Alliant Energy will buy electricity from a northern Iowa wind energy farm that’ll be built by a California-based company. Alliant spokesman John Ruff says “Clipper Wind Power” will build and own the 29 wind turbines on the “farm” and Alliant will buy the power that’s generated. The wind farm will be built in the Spirit Lake area, and Ruff says they hope the project’s up and running by 2003. He says wind is becoming more economically feasible now, and promoting it helps.Coal-fired generating stations still provide the cheapest electricity, but Ruff says wind energy technology is improving and it’s becoming cheaper.Another downside to wind energy is it’s not a continuous source of electricity, particularly — Ruff says — in the “dog days” of summer when there’s no wind and lots of demand for electricity to run the air conditioning.