CALC-143
The Royal Society's 2050 system cost as a multiple of its wind and solar supply cost, at the two ends of its range
What this is
This is the project's own arithmetic, published in full so it can be checked rather than taken on trust. It is not a source. Every input it uses is cited to a record, and the conclusion it reaches only carries as far as those inputs do.
REGISTERED 2026-10-19. Drafted for CLM-1469 (outputs/records/qst-021-notes-records-draft-2026-10-19.md, df4afe6f), checked by an independent reader (b794ec15: PASS), landed at coord's request.
Feeds CLM-1469. Basis: GBP per MWh in 2021 prices, as printed; ratios are dimensionless. A ratio of two printed figures, not a model.
Why it was needed. CLM-1419 holds the Royal Society's range for the average cost of electricity fed into the grid in a 2050 Great Britain system of wind and solar backed by hydrogen storage, GBP 52 to 92 per MWh, and the wind and solar supply cost paired with each end. No record gives the ratio of the two. An article sentence saying the system cost is about double the supply cost needs it.
Inputs.
| Quantity | Value | Source | Tier | Stated or assumed |
|---|---|---|---|---|
| Average cost of electricity fed into the grid, low end | GBP 52/MWh | SRC-781 PDF p.7 (printed p.7), read at a zoom 4 crop; CLM-1419 | T3 | STATED |
| Wind plus solar supply cost paired with the low end | GBP 30/MWh, with low storage costs and a 5% discount rate | SRC-781 PDF p.7 | T3 | STATED |
| Average cost of electricity fed into the grid, high end | GBP 92/MWh | SRC-781 PDF p.7; CLM-1419 | T3 | STATED |
| Wind plus solar supply cost paired with the high end | GBP 45/MWh, with high storage costs and a 10% discount rate | SRC-781 PDF p.7 | T3 | STATED |
Working (python output, transcribed).
low 52 / 30 = 1.7333 difference 22 supply share 0.5769 high 92 / 45 = 2.0444 difference 47 supply share 0.4891 not used (mixed ends) 92 / 30 = 3.067; 52 / 45 = 1.156
Result. At the low end of the range the average cost of electricity is about 1.7 times the wind and solar supply cost (GBP 52 against GBP 30 per MWh), and at the high end about 2.0 times (GBP 92 against GBP 45). The difference is GBP 22 and GBP 47 per MWh.
Where this fails. - The two figures in each ratio are on different bases. The supply cost is per MWh of wind and solar output before transmission (Table 5, PDF p.62, as recorded in CLM-1419). The average cost is per MWh fed into the grid to meet demand. So the difference is not storage alone. It also covers surplus wind and solar output (at the cost minimum, supply is about 1.33 times demand, PDF p.31, as recorded in CLM-1419), storage losses, and GBP 4/MWh for transmission to stores and grid-service batteries (PDF p.64 caption). - Each end changes three things at once: storage cost, supply cost and discount rate. The ratios hold only for the pairs the page prints. Mixing the ends gives 1.2 to 3.1, and these figures are not used. - The wind and solar supply costs are 2040 projections applied to 2050 (Table 5, as in CLM-1419). Figure 24 (PDF p.64) plots each supply cost at both discount rates, so the supply cost itself does not change with the rate in this report. The discount rate acts on the storage and generation side. This reading of Figure 24 is from its axis and key, not from a printed sentence.
Cite this
energyaperture.com/calc/calc-143
CALC-143. The working above, not a source document.