Meeting clean energy goals will require new technologies and major upgrades to the electricity grid. This study looks at how building long-distance transmission lines, using long-duration energy storage (like metal-air batteries or hydrogen), and setting specific targets for emerging sources such as floating offshore wind could affect the Western U.S. electric grid by 2040. We use a computer model that simulates how the grid might evolve to meet electricity demand at the lowest cost, considering different policy choices and technology options.

We test how the system responds when it is allowed to build new transmission, adopt long-duration storage, or is required to include a set amount of floating offshore wind. The model can also choose familiar options like natural gas plants or solar farms. We examine the impacts on system cost, emissions, and where new infrastructure is built.

We find that new transmission lines are consistently the most effective way to reduce costs and emissions, mostly by integrating more onshore wind energy from inland areas. Long-duration storage also helps, but less so. In contrast, requiring floating offshore wind increases overall system costs, as it is rarely chosen by the model when not mandated.