Value chain · CLM-1081
In plain terms
The people who would have to buy the power said in 1980 that a five-gigawatt block that could vanish within minutes in the spring and autumn eclipse periods might need six gigawatts of standby, that the ground station would lose two hundred thousand diodes a year, and that American utilities were unlikely to own one until there were some ten.
The claim as recorded
The utility industry's April 1980 reading of the reference system: the eclipse takes "a few minutes (2-4) to go from full sunlight to full shadow", shutdown "about 5 minutes" and restart "16 to 60 minutes"; "the SPS can be shut down at the rate of 20%/minute and restarted at the rate of 2-7%/minute" against conventional units' "1-5%/minute", so "the capability of conventional units will be the limiting factor"; "The reference system design provides no mechanism for frequency or power level regulation ... This may be a limiting factor on SPS penetration"; "there are about seven billion diodes in a rectenna and their mean time to failure is estimated to be 30 years. Assuming an exponential failure law, the expected number of failures per years is approximately 200,000. This would lead to a corresponding degradation in performance of about 3%/year unless failed diodes are regularly replaced"; the overall system "between 0.6 and 1.2 trillion dollars" in 1977 dollars against "about $20 million" spent to date; PG&E's reserve arithmetic, "a 5 Gigawatt (Gw) SPS in conjunction with another 1,000 Megawatt (Mw) unit could require 6,000 Mw of reserve capacity, which would predominate until monthly peak load reached 42 Gw", and its cost range "5-6 cents/kwhr at a production rate of 1 SPS/yr and 3-4 cents at 4 SPS/yr. One estimate has reached 2.6 cents/kwhr in 1979 dollars"; the CEGB's objection that "Total and virtually instantaneous loss of 5 GW, due to a malfunction or disturbance to the phase control system, would throw an intolerable load on the distribution control system"; and the institutional forecast that "institutional barriers will prevent U.S. utilities from ownership of the ground stations until the first SPS is successfully demonstrated, probably in the Tennessee Valley Authority".
Evidence behind this: T3, utility and consultant abstracts' operational judgments and one asserted cost range, with the diode-failure arithmetic as the source states it.
Scope and limits
EPRI-commissioned and consultants' views; the 0.6 to 1.2 trillion is asserted without derivation.
What it assumes
The 30-year diode MTTF is Patmore's assumption, not a measurement; exponential failures.
Where it comes from
PDF p.645 / printed 625, normalised: "The cost of the overall system is estimated to be between 0.6 and 1.2 trillion dollars.* To date, about $20 million have been spent"; the eclipse, shutdown, restart and ramp-rate sentences as quoted. PDF p.646 / printed 626: the regulation and diode sentences as quoted; "Locating and replacing 200,000 diodes per year would appear to be a Herculean task". PDF p.608 / printed 587: the busbar and reserve sentences as quoted; "given the conservative assumption that mature SPS system costs are only $1,000 per Kw more capital intensive than coal or nuclear systems, the SPS is a major financial risk". PDF p.600 / printed 579: "During these periods, a major block of baseload generation (5 GW) is unavailable and must be replaced by reserve units"; PDF p.601 / printed 580: "less system inertia associated with the rotating mass of conventional machines". PDF p.603 / printed 582: the TVA sentence; "Ownership of ground stations and satellites by U.S. utilities would be unlikely until after some 10 such units". PDF p.530 / printed 509: the CEGB sentence; "base load demand is about 20% of peak (10 GW : 50 - 55 GW)"; "the probability of losing more than 1 GW at any one site was greatly reduced" as the acceptability condition.
Basis: per cent per minute ramp; minutes to restart; diode failures per year; MW of reserve; cents/kWh
Related records
- Answers question
- QST-012 not published in this release
Cite this
energyaperture.com/c/clm-1081
CLM-1081, Energy Aperture, as of 1980-04.
Connected records
Other published records linked to this one. A list, not a judgement.
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