ZDNET Analyst Sees 5-Year Payback for Plug-In Solar Batteries as TOU Rates Drive Savings
Updated
Updated · ZDNet · Aug 26
ZDNET Analyst Sees 5-Year Payback for Plug-In Solar Batteries as TOU Rates Drive Savings
3 articles · Updated · ZDNet · Aug 26
Summary
Most plug-in solar-plus-battery systems should pay for themselves in about five years, the ZDNET analysis found, though returns depend heavily on local sunshine, electricity prices and tariff structure.
Time-shifting is the main value proposition: batteries can store midday solar output or cheap off-peak grid power, but the setup only works well when time-of-use rates have a wide enough peak/off-peak spread.
Round-trip efficiency of 80% to 90% still left savings in the Con Edison example, where a 12 kWh battery refill cost about $0.78 off-peak versus $2.05 in winter or $3.34 in summer at peak rates.
Smaller 3 kWh systems saved only about $0.30 to $0.60 per day in that example, underscoring how losses, surcharges and usage patterns can sharply reduce headline economics.
Upfront costs remain substantial—about $300 for a 180W plug-in solar kit, $1,500 to $2,000 for 800W setups, and roughly $3,000 for EcoFlow's 5,024Wh battery system with installation.