The sun shines almost 280 days a year in New Mexico, making our state a prime location for solar power. But until recently, public agencies couldn’t use this form of renewable energy to lower electricity bills.

That changed in 2011, when two changes to the state’s Public Facility Energy Efficiency and Water Conservation Act went into effect. Legislators added solar to the list of projects eligible for long-term energy performance contracting and allowed non-home rule public entities to sign power purchase agreements (PPA). These amendments freed Bernalillo County to become the first county statewide to install a photovoltaic system at an existing facility.

Located on a mesa 10 miles west of Albuquerque, the Metropolitan Detention Center (MDC) houses almost 2,000 inmates and employs about 500 people. Built in 2002, the 500,000-square-foot jail continuously operates essential security and lighting functions. As a result, it’s the county’s largest consumer of electricity; in 2012, the county paid $981,563 for 12,627,000 kilowatts.

The facility still uses more than other county buildings. But since January 2014, 20% is coming from an onsite photovoltaic system capable of producing 2.4 million kilowatts (KW) every year.

How the system works

The 1 megawatt (MW) installation was financed, designed, built, and is operated by SunEdison LLC, formerly Monsanto Electronic Materials Co. (MEMC). One of the first U.S. companies to manufacture the semiconductors that turn sunlight into electricity, SunEdison is a global developer of solar projects.

Our 8-acre installation comprises 3,960 MEMC brand P300BMC-20 photovoltaic modules arranged in four ground-mounted, single-axis arrays that pivot to follow the sun from east to west every day. Their DC current is converted to AC current by three Solaron 33 inverters manufactured by Advanced Energy Industries Inc. From there, the current flows into the facility’s existing transformer and into the facility.

Although the system is connected to the grid of our local electric utility, the Public Service Company of New Mexico (PNM), it won’t supply PNM. Instead, it will lower overall facility costs by lowering demand during the day, when electricity use is highest (see table on page 28 for financial analysis). The county expects to save $7,000 per year in demand charges, the rates that PNM’s largest consumers pay. The rate increases as demand increases to compensate the utility for ensuring full capacity is immediately available at any given time.

The contract establishes a flat rate for the power generated by the solar project. This “solar rate” is $0.0606 per kilowatt hour, more than the current regular rate but less than the projected regular rate beginning in the fourth year of operation. If the regular rate increases 2.4% annually as expected, we will save more than $300,000 over 20 years.

The purchase agreement enabled the county to invest in renewable energy without going into debt. Construction created about 50 jobs and generated $240,000 in gross receipts taxes. Finally, the project will reduce the county’s use of fossil fuels and CO2 emissions.

As with any first-time project, we learned by doing. As the first county to sign a solar PPA under the revised state law, we encountered, and resolved, several challenges along the way.

Next page: Two legal obstacles addressed