text: Taxes on energy use or on carbon emissions could raise California's electricity bill from $2.6 billion to $10.4 billion, an increase of 12.5 to 50 percent. A tax on motor fuels of $.50 per gallon would add at least $7.7 billion to California's annual driving costs, a 40 percent increase; and a $1.00 tax would add $15.4 billion, an 80 percent increase. A BTU tax on natural gas, oil and coal of $.60 would add 6.1 percent to California's energy costs and a $1.00 BTU tax would increase annual costs by 10.6 percent.