Three decades. That is how much time is left to decarbonize the world’s energy systems to limit global warming to 1.5°C, according to the latest Intergovernmental Panel on Climate Change (IPCC) report. Achieving this feat requires renewable energy systems be deployed at an unprecedented speed and scale. While daunting, however, the good news is that this transformation may not cost as much as many expected just a decade ago, thanks to rapid cost declines in renewable energy technologies.