Not all of these industrial scale solar plants are photovoltaic. Some are solar thermal and include storage. These plants use heated mixed-nitrate salts that can be stored with an energy loss of only a few percent per day. Since there is no change of energy type, e.g. electrical to chemical to electrical as in a battery, they have a storage efficiency that can approach 98%. They can produce electricity at any time of the day and can produce energy at a higher rate than they can store it. They can be used as peaking units and replace natural gas for that purpose. But we will continue to use a lot of natural gas for peaking as it is cheap and plentiful and, although not ideal, produces much less CO2 than coal.

Note that these are best located in Southern California: more sun, fewer cloudy days and more desert land available near transmission lines. There is also a greater demand for air conditioning when the sun is shining, an advantage also for photovoltaic generation.

Battery storage of energy is important. There is a great amount of work being done to make lithium-sulfur rechargeable batteries practical. They have limited practicality now because of their limited cycle life. If the problems can be solved it will almost double the range of electric cars and, either as new or recycled from the electric car market, provide local energy storage as mook suggested.