Prospect Sierra

Combined solar and efficiency for $2.7 million in savings

Prospect Sierra is an independent K-8 school in the San Francisco bay area with two ranch-style campuses, an overall operating budget of $13M, and an enrollment size of 470.

The school is committed to taking bold action to reduce its carbon footprint through financially-responsible solutions, and in 2013, the U.S. Department of Education recognized the school with a Green Ribbon Award for its work in greening the facilities and educating their students in eco-literacy. But Prospect Sierra wanted to do even more. So in 2015, it partnered with Carbon Lighthouse to take their energy and carbon reductions further.

Carbon Lighthouse helped the school achieve its sustainability goals while generating a significant positive financial return. A $400,000 investment yielded $2.7 million in savings through a turnkey energy efficiency and solar PV project Carbon Lighthouse completed. All while making a major positive environmental impact.

2 ranch-style campuses

$400,000 Investment

$2.74 MM Lifetime Savings

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Carbon Lighthouse implemented two turnkey projects: 1) efficiency upgrades and 2) solar PV. The efficiency upgrades will provide $79,400 in lifetime utility savings and a 21% unlevered internal rate of return (IRR). The solar portion will provide $2.66 million in lifetime utility savings and a 15% IRR. Combined, these projects will reduce annual energy costs by $48,800 and eliminate 1,730 tons of Carbon emissions over the life of the project – the equivalent of planting 1,444 trees, and more than half of the school’s carbon footprint due to on-site energy usage.

“I highly recommend Carbon Lighthouse for any school that cares about saving the environment while also saving their budget. They went above and beyond to provide us with timely and high quality service so that we could reach our environmental and financial goals.”

Prospect Sierra
Katherine Dinh, Head of School

The Nuts & Bolts: Our Process

Our first step in delivering these projects was to investigate major building systems at both campuses to identify cost effective energy efficiency opportunities. Working closely with the school facilities team, our engineers identified opportunities to improve the scheduling for HVAC equipment and for some lighting upgrades. Additionally, the facilities team at PSS expressed a desire to modernize their thermostats to a wireless network which would allow them greater insight and control as well as remote access to their building operations. As Carbon Lighthouse was already making upgrades that affected the thermostat systems, our project managers incorporated this desire into the project scope.

After investigating the energy efficiency opportunities in the building, our engineers scoped out the opportunity for a solar PV project. Taking into account the reduced energy footprint of both campuses resulting from the energy efficiency upgrades, our engineers determined the optimal solar project, resulting in fewer panels and bigger savings than a solar project implemented without efficiency upgrades. Our team worked to determine the optimal panel and inverter type, racking system, and tilt for each building. On four of the roofs it was decided that a slightly more expensive but more efficient inverter technology be installed due to shading obstructions on those roofs.

As part of our turnkey project management, our project managers then helped the school navigate the lengthy permitting process and worked out a construction schedule to minimally impact students and staff.

The final solar system size was 105 kW across both campuses. This installation, in combination with the implemented energy efficiency improvements at the two campuses, reduced the school’s on-site carbon footprint by 49%, a huge achievement for the school in pursuit of its sustainability goals, while generating nearly $3 million of savings on a $400,000 investment. Prospect Sierra continues to pursue carbon allowances that will off-set the remainder of their footprint so that they can become carbon neutral in the future.

ClientProspect Sierra
ProjectProspect Sierra

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Special Feature

Carbon Lighthouse is proud to be a recipient of the Frost & Sullivan Technology Innovation Award for 2019.Read more