Global warming impact to our quality and cost of living is large and very catastrophic. Homeowners are well aware of the increasing energy costs to heat, cool and illuminate their homes. The increasing costs of oil and other fossil fuels are daily headlines. The insatiable demand for energy to fuel world growth guarantees that the cost of these limited fuels will continue to increase. Political/economic forces will determine the rate of increase for fossil fuels. In addition, the increasing cost of global warming using fossil fuels is slowly being recognized.
The world is slowly beginning to understand the urgent need for renewable energy sources. However, each of these alternative energy sources brings major advantages and disadvantages. An example is wind generated energy. Wind energy is available to the whole world and generates electricity competitively with fossil fuels. The technology is understood and easy to apply. But, there are big objections to a windmill in “my back yard”. Also, the number of birds and bats that will be crushed with wind power generation is not a warming thought. Wind technology will be a component of our energy solution. However, because of the above concerns, we need other major solutions to meet our demand for energy sources.
This search leads us to solar energy. The amount of sun energy striking our world in one day is sufficient to supply our energy demands for a year. We will not run out of this source in the foreseeable future. The major barrier to harnessing solar energy has been cost and convenience. For example, drying clothes in a dryer is easier than hanging clothes on an outside line, thus convenience precluded efforts to find more energy efficiency. We can convert solar energy to electricity but with a major capital cost. Greater acceptance and use of solar energy will lead to lower cost.
Energy from solar energy can be divided into two major categories:
Passive Solar Energy: This technology ranges from clothes drying in the sun to solar heating for hot water and many other passive techniques. All are important for our present and future quality of life. The technology is well understood and can be implemented as economics and space conditions allow.
Active Solar Energy: One of the active solar energy technologies is converting solar energy directly into electricity. It is called photovoltaic cell or PV. This is a device that converts light into electricity using the photoelectric effect. The first working solar cells were constructed by Charles Fritts in 1883. These prototype cells were made of selenium and achieved efficiencies around one percent. The silicon solar cell was created in 1954. The solar cell has benefited from the development of silicon semiconductors.
Physics of Active Solar Energy:
The physics of photon to electricity conversion is well understood by physicists. The basic model is of a photon from the sun which strikes the cell material and excites electrons that emit electricity. This model is simple compared to the complexity of modern day semiconductors. The major variables of PV electrical generation are cell material and impurities in the cell material.
Manufacturing Technology for Active Solar Energy:
Primarily single crystal, high purity silicon has been used to generate photon to electricity conversion. The manufacturing techniques for single crystal silicon and limited quantities of pure silicon impose a high cost for PV devices. Shortages of refined silicon have been hampering production worldwide since late 2004. This shortage persists to this date and has slowed PV growth. New materials are starting to come forward which should lower the PV materials hurdle.
Efficiency growth of Active Solar Energy:
Since the silicon PV invention in 1954, cheaper fossil fuel prices largely removed solar power from the public consciousness. Annual growth of electrical generation by PV ranged from 10 to 20% percent throughout the 1980’s and 1990’s. Worldwide installation of PV reached 1000 megawatts in 1999. Manufacturing costs for PV arrays has been dropping 3 to 5% over the recent years. This cost drop began to expand the use of PV electricity generation. Total peak power of installed PV was around 6000 megawatts at the end of 2006. Installed PV is projected to increase to over 9,000 megawatts in 2007. The average lowest retail cost of large photovoltaic arrays has declined from $7.50 to $4.00 per watt between 1990 and 2005.
PV materials have also been improving in recent years. The most recent materials approach is to process discrete cells on silicon wafers cut from multi crystalline ribbons which form thin films. This approach is the least expensive of known technologies. This group of technologies includes amorphous silicon cells deposited on stainless-steel ribbon, cadmium telluride (CdTe) cells deposited on glass, and copper indium gallium dielenide (CIGS) alloy cells deposited on either glass or stainless steel substrates. The efficiencies of these new materials are currently at 20%. Many researchers are working to improve the efficiencies. An added advantage of the new thin films is that they are flexible and are currently being used in roofing materials.
Current Trends in Generating Active Solar Energy:
Commercial businesses like Google, IBM, BJ’s Wholesale, Estee Lauder, Kohls, Target, Tiffany & Co., Wal-Mart are installing PV solar energy. From “big box” discount giants to high end commercial businesses PV solar energy is finding acceptance in 2007. The most recent retail-outfitter to become part of this trend is Macy’s, which announced earlier this month that it will install solar powered systems on 26 stores throughout California. These leading companies are turning to solar power because it makes good business sense and supports their environmental initiative. Creative financial arrangements allow these companies to afford the upfront capital costs and payback their loans with energy savings. So what does all this mean to the average home owner? PV Cost per Kilowatt (kWh):
In the California market, where state incentives and net metering are in place, PV electricity prices are dipping below 11¢/kWh, on par with some utility-delivered power. Moreover, according to the U.S. PV Industry Roadmap, solar electricity will continue this trend and become competitive by 2010 for most domestic markets. The outlook is very positive for PV generation of electricity. Once the capital investment is made, the cost of PV electricity is equivalent to fossil fuels and will continue to decrease.
Cost of PV Installation:
The cost of installation is the major barrier that has to be overcome for widespread PV acceptance. Around 59% of world solar product sales installed in the last five years were applications that are tied to the electricity grid. Solar energy prices in these applications are 5-20 times more expensive than the cheapest source of conventional electricity generation. This premium is well beyond the reach of the average home owner.
Fortunately, there are financial models coming forward to enable the consumer to finance PV solar installation and pay for this installation with the electrical savings. In order to make these financial models successful, federal and state incentives are needed and the installation should be connected to the electrical grid. These connections allow the home owner to sell back electricity when excessive amounts are available and to receive electricity when solar conditions do not allow sufficient electricity. Only fifty percent of our states have modernized to allow on-grid PV solar energy.
Berkeley, California is leading the way to enable it citizens to save electrical cost and meet environmental needs. Here is how their plan works. A property owner hires a city-approved solar installer, who determines the best solar system for the property, depending on energy use. Most residential solar panel systems in the city cost from $15,000 to $20,000.
The city will pay the contractor for the system and its installation, minus any applicable state and federal rebates, and would add an assessment to the property owner’s tax bill to pay for the system. The extra tax would include administrative fees and interest, which would be lower than what the property owner could obtain on their own, because the city would secure low-interest bonds and loans. The tax would stay with the property even if the owner sold, although the owner would have to leave the solar panels. The property owner would save money on monthly Pacific Gas & Electric bills because electricity generated by the solar panels would partly replace electricity delivered by the utility. After the assessment expired, the solar panels, of a simple technology that requires little or no maintenance, would continue to partly replace PG&E electricity.
The Berkeley plan is a map for the rest of the world to allow us affordable electricity and meet our responsibilities to the environment.