Renewable energy sources are often located in rural areas far from the urban centers that call for the highest demand for energy. The power grids in existence today were designed to link customers to relatively nearby coal, gas and nuclear powerplants. In order to benefit from the environmental, economic and national security advantages of renewableenergy, the U.S. needs to find affordable and efficient means to transmit the renewable energy from these remote areas to where it is needed most.With private property easements both scarce and expensive, the use of existing freeway right-of-way offers a very attractive option for transmitting renewable
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.