WM Keck Observatory, REC Solar Installs Rooftop Solar Project at Record height in Hawaii

Duke Energy’s REC Solar and WM Keck Observatory have completed the world’s largest commercial solar photovoltaic (PV) system installed at the record-breaking altitude of 13,600 feet.

The rooftop solar project, located near the summit of Mauna Kea, a dormant volcano on the Big Island of Hawaii, will reduce Keck Observatory’s carbon footprint and lower its cost of energy.

The solar PV system is located on the rooftop of Keck Observatory’s telescope facility, between the domes of the twin Keck I and Keck II – among the world’s largest optical and infrared telescopes. The system will annually produce 259.1 MWh of energy, which will reduce the observatory’s electric power needs by about 10-15 per cent and eliminate 183 metric tons of carbon emissions.

Commenting on the project, Mark Devenot, project lead and infrastructure specialist at Keck Observatory, said “incorporating renewable energy generators such as solar PV is important to Keck's core values of stewardship and service. It will reduce our reliance on electricity derived mainly from fossil fuels, which underscores our efforts to be good stewards of the planet.”

Hawaiian Electric approved operation of the PV system in September this year. The system consists of a 133-kW PV array and 332 solar panels that are strategically placed on the unique 20,940-square-foot ballasted roof to avoid snow and ice fall from the domes, as well as high winds that occasionally occur a few times a year.

“One of the biggest challenges was attaching the PV array to this type of roof, which has no structural framework to anchor the system,” Devenot commented.

To address this issue, the solar system was custom engineered for the unique ballasted roof design and to support high winds. The team also had to deal with working at high altitude, which averaged 40 per cent less oxygen than at sea level.

“Incorporating rooftop solar at Keck Observatory has been a special experience for the REC Solar team due to the project's focus on science, safety and innovation,” said Dan Alcombright, managing director, growth implementation at Duke Energy.

At high altitude, the panels will catch more photons and produce more energy than at sea-level locations. This is because sunlight atop Mauna Kea doesn't have to travel through as much of the Earth's atmosphere where the photons could be absorbed by something else. Having 40 per cent less atmosphere, which is one of the reasons that makes Mauna Kea one of the best places on Earth to conduct astronomy, also makes for efficient solar energy generation.