Solar Energy

1. Solar Energy Solar energy is most commonly associated with solar panels on a residential roof, or large arrays placed in the desert to capture and convert the energy from the sun into usable electric power. More and more people are relying on solar systems to either reduce electricity costs or to get off the electrical grid completely. The sun releases immense amounts of energy everyday and this energy is known as Solar Radiation. The sun is 93 million miles from earth and it takes just 8.3 minutes for this energy to travel between the two. Amazingly it takes only forty minutes of this energy from the sun to power the entire electrical needs of people around the world for a year. Why are we not taking advantage of this resource to supply all of our power needs? The sun has been contributing to earth’s energy needs for a very long time. Commonly used fossil fuels such as oil, coal, and natural gas have been deposited through decomposition of materials through sunlight. These forms of energy are not limitless and contribute harmful waste byproducts to the environment we live in. It is estimated that the sun will continue to burn for another five billion years. Why shouldn’t we look at ways to harness the free and clean energy provided?

2. Solar Technology Overview – Industry Growth and Cost The solar energy market worldwide is growing as depicted in the charts below. Germany and Japan are the worldwide leaders in growth, mostly spurred by government incentives. One of the biggest concerns with solar energy is the cost of installation versus the return on investment. This is why government incentives are needed to spur growth in the industry, which does not make it an attractive choice for many people or businesses. As demand grows, manufacturing processes will improve, driving down costs and making solar energy a more attractive alternative. The cost for one watt of solar energy in 1975 was $50, in 2000 the cost had fallen to $5 per watt, and today you can purchase a solar panel at $1.80 to $2.30 per watt. Even though costs have dropped dramatically, energy provided by fossil fuels is still much cheaper.

3. Another area of concern with solar energy, and an area with high growth potential, is the efficiency of a solar panel. Current designs using Photovoltaic cells made mostly of silicon, can convert 15 – 18% of the solar energy that it absorbs. Compare this with fossil fuels that for the most part are 100% efficient, and you have another big hurdle facing solar energy. There are some strides being made in the efficiency of solar energy conversion: “Solar Junction is a 4-year-old company spun out of Stanford University that designs high-efficiency, multi-junction solar cells for concentrating photovoltaic (CPV) solar collectors. The National Renewable Energy Laboratory recently certified that its solar cells can operate at 40.9% efficiency, a significantly higher efficiency than typical silicon solar cells that convert sunlight to electricity at an efficiency of about 15-20%.“ “Spire Semiconductor reportedly set a new world record for solar cell efficiency in October 2010. Working with the US National Renewable Energy Laboratory (NREL) under an 18 month incubator project, the company produced a “triple-junction cell” that has apparently achieved a 42.3% conversion efficiency. Other companies have been working on this technology with great success as well.” There are great strides being made to make solar energy conversion more efficient. This research and development takes time, and multi-millions of dollars to develop, and still will not come close to the efficiency of fossil fuels in the near future. Solar Technology Overview - Efficiency

4. Solar Technology – Current Applications Despite the higher cost and less efficient performance of solar energy technology, there are still a number of applications where the technology is being used. In some cases solar is the only option to having any power at all. Commercial Applications – Many government entities are requiring power companies to provide a certain percentage of renewable energy. This is the reason for the large solar arrays usually located in the desert. Not all renewable energy comes from solar applications Residential Applications – This is commonly done to reduce dependence on the electrical grid or to get off the grid altogether. A solar water heater can reduce your energy bill by as much as 15%. Natural heating and cooling (Passive Solar) utilized in some areas. Outer Space – The International Space Station and most modern satellites rely on solar power. It would be very inconvenient to have to ferry fossil fuels for these applications. Remote Areas - In situations where there is no electrical grid, solar can be the only option. Less developed countries with no power systems use small wattage systems to just have lights. Cell phone relay towers located in remote areas also use solar as a power source. Cars – Still an emerging technology with growing interest because most people associate the use of fossil fuels with cars. Gadgets – There is an ever increasing amount of solar rechargeable gadgets for cell phones, camping, radios etc.

5. Solar Energy – Benefits and Shortcomings Benefits Free – No charge for collecting sunshine (converting to energy is not free) Clean – No harmful by products and it reduces fossil fuel emissions Abundant – The most abundant resource available on earth Incentives – Government provides tax breaks for most applications Satisfaction – Being off grid and not paying the utility company Shortcomings Expensive – Compared to traditional fossil fuel applications Efficiency – Improvements need to be made in this area to improve ROI Design – Some home ownership groups forbid solar panels in certain areas Sun Exposure – If you live in an area prevalent to cloud cover solar arrays must be much larger to compensate – Battery systems required for power at night

6. Solar Energy There is a lot of information available via the internet involving solar energy applications. Interestingly, when visiting two large bookstores looking for reference materials, very little was available. Internet book suppliers have an endless supply of materials, and there are numerous web sites devoted to this topic. You do not have to be an expert to understand solar energy. In most states you don’t even have to be licensed to install a solar energy system. You will need a basic understanding of electricity, and possibly some basic understanding of the sun’s path where you live. For those involved in research and development of improving solar applications, Physics, Electrical Engineering, Thermo Dynamics, and Materials Engineering would be required areas of knowledge. Reference Materials Chiras, Dan. “Power from the Sun,” New Society Publishers -2009 AZ Solar Center.org Clean Technica.com Soalrbuzz.com