Agenda - Planning Commission - 05/07/2009

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Balancing the Sol~r Access Equation By Gail Feldman and Dan Marks, Alep States, cities, and counties across the country are moving quickly to improve the ability of their communities to "build green" and install solar energy systems on new and existing buildings. Will solar panels on ev~ry rooftop replace the white picket fence as the icon of the American dream? That may depend on how well planners develop po.licies and permitting processes that encourage solar energy systems and at the same time mitigate inevitable conflicts, such as when policies that protect trees or encaurage higher density development interfere with sun- light access. This article explores the grawing trend to introduce solar energy in communities and how planners may need to guide land-use policy development to avoid unintended co~- sequences, SOLAR ENERGY SYSTEM BASICS The most common solar technologies used on buildings in the United States are solar pha- tovoltaic CPV) panels that generate electricity and solar thenmalsystems that heat water ar air. Solar PV produces electricity through the conversion of direct sunlight. The semiconduc- tor materials in the PV cell interact with the sunlight to. generate electric current. The most electricity is. produced when the sun's rays are directly perpendicular to the PV panels. Since PV o-nly works with sunlight, most systems are connectedto the utility grid ta.guarantee aro.und-the,clock electricity. The orientatian of a PV system affects its perfor- mance; usually the best location is on a south~ facing roaf. Flat roofs allow the panels to be tilted toward the optimal direction.. PV systems work best without any ob~ structians from treesor structures. Because the sun may be higher in the summer or lower in winter, a placement of the PV involvesari assessment ofthese factors. h1 any specific location, as the surface .area of a PV system exposed to sunlight increases, the amount of electricity produced also increases. Depending on site conditions and economic constraints, residential-scale PV systems can range from 100 to 1,000 square feet. Solar thermal systems use the sun to heafwateror heat-transferring fluids, and each system is comprised aftwo parts: a solar col- lector (panel) and a storage tank. Systems that use active solar require the use of electricity for pumps <lnd circulation and require flat-panel collectors similar to PV. Passive solar water heaters have no electrical components and. rely on direct sun heating the collector panel. Storage tanks have now been developed to. be recessed in into the roof, so they are not seen above the roofline. Salar callectors for solar thermal systems require less. surface area than PV systems. In locations receiving an average amount of sunlight, flat-panel collectors require approximately one-half to onesquare foot af SUITacearea per gallon af daily hot water use. INCENTIVES FOR SOLAR ENERGY SYSTEMS. Accordingto the Interstate Renewable Energy Council, Incentive Programs and Tax Credits resulted in over 26,000 new solar installa' tians nationally in 2007. All but a handful of . states now have incentive programs to add solar photovaltaic CPV) systems to residential or nonresidential buildings. These incentives . range from '$1 to $5 per kilowatt produced. Congress reauthorized the Renewable Energy Tax Credit in 2008 and increased the deduction to 30 percent ofthe cost of installatian begin- ning in 2009. This makes solar substantially more cost-effective by providing an income tax deduction that, for an average $30,000 residential installation, would be $8,000 to $10,000 in a tax year. Cjties i~ northern California recorded mare than 11,500 new solar PV systems be- .tween 1998 and 2007, with many of these 56 ZONINGPRACTICE 4.09 AMERICAN PLANNING ASSaOA1l0N Ipage 2