Electricity (C-evo)

Electricity in the free game C-evo leads to the intrinsically useful advances Radio and Refrigeration and lets you build a very good value city improvement, a Power Station, in any suitable city that has a factory. 
However, if you have the right selection of cooperative friends and are confident of building the Hoover Dam, Electricity will be of no use to you. The Hoover Dam (which can be built in any city that adjoins a river or a mountain) gives each of your cities, in effect, a Hydroelectric Dam, which is a free equivalent of the Power Station with much less pollution.