Why can't we use giant magnifying glasses to magnify the sun's rays and heat water to make electricity?

Question

When I was a kid I used a magnifying glass to burn paper. Rather than using solar energy from Photovoltaics, wouldn't the magnifying glass allow you to boil lots of water and turn the same turbines our coal powered plants do today?

Answer 1

For such power plants, we need clear sky no cloud and zero velocity of wind. That to 24 hrs of day.
Clear sky will give maximum output and zero velocity of wind not damage glass surface so sun rays will concentrate at one spot..
So it is not commercially viable at least on earth.

Answer 2

Giant Magnifying Glass

Answer 3

Theoretically, it would work. Mirrors would be a much, much easier bet to pull off, though.
There are solar furnaces that do this in the world, but not on the scale you're talking about. It'd take lots of space, I used to imagine this scenario, too, when I was first introduced to optics.
It's not practical for magnifying glasses because the size and weight of the glass lenses gets so large they can't support their own weight, they'd distort under their own weight. Arrays of mirrors, however, work pretty well for this on a smaller scale than you're describing.

Answer 4

Actually, you can. Although such systems (still being researched) use reflectors rather than lenses. And oil rather than water - oil can absorb much more heat from the concentrated sunlight without boiling, which would break down the process. The steam is generally produced in a separate heat exchanger, just as with other types of steam turbines.

Answer 5

There was an experiment to do exactly that on Kirtland Air Force Base, except they used a field full of guided mirrors to converge sunlight on the boiler. The facility still exists, but I don't know if it's active.

Answer 6

When we learn to concentrate heat into a beam. (Not Lasers) we can have the magnifiers in space, directing the heat to where it's needed. It might take out the occasional airliner though!

Answer 7

Yes, it helps it you have dry leaves or paper to help start a little fire. You should be able to figure out the strongest burning "ray" by moving the magnifying glass back and forth until it is the smallest darkest circle

Answer 8

we do
several plants do
parabolic troughs magnify sun
focus on OIL in pipes

hot oil pumped to heat exchanger to make steam

regular steam turbine front end.

only large scale now

Answer 9

Who says we can't?

Answer 10

possible however not the most efficient way and completely untaxable