Solar PV deployment: March 2026

This is a pre-release announcement, not a data release. There are no numbers to brief on.

## Memo

What the numbers show

Nothing yet. This is a procedural notice confirming that DESNZ will publish March 2026 solar PV deployment statistics on 30 April 2026 at 09:30. No data is available until then.

Trends

The monthly solar PV deployment series tracks cumulative and new installed capacity across the UK, broken down by installation size band. It captures rooftop (sub-4kW domestic, 4-50kW commercial) and ground-mount (50kW+) separately, which matters because they face different grid constraints and economic drivers.

The series to watch when the data lands:

- Sub-4kW domestic installations have been running at historically high rates since the energy price shock of 2022-23. The question is whether that pace is sustaining now that retail tariffs have fallen from their peak, or whether the payback calculation has tipped back against installation for marginal households.

- Commercial rooftop (4kW-5MW) is where behind-the-meter economics are strongest. Businesses with daytime load profiles — warehouses, supermarkets, manufacturing — face a simpler decision than domestic customers because their consumption pattern matches solar output. Growth here is a leading indicator of how seriously commercial energy buyers are treating grid connection delays: if you cannot get a new grid connection for five years, you put panels on the roof you already have.

- Ground-mount (5MW+) capacity is constrained by grid connection availability, not by economics or planning. New large-scale solar has been stuck behind the same transmission queue as everything else. Any movement in this band likely reflects projects that secured connections years ago finally reaching commissioning, not new capacity entering the pipeline.

What to watch

Behind-the-meter as a grid bypass. The strategic significance of solar deployment data has shifted. It used to measure progress toward a renewable generation target. Now it measures how fast distributed generation is growing as an alternative to grid-supplied power. Every rooftop installation is a demand reduction from the DNO's perspective and a connection queue that was never joined. If commercial rooftop installations are accelerating, that tells you something about the perceived cost of waiting for a grid connection versus the cost of self-supply.

DNO capacity allocation. Distribution network operators are already managing reverse power flows in areas with high solar penetration. The March data will show whether new installations are concentrating in the same constrained zones or spreading to areas with available headroom. DESNZ does not publish locational breakdowns in this series, but the aggregate pace matters for Ofgem's RIIO-ED2 mid-period review — if distributed solar is growing faster than the DNOs' business plans assumed, their reinforcement allowances may need revisiting.

The 30 April publication date sits two weeks before the next quarterly Energy Trends release. Together, the two publications will give the most complete picture of UK generation capacity additions in Q1 2026. Worth reading them as a pair.

No action required on this announcement. Calendar the data release for 30 April and assess then.