This bill requires the department of administrative services to consider proxy carbon pricing in transportation costs and building project costs. It defines "proxy carbon pricing" as the cost of carbon dioxide equivalent greenhouse gas emissions based on modeled rates on a graduated scale over time. The department of administrative services must incorporate a proxy carbon price in cost comparisons for transportation costs and building heating and cooling costs for all new construction and renovations. The commissioner will use a proxy carbon price of $85 per ton starting January 1, 2025, and increase it by $10 every January 1 until January 1, 2050. The carbon dioxide equivalent emissions of natural gas will be determined using a methane multiplier of 1.3 times the carbon dioxide emissions of natural gas to account for 1 percent methane leakage at 80 times the 20-year warming forcing equivalence of carbon dioxide. This act will take effect on January 1, 2025.