Photovoltaic Electricity

Solar Panels on Roof
In full sun nearly half a megawatt streams off this PV array
installed in 2004 by Pacific Power Management. Located in
Auburn, California, the system is among the largest in the USA

Editor’s Note: How photovoltaic cells proliferate could be compared to how a few plants proliferate and eventually become a forest. The primary variable cost incurred to manufacture photovoltaics is electricity, which is produced by, you guessed it, photovoltaics. Each photovoltaic cell will produce twenty times more energy in its lifetime than the amount of energy required in its manufacture, and this ratio continues to improve. From the perspective of energy payback as well as resource availability, photovoltaic cells are perhaps the most renewable energy source available today. They literally can create themselves. They are also absolutely pollution-free.

The problem with photovoltaics remains the costs. But two things mitigate this factor: First of all, photovoltaics are being bought as fast as they can be made. They may not be competitive with electricity derived from natural gas or other conventional sources, but this fact seems to have no impact on world demand for photovoltaics. The market worldwide is growing at 30% per year with no end in sight. Current world output of photovoltaics stands at about 1 gigawatt per year, and the installed base of photovoltaics in the world is probably just under 10 gigawatts. Not much considering the world consumes nearly 20,000 gigawatts of energy (all types – about 500 quadrillion BTUs put another way) per year. But the plants could become a forest.

A second factor which mitigates the cost of photovoltaics is the cost to operate and replace them is far more competitive than the cost to install them. In the table below, using California as an example, it can be seen that the cost to install photovoltaics to replace all of California’s electricity would be a prohibitive 1.5 trillion dollars. But the cost to replace photovoltaics on such an array as they wore out would be a more reasonable 30 billion dollars per year. This is only 50% greater than what Californians currently spend on conventional sources of electricity, which is about 20 billion dollars per year.

Table of Cost of Photovoltaic Power for All of California
It would cost roughly $1.5 trillion to replace California’s electrical capacity with
photovoltaic arrays at today’s prices without subsidies. But the replacement cost
on such an array, once installed, would only be 50% greater than the $20 billion
per year Californians currently spend on electricity.

For the last thirty years the price of photovoltaics has been predicted to plummet within the next five years, and it never did. But in the meantime, the price of photovoltaics has come down, to as low as $2.50 per watt factory wholesale, and under $10 per watt installed. The reason world output isn’t rising faster isn’t because demand isn’t strong, demand exceeds supply by a wide margin. The reason is because investors are convinced the breakthrough in costs is just around the corner, and they’re reluctant to invest $100M in a photovoltaic manufacturing plant that could become obsolete a year later. In many applications, particularly where electricity rates are higher during the day, photovoltaics already cost less – on a replacement basis – than conventional electricity. For this reason, they will continue to represent a long-term investment by companies and by nations that makes compelling economic sense. – Ed “Redwood” Ring

Nearly 100 million miles away shines a star that has been a part of life on earth from the beginning: The Sun.

The sun’s power has inspired many religions in almost every culture. The ancient Egyptians worshipped the sun god, Ra, who was believed to control the day and night by traveling through the twelve domains of the underworld and the twelve domains of the day. The impressive circle of stones found in Great Britain, known as Stonehenge, was designed to track the sun’s orbit around earth 5000 years ago. Ancient temples dedicated to the Incan sun god, Inti, are still standing today.

Solar Panel Installation on Roof
Atlantis Energy’s “Sunslates” generate
electricity while also replacing roof shingles

The sun has had a major influence on our beliefs and an even larger influence on our planet. The location of the sun relative to earth determines the season, we rely on it for light, and we rely on the sun’s rays for warmth. With new technology, the sun can provide us with energy as well.

Nasa Logo

National Aeronautics
& Space Administration

The National Aeronautics and Space Administration (NASA) describes the immense power of the star: “At the core, the temperature is 16 million degrees kelvin (K), which is sufficient to sustain thermonuclear fusion reactions. The released energy prevents the collapse of the Sun and keeps it in gaseous form. The total energy radiated is 383 billion trillion kilowatts, which is equivalent to the energy generated by 100 billion tons of TNT exploding each second.”

Many advances have been made in the solar panel industry and we have the equipment to harness the energy provided by sunlight to run a large part of our lives.

“The first conventional photovoltaic cells were produced in the late 1950s, and throughout the 1960s were principally used to provide electrical power for earth-orbiting satellites.

“In the 1970s, improvements in manufacturing, performance and quality of PV modules helped to reduce costs…In the 1980s, photovoltaics became a popular power source for consumer electronic devices, including calculators, watches, radios, lanterns and other small battery charging applications.” Florida Solar Energy Center

National Renewable
Energy Laboratory

Almost everyone has enjoyed the practical uses of photovoltaics. Just a little light needs to shine on a battery free calculator before the digits appear clearly on the screen. Yet these little photovoltaic systems are more complicated than they seem. Photovoltaics, or solar cells as they are often called, are panels that convert sunlight to energy. The National Renewable Energy Laboratory (NREL, explains that solar cells “are made of semiconducting materials similar to those used in computer chips [PV cells are made of thin layers of phosphorus-doped silicon on top of thicker layers of boron-doped silicon]. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. The process of converting light (photons) to electricity (voltage) is called the photovoltaic (PV) effect.”

Solar Roof on House
This completed photovoltaic array by Atlantis
Energy completely replaces the building’s roof

Solar panels are now more versatile than ever and are gaining as much popularity ON the home as they are IN it. Joe Morissey at Atlantis Energy Systems, Inc. describes the potentials of their product with great enthusiasm: “We have two types of photovolatics and they are literally the building’s skin. You place the skin on the building and you immediately have power generation. The typical solar panel consists of a large aluminum frame that is rectangular. Since most roofs aren’t rectangular these PV frames look very ungainly on a home. Our product lends itself nicely architecturally. They are aesthetic and practical.” Consumers have many choices when it comes to PV producers. “Most of the large-scale PV manufacturers are now making a “roof-shingle” style product, including BP Solar, GE Energy, Sharp, and Kyocera Solar,” says Marianne Walpert, Vice President of Marketing and Sales at Pacific Power.

Atlantis Energy Systems Logo

Atlantis Energy

Neighbors are unlikely to complain about the system even if the house isn’t as pleasing to the eye. Since everyone in a neighborhood shares the same grid, they all get to use the solar electricity (although they don’t enjoy the cost savings). Morissey states that “the power generated by the panels will be sent back to the grid once the battery packs are full, and the power from your home will offset neighbors demand and the local utility company does not have to supply that extra power”
The intricate solar panels are not easy to produce. Morissey explains that “the highest output cell is called single crystal. They are grown like a 7th grade science experiment that involves a growing crystal. But what goes into the photovoltaic cells is highly cleaned quartz sand. It is first smelted, then grown in a form and finally thinly sliced and treated with certain chemicals. Metal contacts are then placed on it and it is prepared for power generation. Everything has to be wired together with one panel wired to the next and so on. The net effect is a steady supply of power. It is an expensive process and used to take a large amount of energy. In the past it was hard to justify the extreme amount of energy used to make it. Back then solar panels where only made for remote locations such as space. As the technology improved, the process of slicing and smelting the product became quite advanced.”

Solar Awnings
In this example the photovoltaics form awnings
that would have to be constructed anyway

Unfortunately, PV cells are still pretty expensive. The Atlantis Energy website explains that “your roofing and electrical contractors will on average be charging $12,000 per 100 square feet (there is just over 1kW per 100 square feet) or $12.00 per watt.” Marianne Walpert of Pacific Power explains: “It is expensive because current PV panels take a lot of energy to make and they need purified silicon. It has to be 99.999% pure, and this is where the expense comes in. Purchasing the raw material, crystallizing it, cutting it into wafers and cells; these are all expensive processes. We all believe that cheaper solar panels will eventually exist, but in the past twenty-five years it has hardly changed at all. The manufacturing process has improved, but everything else is still the same.”

The market for photovoltaics has existed for quite some time, yet the popularity of this product is much lower in the United States than it is in other countries. Solar panels are visible on numerous rooftops throughout Europe and Japan whereas these panels are a rare sight on homes in the states. Photovoltaics are not cheap, but in the long run the investment is a good one: the power bill is less outrageous, the system is environmentally friendly and maintenance is practically non existent.

Sharp Logo

Sharp Solar

“Photovoltaics have caught the public’s imagination,” says Morissey, “it is clean, efficient and there is minimal maintenance. That is what we do, we install the system and then we’re done with it. The movement to solar power is a world wide phenomenon. Remember the time before cell phones? Everyone was hard wired. But there are areas where it is impossible to bring in hard wiring. What about houses in remote locations?” The potential for PV is immense and people seem to realize it. Even with less of a demand in the U.S than other countries PV businesses are doing extremely well. “Right now there is not enough of the product to get it around. Demand has outstripped supply,” says Morissey.

Solar Roof by Atlantis Energy
This photovoltaic array by Atlantis Energy
completely replaces the original roof

With an incredible demand for photovoltaics worldwide, it is obvious that the systems are working. Walpert says “the industry has grown at 40% a year over the last couple of years so obviously people can afford it and demand is rising.” Demand for the photovoltaics is still much higher in Europe than in the United States though. Morissay explains that “demand in Europe is phenomenal because power is more expensive there. The return on investment is higher. The government in Germany is also paying locals up to 54 cents for each kW/hour. If you are generating 20000 kW/year times 54 cents you are talking real money. The system will pay for itself 20 times over. What the government wants to ensure is a redundancy and long lived power so new power plants are unnecessary. They are making a serious shift to wind and solar power generation while the U.S is lagging behind.”

A considerable amount of harmful gases are produced when generating electricity through burning fossil fuels. “Three hundred and twenty five thousand pounds of carbon dioxide, twenty-seven hundred pounds of sulfur dioxide and over one thousand pounds of nitrogen oxide can be mitigated annually by a 100 kW commercial photovoltaic system. That’s about 25 home systems,” says Walpert. Countries like Germany and France have already stopped millions of pounds of harmful pollutants from escaping into the environment by shifting to solar power.

Pacific Power Management Logo
Pacific Power Management

It is surprising that a product that relies on sunlight to function is more popular in overcast Europe than it is in sunny California. The amazing thing about photovoltaics is that direct sunlight is unnecessary for it to function. Of course some light is required, but the cells are actually most efficient in colder conditions. This is why the solar panels are so successful in space. Photovolatics work wonderfully in countries like Germany and Norway where the weather is never too hot. “You think of the northeast [U.S] as being more cloudy,” says Walpert, “but you get about 80% as much energy in Boston as you would in Los Angeles. The sunnier it is, the better it works. Ideal conditions are cool and sunny but power is still produced if it is hazy or overcast.” Energy will be produced regardless of where the building in question is located.

Kyocera Logo
Kyocera Solar

One concern about solar panels is the amount of energy it costs to produce them. Fortunately, it has been established that PV systems pay for themselves in a relatively short time and more than make up for the high cost of their production. The U.S Department of Energy answers the question in more detail: “How long does a PV system have to operate to recover the energy-and the associated generation of pollution and CO2 that went into making the system? Energy paybacks for rooftop systems range from 1-4 years, depending on the system. With assumed life expectancies of 30 years, and taking into account the fossil-fuel-based energy used in manufacture, 87% to 97% of the energy that PV systems generate won’t be plagued by pollution, greenhouse gases, and depletion of resources. Based on models and real data, the idea that PV cannot pay back its energy investment is simply a myth.”

BP Solar Logo
BP Solar

The real question is whether solar energy will ever offset the need for electricity generated by the city’s nuclear power plant. Walpert likes the idea but doubts it will be possible in the near future: “It is highly unlikely be able to rely on pure solar energy until you get the right storage mechanisms. Fuel cells don’t produce energy; they make electricity from the energy stored in hydrogen. If you can imagine enough solar power to make enough hydrogen then it is possible. The obvious problem with solar power is nighttime. Batteries are not that efficient. If you could convert solar to hydrogen and then hydrogen to electricity it would technically be feasible to get all the energy you need from solar.” Systems that utilize both wind and solar panels in a type of hybrid system do exist and have a lot of potential as well.

The benefits of alternative clean energy are immense. Air quality is so horrible in many areas that the fumes block the blue sky for miles. With improved environmental awareness and ever advancing technologies, natural resources like the sun and wind may eventually generate all the power we need to live life without the guilt of over using the A/C.

Email the Editor about this Article
EcoWorld - Nature and Technology in Harmony

2 Responses to “Photovoltaic Electricity”
  1. Steve Yang says:

    Dear Ms. Muhawi,

    I came across your article just now. It was very well done. I would like to see a follow-up article. The advances in technologies have been impressive, and cost trend is encouraging. Your update and survey of state of the art would go a long way in educating and motivating the public about
    photovoltaics. You might also look into the global warming stats and highlight what you found.

    Thanks and looking forward to your response.

    pvsleuth, an EE devoted to energy efficiency.

  2. Anil Ghule says:

    Dear Sir,
    I came across your interesting and thoughtful article. The statistics you have collected and the information in the article is really valuable. I am working on similar lines to produce economic solar cells using Green Chemistry approaches.
    Thank you
    Best regards


Leave a Reply

You must be logged in to post a comment.