Value chain · CLM-1054
In plain terms
The programme reckoned a receiving site would give off about as much heat per square metre as a suburb, a tenth of what the sun puts into the ground, enough for a degree of local warming in still air; one of its two reports prints the figure a hundred times too small, and the climate report suspects that the structure's roughness and reflectivity matter more than the heat.
The claim as recorded
The programme's environmental-welfare volume puts the 1980 reference rectenna's waste heat at "about 7.5 W/m2 ... over a 100 km2 area", "Continuous release of 750 MW of waste heat from a 100 km2 rectenna", "equal to 10% of the net solar radiation at the ground and ... equivalent to the heat release of an average suburban development"; the climate volume prints the same quantity as "approximately 75 kW/km2" (0.075 W/m2) while its Table 1 gives 0.25 MWt per MWe (12.5 W/m2 at 5 GW over 100 km2), says the release is "less than 10% of the average solar net radiation at the surface", and expects "small temperature changes (1 degree C) in conditions of light wind", changes in cloudiness, and that "it is suspected that changes in surface roughness, due to the rectenna structure, and the rectenna's albedo itself will contribute more significantly to atmospheric perturbations than the waste heat".
Evidence behind this: T3-two programme volumes asserting a rectenna waste-heat figure with no calculation shown, and disagreeing by 100x on the printed unit.
Scope and limits
THE TWO VOLUMES DISAGREE BY 100x ON THE PRINTED UNIT AND BY 1.7x ON THE FRACTION (0.15 against 0.25 MWt per MWe); ER-0050's "75 kW/km2" contradicts three statements on its own pages and is taken as a unit error. Neither volume shows the calculation. Waste heat over the rectenna, not the beam's atmospheric absorption (which ER-0050 calls "extremely small").
What it assumes
5 GW delivered over about 100 km2 at 23 mW/cm2 peak; the rectenna's conversion loss as the heat source.
Where it comes from
ER-0055 PDF p.28 raw: "An SPS rectenna would release about 7.5 W/m2 of waste heat over a 100"; normalised: "This energy density is equal to 10% of the net solar radiation at the ground and is equivalent to the heat release of an average suburba~ development". ER-0055 PDF p.94 normalised: "Continuous release of 750 MW of waste heat from a 100 km2 rectenna". ER-0050 PDF p.52 image read: "approximately 75 kW/km2"; PDF p.53 normalised: "This waste heat release is less than 10% of the average solar net radiation at the surface"; "the rectenna may produce small temperature changes (l'C) in conditions of light wind". ER-0050 PDF p.9 Table 1: SPS 0.25 MWt-yr/MWe-yr. ER-0050 PDF p.55 normalised: terrestrial PV "40 W/m2, which is several times larger than is expected from a SPS rectenna".
Related records
- Answers question
- QST-007 not published in this releaseQST-018 not published in this release
- Contradicts
- (internal recorded)
Cite this
energyaperture.com/c/clm-1054
CLM-1054, Energy Aperture, as of 1980.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-522
- CLM-1053The programme's 1980 climate study counted only what the rockets and power plants emitted in use, found the launch carbon small next to...
- Also from SRC-527
- CLM-1052In 1980 the programme's own numbers had a receiving site of about 200 square kilometres per satellite once a safety margin was included...CLM-1055The programme's 1980 look at nuisance and property effects gave space solar its worst marks on six counts, mostly because nobody knew...