LOS ANGELES-What's billed as the nation's largest rooftop solar program starts today, as the Los Angeles Dept. of Water and Power's Feed-in Tariff Program begins with a ceremonial launch.

Environmental and business executives will join mayor Antonio Villaraigosa this morning at the Oxnard Plaza apartments at 11313 Oxnard St. in North Hollywood. After remarks, he will flip a symbolic switch to simulate connecting the building's rooftop solar array to the grid.

Feed-in tariffs allow customers to sell their utility power generated by their rooftop solar installations. The concept hopes to encourage more businesses to install solar and generate carbon-free power. Programs similar to L.A.'s have proved successful all over the world and in the U.S.

The LADWP program currently pays those signing a 20-year agreement 17 cents per kilowatt hour for power sent back to the grid. The amount sold back can vary, since solar installation sizes differ. Program-eligible arrays in L.A. are capable of generating from 30 kilowatts to 3 megawatts of power. 

The amount of money offered for power returned to the LADWP is anticipated to gradually decline by roughly a cent per offering period, as more arrays come online and the cost of solar panels drops. The LADWP program is currently over-subscribed on its initial offering and chose its initial participants via a lottery.

A new offering at a slightly lower rate is expected to start in July and will require an application for the program followed by a lottery to determine who may participate. Most of the buildings that benefit from the feed-in tariff are big, including multifamily units, shopping centers, parking lots, offices, industrial buildings, schools and other larger venues.

L.A. Business Council president Mary Leslie tells GlobeSt.com that her organization backs the program. “We started to analyze what happened in (previous feed-in programs) and realized how elegant this contract was. Businesses have fixed access to the grid. Your roof is an under-utilized asset, just sitting up there. If you can generate power and get paid, 'Wow, okay.' And when you put solar up, there's at least a 5% cooling effect on your building. That could be very good because of what you're paying for air conditioning.”

Leslie is advising those property owners interested in participating in future feed-in offerings to contact a solar developer to talk about such things as roof conditions and whether buying the array or leasing it is the right option for a particular situation. She says most arrays are provided at a zero capital cost to the property owner and provide cash flow that typically results in a 10% to 15% rebate on annual power costs. The results will vary depending on the size of the solar array system. There is also a federal tax credit of 30% available for installations, Leslie says.

As previously featured in GlobeSt.com, the L.A. Better Buildings Challenge, designed to achieve 20% energy savings by 2020 in existing commercial buildings, has been very successful to date.