Rocky Road Power permits oil as backup for gas-fired plant in Illinois

Rocky Road Power LLC has proposed to add oil-burning capability to its existing peaking power facility in East Dundee, Illinois.

The Illinois EPA is taking comment until May 4 on a draft air construction permit for this project. The fuel change will enable the facility to provide electricity at times when the supply of natural gas for the facility is restricted or curtailed.

The Rocky Road facility was developed as a peaking plant. The facility has four simple-cycle combustion turbine generators. Turbines 1, 2 and 4 are identical models and each has a nominal electrical capacity of 135 MW. Turbine 3 is smaller, with a nominal capacity of 41 MW. These turbines currently can only burn natural gas.

The proposed project would involve installation of dual-fuel burners in the turbines to also enable oil, i.e., ultra-low-sulfur diesel (ULSD) fuel, to be burned. The planned addition of oil burning capability to the facility would not change the function of this facility as a peaker. It would enable the facility to provide electricity during periods of very cold weather when the supply of natural gas for the facility is restricted or curtailed.

As part of this project, water injection, an add-on control technology for emissions of nitrogen oxides (NOx), would be installed on Turbines 1, 2 and 4, for use when burning oil. (Turbine 3 is already equipped with water injection.) For Turbines 1, 2 and 4, NOx emissions will continue to be addressed with low-NOx combustion technology when natural gas is burned. Water injection would now also be used in these turbines when oil is burned. This is because low-NOx combustion technology is not as effective for oil as it is for natural gas. Water injection lowers NOx formation in a turbine by introducing water into the combustion zone of the burners. This lowers flame temperatures, thereby reducing the formation of thermal NOx. For Turbine 3, which is much smaller than the other three turbines, low-NOx combustion technology and water injection will now be used for oil, as well as for natural gas.

SO2 emissions are generated from the sulfur contained in the fuel but are found only in trace amounts from combustion of natural gas and ultra-low sulfur diesel.

As part of the permitting of this project, Rocky Road has also requested that tuning of the turbines be addressed. Tuning of the combustion systems of the turbines is conducted to adjust for efficient operation in the upcoming operating season. While a turbine is being tuned and adjustments are made to the combustion settings, emissions of a turbine may be higher than during normal operation. The turbines will be tuned while burning natural gas. Tuning will typically be conducted twice a year, once prior to the summer operating season and once prior to the winter season.

On its website, Rockland Capital identifies Rocky Road as one of its facilities.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.