Letterbox - Molten Salt for Electricity

Dear Watchers:

Some time ago Scientific American stated that there is enough solar power in the U.S. to provide all energy needs. That magazine is regarded to be reliable but it said nothing about how that would be achieved so I did not take it seriously. However the Jan. 2 Wall Street Journal described in detail one possible step along the way. No doubt the Journal did that because if successful the project would be relevant to stock prices of companies involved in the project. Moreover, the U.S. Department of Energy said it would provide $6.2 million to help get the project operational.

The salt used is a mixture of sodium and potassium nitrate. It was chosen because it loses only 1 percent of its heat during a day. Thus it is possible to store heat for use when the sun is not shining.

The system is practical only where there is a sunny climate and large open spaces for 1,200-acre fields of mirrors to reflect sunlight onto a 600 foot tower. Molten salt is heated and then pumped down and stored in insulated containers where it is stored until needed. When needed, the heat is used to produce steam that runs an electrical generator to produce electricity. The plan is to produce enough electricity to supply 500,000 households at continuous capacity.