Value chain · CLM-0850
In plain terms
NASA does test how its carbon figures move if assumptions change, and under its most favourable combination they fall by roughly 86 to 89 per cent, to around 4 grams per kilowatt-hour; but the report prints that best-case number differently in three places.
The claim as recorded
SRC-012 does perform an emissions sensitivity analysis, distinct from its cost sensitivity, in which electric propulsion instead of refuelled chemical transfer cuts modelled emissions intensity by about 54 per cent for RD1 and 63 per cent for RD2, a 15-year rather than 10-year hardware life cuts them by 27 and 29 per cent, and a combined favourable scenario cuts them by nearly 86 and 89 per cent; but the report prints three different RD1 values for that combined scenario, 3.78 gCO2eq/kWh on p.viii, 3.87 in Table 3 on p.22 and 3.6 in Appendix B Table 26 on p.77, and two RD2 values, 4.33 on p.viii and in Table 3 and 4.2 in Table 26.
Scope and limits
These are MODELLED sensitivity outcomes under stacked favourable assumptions, not projections and not results, and each depends on the disputed method at CLM-0845 and on the unprinted denominator at CLM-0848. The combined case changes six inputs at once (pp.21-22): lower launch cost, solar cell efficiency raised from 35 to 50 per cent, lower servicer and ADR first-unit costs, learning curves improved by 5 percentage points, a 15-year hardware life, and electric propulsion for orbital transfer; so it is a best case and not a central estimate. Because the RD1 value is printed three ways (3.78, 3.87, 3.6) and the RD2 value two ways (4.33, 4.2), no value may be quoted as the report's figure without naming the page or table it came from.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
p.19 (PDF p.36): "The emissions decrease is about 54% for RD1 and 63% for RD2". p.20 (PDF p.37): "GHG emissions are reduced by 27% and 29% from baseline for RD1 and RD2, respectively". p.22 (PDF p.39): "GHG emissions decrease by nearly 86% and 89% for RD1 and RD2, respectively"; Table 3 on the same page gives the combined scenario as 3.87 and 4.33 gCO2eq/kWh. p.viii (PDF p.9): "This combination also reduces the GHG emissions intensities (3.78 gCO2eq./kWh for RD1 and 4.33 gCO2eq./kWh for RD2)". Appendix B Table 26, p.77 (PDF p.94), Multiple Variables, gives 3.6 and 4.2 gCO2eq/kWh for the same scenario.
Related records
- Answers question
- QST-008 not published in this release
Cite this
energyaperture.com/c/clm-0850
CLM-0850, Energy Aperture, as of 2024.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-012
- CLM-0006None of the five main studies mentions the international radio-frequency exposure limits, or any safety standard, or a restricted area...CLM-0123NASA's own 2024 study puts space solar power at 12 to 80 times the cost it expects in 2050 from power stations on the ground, a set it...CLM-0124NASA also found that if several things improve at once, rather than just one, space solar power does become cost competitive.CLM-0125On carbon, NASA found space solar power within the range of five renewable ways of making power on the ground (wind, solar, solar thermal...CLM-0144A NASA study found that launching everything into space is by far the biggest cost of a space solar power system, and that most of those...CLM-0192The full list of assumptions behind the headline result of NASA's 2024 study, that space solar power would cost far more than ground...CLM-0193To get to a competitive cost, NASA's own 2024 analysis needs launch costs to halve, solar cells to get much more efficient, satellites to...CLM-0240A from-scratch cost model of the "Innovative Heliostat Swarm" design gets almost the same electricity cost as NASA's own study: about 62...More on the source page.