What are the relative costs of battery-backup vs. non-battery-backup PV systems?
We have a detailed computer program that we use to estimate the installation cost of any system, based upon site-specific installation information. Battery-backup systems are more costly because they involve additional components, such as charge controllers, batteries, battery containers, battery cables and circuit breakers. They also involve higher labor costs because of the additional components that must be wired as well as the rewiring of emergency circuits so they will remain energized during power outages. In general, depending upon system size, roof type and choice of batteries, a battery-backup system can be installed at a cost in the range of $11–$13 per watt, before any incentives are applied. The pre-incentive installed cost of a non-battery-backup PV system will generally be about $3 per watt less for a comparable sized system. So, for example, a 2000-watt battery backup system may cost $24,000 to install, while a 2000-watt non-battery-backup system may cost $18,000 to inst
