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Distributed Solar-Plus-Storage Data and Trends Detailed in New Berkeley Lab Report

23 Jul 2021

As the distributed solar market evolves toward more dynamic forms of deployment, interest in paired solar-plus-storage applications continues to gain steam, but details on the current state of the market are relatively sparse. To fill that void, Berkeley Lab has released an in-depth analysis of this budding market segment. The new report, entitled Behind-the-Meter Solar+Storage: Market Data and Trends, draws on the Lab’s Tracking the Sun dataset to provide an overview and analysis of market trends for grid-connected residential and non-residential behind-the-meter (BTM) solar+storage systems in the U.S. A sampling of key trends discussed in the report are described below. 

Deployment trends: Through year-end 2020, roughly 550 MW of storage has been paired with solar in BTM applications, mostly in the residential sector, and the vast majority located in California. Roughly 6% of all U.S. residential PV systems installed in 2020 and 2% of non-residential PV systems included storage, though much higher rates have been realized within individual states and utility service territories (see Fig. 1).

System characteristics: Among paired residential systems installed in 2020, most employed a single 5 kW battery with either 9.3 kWh (LG Chem RESU 10H) or 13.5 kWh (Tesla PowerWall) of storage capacity, though the portion of systems installed with multiple batteries has been steadily growing (40% in 2020). Most residential systems have the ability to store 30-80% of average daily PV generation, depending on the relative size of the PV and storage components.

Installer market characteristics: Roughly 50% of all residential PV installers and 17% of all non-residential installers have completed at least one paired system, though the residential and non-residential markets are both highly concentrated among a small number of firms. Even among relatively large PV installers, the depth of experience with paired systems varies considerably.

Installed prices: Comparing median installed prices for PV systems with and without storage suggests a storage premium of about $1.2/W-PV for residential and small non-residential systems in 2020, and about half that amount for larger non-residential systems (see Fig. 2). Depending on the data source used, the cost of adding storage to PV ranges from roughly $700-1300/kWh of storage capacity.

Customer financial value: Based on a pro-forma financial analysis, adding storage to residential PV yields a present-value benefit to the host customer of roughly $500-1000/kWh of storage capacity, across several key markets, while adding storage to non-residential PV yields a customer benefit of $1200-2000/kWh.

Customer resilience value: Simulating residential PV+storage systems operated for backup power purposes suggests that a typically sized system with 7 kW PV and 10 kWh of storage would be able to maintain, on average, 60-80% of a customer’s average daily load over the course of a year, depending on the region.

The report, published in slide deck form, is accompanied by a short narrative summary. Both documents are available here: https://emp.lbl.gov/publications/behind-meter-solarstorage-market-data

Lawrence Berkeley National Laboratory | emp.lbl.gov