Public sector decarbonisation: the role of energy storage
This piece was originally published in Energy Manager Magazine, June 2025
Author: Becca Weight, Salix Energy and Carbon Programme Manager
The UK has committed to reach net zero by 2050, while the public sector has set an important interim milestone of reducing emissions by 75% by 2037 compared to a 2017 baseline. These ambitious targets are driving action across the public estate to improve the energy efficiency of public buildings.
The primary way to achieve this is often to improve the building fabric and implement controls and behavioural strategies to reduce the energy demand of buildings and to install a low carbon heating system, typically a heat pump. Whilst these interventions will result in reduced direct carbon emissions, depending on the design and operation of the system the building users can be confronted with uncertainty around optimisation and the possibility of higher annual energy bills. To protect the public purse and ensure the revenue available goes towards delivering vital public services, as opposed to soaring electricity bills, energy storage can be explored as a buffer to these high costs through shifting energy demand away from peaks.
The Heat and Building Strategy (2021) highlighted the need for energy storage to produce a flexible energy system, one that is cost-effective, efficient and secure. The expected role of energy storage is there; through thermal stores (storing hot water in tanks or in district heating systems) and/or battery storage (storing energy as electricity), though the potential feels yet to be fully realised in the UK. The Climate Change Committee’s Seventh Carbon Budget suggests the need to deploy 35 GW of short-duration batteries by 2050, more than a ten-fold increase on 2023 levels, demonstrating we still have a way to go in terms of achieving the flexible energy system we need to decarbonise at scale and pace.
Energy storage will be an important tool in operationalising the decarbonisation of heat across the public sector. Thermal stores have multiple economic, technical and environmental benefits for heat pump systems and district heating as identified in CIBSE AM17 (2022) and CIBSE CP1 (2020); they can provide system stability, resilience and crucially for the public sector, peak-lopping. Peak-lopping means that large storage volumes can be used to meet the demand at peak times, allowing the potential for both reducing the size of electrical grid connection and reducing peak demand charges to optimise energy spending. With public sector organisations often experiencing delays and unexpectedly high costs when requesting an upgrade through their Distribution Network Operator (DNO) as part of a decarbonisation project, the benefits of thermal stores should definitely be considered.
Furthermore, it is expected that the Heat Network Technical Assurance Scheme (HNTAS) will build on the standards set out in CP1. Heat networks currently provide 2-3% of the UK’s heat demand but are expected to provide 20% by 2050 to reach net zero. With the expected future implementation of low carbon heating plant in energy centres, thermal stores will provide future flexibility for heat networks therefore improving the consumer experience. Based on this direction of travel those designing new, or extending existing, heat networks would do well to consider the role of thermal stores as early on as possible to avoid unexpected costs or delays in achieving HNTAS certification.
Battery storage will play a similar role in enabling the public sector to decarbonise their building stock. When combined with renewable energy installed onsite, for example rooftop solar, the energy created can either be used or stored for later use. The ability to use energy generated onsite reduces reliance on the grid, saving the building user valuable money. Depending on demand, batteries can also be used to store electricity imported from the grid at cheaper times of the day which can either be used during peak periods or sold back to the grid.
As with any energy project, an objects appraisal should be conducted to explore the benefits and limitations of energy storage, which will be bespoke to each building. Design, spatial and planning requirements must be considered early on in the design process to give confidence in the feasibility of installation.
At Salix we deliver the Public Sector Decarbonisation Scheme on behalf of the Department for Energy Security and Net Zero. Public sector organisations are eligible to apply for grant funding for heat decarbonisation and energy efficiency projects, with new schemes historically running annually. Applicants are encouraged to take a whole building approach to decarbonisation to ensure that low carbon heating systems are designed appropriately, that the thermal comfort of building occupants is maintained and that projects present good value for public money. To achieve this approach applicants are eligible to apply for thermal stores and battery storage in conjunction with the installation of a low carbon heating measure in each building proposed. Whilst there are some restrictions around utilising grant funding for commercial gain (e.g., applicants are typically not permitted to export electricity to the grid), the inclusion of these measures in the eligible technologies list demonstrates technical justification and political drive for the implementation of these technologies as part of a bundle of decarbonisation measures.
If we are to reach net zero, with critical action required at a time of financial cuts across the public sector, it is crucial for public sector organisations to leverage their experience, passion and funding towards low carbon solutions that provide value over the long term. Energy storage will be an important tool in achieving this, based on the financial savings available, and its role is only expected to grow as we continue our net zero pathway.
