PV Gap

Renee Said:

why the hell hasn't the government invested in solar satellites for an energy solution?

We Answered:

There are two practical problems:

- gathering of energy.
Solar cells are not too efficient, so you need a huge surface to collect the light. The give you an idea, the ISS has enough solar panels to collect 150 kW, but it needs 100 m^2 of solar panels to do that. Now size that up to the size for what a city needs, 1 GW. That's 10,000 times more.

Solar cells are heavy. They are made of silicon. A 1m^2 solar panel has a mass of 20 kg. So to power a city, you need to bring 20 million kg in orbit. I am not going to calculate the energy requirements of that. But to give you an idea, the Saturn V had a mass of 2 million kg.

> only problem that i can see is transmitting the gathered energy back to the receiving station

Right on the dot! This is a problem. You can't do it with high voltage lines, so you use microwave power. Now imagine what happens if your beam is slightly off center?

Conclusion: a much easier and cheaper solution is to cover a desert in the Mid West with solar panels. Solar power from space just doesn't cut it.

Miriam Said:

what is the source of solution for solar energy?

We Answered:

solar energy

Gabriel Said:

Problem & solution with solar energy?

We Answered:

Problems with longevity and reliability of the materials have been mostly solved. That applies both to solar water heating and solar electric panels. A standard warranty for a solar electric panel is now 25 years.

Cost is an issue that is never truly solved, as solar electric will never be free. But panels have reached grid parity (that is, the all-in price of solar electricity is the same or less than buying from the electric company) in some areas such as mine, even without subsidies. Panels are literally less than half the price per watt that they were 4 years ago, when we installed our system. Our house has low energy consumption, we have no air conditioning, electric heat, electric stove, or pool. And still, solar will pay for itself, unsubsidized, in about 15 years. A big electricity user, including tax breaks, could see payback in as little as 3 years if they only offset their top-tier usage. But in places where electricity is already cheap, solar is not yet a good deal. Costs are moving in the right direction, though.

The problem that is yet to be solved is how to have an electric grid that handles massive amounts of electricity injected into it from thousands of tiny sources. The grid can absorb the small amount of solar connected today, but cannot handle every other house having grid-connected solar.