SOLAR POWER PLANTS NEED NOT WASTE WATER

Dependable Solar Products, ETA Engineering part of "Green" award winning team

Recently Lockheed Martin and its financial partners "pulled the plug" on a proposed 290- megawatt solar thermal plant west of Phoenix. This is good news, as solar thermal power plants use a lot of water and are not the best energy solution in the arid Southwest. Most solar thermal power plants generate electricity by concentrating the sun's energy to heat thermo-oil to 400 degrees Celsius. Using a heat exchanger, the thermo-oil heats water to create steam, turn turbines and create electricity.

Utilities are comfortable with steam generation using coal, oil, natural gas or nuclear power as the heat source. We tend to use what we are most familiar with. But with a large portion of the Imperial Valley shut down due to the lack of irrigation water, and other areas facing increased pressure on water supplies, we in the arid Southwest need to be aware of wasteful water usage. Nuclear and solar thermal power plants evaporate about one gallon of water for every kilowatt-Hour (kWh) generated. Palo Verde evaporates the effluent water from Phoenix and its surrounding cities to cool its three large reactors, using hundreds of thousands of gallons of water per year.

Dependable Solar founder and CEO Lane Garrett has been involved in Arizona's solar power industry for more than 35 years. "Scottsdale Fire Station 2 is a great example of how solar electricity can be incorporated into the design of a new building, and how it can add energy-efficiency to any project," said Garrett. "We are pleased that this distinctive project has been recognized for excellence."

Considering the cost of solar thermal power, solar electric modules (Photovoltaic or PV for short) are the better choice. The Lockheed-Martin plant would have cost $5.17 per Watt for construction, plus the ongoing maintenance and water usage costs. Conversely, PV power plants have come down significantly in costs, to under $5.00 per watt, because increased worldwide production of PV modules over the last two years. Pricing will drop even lower next year as additional production and solar grade silicon capacity come on line.

Price is only part of the PV advantage, since there is no water usage, no additional pumping or water infrastructure, and essentially no required maintenance. Unlike concentrating solar power plants, PV flat plate modules respond to diffuse sunlight as well as direct sunlight, giving an overall annual solar collection advantage of about 20 percent. Single axis or dual axes tracking of the sun can increase annual output, further lowering costs. Concentrating systems do not work with cloud cover while PV systems still give significant output.

In addition to large-scale power plants, smaller PV systems can play a part for homeowners and businesses as well. A single 5 kW home PV electric system now costs about $6.00 per Watt before incentives with no maintenance and no water usage. I've had working PV modules on my roof for over 30 years and never even washed them!

Considering all system costs, the best return on investment for most power plants in the Southwest is with crystalline PV modules. Our firm has 26 PV power plants of all sizes in our pipeline of projects. As these and other renewable energy plants come into production in Arizona and adjacent states, we will be able to meet our energy needs while keeping our limited water resources available for more critical uses.

Lane S. Garrett, P.E. is a professional engineer since 1963 and has been very active in the Renewable Energy field since 1975. A graduate of Drexel and Arizona State Universities, he is CEO of ETA Engineering of Mesa, AZ.

ETA Engineering, Inc., and its affiliate Dependable Solar Products, Inc., offer engineering, consulting, design, project management and installation on a turnkey basis. ETA distributes and manufactures a full line of renewable energy products and has designed and installed photovoltaic lighting systems from small remote applications to large renewable power plants of all sizes. The company is also active in efforts toward village electrification in emerging countries. For more information, visit: ETA Engineering or Dependable Solar Products

FOR IMMEDIATE RELEASE CONTACT: Bill Andres