Net-zero energy buildings are growing in popularity throughout the world and the demand for sustainability is increasing every year. One way to reduce energy is to install solar photovoltaic (PV) systems on buildings. While this was a large upfront expense in the past, now the cost of PV systems has dropped dramatically as the industry has scaled up manufacturing and technology has significantly improved.
What are photovoltaic systems?
PV systems convert sunlight into electricity and are one solution to harnessing energy from the sun. The word “photovoltaic” means light (“photo”) and voltage (“voltaic”). The PV cells generate electricity whenever photons strike the photovoltaic material. Most PV array systems are located on the south-facing side of a building’s roof.
Photovoltaic systems perform the same tasks as the solar panels that have been around since the 1800s; however, the difference between the traditional solar panel and PV systems is over 40 years of technological advancement. The industry uses an efficiency rating which measures the percentage of sunlight hitting the solar cell that gets converted into usable electricity. Today, the best performing, commercially available PV systems have 20% efficiency.
Advantages of PV Systems
The advantages to PV systems are that there are no moving parts, so they are easily expandable and modular. The system is also energy independent and environmentally compatible. They usually have long service lifetimes and require minimal maintenance.
The economic benefits are exceedingly great especially for larger buildings. The cost of electricity will never be a factor and other utilities are also cut back on, if they are not made obsolete. Although there are high initial costs, the economic value is realized almost immediately.
LEED and Living Building Challenge requirements
LEED allows a building to take credit for technologies that generate electricity and heat from sun, wind, water flows and waste biomass. Living Building Challenge’s Energy Petal requires that “one hundred percent of the project’s energy needs be supplied by on-site renewable energy on a net annual basis.” It further defines “renewable energy” to included photovoltaics, along with other systems.
Case Study: Brock Environmental Center’s PV system
The Brock Environmental Center, a current work-in-progress project at Hourigan, will use PV systems as a part of its on-site renewable energy strategy. The system will contribute to the facility being a net-zero energy building—targeting LEED Platinum and Living Building Challenge certifications. There will be 164 photovoltaic cells that will provide 60% of the renewable energy for the building.
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