SRC-021

Space Based Solar Power as a Contributor to Net Zero - Phase 2: Economic Feasibility

Published claims resting on this source

• CLM-0170 A UK government-commissioned study estimates the cost of electricity from a mature (fifth-built) space solar power satellite at roughly 3.5 to 7.9 pence per kWh in 2018 money, but this swings by almost 3x depending on how much it costs to launch things into orbit.
• CLM-0171 The same model shows the cost of electricity is noticeably higher for the first unit built than for the fifth, and when this study compares its solar-power-satellite cost to wind and solar costs, those comparator figures do not include the cost of storing or backing up wind and solar power, so it is not a fully like-for-like comparison.
• CLM-0172 The study uses a high assumed rate of return (20%) to work out the headline cost-per-unit-of-electricity figure, but uses a much lower official government rate (3.5%) when working out whether the whole programme is worth public money - these are not the same number and should not be confused.
• CLM-0173 Developing a working space solar power system for the UK is estimated to cost somewhere between about 7.5 and 16 billion pounds (in 2021 prices on the report's own statement for this table) over 18 years, with the higher number reflecting a standard government allowance for cost overruns.
• CLM-0174 On the study's own numbers, a first space solar power system would not, by itself, earn investors the return they would expect (20%) - it would need the UK government to fund roughly half, or more than three-quarters once normal cost overruns are allowed for, of the development cost before private money would follow.
• CLM-0175 For every pound of public money put into the whole programme, the study estimates the UK economy gets back between GBP 1.30 and GBP 1.80. It counts only the publicly funded share of spending, and values wider economic activity rather than just electricity sold.
• CLM-0522 The UK study used a 20% return requirement, based on what institutional investors are expected to want. The US study used 3%, on a one-line assumption of government funding, and did not test what a different rate would do.
• CLM-0538 The US and UK studies are not just using different toughness levels for the same test -- they are answering different questions. The US study asks "what would this cost the government to build and pay for entirely by itself," which is why its rate is so low. The UK study asks "what return would a private investor need to put money in," which is why its rate is so high. Whether the same would hold for a real UK project like the new nuclear power station has not been checked against a held source.
• CLM-0714 The 2021 UK study by Frazer-Nash Consultancy proposed that the satellite fly itself to its final orbit, using its own solar panels to run its own electric thrusters. Chemical tugs would take the parts only partway, to about 5,900 km, just above the inner radiation belt, where the satellite would be built. The study said the plan needed further work and gave no figures for the self-powered trip.
• CLM-1430 Put in 2024 money, a reliable British grid built on wind, sun and stored hydrogen would cost about 61 to 107 pounds per megawatt-hour in 2050. Set against the top of that range, the UK government's space solar study comes in at about half, and NASA's study, rebuilt in 2024 money, at nearly nine times. The two sides are costed differently, so this is a rough guide, not a like-for-like price comparison.
• CLM-1457 A 2021 study for the UK government of the CASSIOPeiA space solar design used two discount rates for two questions: a tough 20 percent, the return it assumed private investors would want, for its cost of electricity, and the government's standard rate at the time, 3.5 percent, for judging whether the whole programme would be worth it for the country. It does not show that pairing the two is standard for other power stations.
• CLM-1467 (low confidence) Keeping people out of the area where the beam is strong is a plausible way for a strong beam to meet the 2020 international limit for public exposure, and international exposure guidance accepts limiting access as a way to comply. Other designs have worked this out: a 2013 Japanese review plans a no-entry area 3.5 kilometres across, and a 2007 international study sizes a 4-kilometre receiver this way. A 1977 US study set aside 204 square kilometres for one receiving site, without saying in its cost table what fixed that size, and costed buying and preparing that land. A 2026 international radio report that takes CASSIOPeiA as its example says the beam can be designed to fall below the public limit at the edge of the receiving site, with a safety zone matching the beam's footprint, about 3.5 to 6.5 by 7 to 13 kilometres in the UK. A diagram in it shows the receiving site taking 245 watts per square metre, but the report gives no figure for the beam's strength at the edge and no cost for the zone. A 2021 UK cost model for a CASSIOPeiA design includes the land for the receiving site but names no safety zone.

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