this NY Times article points out, the biggest problem that solar power has always faced is this: what happens when the sun goes down? Solar panels, after all, are fairly dependent on the 'solar' part.
The solar power storage facilities described in the article aren't the silver bullet. The molten salt used to store the heat (which is used to help produce steam and then electricity) can only retain that heat for "hours". And reading between the lines, the molten salt is prone to freezing (!), and could create outages. It sounds like getting a storage tower back online in that event may not be an easy task, since "once molten, it must be kept that way or it will freeze to a solid in part of the plant where it will be difficult to melt again".
We like reading about technology like 'molten salt', and revel in advances like the storage of solar energy. But what is most interesting in this article is that good money is being wagered on a dramatic shift in the definition of 'peak power':
The notion is that widespread adoption of solar panels — whether on rooftops or in giant arrays in the desert — will change the hours at which prices are highest.Today, electricity prices usually peak in the late afternoon and evening on hot summer days. “Photovoltaic panels will do a pretty good job of chopping that peak” in the late afternoon, said Paul Denholm, a solar specialist at the National Renewable Energy Laboratory in Boulder, Colo. In other words, the new price peak will be pushed to later in the day, to just before and after sunset, when solar photovoltaic production is small or nonexistent...
We currently define peak power, or peak capacity, as the time of day when the most number of people 'open the tap' all at the same time--the heat of the afternoon in summertime when air conditioners are buzzing everywhere. If solar panels become more affordable and are more widely adopted, then all those consumers with solar panels will have the greatest need to tap into stored power...at what time of day? Right.
So while experts believe this technology could drive down electricity costs by 25-30%, the short-term, molten-salt storage model is designed to capitalize on an as-yet-to-exist energy structure; exploit it, even. It's not yet about creating energy security.
Hey, baby steps.