Summary
The week from Tuesday 22 September to Sunday 27 September averaged about 25.4 GW of measured generation, with renewables averaging 40.1% of measured output. The strongest renewable day in the available data was Sunday 27 September, when wind, solar and hydro together averaged 52.8% of measured generation. Gas was highest on Tuesday 22 September and lowest on Sunday 27 September.
For flexible electricity use, the cleanest opportunities are likely to appear when wind is strong, gas is low and demand is not at a peak. This is the foundation for future EV-charging guidance, clean-electricity alerts and weekly newsletter summaries.
The reporting period in key numbers
| Average measured generation | ~25.4 GW across available settlement-period aggregates |
|---|---|
| Average renewable share | 40.1% |
| Highest renewable share | 52.8% on Sunday 27 September |
| Highest average wind output | ~10.8 GW on Sunday 27 September |
| Highest average solar output | ~3.4 GW on Saturday 26 September |
| Highest average gas output | ~12.2 GW on Tuesday 22 September |
What the reporting-period figures show
- Renewables were strongest on Sunday 27 September, when wind, solar and hydro averaged 52.8% of measured generation.
- Wind was the largest swing factor in the available feed, peaking at about 10.8 GW average output on Sunday 27 September.
- Solar was strongest on Saturday 26 September, averaging about 3.4 GW across settlement periods after embedded-solar backfill where needed.
- Gas averaged about 7.8 GW across the period, rising highest on Tuesday 22 September and falling lowest on Sunday 27 September.
- Measured generation was highest on Wednesday 23 September, at roughly 26.8 GW average output.
Renewable and gas comparisons — not carbon rankings
Best low-carbon proxy: Sunday 27 September
Historical carbon-intensity aggregates are not yet part of this weekly report feed, so EnergyMix.info uses renewable share and gas output as cautious proxies. Sunday 27 September had the strongest renewable share at 52.8%.
Lowest gas proxy: Sunday 27 September
Gas generation averaged about 4.1 GW on Sunday 27 September. Lower gas periods are often cleaner, but the report does not yet claim this was the lowest-carbon period without historical carbon-intensity validation.
Higher gas output — not a carbon measurement
Highest gas proxy: Tuesday 22 September
Gas averaged about 12.2 GW on Tuesday 22 September. Gas-heavy periods are usually higher-carbon, but this is labelled as a proxy until historical carbon-intensity highs/lows are added to the report feed.
Wind, solar and gas highlights
Wind
Highest average wind output was about 10.8 GW on Sunday 27 September.
Solar
Highest average solar output was about 3.4 GW on Saturday 26 September.
Gas
Highest average gas output was about 12.2 GW on Tuesday 22 September; lowest was about 4.1 GW on Sunday 27 September.
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Data notes
Compiled by Energy Mix from Elexon generation data and NESO embedded-generation estimates. Energy Mix calculates the totals, averages and comparisons shown here. Source data may be revised. Source attribution does not mean that Elexon or NESO has reviewed or endorsed this report.
Sources: Elexon Insights FUELHH; NESO Historic GB Generation Mix; NESO Demand Data Update. These datasets can share underlying observations; agreement is not independent certification.
Renewable-share and gas-output comparisons are not measurements of carbon intensity. See data sources and methodology for source information. A report-specific reproducible evidence pack was not preserved for this publication.
Original publication introduction and methodology note
A measured weekly report for EnergyMix.info using the available 7-day historical generation feed for Tuesday 22 September to Sunday 27 September.
This report is generated from the available 7-day historical generation feed and validated against external public data. Carbon-intensity highs/lows and interconnector summaries should be treated as future additions unless they are present as validated historical aggregates.
Preserved as part of the original publication. Any broad validation wording in this note should not be read as proof that all reporting days or narrative claims were checked.
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