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).
What role does renewable energy play in the United States? More than 150 years ago, wood supplied nearly 90% of the nation's energy needs. As more consumers began using coal, petroleum, and natural gas, the United States relied less on wood as an energy source. Today, the use of renewable energy sources is increasing, especially biofuels, solar, and wind.