Solar power is in no way a new technology. In fact, it is the root source of all other power on earth. For example, wind is generated by the atmosphere, land, and water absorbing solar radiation at different rates. Fossil fuels are the remains of ancient living matter and we know that the sun is the beginning of the food chain. It provides the energy necessary for photosynthesis.
What is new within the last two centuries is the concept of directly harnessing the energy from the sun for the production of electricity. The term for this is “photovoltaics,” which combines the Greek root “photo,” meaning light, with “volt,” for electricity.
California, known for its green energy interest and very obliging weather, is at the forefront of many new discoveries and developments in the solar world. Of course, this doesn’t mean this field of science is completely without issue for Californians.
From its inception, photovoltaic viability has been limited by efficiency and cost. In order to understand these problems, it is helpful to first conceptualize how photovoltaic conversion works. Basically, it involves utilizing a material to absorb sunlight and produce an electric charge.
Selenium was the first material found to be photoconductive. The first photovoltaic cells created from this operated at a mere 1% efficiency. While selenium does convert sunlight into an electric current, the bandwidth it reacts to is very narrow. This is the reason why the conversion of the light’s energy to an electric charge is done at such a poor efficiency rate.
Up until the past decade, it was considered more efficient to use the thermal properties of sunlight rather than to harness the photovoltaic properties of different substances. For instance, many power plants exist which operate by focusing sunlight to heat a thermally responsive liquid. This liquid is then used to boil water, which in turn creates steam. The steam then spins a turbine connected to a generator to create electricity.
Thermal energy is hardly the ideal of an efficient system. The elaborate process described illustrates just how inefficient the methods of generating electricity from the sun have been. The fact that photovoltaics were considered even less efficient demonstrates why the area has not historically been as appealing of an option.
Luckily, this field of technology has seen many recent advances. These include the production of integrated film solar cells as well as the discovery of a photovoltaic cell which can capture more than 50% of the sun’s energy. Integrated film cells are less efficient than the iconic silicon crystal arrays that are synonymous with solar power. However, they are extremely inexpensive to make, and would have applications that crystal arrays cannot hope to match. For instance, an integrated film could be put on the exterior siding of buildings to produce electricity without altering the aesthetic properties of the siding. Similar applications would be available for vehicles as well. Imagine every building and car as a miniature solar plant and you can see the appeal.
The opposite end of the efficiency spectrum can be found in new research from the Lawrence Berkeley National Laboratory in California. They discovered a three layered substance which can capture virtually the entire spectrum of sunlight and convert it into electric power. The laboratory efficiency of this substance has exceeded 50%. Refinement of the capture system and a means of mass production would make solar power the most commercially viable energy source within the next ten to twenty years.
However, most governments are not content to wait on that eventuality. Worldwide, countries are incentivizing all alternative energy sources, solar power in particular. For instance, German law mandates that utility companies buy back solar power from consumers at a fixed rate. The United States has a similar law, but what makes the German law unique is that a consumer can actually profit from the solar power. In the United States, the best outcome that you can achieve is a power bill of $ 0. The utility does not have to pay you for power in excess of what you use during off times.
Many U.S. tax incentives to install a photovoltaic system for your home or business exist. Perhaps the longest running and most well known example is the California Solar Initiative (CSI). This program pays existing home owners, new home builders, and commercial enterprises for installing solar kits. The incentives are considered necessary because of the high initial cost of a solar array. While an array that runs for 20 years (the engineering standard for solar systems) will end up paying for itself, the high installation cost can be a barrier to many who find them desirable.
Germany leads the world when it comes to photovoltaic installations. This is interesting because the country is well known for its cloudy skies. With that in mind, the fact that other states do not have as mild of weather as California does not cause them a significant disadvantage.
Solar power certainly has a bright future. Between existing research and the new horizons opened by emerging technologies, it has the potential to meet all of our power needs within the lifetime of children born today. This is exciting! The limitations of our world are almost invariably energetic in nature. If energy were not an issue, many other new fields of research would also be open to us.