The plummeting cost of photovoltaic (PV) panels—resulting from lower costs for high-grade silicon and advancements in thin-film technology, solar storage, and electronic control technologies—has a slew of firms rethinking concentrating solar power (CSP) projects. Although there is a CSP project pipeline (including both CSP and concentrating PV) of more than 9 GW in the U.S., and more than 2.4 GW of those projects have signed power purchase agreements, only 509 MW of CSP have been grid-connected to date (see for a detailed list of major projects). Meanwhile, according to the Solar Energy Industries Association, in the first quarter of 2011, grid-connected PV installations in the U.S. surged 66% over the same period in 2010 to reach 252 MW, at a capacity-weighted average price of 5.63 cents/watt. That brought total U.S. grid-connected PV capacity to more than 2.3 GW. Here are some projects (with a combined capacity of 4,056 MW) that have announced a switch from CSP to PV and brief notes about the reasons cited. —Sonal Patel, senior writer