Welsh Government submits battery storage plans for Merthyr Tydfil offices

Proposal targets on-site storage to make Rhydycar offices more energy resilient

The Welsh Government has applied to Merthyr Tydfil County Borough Council to install battery energy storage systems (BESS) at its office complex in Rhydycar Business Park, a move intended to store locally generated electricity, cut peak demand and reduce reliance on grid-supplied power.

The planning submission covers the installation of three BESS units within the existing plant compound to the south of the site's energy centre. Each unit would deliver a power output of 125 kW and a storage capacity of 261 kWh, and be housed in compact enclosures measuring 1,050mm wide, 2,250mm high and 1,400mm deep.

Associated works set out in the application include replacing the current plant compound barrier with a new 1.8-metre high green V-mesh fence, matching the site's existing security fencing, and mounting an inverter on the south-facing wall of the energy centre. The inverter assembly is detailed as measuring 647mm by 629mm by 252mm and will be contained within a steel enclosure.

• Number of battery units: 3
• Output per unit: 125 kW
• Storage per unit: 261 kWh
• Fence height: 1.8 m (green V-mesh)

The application explains that the new equipment will use existing infrastructure where possible. Three new 100mm cables are proposed to run through the existing ducting between the energy centre and the UPS room within the main office building, reducing the need for further intrusive works across the site.

“The proposed development will improve the operational efficiency of the existing office building by enabling the on-site storage and management of electricity.”

The submission highlights how the batteries will allow surplus energy — particularly power generated by existing and planned solar photovoltaic panels — to be stored for use during periods of higher demand. That, the application says, will support demand-side management, lower peak consumption and reduce associated electricity costs for the site.

Local implications and context

Rhydycar Business Park houses several public and private sector operations and sits close to the town centre. For Merthyr Tydfil residents and local organisations, the plans form part of a broader shift towards decentralised energy systems and on-site resilience. By storing generation locally, the offices aim to be less dependent on the wider grid at times of stress, which could be particularly relevant during extreme weather or system outages.

While the submission is framed around operational efficiency for the Welsh Government offices, similar schemes elsewhere have been credited with smoothing demand and enabling greater use of rooftop solar. The planning process will allow the council and neighbours to scrutinise visual, noise and safety impacts associated with battery installations and inverter equipment.

Financial and environmental benefits cited in the application focus on optimising consumption and reducing peak electricity use. The council’s planning officers will now assess whether the proposed works meet local planning policies, including any requirements around siting, appearance and safety. If approved, the works would be contained within the existing compound footprint, with only modest alterations visible from the public realm.

Next steps

The proposal is formally with Merthyr Tydfil County Borough Council. As with other development control cases, the council will consult statutory bodies and neighbours as part of its decision-making process. Any representations or objections received during that period will be considered alongside technical information provided by the Welsh Government in support of the application.

For residents keeping an eye on local low-carbon transitions, the Rhydycar plan is a clear example of how public sector buildings are beginning to combine solar generation with battery storage to manage energy more intelligently on site.