Saving Sunshine

In this nuts-and-bolts examination of a Pennsylvania home that once (albeit indirectly) relied partly on coal as an energy source, master electrician and solar installer Bruce Hankins describes how to keep electricity flowing by using “AC coupling”—a technology that combines a “grid-tied” solar installation with an “off-grid” battery backup, resulting in a setup that provides power regardless of whether the sun is shining. Hankins points out that the homeowners (who were already committed to reducing their carbon footprint) were inspired to make a change after heavy rains left them with a flooded basement and no power—their sump pumps idle and useless. Hankins illustrates how energy can be moved between a) the photovoltaic panels and batteries that generate and store direct current, and b) the power grid, which operates on alternating current. Unfortunately, while this discussion might be interesting to architects and engineers, the details could be overwhelming for general viewers, and even though the material is technical, the film is far is too brief to serve as a do-it-yourself guide. Still, Hankins does carefully explore the considerations that must be taken into account by those interested in shifting to a modified solar power system, and he offers a promising message about the possibility of sustainable energy independence. A strong optional purchase. Aud: C, P. (F. Gardner)