Designs

A certain electric utility is considering exactly two designs (Designs 1 and 2) for a new power generation plant. Each design would result in a plant that would generate the same amount of power annually; but Design 1 would use a single Type A power generator, whereas Design 2 would use three Type B power generators.

Type A generators cost less than Type B generators to fuel per unit of power generated and vent through taller chimneys, which better prevent pollutants from concentrating near the plant. However, Type A generators produce solid waste that is difficult and expensive to dispose of safely.

Type B generators produce no solid waste and, as compared to Type A generators, vent approximately half as much Pollutant X, and even less Pollutant Y, per unit of power generated annually. However, Type B generators vent through much shorter chimneys.

Pollutants by Phase

Both Type A and Type B generators emit (vent) significantly more of Pollutant Y during the startup phase—when a generator is brought to its normal power-generating phase from nonoperation. During startup, unhealthy levels of Pollutant Y can become concentrated at ground level near the power plant. The following table shows, for a single Type A or Type B generator, Pollutant Y emissions, in kilograms per hour (kg/hr), and the resultant contributions from those generators to the ground-level concentration of Pollutant Y, in micrograms per cubic meter of air (mcg/m3), near the plant during the startup and normal generating phases.