The need for energy is something that is difficult to balance with the various environmental challenges. The burning of coal for electricity creates significant amounts of pollution and carbon dioxide, a green house gas. The use of other fuels like gasoline and diesel to power trucks and cars also causes pollution and carbon dioxide. The traditional fuels like coal and oil and gas, in the production of energy, also produce pollution. There are cleaner uses of these fuels, but the fuels remain the same and in the process of combustion or burning the fuel for energy, will always have some form of environmentally harming effects.
After it is vetoed it will go back to the senates who wanted the law and they will think about it again, then they will send it back and see if its approved or vetoed.