Solar Industry Outlook

Electric Power

Solar Energy can be measured in kilowatt-hours (kWh).  1 kilowatt = 1000 watts.  Consume or produce this power for one hour and you have 1 kWh of energy.  1 kWh is the amount of electricity required to burn a 100 watt light bulb for 10 hours.  Directly perpendicular sunlight contains close to one kilowatt of power falling on each square yard at the earth’s surface on a clear day.  This is called the Solar Constant.

• The Earth receives enough energy from the Sun each hour to power the entire world for a year.
• An area of 100 miles by 100 miles, covered with photovoltaic (PV) panels could provide all the electric power currently needed by the U.S.
• In California, covering every available commercial and industrial roof with solar power panels could generate all of the electricity needed in the state during the daytime.
• Sunlight falling on an area the size of a two car garage can provide all the power that a typical house needs.
• Each kilowatt of PV can produce as much as 2000 kWh per year.

The silicon photovoltaic cell was discovered in 1954 by Bell Laboratories by researchers examining the sensitivity of a properly prepared silicon wafer to sunlight.  Beginning in the late 1950s, photovoltaic cells were used to power U.S. space satellites, the Mars Rovers, and stand-alone applications like call boxes, buoys, weather stations, and telecommunication repeaters.

The price of photovoltaic (PV) solar power panels has dropped from $600 per watt over the last 55 years to less than $1 per watt today for large scale thin film panels.  Installed systems cost between  $3 per watt and $8 per watt depending on size, location, incentives and other and conditions.

In 2010, SunPower announced a 24.2% efficient full scale solar cell. This record breaking achievement was confirmed by the U.S. Department of Energy.  Current high-performance panels, on average, convert about 17% of the light that strikes it into electricity. Conventional poly-silicon solar panels convert about 14% of light into electricity.

California has over 75 Megawatts of photovoltaic systems, including 74,000 grid connected houses.  San Diego currently has over 7000 residences with PV systems offsetting electric purchases from SDG&E.

Utility scale solar PV plants can be constructed more quickly and costing less than nuclear power plants.  Solar plants typically produce power when utilities need power the most, rather than 24 hours a day.

Sempra Energy has installed 58 megawatts of ground-mounted PV panels in Nevada for sale of power to PG&E.  The company claims this is the lowest cost solar electric power in the world.

The Sun’s energy that hits solar panels and is not converted into electricity is absorbed in the form of heat.  Heat degrades the output of silicon cells by about .5% per degree centigrade.  So, silicon PV panels put out more electric power when cold and less when hot.

Thermal Power

Sunlight also contains about 3500 BTU’s per square yard per hour.  This can heat 100 gallons of water  4 degrees F per hour.  You can cook food using nothing more than raw sunlight.  Home Energy Systems  demonstrated this at the 2004 Earth Day in Balboa Park, cooking over 300 veggie-burgers with a six foot diameter reflective dish.

California opened its first large solar power plant in 1982.  It now has 360 Megawatts of large solar thermal electric generating stations (SEGS).  The company, Bright Source, has recently broken ground on a central solar receiver (power tower) of 400 MW alongside I-15 near the Nevada border. This will be the largest solar thermal generating plant in the world.

Sunlight travels to the earth in approximately 8 minutes from 93,000,000 miles away, at 186,282 miles per second.  In July 2010 a manned aircraft flew round the clock on nothing more than the Sun’s energy.  The craft flew for a total of 26 hours.  The possibilities are endless.
Illuminating Power

• 50% of incident sunlight is visible light, 40% infrared, and 10% UV
• Direct sunlight falls during 80% of business hours in San Diego.
• The illuminating power of sunlight is 9000 times the minimum we need to read

Normal 100 Watt incandescent bulbs emit 1700 lumens, or 17 lumens per watt.  93% of the electric power consumed is emitted as heat (IR).  They are 12 times more efficient at producing heat than light. Their life is listed at 750 hours

Compact fluorescent lights emit 51 lumens per watt.  Their life is listed at 10,000 hours, but is usually limited by the number of on/off cycles.  They are also fragile.

Recently produced LED lighting can produce 75 lumens per watt.  These withstand vibration, wetness, temperature extremes, and may last 50,000 hours.

Full spectrum sunlight has much better color rendition than most electric lights.  This has been shown to improve retail purchasing behavior and worker productivity, both worth as much as 100 times the value of the electric savings.

Offsetting electric lighting and conditioning the heat produced by lamps may make more sense than producing electric power from sunlight and converting it back into a lower quality electric light.

 

Environmental Power

Silicon from one ton of sand (SiO₂), used in photovoltaic cells, could produce as much electricity as burning 500,000 tons of coal. Offsetting the burning of 500,000 tons of coal will eliminate the release of 1.7 million tons of carbon dioxide into the atmosphere.   This is a cube of pure CO₂ 3000 feet on a side.

Typically, each kWh produced by renewable sources is credited with offsetting 1.3 pounds of CO₂.  Carbon emissions have a true cost which is large and not generally accounted for.  It is difficult to measure the cost of global warming, but more recent studies suggest that when a tipping point is reached sea level may rise in an alarmingly short period of time, threatening coastal cities around the world.  Climate change, as a consequence, is a fact generally accepted by scientists but not industries.

Renewable Energy Credits (RECs) are an attempt to quantify the value of offsetting emissions.  The market is more advanced in Europe than America, but values of each Megawatt hour produced by clean sources will be valued at something between $20 and $50.  This amounts to a value of 2-5 cents per kWh (cpkWh).  This will become a substantial spur for the clean energy industry.

About 2 billion people in the world are currently without electric power at all.  That’s roughly one third of the entire population.  Solar Energy can improve quality of life, productivity, literacy, joblessness, health and hygiene, communications, and help many of these people in remote locations integrate into the modern world.

Distributed generation, many small systems at the site of usage, can offset the need for power line construction, and eliminate transmission losses that may be as much as 9% of all power generated.

Industrial Power

The solar industry has been growing at a rate of 30-40% per year, until the recent economic disruption in financial markets.  Billions of dollars in solar projects were put on hold or cancelled due to lack of financing, at the same time as gasoline rose to $4 per gallon.

China has targeted solar (and wind) as industries to dominate in the future.  In 2007 there were 7 foundries in the world producing Silicon metal.  At the time, China was constructing six new such foundries.  In just a few years China has become the world leading country in producing PV panels.

Right now solar represents one of the best investments people and businesses can make.  Over the lifetime of a solar PV system, the cost of electric power is about 7 cpkWh.  San Diegans with electric bills over $100 per month are paying about four times that in upper tiers of their bill each month.

Solar is on the radar screen,  now, as a growing and significant part of America’s energy mix.  Conventional power plants can generate power efficiently 24 hours a day, but especially in cooling dominated climates, such as the desert Southwest, solar can and will provide large amounts of electric power when the utilities need the power most, and the sun is brightest.