Are “100% Renewable” Electricity Claims Misleading? Evidence on Consumer Awareness and Preferences for Temporal Matching

Green electricity tariffs marketed as "100% renewable" often rely on Energy Attribute Certificates (EACs), which allow a temporal decoupling between consumption and generation. This decoupling has raised concerns about the actual environmental impact of green electricity tariffs and the potential to mislead consumers. This paper examines German households' awareness and preferences regarding temporal matching. Based on a stated-choice experiment with randomized information treatments and over 1,000 participants, we find: (1) 85% of consumers are unaware of the mismatch; (2) informing them reduces willingness to pay (WTP) modestly but statistically significant by 4.1-11.4 percentage points; and (3) an explicit guarantee of temporal matching does not significantly increase WTP. We interpret these findings as an information failure in current green electricity markets, where a non-negligible share of consumers likely base their purchase decisions on incorrect or incomplete information. Various measures could help mitigate it, including clearer definitions and greater transparency mandates, alongside voluntary industry standards and third-party verification.