SRC-016

Life Cycle Assessment of the UK Space Energy Initiative Technology Roadmap

Published claims resting on this source

• CLM-0184 This study's headline carbon-per-kWh figure for a UK space solar power programme leaves out the possible climate effect of soot and aluminium oxide particles released high in the atmosphere by rocket launches, because the science on that effect is still too uncertain to model - and the authors say this gap is normal for this type of study, not unique to theirs.
• CLM-0185 In a 2022 life-cycle study commissioned by the UK Space Energy Initiative, the lightweight CASSIOPeiA design it used as an example for the initiative's planned programme was estimated to be far cleaner per kWh than the old, heavy NASA/DOE design, and in the same broad range as wind and solar on this measure, though above nuclear's 5.1-6.4 range - but the same study found that almost all of a completely different, non-carbon environmental impact (ozone depletion) came from rocket exhaust during launch.
• CLM-0832 A UK-commissioned study modelled the whole planned 2022-2080 fleet of space solar power satellites and found that, spread across all the electricity it would ever deliver, each unit of power would carry about 23.6 grams of CO2, which the authors say is similar to other renewable energy technologies.
• CLM-0833 This 2022 life-cycle study spells out exactly what it counted: the UK Space Energy Initiative's whole 2022-2080 roadmap, from early prototypes through to 25 full-size 2-gigawatt satellites, including their rockets, ground control and the receiving antennas on Earth, with each full-size satellite assumed to operate for about thirty years.
• CLM-0834 The authors say their model does not count the soot and aluminium oxide that rockets release into the upper atmosphere, because the science on how much these matter at different altitudes is still too uncertain, and the results table duly shows exactly zero for that category everywhere despite the study listing a method for it.
• CLM-0835 In a 2022 study, the research team compared its estimated carbon footprint per unit of electricity for a planned UK Space Energy Initiative programme, modelled on CASSIOPeiA satellites as an example design, with its own earlier assessment of the old NASA/DOE satellite design, made with the same calculation tool, which came out about five times higher, and said the newer design's much lower estimate was mainly because it needs far less steel, aluminium and concrete for its receiving antennas and can be built without astronauts.
• CLM-0836 A 2022 life-cycle study set its estimate of 23.6 grams of carbon dioxide equivalent per kilowatt-hour for the UK Space Energy Initiative's planned programme against an average of 233 grams for the UK energy fuel mix in the government's 2020 figures, and quoted a 2021 United Nations commission report's global ranges for coal, gas, nuclear, hydro, solar and wind to show roughly where that programme would sit among them.
• CLM-0837 Although the study's headline number is about carbon, its own results show ozone damage is the far bigger relative problem, at about 32 per cent of a safe planetary limit against under 5 per cent for carbon, and almost all of it comes from exhaust released during the rocket launches.
• CLM-0838 The authors of a 2022 life-cycle study of the UK Space Energy Initiative's planned space solar power programme said that, if the whole programme's emissions were spread evenly across its 58-year life, the electricity generated would pay back that carbon debt in under six years against the average carbon intensity of the UK energy fuel mix in the government's 2020 figures, which they called a hypothesis in the body of the paper but stated as a result in its summary, and the paper gave no equivalent energy payback time.
• CLM-0853 The wide range of published carbon figures for space solar power is not simply disagreement: most of it separates into two causes, which calculation method was used and which satellite design was assessed, and the method effect does not even point the same way in every case. The lowest published figure also counts carbon dioxide alone, while the others count all greenhouse gases, so part of the spread is a difference in what was counted.

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