U.S. Department of Energy - Energy Efficiency and Renewable Energy

Advanced Manufacturing Office – Industrial Distributed Energy

Walk-Through Analysis

This phase of the project review shouldn't take more than two days. During that time, you'll need to collect data describing your plant's energy use and go through a logical progression of questions about your situation, as shown here.

This diagram shows a decision tree for evaluating whether CHP is likely to be cost-effective for a particular installation. You should start by carrying out a site energy audit to identify and implement measures that would result in a significant electric and/or thermal energy savings. You should then review site conditions to determine whether there is adequate access, space, fuel, and supplies for the installation. If not, CHP is unlikely to be cost effective. If yes, consider whether the average site electrical load is likely to be greater than 250 kW during operating hours. If not, CHP is unlikely to be cost effective. If yes, consider the potential thermal loads on the system. If they are greater than 1000 pounds per hour of steam, greater than 700,000 Btu per hour of hot water, or greater than 1,000,000 Btu per hour of fuel input, consider the number of hours per year when the electrical load and thermal load are simultaneouslu at or above their average values. If greater than 2000 hours, use the CHP walk-through paybck estimator. If not, CHP is unlikely to be cost effective.