A number of states are pushing legislation that would require 100% renewable energy supply. But challenges ranging from high costs to the duck curve could make such targets hard to reach. --- A number of states are taking it upon themselves to lower carbon emissions by adopting aggressive clean energy targets. In states like California, Washington, and Massachusetts, lawmakers are considering legislation requiring utilities to get 100% of their electricity from renewable sources. California already generates two-thirds of its power from renewables on peak days, while in Iowa, wind produces a third of the state’s overall electricity. Yet as renewable energy grows in popularity, the falling costs that helped fuel growth can get turned on their head, and overall costs can begin to rise. At the same time, the incremental environmental benefits of renewables can diminish as more wind and solar connect to the grid. Guest Karl Hausker, senior fellow at the Kleinman Center and author of the Risky Business Project report “From Risk to Return, Investing in a Clean Energy Economy,” looks at the pathway to widespread renewable energy with an eye on likely economic and political challenges along the way. Karl Hausker is a senior fellow with the Kleinman Center for Energy Policy and a senior fellow with the World Resources Institute’s Global Climate program. Related Content: Power Over the Twenty-First Century Electric Grid https://kleinmanenergy.upenn.edu/policy-digests/power-over-twenty-first-century-electric-grid Energy Storage in PJM. https://kleinmanenergy.upenn.edu/paper/energy-storage-pjm FERC Clean Energy Policy Roundup. https://kleinmanenergy.upenn.edu/blog/2018/03/29/ferc-clean-energy-policy-roundup