How Solar Energy Works

Each and every day enough more than enough sunlight passes through our atmosphere to power our entire planet for a year. Considering that by 2040 it is estimated that 50% of our energy will be coming from renewable sources, that solar panels have essentially no negative impact on our environment, that they are relatively easy to create, and that they are becoming more and more cost effective – it is obvious solar energy is going to play a major role in our future.

Cost is clearly the largest downfall when considering solar cells are a viable source for renewable energy. Compared to other leading energy sources such as coal, oil, and natural gas it is significantly more expensive – mainly the original installation which costs upwards of 30,000$ for the typical family. The main reasons for these higher prices are the lack of competition in the market and lobbying against solar energy by fossil fuel companies. With that being said, solar panel prices are continuously dropping as demand increases, while becoming more and more efficient at the same time. Government rebates as well as tax credits can also give you around 30% back on your investment right away. Not only this, but you can actually make money off residual energy being sent back into the power grid. In the long run it is an extremely good investment. For example let’s say your monthly energy bill is 250$, that means that in the next year you will spend 3,000$, in the next 10 years you will spend approximately 41,449.34, and 30 years 283,382.36 (taking inflation into account). Although solar energy most likely wouldn’t be able to cover all of your monthly energy needs, it could reduce your bill by 80%, saving you over 2,400$ a year. Considering a 30,000$ system will pay itself back in 10 to 15 years, and the average lifespan of a solar panel system is 25 years you will be getting the majority of your energy for free for 15 years, a time period when energy prices will be at an all-time high.

Solar energy has essentially zero negative impact on the environment in comparison to traditional fossil fuel energy sources. The only potential dangers that it poses to the environment are leftover materials used in the creation of the solar panels such as silicon tetrachloride which if not disposed of properly could pose a risk to the environment. Solar panels also require a fairly large amount of energy to make, which pollutes the air, creates heavy metal emissions, and also releases greenhouse gasses.

The way solar energy production works is actually quite simple. Essentially photons released from the sun come in contact with a semiconductor, the semiconductor absorbs these photons, and finally energy from the photons knocks electrons inside the semiconductor free generating an electric current, although there is a little more to it than just that.

In order to get electrons flowing and creating electricity, an imbalance in charge must be created. This is done by “doping” a semiconductor, such as silicon in this case, with an element such as phosphorus. Phosphorus has five valence electrons, so when you mix it with silicon the result is 1 electron which is easy to move. When this electron is removed, you get a negative charge, also called N-Type silicon. The next step is to dope a separate sheet of silicon, except this time with boron. In this case the opposite happens, a positive charge is created in the silicon – also known as P-Type silicon. This P-Type silicon is looking to gain an electron. When you put the two together a PN Junction is formed. Electrons rush over from the N-Type silicon into the P-Type silicon filling in any available holes, but there aren’t enough. Eventually, equilibrium is reached and an electric field is formed in the middle. These are simply examples of materials which can be used; it can also be done with many others.

Now, once light hits the solar cell it dislodges electrons that are close to the electric field in the middle and sends them off to the other side creating further imbalance in charges. When an external current path is added, electrons are able to make their way back over to the other side and fill in the holes once more – while at the same time doing work. The result is very simple; the electrons provide a current while the electric field in the middle provides voltage. These two combined create power.

Although as of now commercially available solar panels only have an efficiency rate of around 20%, year by year scientists have been able to increase this number which brings great hope for the future. Even though solar panels may not be the best option today, they most certainly will be down the road.