An enormous transition is underway across the electric grid. Power plants that run on fossil fuels are being replaced by solar panels and wind farms and more batteries and electric vehicles are plugging in every day. Once niche, the clean energy industry is going mainstream. Goldman Sachs says it’s an investment opportunity worth as much as $16 trillion through 2030. Within the industry, researchers, entrepreneurs, and workers are bringing a wide range of solutions to bear, from batteries that store energy in molten salt to water turbines that are fish-friendly.

Business Insider has identified the 21 emerging leaders in clean energy that we think everyone should know.