PV Gap

Brian Said:

What would be the best Engineering speciality to take to be involved with renewable/ alternative energy?

We Answered:

Chemistry is fun- you get to blow stuff up! Keep away from the nukes though, we don't want to blow one of them up. Electrical is good. Someone also has to design new systems for installations on houses/businesses.

Jimmie Said:

Renewable Energy and Global Warming? Are Solar and wind helping?

We Answered:

The short answer is 'no', they aren't taking energy out of the air in the long run because whilst wind absorbs energy that was already in the atmosphere it is then used up as electricity, which is ultimately given out as heat and returned to the atmosphere. The net effect is zero.

Renewable energies emit less CO2, even once you include building and maintaining them. This slows global warming.


In terms of absorbing heat, it's a bit more complicated than that. Power stations burn fuel and cause a bit of global warming that way: usually 2-3 units of heat for each unit of electricity (including the electricity which eventually heats the atmosphere).

The effect of solar panels depends on where you put them and their efficiency. If they are 10% efficient and you put them on shiny 90% reflective ice, then they actually mean you absorb 9 units of heat for every unit of electricity you make and they increase global warming - the ratio is 3 times worse than a fossil fuel or nuclear power station. But on the plus side, the carbon savings are a much, much bigger effect.

If you put a solar panel on a dark asphalt surface and you don't change the reflectivity of the surface, then you're getting power for 'free' in heat terms - you're not absorbing any more and your ratio is 1 unit of electricity for 0 units of extra heating...


(I did a physics masters in solar cells and I'm now doing a PhD in climate science - I did the maths already for a solar power system's effect on global warming, e-mail me if you want it)


George Orwell is spreading his ignorance once again. Atmospheric temperatures here:
http://www.skepticalscience.com/Did-glob…
Of course, the atmosphere isn't the only part of the globe. Trillions of tons of ice have melted since 2000 and sea levels have continued to rise as more heat goes into the oceans. In George Orwell's world, more energy in the climate system isn't global warming though.