UK battery product standard in development for small-scale installations

A new product standard for battery storage is being developed for the UK market that could see manufacturers face tighter cybersecurity rules and potentially factory inspections.

UK certification body MCS is consulting on a battery storage product standard that will set new reporting and certification requirements for manufacturers supplying the residential and commercial and industrial (C&I) segments. It could see battery products subject to a similar product standards regime already adhered to by solar panel manufacturers supplying the UK market.

MCS is consulting on a battery storage standard in a bid to close a perceived gap in the certification process. Under current rules, homeowners that wish to gain access to the export tariffs for solar must have their installation carried out by a certified installer, using certified modules. To achieve certification status, solar panels must demonstrate compliance with MCS’s product standard, however no equivalent product standard exists for battery storage.

This is set to change, and MCS is consulting with industry stakeholders on product standard proposals.

Ted Woodward, technical manager for electric at MCS, told ESS News that the certification body decided to develop a product standard “to ensure we could meet the needs of installers and the industry in a rapidly growing market.”

MCS first introduced a standard for battery storage installations in 2020 and Woodward said development work for the new product standard includes engagement with a technical working group, manufacturers and other stakeholders.

“With more battery storage systems installed through the scheme than ever before, the market has now matured to a point where it is the right time to introduce a dedicated product standard,” Woodward said. He added that for consumers, a product standard would mean third-party verified information on the batteries they are buying.

The Energy Storage Association (ESA) welcomed the development of a product standard, telling ESS News that it “thoroughly supports measures to ensure battery products are held to the highest safety standards.”

The ESA is one of the organizations on the MCS working group developing the product standard and while the final shape has not been agreed, the association suggested many battery storage products on the UK market would already be compliant.

“Many BESS products already undergo rigorous factory testing, often including third party audits from parties such as TÜV. We see the role of the MCS standard as providing a locally trusted validation of products which are maintaining those high standards, rather than introducing additional compliance burdens unique to the UK market.”

While the consultation process is ongoing, existing MCS product certification requirements for solar panels reveal the kinds of measures that could be introduced for battery storage.

Existing MCS product certification requirements for solar panels are stringent and manufactures need to demonstrate product testing against relevant technical standards, such as IEC 61215, IEC 61730, have Factory Production Control (FPC) arrangements, demonstrate that production units remain consistent with a tested sample, and undergo ongoing surveillance to maintain certification.

For battery storage, MCS’s consultation proposes minimum safety requirements that include meeting the IEC 62619-2022, the international standard for secondary lithium cells and batteries containing alkaline or other non-acid electrolytes, plus safety requirements for secondary lithium cells and batteries for use in industrial applications; and UN 38.3 international safety standard for transporting lithium metal, lithium-ion, and sodium-ion batteries.

The new standard would apply to AC-coupled systems where both the battery packs and the inverter are in a single enclosure, or multiple close-coupled enclosures. DC-coupled battery packs with or without an integrated battery management system would also be covered under the product standard.

Integrated battery-plus-inverter systems would also need to meet BS EN 62477-1 safety requirements for power electronic converter systems and equipment, IEC 61000 electromagnetic compatibility, and BS EN 18031 for information technology, although that standard would only apply to products incorporating wireless connectivity such as wifi, Bluetooth or other radio interface.

The relevant component would also need to comply with ETSI EN 303 645 regulations covering cybersecurity for internet of things. Baseline cybersecurity requirements might include no default passwords, secure software updates, management of vulnerability such as identifying security flaws, notifying users and issuing fixes, and secure communications between battery, inverter, and any cloud platform of mobile app.

Performance standards would also be set, potentially making comparisons more straightforward for installers and end users. The new rules could make it mandatory to declare a range of performance parameters including nominal energy capacity, input power, output power, roundtrip energy efficiency and expected service life. For products where the nominal energy capacity is not fully available under normal operation, manufacturers will also need to state the usable energy capacity as well.

The deadline to respond to the MCS consultation is 11:59 p.m. on Nov. 10, 2026. MCS noted that while it cannot confirm a timeline on implementation, there will be a transition period for MCS certified installers until an “adequate number” of MCS certified products are available on the market.

“We will continue to keep industry updated across the various milestones as we work towards eventual implementation into our scheme,” Woodward said.