- Renewable & Alternative Energy
Aternative Energy Sources: Solar Energy
With gas prices climbing, the search for cheaper, cleaner, and renewable energy is still underway. There are now electric cars, fuels cells, and general knowledge about wind, solar, tidal, bio-fuel, and ethanol energy that the majority of people are aware of.
What are the pros and cons of these alternative resources? How will they match the energy already provided by nuclear and fossil fuel? Can there really be a change? Are there any other resources out there besides these? Well, let's find out.
First, Solar Energy. How it works, the various types, and the pros and cons of Solar Energy will create this hub.
How Does Solar Energy Work?
Of course, anyone would think, "With the sun. It shines on a solar panel and we get energy". That concept seems simple enough. Just have a sunny day, install a black solar panel, hook it up to a storage container, and BAM! Energy! Well, it's not that simple in terms of solar panels. But in regards to solar heat collectors, it's not that far off.
Solar heat collectors were pretty popular back in the 1970's during the energy crisis. They were boxes painted black on the inside with a glass cover. The sun's rays would enter the box, heat a water mixture inside it, and the water mixture/steam would circulate throughout the house in tubes, heating water or powering radiators. Pretty simple.
But modern solar power deals with something called photovoltaics. These solar panels work by having two semiconductor materials layered. The semiconductors are made of silicon crystals which are "doped" (impurities are added because silicon isn't all that good of a conductor all by itself.) One layer is doped with an element to give it a positive charge (normally boron) and the other layer is doped to give it a negative charge (noramlly phosphorus). Add sun to the PV cell and the electrons from the atoms start bouncing from one layer to the other, which creates electricity. The electricity is then stored and you have energy.
This sounds just dandy. Put one or two on your house and you have free energy! But, there is yet another problem. These are not efficient. The cells do not produce as much energy as you would think. The sun has to go through millions of miles of space, past the ozone layers, fight trees and such, and heat a solar panel. The heat produced is not all that great! Another issue is that some areas of the world get more sunlight than others during the day. And then some days are overcast or cloudy--that harms solar energy collection as well. Not to mention, actual cost of production of the cells.
Tinkering was done. Several different types of PV cells were created. All with the same type of formula, though--a positive charge and a negative charge that reacts with the sun. Cost may have been reduced for these cells, but efficiency suffered as well.
Then, someone thought "Hey! More heat means more energy! Why not try to use the extreme heat from the sun to make energy!" That was the birth of Solar Thermal Concentrating Systems.
These are pretty different from the PV cells. They really use mirrors and water. Three types are in existence: parabolic troughs, parabolic dishes, and central receivers (by far the coolest looking one). Parabolic troughs are essentially rows of curved mirrors with a tube of water running parallel to them that goes to a central collector where the now-turned-steam spins a turbine. These mirrors reflect the sun back into themselves, really getting that area pretty hot.
Parabolic Dishes run of pretty much the same procedure as parabolic troughs. But they reflect their light to a single point to create much higher temperatures.
Central receivers, or power towers, take this one step further. Large quantities of huge mirrors reflect their light on a single point on a very large tower. The area gets really hot and it boils a water mixture to spin a turbine to generate power.
Out of the three, the parabolic troughs have seen higher success in terms of commercial sales. Central receivers require huge amounts of land and parabolic dishes are being tweaked and combined with stirling engines to create energy. But, basically, these are how solar energy is produced.
Solar Power Sounds Pretty Good!
It really does. But, like all forms of energy, there are things that are not so good along with things that are.
- The only pollution produced by solar power is the pollution from the manufacturing of the panels and mirrors and such.
- Solar Power is very quiet compared to other resources.
- Energy can be gathered from any place, no matter how remote.
- Solar Power can save a lot of energy over time and can even be cheaper to install than power lines and infrastructures.
- The areas on the Earth that are capable to use Solar Energy is huge. And further development is making solar energy more efficient on those cloudy days.
- Solar panels can be installed on rooftops, so the land required for it is reduced.
- The cost of installation is pretty high. It pays for itself in the long run, but the initial start-up is hard to do.
- Solar energy can only be used during daylight hours.
- Weather can affect the cells, including pollution. Polluted areas like cities can really knock down a solar cell's efficiency.
So now the questions iare, can this be a source of energy that can be used? Is this a viable resource to turn to? Maybe. It is certainly better than fossil fuels, which pollute and are exhaustible. And when you think about it, how much money do you spend of gas a year to heat your home? Maybe cutting back some expenses and saving, along with further research, will make you decide to opt for Solar Power.