The reasons why energy cooperatives have been recently established especially in green electricity markets in Germany have not yet been fully understood. Grounded in transaction cost economics, we develop hypotheses that explain the benefits of cooperative governance in green electricity transactions. We test our hypothesis with a discrete choice experiment and calculate willingness to pay values for governance of green and conventional electricity providers. Our results indicate that cooperative governance such as participation rights or democratic organization raises utility for customers when the share of green electricity is increasing.