DALLAS — In Texas, wind farms are generating so much energy that some utilities are giving power away.

Briana Lamb, an elementary school teacher, waits until her watch strikes 9 p.m. to run her washing machine and dishwasher. It costs her nothing until 6 a.m. Kayleen Willard, a cosmetologist, unplugs appliances when she goes to work in the morning. By 9 p.m., she has them plugged back in.

And Sherri Burks, business manager of a local law firm, keeps a yellow sticker on her townhouse’s thermostat, a note to guests that says: “After 9 p.m. I don’t care what you do. You can party after 9.”

The women are just three of the thousands of TXU Energy customers who are at the vanguard of a bold attempt by the utility to change how people consume energy. TXU’s free overnight plan, which is coupled with slightly higher daytime rates, is one of dozens that have been offered by more than 50 retail electricity companies in Texas over the last three years with a simple goal: for customers to turn down the dials when wholesale prices are highest and turn them back up when prices are lowest.