Iowa State UniversityIowa State UniversityPower PlantPower Plant

Iowa State University Iowa State University Utility EnterpriseUtility Enterprise

Operates as a rate-based enterpriseOperates as a rate-based enterprise Charges university entities for the Charges university entities for the

utilities they consumeutilities they consume Employs 78 peopleEmploys 78 people Operates two facilities on main Operates two facilities on main

campus and two satellite facilitiescampus and two satellite facilities Has the capability to provide all the Has the capability to provide all the

energy needs of the universityenergy needs of the university

Iowa State University Iowa State University Utility EnterpriseUtility Enterprise

Overall budget of $35.7 millionOverall budget of $35.7 million• Coal - $13.7 millionCoal - $13.7 million• Limestone - $412,000Limestone - $412,000• Ash disposal - $780,000Ash disposal - $780,000• Purchased electricity - $2.05 millionPurchased electricity - $2.05 million• Last year the cost of these items Last year the cost of these items

averaged $45,000 every dayaveraged $45,000 every day

Power PlantPower Plant 6 boilers – total capacity of 900,000 lbs of steam 6 boilers – total capacity of 900,000 lbs of steam

per hour – peak load of 488,000 lbs/hrper hour – peak load of 488,000 lbs/hr 4 turbine-generators – total capacity of 46 4 turbine-generators – total capacity of 46

megawatts – peak load of 34.1 megawattsmegawatts – peak load of 34.1 megawatts 5 chillers – total capacity of 21,000 tons of cooling 5 chillers – total capacity of 21,000 tons of cooling

– peak load of 15,169 tons– peak load of 15,169 tons 4 air compressors – total capacity of 4,000 cubic 4 air compressors – total capacity of 4,000 cubic

feet per minute – peak of 1800 cfmfeet per minute – peak of 1800 cfm 1 water plant – capacity of 1,000,000 gallons per 1 water plant – capacity of 1,000,000 gallons per

day – peak requirements of 1.3 million gpdday – peak requirements of 1.3 million gpd Replacement value of $282 millionReplacement value of $282 million

FY08 Plant ProductionFY08 Plant Production Steam produced – 2,623,141,000 lbsSteam produced – 2,623,141,000 lbs Steam to campus – 1,095,721,000 lbsSteam to campus – 1,095,721,000 lbs Chilled water – 33,343,000 ton-hrsChilled water – 33,343,000 ton-hrs Electricity consumed – 200,886,000 kwhElectricity consumed – 200,886,000 kwh

• Generated electricity – 151,831,000 kwhGenerated electricity – 151,831,000 kwh• Purchased electricity – 45,956,000 kwhPurchased electricity – 45,956,000 kwh

Coal burned – 154,463 tonsCoal burned – 154,463 tons Limestone used – 14,749 tonsLimestone used – 14,749 tons Ash produced – 28,178 tonsAsh produced – 28,178 tons

Other Utility ConsumptionOther Utility Consumption

Natural Gas used – 24,584,000 cubic feetNatural Gas used – 24,584,000 cubic feet Domestic water used – 313,524,000 gallonsDomestic water used – 313,524,000 gallons Sewage generated – 202,684,000 gallonsSewage generated – 202,684,000 gallons

Mechanical Distribution SystemsMechanical Distribution Systems

Steam tunnels – 4.5 milesSteam tunnels – 4.5 miles Direct buried steam – 2.6 milesDirect buried steam – 2.6 miles Chilled water – 5.3 milesChilled water – 5.3 miles Domestic water – 8.3 milesDomestic water – 8.3 miles Natural gas – 4.5 milesNatural gas – 4.5 miles Sanitary sewer – 10.3 milesSanitary sewer – 10.3 miles Storm sewer – 25.2 milesStorm sewer – 25.2 miles Compressed air – 3.5 milesCompressed air – 3.5 miles Replacement value of $113 millionReplacement value of $113 million

Electrical Distribution SystemsElectrical Distribution Systems

High voltage electrical cables – 16.7 milesHigh voltage electrical cables – 16.7 miles Electrical transformers – 515Electrical transformers – 515 Electrical substations – 7Electrical substations – 7 Telecommunications cables – 90 milesTelecommunications cables – 90 miles Street, sidewalk and parking lot lights – Street, sidewalk and parking lot lights –

19001900 Traffic lights – 7Traffic lights – 7 Replacement value - $53 millionReplacement value - $53 million

CogenerationCogeneration Sometimes called combined heat and Sometimes called combined heat and

power or CHPpower or CHP Defined as using a single fuel source to Defined as using a single fuel source to

simultaneously produce thermal energy simultaneously produce thermal energy and electrical powerand electrical power

Thermal efficiencies of more than 70% are Thermal efficiencies of more than 70% are attainable as compared to typical utility attainable as compared to typical utility plant efficiencies of 35-42%plant efficiencies of 35-42%

Iowa State started cogenerating in 1891 Iowa State started cogenerating in 1891 and typically averages 50-55% thermal and typically averages 50-55% thermal efficiencyefficiency

CogenerationCogeneration

ISU Energy SourceISU Energy Source

Currently burning 100% coalCurrently burning 100% coal• Coal comes from southern Illinois and Coal comes from southern Illinois and

western Kentuckywestern Kentucky• Coal is barged to Muscatine, Iowa and Coal is barged to Muscatine, Iowa and

loaded onto trucksloaded onto trucks• Trucks deliver coal to ISU and haul grain Trucks deliver coal to ISU and haul grain

back to the Mississippi to be loaded onto back to the Mississippi to be loaded onto bargesbarges

• Approximately 6200 trucks per year, 25 Approximately 6200 trucks per year, 25 per dayper day

ISU Energy SourceISU Energy Source

Coal is blended to our specifications Coal is blended to our specifications in Muscatine at the dock facilityin Muscatine at the dock facility

Coal QualityCoal Quality• Eastern Bituminous coalEastern Bituminous coal• 11,800 BTU/lb11,800 BTU/lb• 2.4% sulfur (medium sulfur)2.4% sulfur (medium sulfur)• 8.5% ash8.5% ash• 10.5% moisture10.5% moisture

Emissions LimitsEmissions Limits ISU Power Plant had no emissions limits prior to the 1970’sISU Power Plant had no emissions limits prior to the 1970’s Clean Air Act of 1970 required improvements in emissions Clean Air Act of 1970 required improvements in emissions

performance at facilities across the countryperformance at facilities across the country Emission limits have become more stringent over timeEmission limits have become more stringent over time New plant equipment typically had to comply with New plant equipment typically had to comply with

emissions limits that existed at the time of constructionemissions limits that existed at the time of construction Today’s proposed emissions regulations are typically Today’s proposed emissions regulations are typically

retroactive to existing equipmentretroactive to existing equipment• Plants must retrofit pollution control equipment, change to Plants must retrofit pollution control equipment, change to

different cleaner fuels, or replace equipment with new that different cleaner fuels, or replace equipment with new that meets new regulationsmeets new regulations

• Implementation of new regulations are now often delayed due Implementation of new regulations are now often delayed due to litigation by environmental groupsto litigation by environmental groups

Emissions LimitsEmissions LimitsPollutant Stoker Boilers CFB Boilers

     

Sulfur Dioxide 5.0 lb/mmBTU1.0 lb/mmBTU (30 day average) 1.42 lb/mmBTU (3 hr average)

90% removal

Nitrogen Oxides none0.40 lb/mmBTU (30 day average)

0.40 lb/mmBTU (3 hr average)

Carbon Monoxide none 200 ppm

Particulate0.389 lb/mmBTU

40% Opacity0.034 lb/mmBTU

10% Opacity

Fluoride none 0.039 lb/mmBTU

Lead none 0.0015 lb/mmBTU

Beryllium none 0.00063 lb/mmBTU

Emissions ControlsEmissions Controls

ISU retrofitted pollution control ISU retrofitted pollution control equipment for particulate on all equipment for particulate on all boilers through the late 1970’sboilers through the late 1970’s

Switched from high sulfur Iowa coal Switched from high sulfur Iowa coal to washed Iowa coal and eastern to washed Iowa coal and eastern coalscoals

Installed new circulating fluidized Installed new circulating fluidized bed boilers in 1988bed boilers in 1988

Mechanical Dust CollectorsMechanical Dust Collectors Retrofitted to existing boilers in the mid-Retrofitted to existing boilers in the mid-

1970’s 1970’s Collect particulate by centrifugal forceCollect particulate by centrifugal force Efficiency drops as ash particles get Efficiency drops as ash particles get

smallersmaller Collection efficiency is 90% at bestCollection efficiency is 90% at best Boiler 5 is fitted with a mechanical dust Boiler 5 is fitted with a mechanical dust

collector onlycollector only Opacity when Boiler 5 is operating is Opacity when Boiler 5 is operating is

typically 15-20%typically 15-20% Emissions rate is 0.35 lb/mmBTUEmissions rate is 0.35 lb/mmBTU

Mechanical Dust CollectorMechanical Dust Collector

Electrostatic PrecipitatorElectrostatic Precipitator

Retrofitted to Boilers 3 & 4 in the late Retrofitted to Boilers 3 & 4 in the late 1970’s1970’s

Collect particulate by electric chargeCollect particulate by electric charge Collection efficiency is about 97%Collection efficiency is about 97% Boilers 3 & 4 are fitted with a mechanical Boilers 3 & 4 are fitted with a mechanical

dust collector and an electrostatic dust collector and an electrostatic precipitator in seriesprecipitator in series

Opacity when Boilers 3 & 4 are operating Opacity when Boilers 3 & 4 are operating is typically less than 10%is typically less than 10%

Emissions rate is 0.05-0.08 lb/mmBTUEmissions rate is 0.05-0.08 lb/mmBTU

Electrostatic PrecipitatorElectrostatic Precipitator

Electrostatic PrecipitatorElectrostatic Precipitator

Fabric Filter or BaghouseFabric Filter or Baghouse

Baghouses were originally supplied Baghouses were originally supplied with Boilers 1 & 2with Boilers 1 & 2

Collect particulate by filtering Collect particulate by filtering through 1,354 filter bags, each 6” in through 1,354 filter bags, each 6” in diameter by 14 feet longdiameter by 14 feet long

Collection efficiency exceeds 99.5%Collection efficiency exceeds 99.5% Opacity on Boilers 1 & 2 is less than Opacity on Boilers 1 & 2 is less than

5%5% Emissions rate is 0.025 lb/mmBTUEmissions rate is 0.025 lb/mmBTU

Fabric Filter or BaghouseFabric Filter or Baghouse

Fabric Filter or BaghouseFabric Filter or Baghouse

Fabric Filter or BaghouseFabric Filter or Baghouse

Fabric filters are used on many material Fabric filters are used on many material handling systems in the plant as wellhandling systems in the plant as well• Ash handling systemsAsh handling systems• Coal, lime and ash silo ventsCoal, lime and ash silo vents• Coal handling system transfer pointsCoal handling system transfer points

Primary use is to control fugitive dusts as Primary use is to control fugitive dusts as materials are transferred from conveyor to materials are transferred from conveyor to conveyor, into silos, etc.conveyor, into silos, etc.

Circulating Fluidized Bed BoilersCirculating Fluidized Bed Boilers

Burns coal in conjunction with limestoneBurns coal in conjunction with limestone Limestone constituents react with the Limestone constituents react with the

sulfur to produce CaSOsulfur to produce CaSO44 which is removed which is removed with the ashwith the ash

Eliminates more than 90% of the sulfur Eliminates more than 90% of the sulfur dioxide emissionsdioxide emissions

Low combustion temperatures and staged Low combustion temperatures and staged combustion reduce the emissions of combustion reduce the emissions of nitrogen oxidesnitrogen oxides

Circulating Fluidized Bed BoilersCirculating Fluidized Bed Boilers

Stoker BoilersStoker Boilers

These boilers have no means of controlling These boilers have no means of controlling sulfur dioxide or nitrogen oxide emissionssulfur dioxide or nitrogen oxide emissions

Fuel is purchased with sulfur contents low Fuel is purchased with sulfur contents low enough to meet the requirementsenough to meet the requirements

Future regulatory requirements for SOFuture regulatory requirements for SO22 or or NONOXX will require installation of additional will require installation of additional pollution control equipment, fuel switching pollution control equipment, fuel switching or other compliance methodsor other compliance methods

ISU Compliance EffortsISU Compliance Efforts

Operate equipment as efficiently as Operate equipment as efficiently as possible, minimizing coal possible, minimizing coal consumption and emissionsconsumption and emissions

Operate pollution control equipment Operate pollution control equipment properlyproperly

Operate most efficient units as much Operate most efficient units as much as possibleas possible

Continuously look for alternatives to Continuously look for alternatives to improve performanceimprove performance

Emissions SummaryEmissions Summary      Sulfur Dioxide Nitrogen Oxides Particulate Matter

 Boiler

Efficiency

Percent of Steam

Production

DNR Limit

Average 2005-07

DNR Limit

Average 2005-07

DNR Limit

Average 2005-07

Boiler 1 87% 30% 1,029 200.7 412.0 74.9 35.0 13.6

Boiler 2 87% 35% 1,029 217.9 412.0 75.8 35.0 19.0

Boiler 3 82% 14% 5,795 1,067.9 None 128.7

584.1 Combined

32.8

Boiler 4 82% 20% 6,178 1,516.8 None 183.4 38.4

Boiler 5 78% 2% 4,886 117.4 None 9.6 18.1

Boiler 6 78% 0% 0 0 None 0 0

                 

Total   100% 18,917 3,120.7   472.4 654.1 121.9

Note: All emissions are expressed in tons per year

Emissions Reduction OpportunitiesEmissions Reduction Opportunities

Continue cogenerationContinue cogeneration• Reduces coal burn by 15,000 tons per yearReduces coal burn by 15,000 tons per year• Reduces limestone consumption by 1,600 tons Reduces limestone consumption by 1,600 tons

per yearper year• Reduces ash production by 2,600 tons per yearReduces ash production by 2,600 tons per year• Saves over $1.5 million per yearSaves over $1.5 million per year• Results in emissions reductions ofResults in emissions reductions of

37,000 tons less carbon dioxide37,000 tons less carbon dioxide 310 tons less sulfur dioxide310 tons less sulfur dioxide 50 tons less nitrogen oxides50 tons less nitrogen oxides

Emissions Reduction OpportunitiesEmissions Reduction Opportunities

Conserve EnergyConserve Energy• Shut off lights and equipment that you Shut off lights and equipment that you

aren’t usingaren’t using• Utilize energy efficient devicesUtilize energy efficient devices• Adjust thermostatsAdjust thermostats• Energy conservation is 100% efficient at Energy conservation is 100% efficient at

emission reductions, if you don’t use the emission reductions, if you don’t use the energy, there are no emissionsenergy, there are no emissions

• Saves money for other thingsSaves money for other things

Emissions Reduction OpportunitiesEmissions Reduction Opportunities

Add more pollution control Add more pollution control equipmentequipment• Effective but very expensiveEffective but very expensive• Baghouse - $6.0 million per boilerBaghouse - $6.0 million per boiler• Scrubbers - $12-15 millionScrubbers - $12-15 million• Install new coal boiler - $60+ millionInstall new coal boiler - $60+ million

Emissions Reduction OpportunitiesEmissions Reduction Opportunities

Switch fuelsSwitch fuels• Low sulfur eastern coals – costs are 25-50% Low sulfur eastern coals – costs are 25-50%

higherhigher• Low sulfur western coals – BTU content 25% Low sulfur western coals – BTU content 25%

lower, not suitable for ISU boilerslower, not suitable for ISU boilers• BiomassBiomass

BTU content is 40% lower, and density is 50% of coalBTU content is 40% lower, and density is 50% of coal Volume of fuel required increases nearly 4 timesVolume of fuel required increases nearly 4 times Emissions of NOEmissions of NOXX increases due to fuel volatility increases due to fuel volatility Transportation costs can make biomass fuels not Transportation costs can make biomass fuels not

economicaleconomical

• Natural gas – costs are 100-150% higherNatural gas – costs are 100-150% higher

Emissions Reduction OpportunitiesEmissions Reduction Opportunities

Wind EnergyWind Energy• ISU is participating in development of a ISU is participating in development of a

wind farm near Ameswind farm near Ames• Cost of energy appears economicalCost of energy appears economical• Have requested 5 megawatts of Have requested 5 megawatts of

capacity which would provide about 7% capacity which would provide about 7% of current energy consumptionof current energy consumption

• Capacity factor expected to be 37-38%Capacity factor expected to be 37-38%

Questions?Questions?