a top down view of solar panels on a commercial rooftop
The trade group warned that the plan could discourage investment in Scottish renewables. Image: CHUTTERSNAP via Unsplash.

The head of Scotland’s solar energy trade group has criticised plans to reform the grid to enable greater uptake of rooftop solar, noting that Scotland will not benefit from the proposed reforms.

Last week, the National Energy System Operator (NESO) issued a proposal to raise the threshold for conducting a transmission infrastructure assessment (TIA) from 1MW to 5MW. The current TIA process has been criticised for putting cost and bureaucratic barriers in place, effectively blocking many local power projects over 1MW in size. As such, industry trade group Solar Energy UK praised the plans as the removal of “a burdensome element of red tape that has added many years to getting projects off the ground”.

However, Solar Energy Scotland has criticised the fact that owing to technicalities in the way the Scottish electricity grid is set up, the TIA threshold in Scotland will not be raised above its current 200kW level, something which the trade group notes will “undermine Scotland’s solar energy industry and jeopardise Scotland’s own climate and energy targets, such as the 4-6GW solar deployment ambition by 2030”.

“While it’s certainly welcome south of the border, this move will put Scottish businesses at a disadvantage, not to mention the Scottish economy, energy security and decarbonisation efforts. We need to cut these overly cautious bureaucratic rules in Scotland in the same way as England and Wales to maintain a level playing field” said Josh King, chair of Solar Energy Scotland.

Furthermore, the plan to widen the gap between English and Scottish TIA thresholds has been called out as a potential risk to future investment in Scottish renewables, with Solar Energy Scotland calling the matter a “critical issue for Scotland’s renewable energy sector”.

In 2024, Scottish and Southern Electricity Networks (SSEN) raised the TIA threshold in Scotland from 50kW to its current level of 200kW, a move that proved immensely successful for small-scale solar installations in Scotland. The raising of the threshold expedited the approval and delivery of 35 projects in central and northern Scotland with a combined capacity of 5.2MW.

Scotland’s rooftop solar ambitions

In June 2024, the Scottish government removed planning permission requirements for home rooftop solar installations, allowing for the installation of flat roof systems on homes under permitted development rights as long as they do not protrude more than one metre from the roof surface.

However, just days after announcing this change, the Scottish government withdrew a scheme which provided interest-free loans for Scottish homeowners who wanted to install solar panels or battery energy storage systems (BESS) at home. Solar Energy Scotland later urged the government to reinstate the system, estimating that every £10 million allocated to interest-free solar and battery loans — all of which would be repaid — would lead to up to 1,000 households installing these technologies.

Solar Energy Scotland has previously criticized the Scottish government for falling behind on standards for rooftop solar, noting that the Scottish government’s suggestion that new buildings be built to the Passivhaus ‘Classic’ energy efficiency standard is outdated, as the Passivhaus Classic energy efficiency standard has been superseded by the ‘Plus’ and ‘Premium’ forms.

Unlike Classic Passivhaus, both of the newer versions of the standard mandate the installation of renewable energy systems in new buildings.