When actions meet attitudes: Public and solar-adopter preferences for clean transportation and energy policies

Policymakers across the United States continue to promote the electrification of transportation while expanding the share of renewable energy generation to decarbonize the power grid. Previous studies have typically examined these policy domains separately and often overlooked how citizens who have already made tangible clean-energy investments perceive such initiatives. Using New Mexico as a case study, this research fills that gap by jointly examining public and rooftop-solar owners' willingness to pay (WTP) for policy combinations that link the Clean Car Rule (CCR) and Renewable Portfolio Standard (RPS). The study is distinctive in surveying two complementary groups (a representative sample of 940 New Mexico residents and a second group of 438 rooftop solar adopters who installed systems after 2020) allowing us to compare stated policy preferences across groups distinguished by revealed environmental behavior. Employing conventional and hybrid mixed logit models estimated in WTP space, we account for both observed attributes and two latent attitudinal variables, environmental concern and policy support, identified through exploratory factor analysis. Results indicate that both groups express significant and positive WTP for electrifying the transportation sector and expanding clean energy generation, though solar adopters display higher support for renewable portfolios, rooftop solar carve-outs, and policies that promote clean-energy integration. Joint Wald tests and likelihood ratio tests confirm that these preference differences are statistically significant across samples. Individuals with stronger pro-environmental attitudes and favorable policy beliefs also exhibit higher WTP for clean transportation and energy attributes. These findings indicate the importance of incorporating revealed-behavior subgroups into stated-preference studies to better understand heterogeneity in public support for decarbonization. Policy implications include the value of pursuing balanced state-level portfolios that align renewable deployment with electric-vehicle policy ambitions.