# Questions tagged [renewable-energy]

Questions related to energy produced by renewable systems such as solar, wind, water and geothermal.

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### Is there any technical bar from restarting the nuclear power plants of Germany?

Any that makes it impractical or, yet worse, impossible? If no, how long should it take for Germany to get them back online?
66 views

### Different equations for Hydropower

I was doing some reading in hydropower and I came across these two power equations: $$P = ρghQ$$ and $$P = QHg$$ Q is flow rate, ρ is water density, g is gravity, h is height, and H is head. I do ...
• 271
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### Does a fully mechanical heat pump make sense?

Is it reasonable to operate a fully mechanical heat pump? For example, using a linear back-and-forth motion from a vortex bladeless turbine to operate a mechanical compressor to heat (or cool off) a ...
• 115
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### Is it better to charge my electric car on windy days?

There are various dashboards (for example, here) that show the current energy generation mix and the overall CO2 emissions (gCO2/kWh). In the UK renewables can make up a large proportion of the total, ...
• 13
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### How large would a solar panel array need to be in order to supply all the world's energy?

This story from 2016 claims that all the world's energy needs could be supplied by covering 1% of the Sahara in solar PV panels. Was (is?) this true, and if not, how would you go about approximating ...
• 121
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### Can tidal turbines be used as run of the river generators

I see that the British government is supporting a project to generate energy using tidal turbines. I am wondering if the same design would be effective and economic also for run of the river power ...
210 views

### How do 3 blade turbines come so close to the Betz Limit?

I have seen many diagrams (see attached) that indicate that modern 3 blade turbines are nearly 50% efficient, which is about 80% of the Betz limit. Betz calculated his limit based on a theoretical ...
• 121
1 vote
28 views

### what are some books/academic journals which I could read on renewable energy/technology? [closed]

Book suggestions on renewable energy technologies/sources
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### What theoretical efficiencies can wind / hydro turbines achieve? [closed]

The high water has some energy E = mgh. In the basic school, we were told that hydropower plants extract the energy of "falling water". Now, that banned principle says that if your water falls upon ...