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.”
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.