WisdomTree's index is designed to "track the performance of global companies involved in the renewable energy value chain as part of the electrification and decarbonisation megatrend", the company explained. Those companies will also need to satisfy WisdomTree's ESG criteria, it added. WisdomTree unveils California Carbon Allowance ETP Chris Gannatti, global head of research at WisdomTree, said: "The transition towards cleaner and more sustainable energy sources is our best chance of tackling climate change. Renewable energy is at the heart of this endeavour and we see several key drivers that could propel the growth in renewable energy usage. "Since the war in Ukraine, energy security has been a priority for countries as it became clear the world had to reduce their dependence on fossil fuels.