Commercial Building Case Study

Half-off the grid, California, US


A commercial building in California has constant high power requirements. The grid purchasing costs for them consists of energy charges and demand charges, and demand becomes a large part of their bill when they use a lot of power over a short period of time.

Since California has high solar insolation throughout the year, a grid tied renewable system integration would certainly help alleviate demand charge problems.


In this commercial building case study, inclusion of a battery energy storage system allows more contribution from solar PV into the mix, taking the commercial building practically half-off the grid. BESS integration also allows for demand response activities for the building like peak shaving, energy arbitrage amongst others.

Cost Saving Benefits

The overall project cost is US$616,350. The local electricity rate is US$0.17/kWh. Assuming 8 hours of sunshine per day, and with demand charge reduction of US$5000 per year, the annual savings will be US$152,431. This results in a payback period of just 4 years.

Daily ProductionDemand Charge ReductionAnnual RevenuePayback
2376 kWhUS$5000US$152,431~4 years

About The System

The system comprises of a 109 kWh BESS integrated with a 297-kW solar PV array and the grid. This setup will be able to support the buildings’ power demands during peak periods using the energy stored. Since the BESS is charged during off-peak period with either solar PV or the grid, significant amount of bill savings will be made.


Work with TROES

Power your next project using energy storage. Our Sales and Engineering team will work with you to find out if energy storage makes financial and economical sense.