Reducing our reliance on carbon-intensive energy sources is key to reaching Seattle's greenhouse gas emissions and carbon neutrality goals as outlined in the 2013 Climate Action Plan.
Renewable energy sources include photovoltaic (solar), solar thermal, wind, hydroelectric, geothermal, waste heat recovery among others. Renewable energy systems can range in size and complexity from a residential solar hot water system to a utility-scale solar array or wind farm. . Renewable energy systems can be co-located with a building (onsite systems) or geographically separated from the energy users (offsite). Seattle City Light's primary energy source-hydroelectric energy generated at City-owned low-impact dams-is also considered a form of renewable energy, helping City Light claim the title of "the nation's greenest utility." To learn more about renewable energy, visit the US Department of Energy's Office of Energy Efficiency and Renewable Energy website.
Onsite renewable energy production
At the residential and commercial scale, photovoltaic (solar electric) systems are the most common type of renewable energy. Solar hot water systems are also often cost-effective at the building scale. Onsite renewable energy opens up the opportunity for a home or commercial building to produce as much energy as it consumes. Such "zero net energy" buildings can claim significant bragging rights for being on the forefront of the sustainability movement. Seattle City Light offers incentives to businesses and households looking to install renewable energy systems. Look to their pages on customer generation for information if considering installing an onsite solar energy system. Seattle's Department of Planning and Development also offers a tip sheet on permitting solar energy systems. Onsite renewable energy systems are eligible for incentives from City Light, the State of Washington, and the federal government.
Offsite renewable energy production
Site limitations may make it difficult or impossible for a building to generate its own renewable energy onsite. Moreover, offsite renewable energy systems can take advantage of size, height, or economies of scale unavailable to individual onsite systems. For example, most wind energy systems aren't as effective when installed on a building in the city, and may run into height restrictions. Renewable energy sources can also power district energy systems. For businesses and homeowners who have determined that an onsite renewable energy system is either financially or practically out of reach City Light periodically offers customers shares in a solar array installed in a public space through its Community Solar program. Additionally, customers can purchase green power anytime from the utility through its Green Up program.
A classic green building mantra is "reduce, then produce." The saying highlights the fact that energy conservation is nearly always cheaper than increasing supply through onsite energy production. (Conservation is normally more cost effective than expanding supply even at the utility level-the reason conservation has been part of Seattle City Light's demand management strategy for over thirty years.) A smart green building project will examine energy conservation measures in conjunction with onsite renewable energy system options to come up with the combination of conservation and generation with the best return on investment.