Climate Solutions Act of 2017 This bill amends the Public Utility Regulatory Policies Act of 1978 by directing the Department of Energy (DOE) to promulgate regulations that require the percentage of electric energy generated from renewable sources that is sold at the retail level to increase each year beginning in 2020 so that in 2050 and each subsequent year, the percentage is at least 80%. DOE must also promulgate regulations that set cumulative energy savings targets for retail electric energy and natural gas suppliers that require each supplier to secure annual savings that are achieved through end-use efficiency improvements at customer facilities. For electric energy suppliers, the targets must increase from .25% of sales in 2020 to 1.5% of sales in 2025 and each year thereafter through 2030. For natural gas suppliers, the target must increase from .25% of sales in 2020 to .5% of sales in 2025 and each year thereafter through 2030. DOE must allow suppliers to achieve the targets through a market-based trading system. The Environmental Protection Agency (EPA) must promulgate annual emission reduction targets for each of 2030 through 2050 to ensure that U.S. greenhouse gas emissions: (1) in 2035 are at least 40% below those in 1990, and (2) in 2050 are at least 80% below those in 1990. The EPA must promulgate final regulations to implement those targets within 7 years and review them at least every 5 years thereafter.