Watthub Renewables and Sunrock Distributed Generation completed a 322-kilowatt solar photovoltaic system at the three-story Class A medical office building, Irvine Legacy Medical Plaza, in Irvine, California. The solar panels were installed on a carport covering approximately 108 parking spaces, transforming the exposed asphalt pavement into shaded parking spots and making it the primary power source for the building.

The system is projected to generate approximately 515,690 kilowatt-hours of electricity in its first year, covering the majority of the plaza's annual power consumption. Delivered under a 25-year power purchase agreement, the project requires no upfront capital investment from Irvine Heritage owners. Watthub and Sunrock DG handle financing, design, and contracting, with services provided by SunRenu Solar. Sunrock DG now owns and maintains the photovoltaic array, while the property purchases the generated electricity at rates lower than those of Southern California Edison.

The Irvine Legacy Medical Plaza was built in 2008, covering slightly over two acres with approximately 40,000 square feet of medical office space.

"Medical clinics are among the rare property types where parking spaces become part of the patient experience," said Aaron Moston, director of Watthub Renewables. "Imagine someone who just had a medical or dental procedure at 2 p.m. in August. Whether their car is at 140 or 95 degrees is no small matter. Before our production model was operational, the carport was the most suitable structure for this site—and it happened to be the best south-facing real estate on the property, which made the entire project successful."

The Alvin Legacy Medical Plaza operates under a master metering model, which means the entire building obtains electricity from a single source via a Southern California Edison (SCE) account at the GS-3-TOU commercial rate. This cost is then passed through tenant rents rather than individual utility bills. Over the years, this has resulted in every clinic within the building bearing a portion of the electricity cost they cannot see or control—a fee from a utility region with continuously rising rates, including peak-time charges during summer months.

Since solar power generation is net metered at the main electricity meter, the savings on electricity costs are not allocated to any single tenant—they reduce the overall building's total electricity expenses.

"The master meter is often seen as a disadvantage—tenants cannot see their own electricity consumption, while all fluctuations in utility costs are borne by the owner," said Wilson Zhang, CEO of Sunrock DG. "For solar projects, the situation is exactly the opposite. One meter, one grid connection, one utility bill, and every unit in the building automatically benefits. This is the simplest way to introduce solar into multi-tenant properties."

Earlier this year, another 300-kilowatt solar carport project was developed for the Ford Hill Medical Association in Ford Hill, California. The system was also put into operation through a power purchase agreement.