Wolfgang Jacoby - Denkwerk Zukunft

Indirekte Sonnenenergie
continents ~30 % of E o; in conflict with food production and much surface area would be needed.
All other conversions together amount to only a fraction of direct energy extraction.
Oliver Schwarz: Von der in Luft, Wasser und Erdboden vorhandenen thermischen Energie kann
allerhöchstens der Anteil η = 10K/288K = 0.035 in Nutzenergie umgewandelt werden.
Data collected from the Internet
Wind power theoretically 100% E o, but requires much area (Germany: 30% of area at 20% efficiency)
The Gulf Stream mechanical power, ~10 21±0.5 J/a (3×10 13 W): propellers could provide >100% E o (plans
exist) – but would upset the global climate balance and cool Europe.
Wave power ~10 13 W, ~20 % exploitable worldwide, only ~15 % of E o.
Hydropower exploited at about 1/4 of its potential, ~2.8×1012 Hydropower exploited at about 1/4 of its potential, ~2.8×10 W – only ~20 % of Eo. 12 W – only ~20 % of Eo. Bioenergy inefficient, ~1 W/m 2 stored in organic matter on average: ~2×10 13 W on average
It is often assumed that efficient use of renewable energy will solve all future problems.
But it does not permit unlimited growth and realistic limits of growth are short, much shorter than discussed for safe
storage of nuclear waste!
Solar power, if developed with high priority, could keep up world economic growth for a period of order 100 years – only.
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