Green Engineering's Full G99 Compliance, Ensuring Reliable Connections to the Grid

Green Engineering is proud to announce that all of its generation and infrastructure projects are now fully compliant with the UK’s G99 regulations, underlining the company’s commitment to quality, safety, and the reliable delivery of high-voltage connections.

Formerly known as G59, the national standard was updated to Engineering Recommendation G99 in 2019 to reflect the rapid growth of renewable generation and storage systems. G99 governs how power generating modules connect to the UK distribution network at all voltage levels, including 33kV, 132kV and even up to 400kV. The regulation applies to technologies such as solar farms, wind projects, battery storage and major substation works, ensuring that new connections integrate smoothly with the grid.

As a trusted substation contractor and Independent Connection Provider (ICP), Green Engineering delivers projects that involve complex EHV (extra-high-voltage) systems, from cable route design and installation through to substation builds and commissioning. Achieving full G99 compliance demonstrates that every stage of this work meets the highest technical standards required by Distribution Network Operators.

Compliance covers a wide range of requirements, including fault ride-through, reactive power support, frequency stability and robust interface protection. It also involves rigorous modelling, documentation, and witnessed testing before energisation. By meeting these obligations, Green Engineering provides clients with complete assurance that their assets are safe, resilient and future-ready.

“G99 compliance, building on the earlier G59 framework, is vital to protecting the UK grid as it evolves,” said a Green Engineering spokesperson. “Our full compliance at 33kV, 132kV and 400kV levels shows our strength not only as an engineering contractor but also as a trusted Independent Connection Provider.”

This achievement reinforces Green Engineering’s reputation for delivering complex, high-voltage, compliant energy solutions that support the UK’s transition to a low-carbon future.