This Calculator should be used as an estimating tool ONLY. 1  Enter the dimensions below to calculate how many bags of concrete you need. After entering the dimensions of the pad, click on Calculate and the calculator will provide you with the amount of concrete. 2  ft in. 3  ft in.  ft in.
According to the International Renewable Energy Agency (IRENA), renewable energy employment in the United States reached 724,000 jobs in 2014, a 16 percent increase from the previous year (IRENA does not include large-scale hydropower in their estimates).
Water. Water, or hydropower, is the renewable energy source that produces the most electricity in the United States. In 2009, it accounted for 7 percent of total U.S. electricity generation and 35 percent of generation from renewables in 2009, according to the U.S. Energy Administration.