Coal to Boilers

The university utilizes coal as its energy source. The power plant operators burn the coal in 5 different boilers to produce steam. The boilers are operated in a manner to efficiently burn the coal while minimizing emissions into the environment. This number is the amount of coal currently being burned in all operating boilers. For comparison, a semi-truck holds 25 tons of coal. The coal flow to the boilers varies as the demands for energy by the university increase or decrease.

The coal used by Iowa State comes from Southern Illinois and Western Kentucky. The coal is shipped up the Mississippi River by barge to Muscatine, Iowa, where it is blended together and loaded onto trucks. The trucks deliver the coal to Iowa State and then pick up grain to be returned to the Mississippi River and loaded on barges for shipping downstream.

Lime to Boilers

Two of the boilers at Iowa State are circulating fluidized bed boilers. These boilers are highly efficient and are specially designed to burn limestone with the coal. Constituents of the limestone react with the sulfur in the coal which forms calcium sulfate. This material is collected with the ash and reduces the emissions of sulfur dioxide from these two boilers by over 90%. The limestone comes from near Iowa Falls, Iowa. This number is the amount of limestone currently being consumed by each of the two fluidized bed boilers.

Ash Produced

All coals contain impurities that will not burn that end up as ash. In addition, all the limestone used in the circulating fluidized bed boilers also ends up as ash. There are two types of ash; bottom ash which are the large particles of ash that come from the bottom of the boiler, and fly ash which are the very fine particles of ash. The fly ash is collected with pollution control equipment before the combustion products are discharged up the stack. The amount of ash produced is the current amount of all ash being produced by all operating boilers.

All ash is re-used for other purposes. Most of the ash is being used to reclaim areas of a rock quarry near Waterloo. The remaining ash is used for soil stabilization or manufacturing of a compost material.

Purchased Power

Iowa State has the capability to generate all the electricity for the campus or can choose to purchase electricity. The goal for the plant operators is to provide electricity to the university at the lowest possible cost while maintaining a safe and reliable operation. They achieve this goal by balancing electricity produced by our own generators and electricity purchased from others for each hour of every day. If electricity is not available for purchase at economical prices, the operators will produce the electricity with our own generators.

Iowa State purchases electricity on the wholesale market. The purchased electricity is scheduled for each hour of the day based on projected prices for each hour. Iowa State operators work together with operators at the City of Ames power plant to coordinate electricity purchases from Ames or other utilities wherever it is more economical. If electricity is supplied from other sources, the City of Ames operators must coordinate delivery of the power to Ames on the transmission system.

400 lb. Steam Produced

Steam is produced by the boilers at 400 lbs pressure and at a temperature of 750° F. The steam is used to produce electricity or chilled water. Some of the steam produces electricity first and then is either sent to campus or is used to produce chilled water. The 400 lb steam produced is the total of all steam currently being produced by all operating boilers.

ISU Generated Power

Iowa State has four turbine-generators that are used to produce electricity. The generators provide power to campus at either 13,800 volts or 4,160 volts. The total ISU generation is the total amount of electricity being produced by the ISU generators.

Campus Power

This is the actual amount of electricity currently being consumed by the university. This total includes the main campus, Iowa State Center, the stadium complex, the College of Veterinary Medicine and the power plant.

Campus Steam

This is the actual amount of steam currently being consumed by the campus including main campus, Iowa State Center, the stadium complex and the College of Veterinary Medicine. The steam is sent to campus at 90 lbs pressure and 400 degrees F. The steam is used to heat the buildings, produce hot water and for other process and/or research needs. The condensed steam is returned to the power plant boilers and made into steam again.

Campus Cooling

This is the actual amount of cooling being used in the campus buildings, including main campus and the Iowa State Center. Chilled water consumption is measured in tons. One ton of cooling is equivalent to 12,000 BTU per hour. For perspective, a typical home air conditioner is rated at 2-3 tons of cooling.

Chilled water is used for cooling the building space itself or is also used for cooling of research equipment. The chilled water system operates in a continuous cycle where water at 40 degrees F is sent to campus, cools the buildings and then returns to the power plant chillers. The chillers cool the water again and send it back out to campus.