Value chain · CLM-0818
In plain terms
A 2002 Japanese input-output study estimates that building and launching a 1978-design fleet of 60 solar power satellites would release about 20 grams of carbon dioxide for every kilowatt-hour they generate over an assumed 30-year life, counting carbon dioxide only rather than all greenhouse gases, and counting only production and launch rather than operation.
The claim as recorded
In the SPS-Baseline scenario, being 60 satellite and rectenna pairs of 5 GW each per the 1978 DOE/NASA Reference System at an assumed 30-year satellite lifetime and 24-hour 365-day continuous full-output supply, total lifecycle CO2 from production and construction only, with no in-orbit operational combustion and no maintenance, is estimated at 1.58 billion tonnes CO2, equivalent to 20 g CO2/kWh, on CO2-only accounting and NOT CO2e, via a 1990 Japanese environmentally-extended input-output table of 405 sectors.
Scope and limits
CO2 ONLY, not CO2e. This figure may NOT be compared directly with any gCO2e/kWh figure without stating that the comparison is not like for like. Excludes maintenance, which the paper states would add "some 30 %" at a 1 per cent per year maintenance ratio. Excludes electricity-distribution CO2 for SPS specifically, while the Table 6 comparators include it, so the gap shown in Table 6 is not symmetrical. The design is the 1978 DOE/NASA Reference System, not any modern concept. The 30-year lifetime that the paper assumes for the per-kWh conversion matches the Reference System's own guideline of a 30-year system life (SRC-085 PDF p.22). Continuous full output is the paper's own assumption (its Table 1): the Reference System report expects Earth eclipses to shut each satellite down for up to about 75 minutes a night for about six weeks in spring and autumn (SRC-085 PDF p.109), so a 100 per cent availability assumption is optimistic.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
Abstract (unnumbered title page, PDF p.3): "The baseline scenario shows that CO2 emissions from SPS per unit of energy generated, at 20g CO2 per kWh, is almost the same as from nuclear power systems at 22g CO2 per kWh, and much less than LNG-fired power generation at 631g CO2 per kWh, and coal-fired energy at 1,225g CO2 per kWh." Table 3 p.4 Total row: 158007, in units of 10 thousand tons of CO2, i.e. 1.58 billion t. Section 6 p.6: "52,670(billion g/year) / 2,628(billion KWh/year) = 20g/kWh."
Related records
- Answers question
- QST-008 not published in this release
Cite this
energyaperture.com/c/clm-0818
CLM-0818, Energy Aperture, as of 2002.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-216
- CLM-0819A 2002 Japanese input-output study estimates that if each new satellite were built with electricity from those already working, a fleet of...CLM-0820For comparison in the same units, a 2002 Japanese study of space solar power reports about 22 grams of carbon dioxide per kilowatt-hour for...CLM-0821In a 2002 Japanese study of the 1978 US design, a table splits the estimated carbon dioxide from building and launching the system by part...CLM-0822In a 2002 Japanese study of the 1978 US design, building the launch rockets and the vehicles that move cargo and crews between orbits...CLM-0823A 2002 Japanese study's carbon dioxide figures for space solar power come from Japan's 1990 economic input-output tables, with 405 industry...CLM-0824This is a 2002 discussion paper that says it summarises two 1998 discussion papers by an overlapping group of authors, does not point to...CLM-1462 (low confidence)A 2020 paper's finding that its detailed method gave five to six times the carbon of an earlier, simpler study of the same 1978 design...