The Emissions tab in the Simulation Results window shows the total amount of each pollutant produced annually by the power system in kg/yr. Pollutants originate from the consumption of fuel and biomass in generators, the boiler, and the reformer, as well as from the consumption of grid power. Pollutants consist of carbon dioxide, carbon monoxide, unburned hydrocarbons, particulate matter, sulfur dioxide, and nitrogen oxides.
Sales of power to the grid result in reduced grid emissions. HOMER credits the power system with these reductions. The system can even achieve negative emissions of one or more pollutants if it sells a lot of low-emissions electricity to the grid.