28-09-2012, 04:46 PM
Earth based solar power
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Earth based solar power
Why bother putting solar panels on a satellite when you could generate electricity by putting them on the ground or on rooftops here on Earth? The obvious problem is that any point on land is in the dark half of the time, so solar panels are useless during the night. During the day clouds can also block sunlight and stop power production.
The idea of generating power in space has been around for a while, but has never really gotten off the ground.
In orbit, a solar power satellite would be above the atmosphere and could be positioned so that it received constant direct sunlight. Some energy would be lost in the process of transmitting power to stations on the Earth, but this would not offset the advantage that an orbiting solar power station would have over ground based solar collectors.
There are also opportunity costs associated with both options. On Earth, land used for generating solar power is not being used for other things. Rooftop space may not be valuable, but acres of farmland are. There is also only a limited number of available slots in geosynchronous orbit where a satellite could be placed to continuously beam power to a specific receiver. Where land is at a premium, a satellite would have an advantage over a ground-based system.
For places with plenty of sun and available land, satellites couldn’t compete with generating solar power locally. It would be difficult to argue for the need of an orbital system if every place had San Diego’s weather and climate, but since this isn’t the case there would be demand for beaming solar power to locations that couldn’t generate it otherwise. Using solar panels here on Earth though is far easier and less expensive, so much of the focus on renewable energy solutions is not on satellite systems.
High cost of launching
Another barrier is that launching anything into space costs a lot of money. A substantial investment would be needed to get a solar power satellite into orbit; then the launch costs would make the electricity that was produced more expensive than other alternatives. In the long term, launch costs will need to come down before generating solar power in space makes economic sense. But is the expense of launching enough to explain why so little progress has been made?
There were over 60 launches in 2003, so last year there was enough money spent to put something into orbit about every week on average. Funding was found to launch science satellites to study gravity waves and to explore other planets. There are also dozens of GPS satellites in orbit that help people find out where they are on the ground. Is there enough money available for these purposes, but not enough to launch even one solar power satellite that would help the world develop a new source of energy?
In the 2004 budget the Department of Energy has over $260 million allocated for fusion research. Obviously the government has some interest in funding renewable energy research and they realize that private companies would not be able to fund the development of a sustainable fusion industry on their own. From this perspective, the barrier holding back solar power satellites is not purely financial, but rather the problem is that there is not enough political will to make the money available for further development.
Competing with other options
Even if a solar power system was built and launched there would still be the economic problem of producing electricity at a cost that is comparable to other options. Government subsidies can help get this new industry on its feet but it will need to compete in the market in order to survive. This is a challenge for all emerging renewable energy solutions.
Current non-renewable energy supplies are cheap. Even with the recent increases in the price of oil, it is still historically low. Adjusted for inflation, gas prices are still much lower than they were during the oil crisis in the 1970s. With current prices there is little incentive for customers or producers to pursue alternatives. Even if oil prices continue to increase, it is not likely that this will be enough to drive demand for alternatives. Although we will eventually run out of oil, coal, and other non-renewable energy sources, in the short term rising oil prices will simply generate more oil.