Sept. 27 — Though they aren’t as sexy as perpetually-discussed-but-rarely-passed carbon taxes, and they are flawed and insufficient in a number of ways, RPSs have been the quiet workhorses of renewable energy deployment in the US. According to one Lawrence Berkeley Lab report, fully 62 percent of the growth in US non-hydro renewables since 2000 has been undertaken to satisfy RPS requirements.

— Vox