Energy Technology Explorer

Nuclear (large-scale)

• DESNZ has not published a generic nuclear cost/LCOE estimate since its 2016 report cycle, and Hinkley Point C and Sizewell C costs were excluded from the 2025 Electricity Generation Costs report by name (see file header) — no capital-cost or LCOE figure is shown here rather than reproduce a decade-stale generic estimate. Sizewell C's own PROJECT cost (not a generic per-technology LCOE, and not comparable to the £/kW figures elsewhere in this table) is now public via the National Audit Office's independent value-for-money audit — set out below.
• The 17,000 MW TEC Register pipeline figure is a raw sum of everything tagged "Nuclear" in the connection queue, at whatever stage — it is not a forecast of what will actually be built — the same caution applies here as to the wider connections queue.

SMR (small modular reactor)

• DESNZ's own words (Electricity Generation Costs 2025, p.28): "GBE-N's SMR Programme is in the early stages of development and cost estimates are expected to mature." No build-time, lifespan, load-factor, cost or pipeline-capacity figure is shown — genuinely not yet published by DESNZ, not withheld.

Offshore wind (fixed-bottom)

• Assumed (48%) vs observed fleet (36.1%) load factor differ because the assumption models a new, larger 2030-vintage turbine design — the real fleet includes older, smaller, lower-yield turbines. Neither figure is wrong; they answer different questions.
• The REPD "nameplate" capacity figures here are NOT the same measure as the de-rated installed-capacity figures shown on the Powering Britain page: DUKES adjusts wind and solar capacity downward for expected availability, so the two are not directly comparable.
• The 60.7 GW REPD pipeline figure includes every filed project regardless of how likely it is to actually connect — NESO's own reform-adjusted 2030-aligned figure for offshore wind specifically is 32.1 GW, a genuinely different, more filtered number answering "what NESO now expects to connect by 2030" rather than "what has been proposed".

Onshore wind

• Assumed (36%) vs observed fleet (24.0%) load factor gap reflects both siting/turbine-generation improvements assumed for new 2030 builds and the real fleet's mix of older sites.

Solar PV (large-scale)

• DESNZ's assumed and DUKES' observed load factors are closely aligned (12% vs 11.1%) — unlike wind, solar's physics (fixed panel output per unit of sunlight) leaves less room for a "newer design performs better" gap.

Gas (unabated CCGT)

• DESNZ publishes THREE LCOE figures for gas, at three assumed load factors (93%/30%/5%) — the ~4x cost jump from 93% to 5% is the clearest illustration in this whole table of why dispatchable-but-idle capacity costs so much more per unit of energy actually delivered.
• The real UK gas fleet runs at ~29.7% average, closer to the 30% scenario than the 93% one — reflecting its actual role backing up variable renewables and following demand, not running flat-out as the 93% figure would imply.

Gas + CCS (carbon capture and storage)

• UK gas-CCS projects (e.g. the Track-1 CCS clusters) are in development but were not separately identified by plant type in the NESO TEC Register at the time of ingestion — pipeline capacity is left unsourced rather than estimated.

Batteries (grid-scale)

• Not covered by DESNZ's 2025 Electricity Generation Costs update — no capex/LCOE figure published in that series for batteries. "Load factor" and "LCOE" are not meaningful comparisons for a storage technology on the same terms as a generator (a battery consumes energy to store it, then re-sells it — it does not generate net energy).
• The 124 GW REPD pipeline figure is the largest of any technology in this table by a wide margin, and includes many speculative/early-stage applications — treat as an upper bound on interest, not a forecast of what gets built (NESO's own reform-aligned 2030 figure for battery storage specifically is 34.5 GW).

Pumped storage hydro

• Not covered by DESNZ's 2025 Electricity Generation Costs update — the UK's existing pumped-storage fleet dates from the 1960s-80s and was not re-costed in this edition.

Interconnectors

• Not a generation technology — no capacity/capex/LCOE comparison applies on the same terms as the rows above. See electricity-net-imports-twh in the main registry (DUKES Table 5.13) for the UK's actual net import/export flow via all interconnectors combined (France, Ireland/Northern Ireland, Netherlands, Ireland/Wales, Belgium, Norway, Denmark): 29.7 TWh net imported in 2025.
• Per-interconnector nameplate GW capacity figures exist at Ofgem/NESO but were not verified this session — left unsourced rather than estimated.

Tidal stream

• Labelled FOAK (first-of-a-kind) by DESNZ — its cost figures reflect an immature, small-volume industry; by far the highest £/MWh of any technology DESNZ costs in this report, over double onshore/offshore wind or solar.

Hydro (natural flow)

• DUKES' 1,612 MW figure (all UK generating companies) is a DIFFERENT, larger population than REPD's small+large hydro operational total (~670 MW) — REPD tracks renewable-support-scheme-eligible projects specifically, not every hydro scheme DUKES counts. Both are genuine, correctly-sourced figures for different populations, not a contradiction.
• Not covered by DESNZ's 2025 Electricity Generation Costs update — no current capex/LCOE figure.

Hydrogen-to-power (CCHT/OCHT)

• The DESNZ figures shown are for "CCHT 50% 900MW" — a first-of-a-kind (FOAK) combined-cycle plant burning a 50% hydrogen / 50% natural-gas blend, NOT a 100%-hydrogen plant (DESNZ separately models a 100%-hydrogen "OCHT", which is substantially more expensive — £396/MWh at 93% load factor — and is not the figure used here).
• REPD's tiny 2.7 MW "Operational" figure reflects how early-stage hydrogen-to-power is in the UK today — almost entirely still in the pipeline, not built.