Value chain · CLM-0811
In plain terms
In a 2020 modelling study of the 1978 NASA/DOE space solar power design, the carbon per kilowatt-hour fell the longer the satellites were assumed to keep running, because the fixed launch and manufacturing emissions spread over more electricity; but the paper says it would take 67 to 77 extra years beyond the 30-year base case before that design matched ground solar panels, which it calls hard to envision.
The claim as recorded
In the same model, extending the operational mission by 20 years reduces modelled lifecycle intensity to 72.67 gCO2e/kWh for the silicon option and 78.89 gCO2e/kWh for the gallium arsenide option, and the paper states it would take a mission extension of 67 years for silicon and 77 years for gallium arsenide, giving total mission lifetimes of 97 and 107 years respectively, for either option to fall below terrestrial photovoltaics, a prospect the paper itself calls "currently hard to envision".
Scope and limits
A sensitivity result only. The paper models no engineering path to a 97 to 107 year mission lifetime, which is far beyond the reference system's own 30-year per-unit design life, and it characterises such an extension as "currently hard to envision" in its own words. This record may NOT be used to imply the design is engineered, qualified or intended for those lifetimes. The comparison target is terrestrial PV as represented in this paper's own comparator set, 44.05 gCO2e/kWh in Figure 11 (p12), an average of OpenEI estimates whose emission figures span 1970 to 2010 (p6, Table 2), not a current measured PV figure. Figure 12 (p13) plots extensions of up to 20 years only; the 67 and 77 years are stated in the text, beyond the plotted range.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
p12-13: "if the mission were to be extended 20 years, the carbon footprint of the technology would fall to 72.67 gCO2e/kWh for the silicon option and 78.89 gCO2e/kWh for the gallium arsenide option. It would take a mission extension of 67 years for the silicon option to overtake terrestrial-based PVs and 77 years for the gallium arsenide option. This equates to a mission lifetime of 97 years and 107 years respectively, a prospect which is currently hard to envision."
Related records
- Answers question
- QST-008 not published in this release
Cite this
energyaperture.com/c/clm-0811
CLM-0811, Energy Aperture, as of 2020.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-212
- CLM-0316In 2009 three researchers guessed that, once the energy to deliver and use it is counted, an oil-based fuel must return at least about 3...CLM-0810A 2020 modelling study estimated that, across its whole operating life from 2040 to 2100, the 1978 NASA/DOE space solar power design would...CLM-0812A 2020 modelling study of the 1978 NASA/DOE design estimated that its ozone-depleting emissions, almost all from burning rocket fuel at...CLM-0813The paper's detailed component-by-component calculation gives a carbon figure five to six times higher than an older top-down calculation...CLM-0814A 2020 conference paper's own cost model put the whole 60-satellite programme of the 1978 US reference design at about 3.86 trillion US...CLM-0815The 2020 study of the 1978 NASA/DOE design did not count any warming from the microwave beams themselves, saying that is too hard to...CLM-0816In their 2020 study of the 1978 NASA/DOE design, the authors list their own weak points: only whole-system detail rather than part-by-part...CLM-0817The authors state openly that a space-solar-power advocacy non-profit paid for this study, that part of the reason was to test or support...More on the source page.