The U.S. ethanol boom has been brought up short by market glut, making corn-based fuel “2007’s worst energy investment,” a Bloomberg News Service article declared today. President Bush made ethanol a centerpiece of his energy plan and lavished it with subsidies; ethanol distilleries that went up quickly in anticipation are now having to shut down. Producer Pacific Ethanol Inc., backed by Microsoft cofounder Bill Gates, dropped 70 percent in New York trading this year. The biggest producer of the fuel, U.S. ag giant Archer Daniels Midland, may have to begin exporting it. Analysts suggest that the ethanol market may stabilize by late 2008, giving us a little more time to try to knock some sense into corn-biofuel boosters.