With the cost of photovoltaic devices and wind power dropping dramatically, the economics of some forms of renewable power are becoming increasingly compelling. But these sources of power come with a significant limitation: intermittency. Solar can't generate power around the clock (and output drops during cloudy days), while wind power can suffer from low output that can last days. There are various ways to work around some lack of production—grid-scale storage and careful matching of supply and demand—but some degree of what's termed "baseline power" is needed to ensure the stability of the grid.
There are ways to provide this baseline power that don't involve significant carbon emissions, like nuclear and hydro power. But those come with their own set of issues. So a group of European researchers decided to look into a form of renewable power that hasn't attracted as much attention: concentrating solar power (CSP), sometimes termed solar thermal power.
CSP involves the use of mirrors to focus sunlight onto a liquid, rapidly bringing it up to extremely high temperatures. The resulting heat can be used immediately to generate electricity, or some fraction of it can be stored and used to drive generators later. Depending on the details of the storage, CSP can typically generate electricity for at least eight hours after the Sun sets, and some plants have managed to produce power around the clock during the summer.