Can We Meet Our Energy Needs with Solar?

I'm not sure what Stephen Lacey meant by "powering the entire U.S. with solar". One obvious interpretation is that it means that all of the US power comes from solar. From the interviews I can only assume that it was meant to mean something quite different.

But if that was what was meant then there was a giant elephant in the room with Ken Zweibel that got completely ignored. Solar only produces power for 8 hours a day (if you are lucky). What do you do for the other 16 hours? Ken talked about the "easy" problem - the short term loss of power from cloud cover but ignored the night or a string of cloudy days. The nights are a certainty and the string of cloudy days happen not infrequently - even in the South West.

Zweibel talked a lot about solar PV technology (obviously his area of expertise) but never talked seriously about electrical energy storage technology that can store the kind of TWhs you would need to rely on all solar. Solar thermal may have a part answer with heat storage but the technology still has a long way to go for solar PV.

I was amazed that Stephen didn't even raise this critical question. In my opinion it will be the cost effective energy storage problem that will hold back solar power not the solar technology.

Martin --
I'm actually surprised it took this long for someone to make a comment like yours. I do agree, we didn't talk extensively about the long-term storage picture, which is one of the most important components of this conversation.

Unfortunately, it's a lot more difficult to do the topic justice with a single-interview format. This type of topic really needs to be addressed in a more dynamic way.

However, I think there are storage/back-up methods out there for solar today. Those include: Wind (where feasible) Compressed air, and something like molten salt or oil (which you mentioned). Then further in the future, we're talking about huge flow batteries. While we still have a way to go before some of the next-generation storage techniques are viable, there are technologies out there today that can provide the bridge.

Therefore, I think we can start having realistic discussions about such a high penetration of solar today.

Anyway, I appreciate your comment.

PS -- I should have made it clear that Zweibel was talking about 70 percent of our electricity and 35 percent of total energy by 2050.