the UK gas and electricity transmission systems, we share the view that we should explore the alternatives for providing low carbon heat. Electrification of heating will not provide the whole answer because it will not be efficient to build power stations and electricity networks to supply electric heat for the one or two months a year when it is really cold. Our own work on the use of biomethane for injection into the gas grid indicates this could make a significant contribution to domestic heating. And as this report sets out, other technologies such as CHP and solar thermal will also have important roles to play in a decarbonised energy future.”