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How the Welsh Government Energy Service supported Hywel Dda University Health Board’s first solar farm.

First published:
19 July 2023
Last updated:


Hywel Dda University Health Board provides healthcare services to a total population of around 382,518 (2021) people throughout Carmarthenshire, Ceredigion and Pembrokeshire. It operates multiple buildings at its Hafan Derwen site in Carmarthen, including offices and clinical buildings which operate 24/7, with a high total annual electricity demand in the region of 550 MWh (2022-23. To reduce carbon emissions and lessen energy costs, the Health Board wanted to explore the opportunity to create build a solar farm on an adjacent piece of land that they owned. This case study clarifies the steps Hywel Dda followed to transform this original idea into a 450kW solar farm, complemented by a 120kW battery, to power its buildings.

Feasibility study

The first step to any decarbonisation project is to undertake a feasibility study analysing the opportunity, risks, and cost in order to prepare an internal business case. The Welsh Government Energy Service can support early-stage feasibility studies, and our typical approach to this is shown in the diagram below. The support provided to the Health Board for this project is highlighted in purple.

Steps of a robust feasibility study

  • Planning policy review: To understand local/national planning constraints
  • Constraints assessment: To identify constraints which could impact the scale and siting of the development account for the results of the constraints assessments
  • Development siting: To provide an initial high-level indication of potential siting and scale of development accounting for the results of the constraints assessment
  • Energy modelling: To assess the potential level of generated electricity an identified private off-taker could consume and the associated savings impact to the off-taker
  • Grid connection feasibility: Assess connection potential from network operators, as relevant (e.g.; budget estimates, connection surgeries...)
  • Financial assessment: High level financial modelling of possible development scenarios
  • Site visit: Undertake a site visit to confirm and further investigate findings from previous actions
  • Risk summary and next steps: Summarise project risks and next steps to investigate these further and progress the project

Identification of site-specific development opportunity

As part of the feasibility study, an early-stage design was developed by the Energy Service. This detailed the potential development opportunity and was very similar to the final project which comprises of:

  • 450kW ground-mounted solar farm: The identified land was estimated to provide potential for approximately 500 kW of solar PV, this was later refined to 450kW.
  • 120kW battery storage: The neighbouring health board buildings operate 24/7, so installing a battery would allow surplus electricity generated during the day to be stored and consumed at night, increasing the savings to the health board.
  • Direct private wire to neighbouring buildings with an export arrangement with the local Distribution Network Operator (DNO): The main objective of this development was to cover the electricity needs of the adjacent buildings with a direct private wire. However, setting up export arrangements allows the Health Board to sell surplus energy back to the grid when the battery is fully charged and the buildings are not consuming all the electricity generated. It is estimated that around half of the electricity generated will be used onsite.

Feasibility study sketch layout, Hywel Dda UHB

Feasibility study sketch layout, Hywel Dda UHB

Grant funding application

Once the business case was approved internally, Hywel Dda looked for available funding.

£1.186M was grant funded for the project via the Welsh Government Funding Programme for Targeted Improvements in the NHS Estate 2021/22.

“It was essential to have WG Energy Service’s Team on board at the early stages of project development to provide the expertise and advice to allow the Health Board to initially scope the project, secure funding and access appropriate frameworks to deliver the scheme. The team provided invaluable support throughout the scheme, ensuring that the key aims and objectives were met by the awarded contractor”

Paul Williams, Head of Property Performance at Hywel Dda UHB.


There are multiple possible approaches for procuring development and installation support for a solar farm.

  • The organisation could lead on the development of the planning application themselves with support from the Energy Service, commissioning all of the relevant studies required for the planning application and bringing the details together to form the planning submission. This would require the most capacity from the organisation and the development risk remains with the organisation, but the approach may result in lower third party costs.
  • The organisation could procure a planning consultant to develop and manage the planning application process. The consultant would bring together all of the required studies for the project’s planning application, reviewed by the organisation. This would be less involved for the organisation but come at a greater cost.

Following planning consent, the organisation would need to arrange for final design, installation and supply of the PV. The Energy Service can provide support with the preparation of the technical procurement documents and procurement process.

  • It is possible to procure a contractor to deliver the full project from the outset including planning, design and installation.

This setup is less complex and involved and could allow the development risk to be passed to the contracting party. Contract breakpoints would be required to ensure that the organisation could halt the project if the project risk increases beyond a point the organisation can tolerate.

  • Planning and Renewable Energy contractors can be sourced and procured via a national procurement portal such as Sell2Wales or via a dedicated Framework. Frameworks allow public sector organisations to procure goods and services from a list of pre-approved suppliers, with agreed terms and conditions and legal protections. Frameworks are often divided into ‘lots’ by product or service type, and sometimes by region. The Energy Service can support sign-posting to appropriate available frameworks.

For the Hafan Derwen solar farm, the Health Board appointed Asbri Planning to lead the planning application and procured Absolute Solar & Wind via the ESPO framework, to design, install and monitor the scheme. The Energy Service supported the procurement process, including the identification of appropriate frameworks and the development of technical specification documents.


The construction started onsite in February 2022 and the project was commissioned in March 2023. The construction period for a project of this scale would usually take less than 6 months. However, the project saw significant delays due to global supply chain issues and the show-stopping impacts of covid-outbreaks when constructing within a healthcare environment.

120kW battery storage

Enhancing activities

Ground-mounted solar farms can be used to enhance biodiversity. As a part of this development that covers just over an acre of land, fruit trees and over 350 wildflower bulbs have been planted. This will provide additional habitat for wildlife, including pollinators and other insects, which the Health Board hopes will lead to an increase in bird and bat species at the site. This area will also include seating areas and information boards explaining the benefits of each of the plants to the local environment, for staff members and patients to enjoy.

Finally, to take advantage of the site disruption and having contractors onsite, trenching for planned EV charge points was also undertaken to allow easy installation and integration with the solar farm, of future EV charge points in the nearby car park.

“We’re proud to have switched on our first solar farm, which will help power our Hafan Derwen site in Carmarthen and support our commitment to reducing carbon emissions. “This project also demonstrates the health board’s commitment to improving the natural environment and access to green spaces.

“The creation of a green space is a fantastic initiative providing staff, and patients with an outdoor space to enjoy and learn about the local environment. The planting of fruit trees and wildflower bulbs will not only enhance the area visually, but also provide a habitat for wildlife, contributing to the conservation of the local ecosystem.

“Overall, this project is an excellent example of how sustainable energy practices can benefit both the environment and local communities.”

Lee Davies, Executive Director of Strategic Development and Operational Planning at Hywel Dda UHB.

Hywel Dda solar farm

Find out more

Find out more about how the Welsh Government Energy Service can help your community enterprise or public sector organisation:


Twitter: @_energyservice

linkedin: welsh-government-energy-service

The Welsh Government Energy Service (“WGES”) is funded by the Welsh Government with the aim of developing energy efficiency and renewable energy projects that contribute to public sector decarbonisation and national energy targets. The WGES is delivered by the Carbon Trust, Energy Saving Trust and Local Partnerships (the “Delivery Partners”). This report (the “Report”) has been produced by the Delivery Partners and, whilst the views expressed in it are given in good faith based on information available at the date of this Report:-

(i) these views do not necessarily reflect the views of the Welsh Government, which accepts no liability for any statement or opinion expressed in the Report;

(ii) the Report is intended to provide general guidance only, rather than financial, legal or technical advice for the purposes of any particular project or other matter, and no-one in receipt of the Report should place any reliance on it in substitution for obtaining their own advice from an appropriate third party advisor; and

(iii) any person in receipt of this Report should therefore obtain their own financial, legal, technical and/or other relevant professional advice insofar as they require specific guidance on what action (if any) to take, or refrain from taking, in respect of any project, initiative, proposal, involvement with any partnership or other matter to which information contained in the Report may be relevant; and

(iv) the Delivery Partners accept no liability in respect of the Report, or for any statement in the Report and/or any error or omission relating to the Report.