Question

What "breakthrough" from a theoretical point of view is needed for solar energy to become feasible energy alternative?

Answer 1

Although I am no big friend of the solar panels today - because they are subsidized - I think it is correct to say that from a theoretical point of view, we are already "there".

Solar panels are typically guaranteed to work for 10 years at their 90% capacity and/or for 25 years at their 80% capacity.

The price of a piece of solar panel producing 1 Watt may be as small as USD 1.30 today, see

http://www.ecobusinesslinks.com/solar_panels.htm

However, this is a Watt when it's actually running and in average, it's only running at the maximum capacity for 2 hours a day in average. Clouds, nights, and bad angles are a problem. So a Watt panel only produces 2 Wh per day or 730 Wh per year or 10 kWh per 15 years or so which is the estimated lifetime.

So assuming no extra expenses when the panel is already installed, and no expenses for their liquidation, you pay the minimum of USD 1.30 per 10 kWh, or USD 0.13 per kWh. That's actually acceptably cheap - a few times cheaper than the electricity sold in many European countries and pretty much identical to the consumer electricity price in the U.S. No profit.

In reality, countries such as my homeland introduced lots of subsidies and lots of solar panels were installed that were not yet cheap enough; and they were installed in places with suboptimal inflow of solar radiation. The counting implied that the electricity was five times more expensive than what it was sold for - the difference had to be paid from the subsidies.

But I think it's a purely technological question and we're on the edge of having solar panels that are profitable at the current market prices. Of course, you must also find the place where they're installed - on the arable land, you should also add the rent and/or opportunity costs for the food that could be grown up there. It's a barbarianism to use arable land for solar panels.

However, there's a lot of useless space where the panels could work - e.g. Sahara - and in a couple of years or a decade, the solar panels may become OK economically. It's now a job for the engineers to improve the materials and other things. of course, the main problem for solar panels today remain the fossil fuel (especially coal) competitors that are simply cheaper, so offer the energy companies to guarantee a safe and healthy profit, too.

But I want to say that if we ran out of the fossil fuels in some time, there would be no "physics obstacle" and almost no "economic obstacle" preventing us from switching to electricity that could be produced by solar panels. It's plausible that some totally new kind of a material will replace the materials used today - graphene (a layer of graphite, carbon) seems pretty promising at this moment (most existing solar panels contain silicon); it's conceivable that the evolution will be gradual and less dramatic. At any rate, there's no longer any reason to subsidize the solar panels. Quite on the contrary, the subsidies should be removed everywhere in the world to encourage the engineers to make the last steps needed for profitability.