Coal-fired electricity power plants in China have a heat conversion efficiency of 37–38% with the current subcritical engine units. Emerging technologies can increase the efficiency to 41–42% with supercritical units and to 46–48% with ultrasupercritical units (17). Adopting these new engine units would lower the carbon footprint for electricity from the current 1.12 kg CO2-eq kilowatt-hour (kWh −1) to 1.08 or 1.03 kg CO2-eq kWh−1. Again, the benefits would be applicable across the whole economy, and not just in the N fertilizer industry.