Many rivers to cross

The cost of solar, wind and storage continues to fall, improving cost-emissions tradeoffs for electricity grids. However, there are still many rivers to cross on the road to decarbonization. While renewables have begun to make inroads in electricity, they have barely made a dent in transportation, industry and building/home energy use. This year’s topics include renewable energy projections to 2040; the improving economics of high-renewable electricity grids; unsettled questions on hydraulic fracturing of unconventional oil and gas; Russia’s lower-carbon energy exports and its geopolitical influence; the murky decarbonization potential of forest biomass; and the imaginary greenness of college campuses.