Community solar; solar microgrids

Community solar and net metering encourage solar power consumption in homes, as well as residential and commercial properties. Both are undeniably positive ideas. Community solar refers to energy generated by solar microgrids (arrays of solar photovoltaic [PV] panels) that are invested in by groups of residential and commercial property owners, as well as small businesses; forming community-customer groups that share the energy generated by the solar microgrid (community solar customer groups can be formed by just a few members of the public, or any combination of the aforementioned entities).

Why invest in community solar?

Energy customers often invest in community solar projects for various reasons. Sometimes, they can’t have solar panels on their rooftops or property due to their properties being physically unsuitable for PV arrays. Other times, the roof/ property is often in shade by another building or trees. Often, the rental contract or community HOA doesn't allow solar panels to be installed on the property. Another attractive reason for making the investment is that community solar is more affordable than putting solar panels on their property. Also, investors in community solar enjoy financial benefits such as receiving credits on their electricity bills for their share of the community PV project.

The solar microgrids developed for community solar projects are constructed by individual private developers or organized groups of investors/ developers. Projects can also be done by private utilities, public utilities, the municipality itself, or a combination of these entities working together on a community solar project. Community solar is developed in select areas that are suitable for solar, and have a demand for the service. Projects can range from a few dozen panels to thousands. Residential energy customers and businesses that want solar, but can't/ don't put solar panels on their rooftops or elsewhere on their property, can invest in community solar.

How does community solar work? 

Energy customers interested in getting power from a few or more of the panels in the community solar microgrid sign a contract to buy energy from the community solar development. Customers then receive credit for the power they consume. Community solar rates are priced per KwH of electricity; and electricity from community solar developments is usually priced at a fixed rate.

Here's a simple diagram of the functional flow of community solar:

A great example of a successful series of community solar developments can be found in Austin, Texas. Austin Energy is a community-owned utility, a not-for-profit, enterprise of the City of Austin. The 8th largest public-owned utility in the United States is Austin Energy. Austin Energy, in partnership with the City of Austin, as well as other private businesses and community members, has developed community solar projects. Though successful public-private partnerships, they provide community solar service throughout the Austin city community.

Net Metering

Net metering is for homeowners and business owners who have solar PV systems on their rooftop or on their property, and may generate more electricity than the property uses during the day when the sun is out. Owners with solar panels on their property net metering allows  property owners to sell the electricity they aren't using back to the utility for credit to their utility bill. Solar-generated electricity is sent from properties in net metering systems back to the grid; to power other homes and businesses in the community.

Other types of renewable energy generated on properties; biomass, anaerobic digestion, geothermal (to name a few) - are found in net metering systems throughout Europe. Solar is still the most commonly used form of renewable energy in Europe, and almost exclusively the form found throughout the US.

How does net metering work?

Many states in the United States, and many countries, have passed net metering laws, and as a result, solar PV ownership has continued to grow exponentially in areas where net metering has been legislated. Net metering programs work to help property owners with solar PV on the property make the cost of the solar panel purchase + cost of installation of their solar PV units back. Customers then enjoy a profit from their investment after passing the break-even point of the initial solar PV investment.

Solar PV systems are connected to the grid via the owner’s service panel and meter in order for the solar PV installation and property owner to participate in the net metering program. The owner of the PV system is credited when excess energy is generated than that which is needed for the home, i.e. times when the meter moves “backward”. The customer then pays the “net” of the meter moving in both directions – forwards to measure power purchased (when the home demand is greater than the power generated by their PV panels), and backward when power is returned to the grid. The net consumption is then charged on the utility bill.

Some states still don't have net metering laws, so utilities may offer net metering programs voluntarily and also as a response to local municipality regulatory decisions. Due to the variety of net metering mandates passed by state legislatures, or adopted as policy by regional utilities, or local municipal utilities, and the variety of net metering laws and regulations throughout the United States; net metering measures vary widely across the country. However, all net metering programs work to compensate solar energy generating homes and businesses for selling excess solar energy generated with the property owner's solar PV installations, when this energy is sold back to the utility for use in the grid.

Both community solar and net metering encourage power consumption in homes by means of solar energy. Both are great ideas for states in the U.S. (where both of these ideas have found some success), and for countries all over the world. Both represent concepts that enable renewable energy to reach more of the public (illustrated more in the case of community solar), and both make owning solar more attractive (highlighted more in the case of net metering). Whether the purpose is to spread clean energy, or to reap the financial benefits of the solar boom, both community solar and net metering are undeniably positive ideas. 

Please see:

Austin, Texas: A Sustainable City

Please also see:

Renewable energy: solar and solar thermal (PV and CSP)