"The grid is an accident of history and of culture, in no way intrinsic to how we produce, deliver and consume electrical power. Yet this is the system the United States ended up with, a jerry-built structure now so rickety and near collapse that a strong wind or a hot day can bring it to a grinding halt. The grid is now under threat from a new source: renewable and variable energy, which puts stress on its logics as much as its components. In entertaining,...