PV electricity is as useful as traditional energy sources, but is much less polluting. In addition, PV systems are mobile, silent, durable, virtually maintenance-free (they don't have any moving parts), modular (equipment can be added incrementally to meet expanding energy needs) and easy to install. More importantly, PV systems are extremely dependable. According to the National Renewable Energy Laboratory, photovoltaics are "the most reliable source of electric power ever invented."
Most PV systems generate power at the point of use, particularly where decentralized power is necessary. These are called "stand-alone" systems. PVs can also be connected to the grid. "Grid-connected" systems don't require a battery: the grid can "buy back" excess generated energy and supply backup power when the solar panel is not exposed to sunlight. (see Grid-Connected PVs, p. 24). Finally, large PV arrays can add electricity to a utility's central power plant.
WHAT THEY LOOK LIKE
Several dozen photovoltaic cells, each typically about four inches in diameter, combine to form one "module" -- the basic building block of a photovoltaic system. Multiple modules wired and mounted together in a weatherproof encasement form an "array" which can supply from a few watts to several megawatts of power. Besides the array, there are typically only two other components in a PV system: a charge controller, which prevents unwanted battery discharging or overcharging; and an invertor, which converts the direct current generated by a solar panel to the alternating current needed to run many appliances.
WHERE PHOTOVOLTAICS ARE COST-EFFECTIVE
The price of photovoltaics has dropped about 99 percent since the 1970s, due to steady advances in technology and recent expansions in production. And, though the cost of a functional stand-alone system is still often more expensive than getting electricity from readily-available power lines, using PVs saves money in an increasing number of applications where power line connections are not readily available or are impractical. PVs have become the cheapest way to provide electricity in three situations:
(1) For small energy applications (< 5 kW) in areas 1/2 mile or more from the nearest grid extension. At this distance, dry-cell batteries or electric generators powered by diesel fuel or gasoline are traditionally used since electric power from the grid is prohibitively expensive. But compared to diesel generators and disposable batteries, PVs cost less. This is particularly true with "small" power applications. For sytems requiring less than 5 kW, buying and maintaining PVs typically averages only 37 percent of the cost of buying, fueling and maintaining gasoline or diesel generators, according to research by Holger Eisl and Dr. Barry Commoner's Center for the Biology of Natural Systems (CBNS).
Disposable batteries, used to power applications such as Coast Guard navigational buoys, are even more expensive -- ranging from $6-$60/kWh. Further, disposing of these batteries now costs almost as much as buying them. As a result, the life-cycle cost of using photovoltaics to charge rechargeable batteries is less than six percent of the cost of using disposable dry-cell batteries, according to CBNS. Consequently, PVs are being used to supply an estimated 12.5 megawatts (mW) of power for communication systems, monitoring equipment, water pumping, lighting, electric fences and warning signals in remote locations.
(2) With mobile end-uses, for example highway message boards or construction arrow boards. Since warning boards need to be mobile, a utility connection is impractical. Again, compared to using a diesel generator, PVs are cheaper. As a result, PV message and arrow boards are increasingly found on urban, as well as rural, roads.
(3) In urban settings where hooking up power lines would require costly pavement excavations, for example installing new street lights in certain settings. PV-powered lights avoid the cost of digging up and later repairing surface pavement. Consequently, they are in many cases cheaper from the outset than connecting lights to the utility grid.
WHEN YOU ADD ENVIRONMENTAL COSTS, EVEN MORE USES MAKE SENSE
When federal, state and local governments use a polluting energy technology, they pay for more than just the machinery; they also often ultimately pay to clean up the resulting pollution. These environmental costs should be factored into price comparisons between competing energy choices.
Using photovoltaics averts the cost of cleaning up fuel spills, for example. According to the Photovoltaic Design Assistance Center (PVDAC), the clean-up cost of one fuel spill, whether on land or water, is usually greater than the cost of purchasing and installing an entire photovoltaic system.
Several state and federal agencies have produced important dollar estimates for the costs of air pollution generated by fossil fuel combustion. A directive issued by the National Park Service's (NPS) Denver Service Center in 1994 put the costs of air pollution at:
The NPS now uses these estimates in all facility life-cycle cost calculations. And, finally, many of the real costs of diesel pollution, for instance lung disease and increased cancer deaths, cannot be given a dollar value. Diesel generators add to the risk of cancer in part because they create dioxin. According to the US Environmental Protection Agency's 1994 Dioxin Reassessment report, diesel particulates account for 1.5 percent of the nation's total dioxin emissions. EPA links dioxin to health problems such as cancer, neurotoxicity, immunotoxicity, and reproductive, developmental and endocrine toxicity, including diabetes.
CHOOSING THE RIGHT PV SYSTEM
To assure reliable solar energy in rain or shine, Seattle or Albuquerque, buyers must choose PV systems that are large enough to meet their energy needs in worst-case weather conditions. Government purchasing agents and other consumers can specify appropriate size arrays and sufficient battery capacity based on local "insolation" levels (the average intensity of sunlight in the geographic area of use, see map below), the expected number of consecutive sunless or cloudy days, and the hours and months of intended use.
Also, vendors may offer several types of solar cells. Though differences in cells may seem complicated, the final PV system is relatively simple. Solar photovoltaic systems can be quickly and easily expanded to produce more electricity, as needed.
Communications
Cathodic protection
Electricity for remote locations
Battery charging for vehicles
Monitoring in remote locations
Warning signs
Water pumping
Restroom facilities
Emergency power source
Reprinted with permission from the Interstate Renewable Energy Council, as it appeared in their 1993 report, "Procurement Guide for Renewable Energy Systems." An updated guide is expected in the fall.
Solar outdoor lights look like regular outdoor lights, but they are anything but ordinary. During the day, PV panels collect energy and store it in a deep-cycle, maintenance-free, gel-cell battery. The battery powers the lights at night and can store enough energy to run the lights for 5-7 consecutive days without sun. A small microprocessor enables the panel to act as a photocell, turning the light on at dusk and off at dawn. It also regulates battery charging. Generally, the solar light controllers last 10 years while the PV panels are often covered by warranty for 20 years. A variety of solar street lights are available from the US General Services Administration.
As self-contained units, solar outdoor lights are very dependable. During Hurricane Andrew in Dade County, Florida, solar street lights withstood 165 mph winds and continued to perform flawlessly while surrounding grid- connected lights were down for two weeks.
The cost of solar-powered outdoor lights often compares favorably with electricity-powered lights. Municipalities or building managers, as mentioned above, must pay for the trenching costs associated with grid-connected lights. The cost of excavating pavement alone can run as high as $25 per foot. There is also an additional cost rarely factored into street light purchasing decisions: the future cost of repairing roads in the places where utility cuts weakened their structure. Broken pavement is never quite the same. The City of Burlington, Vermont and Maricopa County, Arizona both found in separate studies that utility cuts reduce the life of pavement by 8-10 years. It costs Burlington, for example, an estimated $500,000 a year to repair pavement damaged by utility cuts.
By comparison, solar street lights require minimal maintenance, trenching, and road repairs -- as well as no wiring, metering or electric bill. When all of these cost savings are factored into the lighting decision, choosing non-polluting solar street lights is often a sound purchasing decision.
Recognizing these benefits, planners have used solar outdoor lights to add new lighting in a number of urban settings, particularly to meet safety concerns. In May 1995, the City of Orlando Transit Authority (LYNX) equipped 55 bus shelters with solar lights instead of connecting them to the grid. They saved money immediately (by avoiding cutting through cement) and over the long-term (by guaranteeing no new trenching or wiring will be necessary if route changes require the shelters to move).
Similarly, when Wendy's Restaurant in Marietta, Georgia added lights to a dark back alley where employees dumped trash at night, they found installing three PV-powered lights was cheaper than digging up the lot to install grid-connected lights.
Thus far, however, solar street lights have been restricted to warmer, sunnier climates. The only light fixtures presently compatible with the direct current (DC) electricity generated by PV panels are fluorescent lamps, which do not perform well in the cold weather of the northern United States, and low-pressure sodium fixtures, which are limited because of their narrow light spectrum. The best outdoor lights would be high-pressure sodium lamps, but DC- compatible high-pressure sodium ballasts are not yet commercially available.
This may change very soon. A company has developed a (DC)-compatible high-pressure sodium ballast and has submitted it for testing to the National Renewable Energy Laboratory. If all goes well, these lamps could be available by the end of the summer.
John Stevens, a senior member of the PV Design Assistance Center's technical staff, believes the availability of high-pressure sodium ballasts that accept direct current "would revolutionize" the outdoor lighting market. Solar street lights would be able to function as efficiently as grid-connected lights in colder regions, and they would become more cost-effective in less-sunny regions of the country.
Nonetheless, as the following case studies demonstrate, there have been many successful solar lighting projects that have used PV fluorescent or low-pressure sodium lamps.
In 1989, the City of Albuquerque, New Mexico installed 21 PV-powered lights over the six mile length of the new Tramway Boulevard Bike and Walking Path. By choosing solar instead of the grid, the city saved money immediately. The project eliminated the expense of electricity, and it was less expensive up-front than the option of installing underground utility service. The city saved $500 per light for total savings of over $10,000, immediately.
The city initiated the project in response to the state of New Mexico's request for energy conservation proposals. After officials determined solar lighting would be cost-effective, the city applied for and received a grant from the state covering the expenses. Sandia National Laboratories gave the city free technical assistance.
Each 35-watt light uses 250-watt PV modules. The lights use low-pressure sodium bulbs, which are sufficient for bikers, strollers and joggers and don't contribute to urban light pollution. The total cost of each solar light was $2500. In contrast, each grid-connected light would have cost $3000, including $250-$1000 to cut into the nearby road and connect the posts to the grid. In 1992, Sandia's PV Design Assistance Center again assisted the city in refurbishing lights and replacing batteries and installing new charge controls. For the past three years, lights have met the city's needs with minimum maintenance. Public response has been nothing but positive.
As a result of the positive experience with PV lighting, the city has also installed PV-lit bus shelters and school flashing lights.
For More Info: Hal Post, PV Design Assistance Center, Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185; (505) 844-2154; Fax: (505) 844-6541; E-mail: hpost@sandia.gov.
In August 1995, the US General Services Administration (GSA) found they needed to build a parking lot for tenants of the George C. Young Federal Building in Orlando, Florida. To provide adequate safety lighting for the lot, the GSA would have had to repair the pre-existing, damaged electrical wires which had been buried under the asphalt. After adding the cost of searching for the broken wiring, GSA determined that solar lights would be immediately less expensive, in addition to saving electrical and maintenance costs over the long term.
Because a range of solar street lights can be ordered directly from the GSA schedule, GSA easily solved their problem by purchasing three all-night street lights at a cost of $2934 each. The maintenance required for the solar lights is expected to be no more than replacing each fluorescent bulb every 2.5 years (at a cost of $10/bulb) and replacing the battery every 5-7 years. The battery keeps the lights running for five consecutive days without sunshine. Each light prevents 1000 pounds of CO2 pollution each year. According to GSA Building Manager George Post, the system has had no problems since installation, with the exception of one burned out flourescent bulb.
For More Info: George Post, GSA, 501 East Polk Street, Room 600, Tampa, FL 33602; (813) 225-7739.
Source: Photovoltaic Purchasing Guidebook for Local and State Governments, A project of the Urban Consortium Energy Task Force of Public Technology, Inc. and the City of Albuquerque.
SOLAR MESSAGE BOARDS ARE CHEAPER
Solar message boards cost less than their diesel counterparts because they require less maintenance, last longer and don't need fueling. Assuming the "average" diesel board requires 20 gallons of fuel every 5-6 days (at $1.50/gallon); 1.5 hours of labor for each fueling round-trip ($15/hour); and an oil change every 10 days ($15 plus 1.5 hours of labor for each oil change), fuel and maintenance costs for the diesel board will be approximately $375 per month. In contrast, PV board maintenance is minimal. Solar-powered boards typically require battery checks every 2-3 weeks and panel wiping (involving about two hours of labor per check) a few times a year. This brings the solar board's maintenance costs to about $60 per month. Based on these assumptions, a photovoltaic board will save $3,780 annually in fuel and maintenance costs. Though a photovoltaic board typically costs about $7,000 more to purchase than a diesel board, fuel and maintenance savings alone pay for the difference in cost in about two years, with net savings accruing thereafter, according to simple payback calculations.
NO MORE DIESEL
Another compelling reason to convert to PV message boards is that they eliminate hazardous diesel pollution. According to the US Environmental Protection Agency and energy analysts in the United Kingdom, diesel generators give off 0.25 kg/kWh of carbon dioxide (CO2), 1.25 g/kWh of sulfur dioxide (SO2), and 18.8 g/kWh of nitrogen oxide (NOx). This poses direct health risks to construction workers, passing motorists and neighboring communities while contributing to air pollution in general. The trucks needed to carry fuel to diesel message boards compound local air pollution problems.
THE NUTS AND BOLTS
The size of a PV array needed to power a solar message board varies based on local sunlight conditions and the time of year the system is designed to operate. Many year-round solar message boards employ a 425-watt array. It is often no wider than the sign itself and can be tilted or rotated to face south for maximum charging no matter which direction the message board faces. This also allows them to be cleaned easily. Many solar-powered message boards also come with cellular phones that enable operators to re-program messages from afar.
Richards is not aware of any problems with the boards since they were first bought in 1995. The Department is confident enough with its decision to go solar that it has put out a bid for 50 more units for August 1996. The Department now requires all newly-purchased message boards to run on solar power.
For More Info: Mark Richards, Virginia Department of Transportation, 1401 East Broad Street, Richmond, VA 23219; (804) 225-3832; Fax: (804) 786-2888.
Emergency call boxes are ideal for photovoltaics because cellular phones need only a small amount of energy to operate and require reliable power in remote locations where power lines don't reach. The typical PV-powered call box system consists of a two-way cellular telephone, an 8- or 10- watt PV panel, a sealed, rechargeable lead-acid battery and an antenna. Systems cost about $1,500 to purchase, $700-$800 to install, and $350 annually to maintain. (Depending on the carrier, cellular service runs about $400 annually.) In California, maintenance crews visit each call box twice a year to wipe off the panel to ensure maximum efficiency and to replace any worn out batteries.
Since 1985, more than 26 of California's 58 counties have installed PV-powered call boxes. San Diego County's 1,663 PV call boxes make it one of the largest SAFE programs in the state. According to Mike Perkins, San Diego Program Manager for SAFE, the system is widely used and a great success. Each month, the San Diego call box system handles between 12,000 and 13,000 emergency calls. Callers are connected to a local highway patrol within an average of less than one minute, and stranded motorists never have to walk far since major San Diego freeways feature call boxes opposite each other every half mile.
Running power lines along the California highways to link each call box to the grid was never seriously considered as an alternative. According to the Barry Commoner's Center for the Biology of Natural Systems, the 10-year life-cycle cost of photovoltaic call boxes is 23 percent of what grid-wired boxes would cost. As Perkins notes, "Solar is much more convenient -- dig a hole, sink in the call box, adjust the antenna and you're done." According to Perkins, only a couple of hours are required to install each call box.
The SAFE program is organized through the California Department of Transportation (Caltrans). Each county is responsible for installing and maintaining its own call boxes. Funding comes from the state Department of Motor Vehicles, which pays for the
program through a one-dollar, vehicle registration fee assessed on a county-by-county basis. More call boxes are added as needed. According to Perkins, Californians widely accept this method for funding highway safety. "Most people feel a one dollar tax is cheap insurance," he notes. In addition, Perkins explains, "[B]ecause of the decreasing costs and tremendous success, we may be able to suspend the one dollar vehicle tax in major metropolitan areas."
California is not alone in using photovoltaics to improve highway safety. Several other states, including Arizona, Colorado, Maryland, Minnesota, Ohio and Texas, have also created limited PV call box systems.
When it comes to highway safety, enabling motorists to make emergency calls is just the start for PV-powered call boxes. Already SAFE is developing ways PV call boxes can reduce weather-related highway accidents. By equipping them with small computers, sensors and video cameras, highway departments can assess where roads are slippery or impassable due to poor visibility. This information can help drivers avoid dangerous conditions ahead. As Perkins notes, "Cellular and photovoltaic technology go hand-in-hand. These call boxes are the foundation for an intelligent traffic network."
The California SAFE program is now developing electronic specifications that highway departments anywhere in the country can use to assemble emergency call boxes that also act as weather warning centers. SAFE's study, funded by the Federal Highway Administration, identifies call box sensing devices that are fully compatible with cellular technology. In July, it will make its recommended specifications available, in hard copy and on the Internet. But since existing PV call boxes can be retrofitted with diagnostic equipment, highway departments need not wait. They can act today, using solar technology, to dramatically improve the safety of the highways they administer.
For More Info: Mike Perkins, San Diego Program Manager for SAFE, MS 0332, 5555 Overland Ave., San Diego, CA 92123; (619) 694-2190; Fax: (619) 694-8914.
RESTROOMS
PV-powered restrooms enable administrators to offer lighting, water and ventilation to remotely-located restrooms such as highway rest stops, public beaches, outdoor recreation parks and public campgrounds. Sandia National Laboratories estimates that thousands of sites exist where PV restrooms could be installed.
Solar powered restrooms are cost-effective because photovoltaics run ventilation fans, interior and exterior lights, and auxiliary water pumps for sinks and showers for less than the cost of connecting power lines or using maintenance-intensive gas or diesel generators. By making this power available where it was previously prohibitively expensive, photovoltaics improve sanitation and odor control. By making ventilation fans possible, PVs also help state and federal agencies comply with recent environmental regulations, which require self-contained composting toilets, without sacrificing odor control.
Since 1987, PVs have powered a self-composting restroom facility on Prospect Mountain in the New York Adirondacks. PVs power the ventilation fans, a
liquid pump and auxiliary maintenance lights. PVs were cheaper than extending a grid connection, the only alternative supervisors considered practical. According to New York Dept. of Environmental Conservation staffperson Gary West, "the system has worked really well." Since 1987, its success has spawned several imitations on the Lake George islands.
For More Info: Bob Barshied, Director, Division of Operations, New York State Dept. of Environmental Conservation, 50 Wolf Road, Albany, NY 12205; (518) 457-3559.
RECREATIONAL SITES
Entire recreational sites can be affordably powered by the sun. Some new sites run on PVs exclusively. At other sites, where photovoltaics were added as a retrofit, the existing generator is integrated into the new system as backup power.
The Cholla Recreational Site was built in 1992 by the National Forest Service and the Bureau of Land Reclamation to offer visitors modern amenities near Roosevelt Lake in Arizona. Here, all power needs are handled by PVs, including:
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* lighting and ventilation for each of the three shower buildings and 10
restrooms; * power for the campground hosts' RVs; * lighting and air conditioning at the entry station; * power for a fish cleaning station; * area lighting for informational signs; * security lighting at the boating site; and * making potable, disinfected water available from a 165-foot well.
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According to Fred Bloom, Supervisor and Facility Engineer for the National Forest Service, Cholla's photovoltaic systems have "performed really well." What impresses Bloom is that "the number of qualified PV installers has grown and the dependability of PV vendors has increased exponentially." The only problems the site has had resulted from lightning damage to some PV arrays. This did not, according to Bloom, indicate any technological shortcomings.
For More Info: Fred Bloom, U.S. Forest Service, 2324 East McDowell Road, Phoenix, AZ 85006; (602) 225-5317; Fax: (602) 225-5295.
Traditionally, navigational buoys use large, wasteful, disposable dry-cell batteries for power. This comes at an enormous cost. In 1993, the life-cycle cost of energy supplied by disposable batteries ranged from $60 to $600 per kWh, depending on the type of battery. In contrast, using photovoltaic cells to charge rechargeable batteries on-site costs far less -- about 6 percent of the cost of using dry-cell disposables over its life-cycle, according to 1993 calculations by Holger Eisl, researcher at the Center for the Biology of Natural Systems (CBNS). These savings are due to the greater efficiency of using rechargeable batteries made possible by on-site photovoltaic electricity, as well as avoided disposal costs.
The financial and environmental benefits are well worth the conversion. As of 1993, federal, state and local governments bought $200 million worth of disposable batteries annually for applications such as powering navigational buoys. If they replaced these with rechargeable batteries and photovoltaic charging systems, they would have saved about $196 million annually, according to CBNS's research. At the same time, the additional orders for PV modules would have increased the PV industry's solar cell production by 10-20 megawatts (a full 1/8 of the present total PV production), driving the price for photovoltaics down to $4.73 per peak watt in 1992 dollars, CBNS estimates.
Each buoy and lighting beacon uses a single PV module to supply 6-9 watts of intermittent power. Though many solar-powered buoys operate in harsh environments, they are able to provide superb reliability since special modules are available that resist salt water corrosion.
Recently, the Coast Guard has begun converting major lighthouses from generator or underwater cable power to photovoltaic power. The Coast Guard has already retrofitted about a dozen smaller lighthouses, mostly in New England, that previously ran on either diesel fuel or electricity from under water cables. PV arrays will supply from .5 kW to just over 1 kW for major lighthouses in California, lower Alaska and cloudy Washington State. This latest series of retrofits has become feasible due to recent advances in lighting efficiency. The motivation for going solar is compelling. As Grasson points out, diesel generators are maintenance intensive (requiring service every four months), and fueling costs are very high. In contrast, Grasson has found PV systems require maintenance only twice a year, battery replacement every 10 years, and PV panel replacement every 20 years. Underwater cables are also more expensive than solar. Grason says if a cable is accidentally cut, it is cheaper to install a photovoltaic system than lay a new cable.
For More Info: John Grasson, U.S. Coast Guard Civil Engineering Division, 2100 Second Street, SW, Washington, DC 20593-0001; (202) 267-1892.
Solar school zone flashers offer the same advantage as solar street lights: by eliminating the need for trenching underground, they are often immediately less expensive than connecting flashing signs to the utility grid. Solar school zone flashers also:
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* can be installed more quickly; * can be moved more easily if traffic conditions change; * increase the system's efficiency by supplying DC power for a DC load; * are more aesthetically pleasing than systems with above-ground wiring; and * can be installed with less help from an outside consultant. |
Solar-powered school zone flashers operate like solar street lights. A photovoltaic (PV) panel, in many cases rated between 60 and 85 peak watts, is mounted at an angle a few feet above the top flashing beacon. During the day, the PV panel collects energy which is then stored in a deep-cycle, 12-volt battery. The battery is kept in a weatherproof enclosure beneath the sign, along with a charge regulator and other electric circuitry needed to activate the sign at appropriate hours. The battery powers the flashers as needed.
City officials have been very happy with the performance of their solar flashers. According to Carrollton Signal Supervisor Andrew Souder, the equipment has been working well. As the National Renewable Energy Laboratory reported in 1993, no other recent city project has generated as many "positive comments and pats on the back" for Carrollton officials than their use of solar school zone flashers. This success has inspired the city Traffic Department to also use a photovoltaic system to power 12 high-water flood area warning signs and one sharp-curve hazard beacon, which have also performed very well according to Souder.
For More Info: Andrew Souder, Signal Supervisor Traffic Dept., 1420 Hutton, Carrollton, TX 75006; (214) 466-3609; Fax: (214) 466-0511.
Since 1989, Anne Arundel's Department of Public Works has installed 12 solar school zone flashers. In the last five years, all new flashing school signs have been solar-powered. County Traffic Engineer Kevin Newton estimates that each new solar school zone flasher pays for itself in two years or less since the cost of installing a solar system is typically so close to the cost of installing a grid-connected system.
Anne Arundel's solar signs cost about $4,000 each, according to Newton. The self-contained solar units have been installed by the Department's traffic signal shop staff, eliminating the need for an expensive outside contractor. Newton says the Department has had no major problems with their solar signs since installation. The Department's attitude about solar school zone flashers is summarized by Jim Schroll, Chief of Traffic Engineering: "Energy conservation, dependability and economy all contribute to providing better service to county citizens, and that's what we're here for."
For More Info: Kevin L. Newton, Dept. of Public Works, 1 Harry S. Truman Parkway, Annapolis, MD 21401; (410) 222-7331; Fax: (410) 222-7366.
The following five agencies lead the federal government in putting photovoltaics to work.
NATIONAL PARKS SERVICE
The National Parks Service, which administers national parks, monuments, historic sites, seashores, and recreation areas, has at least 455 PV systems in use today. 97 percent of these systems "met their use objectives," according to the Parks Service's internal survey. 31 percent of these systems are used for resource monitoring; 27 percent for communications; 25 percent for water pumping, remote facility power, and lighting; 7 percent for ventilation and 10 percent for other uses such as security systems and electric fences. These PVs are used over a broad geographic area and in many climates. 61 percent of the systems are used on a year-round basis while 34 percent are used seasonally. A majority of the systems supply power for applications requiring less than 1 kW.
Since 1992, the Parks Service has been working with the Photovoltaic Design Assistance Center (PVDAC) at Sandia National Laboratories to increase the use of renewable energy resources in its parks. This effort is a central component of its Strategic Plan, drafted in 1991, "to achieve sustainablility in all national parks and operations." Encouraged by past successes, the Parks Service has identified 643 additional projects where PVs would be cost-effective. 31 percent of these projects would supply remote facility power; 19 percent street, outdoor and indoor lighting; 17 percent communication systems; 12 percent water pumping; 6 percent resource monitoring equipment; 4 percent information/ warning signs; and 11 percent other uses.
For More Info: Douglas DeNio, PE, National Park Service Center, PO Box 25287, Denver, CO 80225-0287; (303) 969-2162.
DEPARTMENT OF DEFENSE
The Department of Defense (DOD) has installed approximately 3,000 small-to-medium remote PV systems for the Army, Navy and Air Force. PVs are used for remote building energy needs (such as air conditioning, lighting and refrigeration), outdoor and runway lighting, communication centers, and meteorological sensing stations. The DOD's PV systems average about 1 kW in size and range from 10 w to 350 kW.
But the DOD is just getting started. It has created a Tri-Service Photovoltaic Review Committee, chaired by Garyl Smith, to identify and implement new PV projects. The PV Review Committee has identified 3,900 potential intermediate-to-large remote applications (which would cumulatively supply 423 mW of power) and 51 mW of additional small remote applications. Although the Review Committee has not formally surveyed the performance of existing systems, Chuck Combs, Navy Member of the Photovoltaic Review Committee, says, "I'm very confident their performance is good."
For More Info: Chuck Combs, Naval Air Weapons Station, Energy Program Office (823BOOD), China Lake, CA 93555; (619) 939-0048; Fax: (619) 939-7366; E-mail: chuck_combs@lmdgw.chinalake. navy.mil.
FOREST SERVICE
Presently there are over 500 PV systems in use within the US Forest Service. The satisfaction rate for the systems is 98 percent. As with the National Parks Service, the PVDAC is working with the Forest Service to identify future projects where photovoltaics make environmental and economic sense. So far, at least 200 additional projects have been identified. In July, the Forest Service released a detailed report on its existing solar systems titled Renew the Forests.
For More Info: Fred Bloom, Supervisor and Facility Engineer, US Forest Service, 2324 East McDowell Road, Phoenix, AZ 85006; (602) 225-5317; Fax: (602) 225-5295.
BUREAU OF LAND MANAGEMENT (BLM)
The BLM is currently using PV power for over 150 projects, including communications, facility power, water pumping, resource monitoring and outdoor lighting. The overall satisfaction rate with these systems is greater than 97 percent, according to the BLM's internal survey. PV systems are located at sites ranging from Glacier Mountain, Alaska to Twin Peaks, Idaho. With PVDAC's help, the BLM has identified 102 potential sites for new cost-effective PV projects.
For More Info: Trent Duncan, Bureau of Land Management, Utah State Office, PO Box 45155, Salt Lake City, UT 84145-0155; (801) 539-4090; Fax: (801) 539-4260.
COAST GUARD
Since 1984, the Coast Guard has been leading the way in using photovoltaics in place of disposable batteries to power navigational buoys. Over 15,000 systems are in operation.
For More Info: see Using the Sun to Guide Ships at Night, p. 13.
Photovoltaics Now -- Photovoltaic Systems for Government Agencies, Michael G. Thomas, Harold Post and Anne VanArsdall, PV Design Assistance Center, 1994. This free publication provides an overview of 11 cost-effective PV applications for government agencies, including applications with a discounted payback period of three years or less. For More Info: Judy Mori, Sandia National Laboratories, PV Design Assistance Center, PO Box 5800, Albuquerque, NM 87185; (505) 844-3698; Fax: (505) 844-6541; E-mail: jtmori@sandia.gov.
Stand-Alone Photovoltaic Systems: A Handbook of Recommended Design Practices, PV Design Assistance Center, 1995. This comprehensive guide presents information on choosing the right stand-alone PV system, featuring 16 examples of multi-use PV systems. For a free copy: see above.
Maintenance and Operation of Stand-Alone Photovoltaic Systems, PV Design Assistance Center, 1988. This guide is for all personnel involved in the operation, inspection, repair and maintenance of PV systems. For a free copy, see above.
Renew the Parks: Renewable Energy in the National Park Service -- Photovoltaic Systems, PV Design Assistance Center and National Park Service, 1995. Renew the Parks is a description of PV use in the National Parks. For a free copy, see above.
Photovoltaics for Municipal Planners, National Renewable Energy Laboratory (NREL), 1993. This publication describes 14 cost-effective PV applications in urban areas, including case studies. The manual is free. For More Info: Energy Efficiency and Renewable Energy Clearinghouse (EREC), PO Box 3048, Merrifield, VA 22116; (800)DOE-EREC [363-3732]; Fax: (703) 893-0400; E-mail: doe.erec@nciinc.com.
Photovoltaic Cells: Converting Government Purchasing Power Into Solar Power, Holger Eisl and Barry Commoner, Center for the Biology of Natural Systems, 1993. In this workbook, CBNS presents a thorough analysis of PVs. The guide maps out a plan for how government procurement can drive down the cost of PV electricity to where grid-connected applications are as inexpensive as utility electricity. The workbook costs $15. For More Info: CBNS, Queens College - CUNY, Flushing, NY 11367; (718) 670-4180; Fax: (718) 670-4189.
Park Power: Using Solar Energy for Public Spaces, (Part of IREC's "Workshop In a Box" Series). Park Power is the first in the Interstate Renewable Energy Council's new series of technical workshops on using solar energy. Each "Workshop in a Box" will walk agencies through the entire process of procuring solar technologies by providing agency-specific training and follow-up assistance. All of the workshops will incorporate local conditions and considerations into trainings and discuss details such as solar system design, sizing and maintenance. For More Info: Jane Weissman, Exec. Dir., Interstate Renewable Energy Council, 15 Hayden Street, Boston, MA 02131; (617) 323-7377; Fax: (617) 325-6738; E-mail: weissmanpv@aol.com.
PV Yellow Pages, Paul Maycock, updated annually. PV News, Editor: Paul Maycock. The PV Yellow Pages is a thorough listing of approximately 600 system and component distributors, designers and consultants. The book costs $40.00. PV News follows the status of the US and world photovoltaic markets. Subscriptions cost $100/yr. For More Info: Paul Maycock, PV News, 8536 Greenwich Road, Catlett, VA 20119; Phone and Fax: (540) 788-9626.
PV Design Assistance Center. The Center is involved in all aspects of PV system design, procurement, installation. It makes free assistance available to government agencies, utilities, designers, and architects. PVDAC also distributes several comprehensive and easy-to-follow publications that guide readers through PV design and maintenance. For More Info: PVDAC, Sandia Nat'l Laboratories, PO Box 5800, Albuquerque, NM 87185; Mike Thomas: (505) 844-1548; Hal Post: (505) 844-2154; Fax: (505) 844-6541; Publications: (505) 844-3698; E-mail: jtmori@sandia.gov.
Real Goods Trading Company. Real Goods is an excellent catalog of earth-friendly products. It includes a wide selection of solar-powered flashlights, outdoor lighting fixtures, battery recharges, photovoltaic arrays, and even lawnmowers. It caters to people who want to live "off the grid," and lists sustainable living causes and reference books. For More Info: RealGoods Trading Co., 966 Mazzoni Street, Ukiah, CA 95483; (800) 762-7325.