I found this information on the National Rural Electric website. You can visit their page explaining what a rural electric co-op is all about. About Co-ops
Basically, the principles of a rural electric co-op are these:
Cooperatives are voluntary democratic organizations controlled by their members who actively participate in setting policies and making decisions.
President Roosevelt created the Rural Electrification Administration (REA) in 1935 by Executive Order within days of being sworn in as President. There are more than 900 electric cooperatives today, with an average of 7 customers per mile.