There’s more interest than ever in installing home solar systems with energy storage, particularly as states like California adopt time-of-use and other charges that can make stored energy more valuable. But a report out today (March 28) from the Department of Energy (DOE) National Renewable Energy Laboratory (NREL) showed that the costs of energy storage systems are still high and revealed new soft costs associated with such systems.
A number of factors are at play. The costs of PV systems have down precipitously over the past decade and as more companies are getting into energy storage and new battery technology is becoming commercialized by companies like Tesla, its costs cost are falling, too. Meanwhile, time-of-use charges can make stored energy more valuable, either by using energy when electricity from the grid costs more or selling back to the grid when reimbursement rates are highest. That can reduce the time it takes for energy storage systems to pay for themselves and start saving system owners money.
To help consumers and system installers better understand the costs and issues NREL, DOE and the Rocky Mountain Institute published the report, "Installed Cost Benchmarks and Deployment Barriers for Residential Solar Photovoltaics with Energy Storage: Q1 2016." It details the additional costs of battery systems—including their soft costs.
"There is rapidly growing interest in pairing distributed PV with storage, but there's a lack of publicly available cost data and analysis," said Kristen Ardani, lead author of the report and a solar technology markets and policy analyst at NREL. "By expanding NREL's well-established component- and system-level cost modeling methodology for solar PV technologies to PV-plus-storage systems, this report is the first in a series of benchmark reports that will document progress in cost reductions for the emerging PV-plus-storage market over time."
The report explained that the costs are dependent on a number of factors, including whether a system is designed as an alternating current (AC)- or direct current (DC)-coupled system and whether it was installed when a rooftop solar system was installed or later retrofitted. It offered the example of installing a 5.6-kilowatt (kW) PV array and a 3-kW/6-kilowatt-hour (kWh) battery DC system, which would cost $27,703. An AC battery system would cost slightly more, $1,865. If an AC energy storage system was added later its costs would increase by $3,218.
The energy department and NREL said the report helps offer deeper insights into where future cost reductions can be achieved. They also plan to continue to update the report regularly to benchmark and track where such cost reductions are occurring and how to reduce barriers to help lower costs further.Tweet