Presentation on theme: "Solar Energy. The Earth receives energy at a rate of 1365 W/m 2 ( R 2 )=174,000 TerraWatts R=6.37x10 6 m (Area =1.3x10 14 m 2 )"— Presentation transcript:
The Earth receives energy at a rate of 1365 W/m 2 ( R 2 )=174,000 TerraWatts R=6.37x10 6 m (Area =1.3x10 14 m 2 )
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
Multiply by 0.17 to reflect typical efficiency of solar collectors Terra Watts From Sustainable Energy Without Hot Air
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/m 2 for heating Need is about 30 kWhr/day /family 10 hr days 3 kW =3000 W Assumming an average power of 60 W/m 2 Area of 50 m 2 3m high by 17 m wide
How much non-Fossil Fuel energy must be created in the next 25 years? 495 x10 15 BTU per year =522 x10 18 Joules/year= 522 ExoJoules =16 TW =56 KWhr/day/person =$4.50 /day/person
From Sustainable Energy Without Hot Air Figure 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 (thats per square metre of device surface); these fluxes are similar to the fluxes delivered by standard solar heating panels and solar photovoltaic panels, but Heliodynamicss 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 Some Miscanthus grass enjoying the company of Dr Emily Heaton, who is 54 (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
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/m 2. 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, ) in 2006 was 300MW (24 kWh/d per person). More than half of Icelands electricity is used for aluminium production. Photo by Gretar ´Ivarsson. From Sustainable Energy Without Hot Air
Hydro-Electric Three Gorges Dam On Yangtze River in China Approximately 9 G Watts=0.009 Terra Watt