Throughout the last 10 years, the Plymouth Public Schools (PPS) district in southeastern Massachusetts had been taking steps that would eventually earn it top honors for its environmental initiatives. What started with energy conservation that parlayed into energy-efficient upgrades and retrofits—including LED lighting, web-based thermostat controls and energy monitoring—has been topped off with 10.6 megawatt (MW) DC of generated energy from four different solar photovoltaic systems.
Together, these projects will help supply the 10.5 million kilowatt-hours of energy the district uses, which encompasses 13 pre-K through 12th grade schools and various administrative buildings. The additional energy will satisfy most of the needs of Plymouth’s public buildings.
PPS’s solar installations are unique: three out of the four projects are located offsite due to a mechanism that Massachusetts spearheaded called virtual net metering or remote net metering. Unfortunately, only three states have made remote net metering possible: Massachusetts, California (in certain circumstances) and New York, which approved it in April 2014.
Remote net metering allows a customer to receive solar energy credits on a utility bill even if the solar power installation is built on a remote site. In the case of PPS, the district is the energy “off-taker” receiving energy savings on its utility bill, and the installations are hosted on private land within the territory of NSTAR, a local utility. On top of that, the installations were financed through a third-party financing mechanism called a power purchase agreement (PPA), and they cost the district nothing to install.
In a case like PPS’s in which the installation is offsite, the developer and/or financier leases land from a property owner, builds the installation as its own and sells the power to the off-taker during a period of time (typically 20 years). As a result, PPS will pay nine cents less per watt than what the utility charges for conventional energy.
Plymouth’s projects include three offsite systems financed and developed by Borrego Solar: a 5.7 MW project in Plympton and the largest for any school or district in the state; a 3.5 MW installation in Freetown to be completed by the end of 2014; and a 1.4 MW project in Wareham. The fourth is a 342 kW system on the roof of the newly constructed Plymouth North High School.
Through these solar initiatives, PPS will save more than $800,000 per year in energy and is projected to save more than $20 million during the 20-year term of its PPA contract with Borrego Solar.
Benefits of an Offsite System
The only caveat of an offsite installation is that it must be built within the same utility service area. While this type of program is currently available in only three states, it is a sign of what’s to come on a larger scale. It enables solar access to customers who aren’t able to build solar onsite due to less-than-ideal locations, and it enables structures to benefit from solar in a way that is uniquely suited to their energy demands.
With the offsite installations, PPS was able to capture a much larger financial savings compared with what would have been possible if the district had stuck with rooftop installations. Most of the district’s rooftops weren’t an option because they were built under previous snow-loading codes—a problem that many states with similar winter climates will face. So in order to install rooftop solar, the roofs of several of PPS’s campuses would have to be rebuilt to meet building load standards for the additional weight required for photovoltaic systems.
By moving offsite, PPS was able to reduce the burden of additional infrastructure upgrades as well as minimize other maintenance and safety concerns.
When PPS first began looking into cutting its energy costs, there weren’t many legal resources or administrators available to negotiate contracts. Therefore, the partnerships formed with the solar developer and the contractor managing the energy efficiency projects were invaluable. The district has shared lessons learned with other municipalities and is a perfect example of why Massachusetts’ Green Communities Act was created in 2008, which is when remote net metering became available.
What began a decade ago with behavior-based actions to reduce energy use has resulted in PPS becoming a completely green district and effectively creating its own stimulus plan. Cost savings from energy-use reductions enable PPS to continue pursuing generation and efficiency projects with new technologies.