Oregon utilities are required to report how much they spend helping low-income households with their bills and, guess what, the giant, corporate, private power companies turn out to be more generous than the state’s legions of power coops and municipal power companies.

A proof of the superiority of the market? Well, no. The story is more complicated and holds a different lesson, as the NW Energy Coalition reports.

Oregon’s private utilities are required by law to spend roughly $5 of every $1,000 helping their poorest customers pay their power bills. I’m no fan of most subsidies to resource consumers, but I like this one. Low-income families spend a larger share of their money on energy than do other families, so rising energy prices hit them especially hard. I’d prefer a more generous system of low-income weatherization (aka, subsidized efficiency upgrades) than subsidies to energy consumption, but in practice, the bill-payer assistance programs are a good way to find families who need weatherization help.

Public utilities are exempt from the obligation to assist their low-income customers, but they pledged to the legislature that they’d match the privates or do better. After all, they declared, they were public organizations, accountable to local elected officials. They could be counted on to do the right thing.

Apparently, they had their fingers crossed. With the exceptions of Salem, Umatilla, and Ashland, every other public utility gave out less help—and often far less help—than the private utilities.

The real lesson isn’t that private companies are more charitable than public agencies. Rather, it’s that enforceable mechanisms (e.g., laws and contracts) that bind everyone to an agreed upon level of public-spiritedness work better than voluntarism.