Value chain · CLM-1078
In plain terms
Put on stilts in fifty metres of North Atlantic the 1980 rectenna cost fourteen times its land price; strung from cables without its ground screen it came down to about twice, and Europe had a dozen shallow patches of sea to put one in.
The claim as recorded
The first costed offshore rectenna: at a site off the north-east US in "49.4m (162 ft)" of water, "Approximately 25,000 support towers would be required for a 5 GW antenna using the above reference system rectenna", and "the total cost of a 5 GW rectenna using the piled guyed tower and reference rectenna panel is estimated at $36 billion. This is considered too expensive for serious consideration. The reference system is not suitable for offshore use"; a "clothesline concept" without ground screen cuts the towers "from 25,000 to 3,000" and the cost to "$5.7 billion"; a North Sea floating rectenna was "estimated ... at about $6 billion"; icing tests lead "to the conclusion that a protective radome will be required over the active elements of the rectenna including a portion of the ground plane. This conclusion probably also holds for land rectennas located everywhere except perhaps in the desert southwest"; and the European survey found "some twenty such areas of suitable size ... comprising some 20,000 square kilometres" under 25 m depth 10 to 50 km offshore, twelve candidate areas "Belgium 1; Denmark 2; France 2; West Germany 2; Netherlands 2; U.K. 3", with the footprint at 50 deg latitude "elongated by a factor of two" and, on land, a 53 deg rectenna "44 km instead of 26 km" long and "from 400 to 730 km2".
Evidence behind this: T3, a preliminary offshore-rectenna feasibility abstract with its own cost estimates, a second-hand North Sea figure and a European siting survey.
Scope and limits
"Preliminary"; the clothesline design is "not ... optimized for cost, efficiency or minimal harmonic reradiation"; Collins's $6 billion is a private estimate cited at second hand.
What it assumes
The reference rectenna panel and wire-mesh ground screen; Gulf of Mexico structure costs as the calibration.
Where it comes from
PDF p.370 / printed 348, normalised: results 3, 5, 7, 10 and 11 as quoted; "Suitable candidate sites exist off the northeast coast and probably all along the east coast and Gulf of Mexico"; "The least expensive of these was the piled guyed tower". PDF p.371 / printed 349: "Peter Collins in England has estimated the cost of a North Sea floating rectenna at about $6 billion"; sea birds "will land and roost on it"; "We have demonstrated that an offshore rectenna near east coast load centers is feasible. We have not yet demonstrated the practicality". PDF p.550 / printed 529: the twenty areas and 20,000 km2; "twelve areas were selected ... many in water depths of 10 metres or less"; the country list. PDF p.551 / printed 530: "At 50 Latitude the footprint of the SPS microwave beam is elongated by a factor of two"; offshore siting "so that no human habitations were within 15 km or more of the microwave beam centre". PDF p.106 / printed 83: "The long axis of the ellipse ... would become 44 km instead of 26 km with a short axis of 20 km. The area would grow from 400 to 730 km2"; "More than 80% of the major consumption centres are located within 300 km of a coastline".
Basis: billions of dollars; number of support towers; m water depth; km2 of shallow water
Related records
- Answers question
- QST-007 not published in this release
Cite this
energyaperture.com/c/clm-1078
CLM-1078, Energy Aperture, as of 1980-04.
Connected records
Other published records linked to this one. A list, not a judgement.
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