In order to obtain and maintain a green real estate loan, the loan recipient must construct or renovate existing buildings to have minimal impact on the environment. The ultimate goal for green architecture is to achieve a zero-emissions (also known as "net-zero") building standard. A zero-emissions building uses only renewable energy sources (meaning sources that do not emit carbon dioxide) for its energy supply, including lighting, heating, cooling and vehicle charging.
A building cannot achieve the net-zero standard through the use of high-efficiency energy sources alone; supplemental renewable energy generation is also necessary. For properties that have limited space for the generation of renewable energy (primarily in heavily populated, densely built cities), energy may be produced by renewable sources off-site at nearby locations.
Practically speaking, what energy alternatives can help a building produce minimal emissions?
Carbon Pollution-Free Electricity
One significant step toward accomplishing a net-zero building standard is to replace technologies that consume fossil fuels with technologies that operate via carbon pollution-free electricity (CFE). According to the U.S. General Services Administration (GSA), sources of CFE include marine, solar, wind and geothermal energy, among others.
- Solar energy is produced by converting sunlight into energy. This conversion is performed by reflecting sunlight off mirrors (solar panels) and concentrating it onto receivers that then harness and convert it into heat. This heat may be used to produce electricity or stored for later use. Solar panels perform best when installed on south- and west-facing roofs sloped at angles between 15 and 40 degrees. Solar panels are wired and connected to an interior electrical panel. According to the U.S. Department of Energy's (DOE) Office of Energy Efficiency and Renewable Energy, enough sunlight touches the earth in just 90 minutes to provide the entire earth with all of its energy supply for one entire year.
- Wind energy is created when the blades of wind turbines capture the blowing wind's energy. The wind spins a turbine's blades, which are connected to a generator (either directly or through a shaft and gears). The aerodynamic force of the spinning blades rotates the generator, producing electricity. A professional can install a wind electric system (which includes, among other elements, the wind turbine, tower and wiring) after assessing the ideal location based on wind patterns. The installer also determines whether the system should be connected to the electric grid or isolated and off the grid. It is essential to confirm that installation of a wind energy system complies with local zoning ordinances.
- Geothermal energy is produced by the earth's heat, created by reservoirs of hot water (either naturally existing or manmade) below the earth's surface. By drilling wells into underground waters, steam and hot water can be tapped and then pulled to the earth's surface for the generation of electricity. A geothermal heat pump and system may be built beneath a property's yard or installed directly under a building. The installer will decide whether a vertical or horizontal loop is best, as well as sizing of the system. According to the Office of Energy Efficiency and Renewable Energy, realizing America's maximum geothermal potential would result in a reduction in emissions equivalent to removing 26 million cars from U.S. roads each year.
- Marine energy is generated by waves, currents, tides and temperature changes and can be produced by oceans, rivers, lakes, streams and other bodies of water. To harness marine energy, large-scale infrastructure is required. Marine energy is particularly accessible and advantageous for coastal communities that can rely on it during storms and outages of traditional electricity. Marine energy is lauded for its reliability, as it depends largely on the movement of the ocean, which is guaranteed. Experiments with wave farms around the world are ongoing. According to the National Renewable Energy Laboratory, nearly 60 percent of America's annual electricity demand could be met with the use of available marine energy.
A Net-Zero America?
Currently, the U.S. federal government is working to use 100 percent CFE in government buildings in order to cut emissions from federal buildings by 50 percent by 2032 and achieve net-zero emissions by 2045.
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