Zero net energy (ZNE) buildings, which generate as much power as they use through innovations like rooftop solar panels, added insulation, and natural ventilation, tend to be the province of the wealthy, due to their higher construction costs. But a grant from the California Energy Commission (CEC) is bringing total energy efficiency to an unlikely spot: a 1907-era single-room occupancy (SRO) hotel in the Tenderloin. 

As Fast Company reports, the William Penn Hotel at 160 Eddy St. (between Powell and Mason) is set to receive a zero-net-energy retrofit in the near future, intended to preserve its historic facade while cutting down on utility bills for its 94 low-income residents. The CEC is contributing $3 million to the project, and the San Francisco 2030 District, a public-private collaborative dedicated to energy-efficient "high performance" buildings, will help make it happen.

The William Penn is owned by the Chinatown Community Development Center, which manages 2,000 SRO rooms across the city. If the project is successful, the CCDC plans to examine cost-effective ways to expand it to all of its SRO properties. The organization is also calling for local startups in the space to apply to use the project as a testing ground. 

ZNE buildings could very soon become all the rage in California: the CEC has called for all new home construction to be zero net energy by 2020, with commercial buildings following in 2030.