The system would set a price for greenhouse gas emissions , such as carbon dioxide , and polluters would obtain and trade credits for emissions over a set threshold . Worst known oil spill heightens debate over how to meet nation 's energy needs . NEW : Senate shelves slimmed - down energy bill , blaming conservative ##s . NEW : House says Sen. Harry Reid rushed bill through without trying to win Democratic support .
Worst known oil spill heightens debate over how to meet nation 's energy needs . NEW : Senate shelves slimmed - down energy bill , blaming conservative ##s . NEW : House says Sen. Harry Reid rushed bill through without trying to win Democratic support .