Wind farmers are farming subsidies.

Production Tax Credit and state Renewable Energy Credit revenue are making in economically rational for wind producers to keep churning their megawatts out even though the energy is not needed. In West Texas so much energy is produced that at times the market value of the energy is zero (consumers at the wholesale level get paid to use power).

Link:
Frequent negative power prices in the West region of ERCOT result from wasteful renewable power subsidies - Knowledge Problem