A Renewable Based Direct Current Building Scale Microgrid

Renewable based DC Building microgrid to save energy and lower costs.

Robert Bosch LLC


Palo Alto, CA

Recipient Location


Senate District


Assembly District



Amount Spent



Project Status

Project Result

The project is complete and the final report is in the publication process. The microgrid, operated by a Bosch microgrid controller system, reduced the need for inverters for PV and rectification equipment for the loads. The microgrid improved the overall utilization of solar energy by roughly 7-10% as compared to conventional AC systems, while lowering component complexity and costs.

The Issue

Microgrids can enable a building owner to lower operating costs and to operate in a grid outage. Microgrids developed to date rely on converting direct current (DC) from renewable generation to alternating current (AC) to support building loads. However, DC to AC conversion results in energy losses. A potential solution to further increase the benefits of microgrids is to develop a DC-based building with DC loads (e.g., lighting, fans). DC buildings are a research area that has not been evaluated fully by extensive research, and require proof of concept to gain traction in the market.

Project Innovation

The team developed a DC microgrid that connects on-site generation directly with loads and provides a low cost, energy-efficient solution for warehouse facilities. Solar PV is directly connected to energy-efficient DC lighting, a DC energy storage system, and ventilation to form a DC building microgrid.

Project Benefits

This project demonstrated the feasibility and benefits of a commercial-scale DC building microgrid that uses multiple DC technologies to provide reliable power to the loads on DC circuits, resilience during grid outages, increased energy efficiency and renewable energy utilization with lower losses. Additionally, the project team was able to obtain Title 24 approval for their DC design and an interconnection agreement with the local utility. Both steps were first of a kind approvals for a facility such as the large automotive distribution facility used for the demonstration.

Lower Costs


By operating advanced technologies such as LED lighting and energy storage systems on DC power as opposed to AC power, installation and operating costs will be reduced, improving the economics for microgrid deployment.. The project was able to demonstrate an overall energy efficiency improvement of the lighting, ventilation and fork-lift charging loads improved by approximately 3-5% due to DC operations, while the efficiency of the energy storage device improved by 8%.

Environmental & Public Health

Environmental Sustainability

If adopted by 2-5 percent of commercial buildings in California, a DC microgrid can result in 128 gigawatt-hours per year of energy savings. This translates to avoided carbon dioxide emissions of 36,000 metric tons per year, and avoided NOx emissions of 343 metric tons per year.

Greater Reliability


Bosch has validated that this microgrid supports all the critical loads during a grid outage for smooth operations (e.g., warehouse lighting, ventilation, fork-lift charging), and eliminates the requirement to run the diesel generator.

Meet the Team

Connect with the project team members that are helping California lead clean energy innovation.

Key Project Members

Project Member

Sharmila Ravula

Director- Business Development (RBNA/PJ-DCMG)



Johnson Controls, Inc.


Navigant Consulting, Inc.


Maxwell Technologies


Regents of the University of California, Davis - California Lighting Technology Center


Baker Electric


KPFF Consulting Engineers


Sylvester Roofing Co., Inc.


Match Partners


Maxwell Technologies




Robert Bosch LLC


Regents of the University of California, Davis - California Lighting Technology Center


Imergy Power Systems


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