Flywheel storage for photovoltaics: an economic evaluation of two applications

Abstract

A worth analysis is made for an advanced flywheel storage concept for tandem operation with photovoltaics currently being developed at MIT/Lincoln Laboratories. The applications examined here are a single family residence and a multi-family load center, 8 kWp and 100 kWp, respectively. The objectives were to determine optimal flywheel sizing for the various operating environments and to determine the financial parameters that would affect market penetration. The operating modes included both utility interface and remote, stand-alone logics. All studies were performed by computer simulation.

The analysis concludes that flywheel systems are more attractive in residential applications, primarily because of differences in financing parameters and, in particular, the discount rate.

In all applications flywheel storage is seen to increase the optimum size of a photovoltaic system. For stand-alone environments, optimum configuration sizing is fairly insensitive to hardware cost of photovoltaics and flywheels for a given reliability when no diesel generator is included.

Overall, the worth analysis finds a high sensitivity in the areas of discount rate, PV capital cost, flywheel capital cost, and diesel fuel costs.