Questions tagged [renewables]

a resource that can be created or used over and over again without depleting the materials from which it is made.

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7
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3answers
137 views

Is “renewable” a proper term for both solar and hydro power?

The common definition for renewable energy sources includes at least: Wind Solar Biofuels Hydro Geo-thermal However, the common definition of renewable makes this grouping a bit awkward. Webster ...
3
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3answers
278 views

Are trees more productive than wind turbines?

Tree farm assumptions: 250,000 square meters (m2) tree farm A 1 ton tree contains 1 MWh of energy Each tree takes 10 m2 of space Total energy for this farm is thus 25 GWh Wind farm assumptions: 5 ...
8
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3answers
157 views

Is pellet fuel a sustainable energy source in the way it's used now?

Pellet fuel is considered a sustainable energy source. But the way it's used now seems to produce air pollution which I think should not happen in case of sustainable energy source. So is pellet ...
6
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2answers
327 views

Are RECs (Renewable Energy Certificates) an effective method to “green” industry?

Chris Goldie's answer to a question on sustainable web infrastructure brought this question up. From the US Environmental Protection Agency: A renewable energy certificate, or REC (pronounced: rěk)...
5
votes
1answer
70 views

Is there an “energy returned on materials invested” index for energy sources?

We already try to measure how much energy is invested (EROEI) in the production of energy, but I have a hard time finding numbers on the materials invested. For example: What is the total energy a ...
1
vote
1answer
232 views

Does a PV panel take more energy to build than it generates in its lifetime? [duplicate]

Industrial energy costs are $1 per million BTU (MMBTU) or 300kWh, or $3*10^-6 per watt hour (Wh). http://www.eia.gov/consumption/manufacturing/ Solar has 1 kg of 9n silicon per 100W, at $20/kg. ...