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Solar Energy
The Earth receives energy at a rate of
1365 W/m2 (R2)=174,000 TerraWatts R=6.37x106 m (Area =1.3x1014 m2)
• Multiple by ½ since any collector will be in the sun for ½ a day
• 87,000 TWatts
Multiply by ½ again for the angle of the collector not pointing directly at the sun.
43,500 TWatts
Multiply by 0.3 for useable area on Earth
13,000 TWatts
Multiply by ½ for average clear sky conditions and absorption by our atmosphere.
=6500 TW
“From Sustainable Energy Without Hot Air” http://www.withouthotair.com/
• Multiply by 0.17 to reflect typical efficiency of solar collectors
870.0 Terra Watts
“From Sustainable Energy Without Hot Air” http://www.withouthotair.com/
Multiply by _________ to get estimate of land that we want to cover up.
Usable Solar _________________
For Portland Oregon 30W/m2 for photovoltaic and 80 W/m2 for heating
Need is about 30 kWhr/day /family
10 hr days 3 kW =3000 W Assumming an average power of 60 W/m2 Area of 50 m2 3m high by 17 m wide
How much non-Fossil Fuel energy must be created in the next 25 years?
495 x1015 BTU per year =522 x1018 Joules/year= 522 ExoJoules=16 TW=56 KWhr/day/person=$4.50 /day/person
“From Sustainable Energy Without Hot Air” http://www.withouthotair.com/
Figure 6.19. A combined-heat-and-power photovoltaic unit from Heliodynamics. A reflector area of 32m2 (a bit larger than the side of a double-decker bus) delivers up to10 kW of heat and 1.5 kW of electrical power. In a sun-belt country, one of these one-ton devices could deliver about 60 kWh/d of heat and 9 kWh/d of electricity. These powers correspond to average fluxes of 80W/m2 of heat and 12W/m2 of electricity (that’s per square metre of device surface); these fluxes are similar to the fluxes delivered by standard solar heating panels and solar photovoltaic panels, but Heliodynamics’s concentrating design delivers power at a lower cost, because most of the material is simple flat glass. For comparison, the total power consumption of the average European person is 125 kWh/d.
Figure 6.10. Some Miscanthus grass enjoying the company of Dr Emily Heaton, who is 5’4” (163 cm) tall. In Britain, Miscanthus achieves a power per unit area of 0.75W/m2. Photo provided by the University of Illinois.
“From Sustainable Energy Without Hot Air” http://www.withouthotair.com/
Wind
The UK has the best wind resources in Europe.Sustainable Development Commission
Wind farms will devastate the countryside pointlessly.James Lovelock
How much wind power could we plausibly generate?
If the typical windspeed is 6m/s (13miles per hour,or 22 km/h), the power per unit area of wind farm is about 2W/m2.
Cover the Earth 260 TW??????
How much wind power could we plausibly generate?
If the typical windspeed is 6m/s (13miles per hour,or 22 km/h), the power per unit area of wind farm is about 2W/m2.
Geothermal
Geothermal power in Iceland. Average geothermal electricity generation in Iceland (population, 300 000) in 2006 was 300MW (24 kWh/d per person). More than half of Iceland’s electricity is used for aluminium production.Photo by Gretar ´Ivarsson.
“From Sustainable Energy Without Hot Air” http://www.withouthotair.com/
Hydro-Electric
Three Gorges Dam On Yangtze River in ChinaApproximately 9 G Watts=0.009 Terra Watt
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