PITA Fiscal Year 2008 Projects - Environmental Technologies

Thermal Plant Emissions Due to Renewable Electric Power

Principal Investigators: Jay Apt, Lester Lave, Warren Katzenstein

Wind and solar power exhibit significant variability and require an independent power source to counter their power fluctuations to be successfully integrated into the electricity grid in large quantities. If left unabated, the significant intermittency of wind and solar cause voltage and frequency instabilities. While a number of technologies can provide fill-in power, natural gas turbines are the most likely choice where hydroelectric power is not available (as in Pennsylvania), due to their fast response times, high efficiencies, and low capital costs.

The proposed research will examine the impact on air emissions when combustion plants are used to counter the variability in power from a large wind farm and from the 800 MW of solar power required by Pennsylvania’s Advanced Energy Portfolio Standard (AEPS). The assumption heretofore has been that for every MWh of energy displaced by wind or solar photovoltaic (PV) power, a MWh’s worth of emissions is eliminated. However, when natural gas turbines are forced to ramp their power up and down to follow the fluctuations of wind or solar PV power, air emissions increase and efficiency decreases. We will model the integration of wind power with natural gas turbines based on high-resolution gas turbine emissions and wind power data obtained from Pennsylvanian companies (Allegheny Energy and The PJM Interconnect, Inc.). We will model the extent to which wind power is able to reduce CO2 and NOx emissions and we will explore methods and strategies to maximize the reduction in emissions. With the model we will provide recommendations to the state of Pennsylvania to optimize the AEPS to reduce greenhouse gas and NOx emissions at minimum cost.