In the fourth quarter of 2023, the US energy storage market saw an addition of 4,235 MW across all sectors. Both the grid-scale and residential storage segments achieved record-breaking installation volumes with significant quarterly increases.

The grid-scale segment continued to expand, setting a record for quarterly capacity deployment:

- With an increase of 3,983 MW in the grid-scale segment, installations surged by 358% compared to Q4 2022.

- California and Texas installations contributed to 77% of the Q4 additions, pushing the quarter's total capacity beyond 3 GW, almost reaching 4 GW for the first time.

- In terms of MWh, California led with a 56% share in Q4, installing 6,593 MWh. The total of 11,769 MWh added in Q4 2023 marked a 105% increase from Q3, surpassing the previous record of 5,728 MWh.

The residential segment showed rapid growth, with California becoming the first region to install over 100 MW in a single quarter:

- California installed 48% more MW of residential storage in Q4 2023 compared to the previous record in Q3 2023. The state achieved a 31% attachment rate in Q4 and is anticipated to continue growing despite the decline in the NEM 2.0 pipeline.

- Puerto Rico experienced its most successful year yet due to various storage incentives, surpassing California to become the largest US market in 2023 with 287 MW installed.

The growth of the CCI segment remained stagnant and concentrated:

- Massachusetts recorded its best quarter in two years, deploying 9.7 MW of CCI storage. However, the state did not show growth in annual installations from 2022 to 2023.

- New York emerged as the top CCI storage market for the second consecutive quarter, narrowly surpassing California with 12.0 MW installed. Despite this quarterly achievement, New York also failed to show year-over-year growth.