Midwest Energy News’ Dan Ferber interviewed Willett Kempton of the University of Delaware about his recent study that explained how we could be powered solely by renewable energy by the year 2030.

You have a diversity of sources because you’re more likely to have power generated when you need it if you have onshore wind and offshore wind and some solar. A lot of the time you’re generating more power than you need. And when you are doing that you store it, but before long your storage fills up, so most of the time you’ve got excess power.

Sometimes, when you don’t have enough power being generated by renewables, you discharge your storage and run on that, plus whatever renewables you’ve got. And a few times per year, you actually have to look to some other source. In our analysis we used fossil, using legacy plants that are already in existence, and just running them much less frequently.

So, that’s what the system looks like: Lots of apparently excess renewables, a very small amount of storage, and some older fossil plants that are being kept around for these situations.

Read the whole interview at http://www.midwestenergynews.com/2013/01/11/qa-can-renewables-alone-witih-storage-power-the-grid/