Turbine Inlet Cooling. A Valuable Tool to INCREASE Electric Energy Production

Transcription

1 Turbine Inlet Cooling A Valuable Tool to INCREASE Electric Energy Production March

2 Peak Temperatures Are High Across the United States 2

3 Capacity of Combustion Turbine Power Plants is Reduced in Hot Months Fuel Winter Capacity, MW Summer Capacity, MW MWs Lost in Summer Capacity from Winter Capacity Coal 319, ,800 2,386 Petroleum 59,577 55,647 3,930 Natural Gas 438, ,028 31,699 Source: U.S. Department of Energy s Energy Information Agency 2010 Database 3

4 Major Problem for Regulators Available electric energy from conventional gas turbine plants is greatly diminished during hot summer months According to the U.S. Department of Energy, hot weather reduces electric power generation capacity of gas turbine plants by as much as 31,000 MW This supply loss occurs at the very same time when electric power demand is peaking due to increased air conditioning load 4

5 High Air Conditioning Loads are Major Contributors to Peak Demand Source: Scot Duncan Presentation at ASHRAE June

6 Combustion/Gas Turbine Plants Have Two Fundamental Problems During hot weather, CTs energy output can drop up to 35% below rated capacity (based on 59 F) High heat causes gas turbines to work harder and lose up to 15% efficiency, thereby increasing fuel use (heat rate) and emissions per kwh 6

7 In Hot Weather a CT s Energy Efficiency Goes Down as its Heat Rate Goes Up Heat Rate, Percent of Desig Aeroderivative 103 Frame Ambient Dry-Bulb Temperature, F Fuel Use Increases and Efficiency Decreases (as Demand Peaks) Note: Heat rate is directly proportional to fuel used per kwh and inversely proportional to energy efficiency 7

8 A CT s Generation Capacity Goes Down as Ambient Air Temperature Goes Up 105% EFFECTS OF COMPRESSOR INLET AIR TEMPERATURE ON GAS TURBINE POWER OUTPUT PERIOD OF GREATEST DEMAND % OF RATED POWER 100% 95% 90% 85% 80% ISO DESIGN POINT NEW AERO-DERIVATIVE POWER OUTPUT Compression Ratio = 30 OLD "FRAME" POWER OUTPUT Compression Ratio = COMPRESSOR INLET AIR TEMPERATURE, degrees F This CT shows up to 19% capacity loss at peak demand Punwani

9 Generation Capacity Loss Coincides with Peak Demand Peak Power Demand Ambient Temperature Scale = 77 to 122 F (25 to 50 C) Daily Generation Profile GT Output Scale = 75% to 100% Lowest Generation Capacity 9

10 Losing CT Generation Capacity and Efficiency Due to Hot Weather also Means Other plants must be brought online. Usually, such peaking plants are: Less efficient than gas turbine plants More costly to operate than gas turbine plants Emitters of larger amounts of greenhouse gases than gas turbine plants 10

11 Various Power Generation Technologies Help Meet Power Demand Resource [MW ] 52,000 50,000 48,000 46,000 44,000 42,000 40,000 38,000 36,000 34,000 32,000 30,000 28,000 26,000 24,000 22,000 20,000 18,000 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2, EST IM A T ED PEA K D A Y RESOURC E SUM M A RY Wind Generation Pe ak e r Hyd r o W in d Im por t T h e r m al Efficient Base Load QF Nucle ar Inefficient Peaker Tim e [Hours] Nuclear QF Therm al Im port W ind Hydro P eaker Source: Scot Duncan Presentation at ASHRAE June

12 Summer Emissions (lbs/kwh) of CO 2 (California) Y-Axis Unit: CO 2 Emissions, Lbs/kWh 12:00 AM 2:00 AM 4:00 AM 6:00 AM 8:00 AM 10:00 AM 12:00 PM 2:00 PM 4:00 PM 6:00 PM 8:00 PM 10:00 PM Source: Scot Duncan Presentation at ASHRAE June 2007 SCE PG&E SDG&E 12

13 As Power Demand Increases During Hot Weather Electricity Prices Go Up This example shows the cost of electricity can be up to 4 times higher in peak periods as in off-peak. Rates can be even higher depending on scarcity of supply. PJM Interconnection LLC 13

14 Turbine Inlet Cooling (TIC) Overcomes the Effects of Hot Weather on CT Plants 100 Rated Capacity Net CT Power Output,% of Design No C ooling W ith TIC Rated C apacity With Cooling No Cooling Am bient D ry-b ulb Tem perature, F Punwani

15 TIC Technologies are Simple and Proven TIC is simple Ambient Air To Turbine Cool the ambient air before it enters the turbine Same process as cooling air before it enters buildings TIC technologies are proven as thousands of plants worldwide utilize TIC TICA website shows plants benefiting from TIC 15

16 TIC Technology Options Evaporative Systems Wetted Media, Fogging or Indirect Chiller Systems Mechanical or Absorption Chillers + Thermal Energy Storage Wet Compression System LNG Vaporization System* Hybrid Systems *Where Liquefied Natural Gas (LNG) is available 16

17 Examples of how TIC Technology Enhances Energy Output Net Output Enhancement, MW F DB and 80F WB 95F DB and 60F WB Wetted Media Fogging Electric Chiller Wet Compression Combined-Cycle System: Two 501FD1 and one ST Sources: Wet Compression: Caldwell Energy, Inc. All Others : D.V. Punwani Presentation, Electric Power

18 Ability of TIC to Enhance a CT s Energy Output Depends on Several Factors CT Design, Location, and Altitude, among others Weather Data (dry-bulb and coincident wet-bulb temperatures) for the geographic location of the CT Selected ambient design conditions The TIC Technology selected Selected cooled air temperature (if allowed by the TIC technology) TIC parasitic load Pressure drop across the component inserted upstream of the compressor (insertion loss) 18

19 Power Plants that Burn Fossil Fuels Are significant producers of carbon dioxide and other GHGs and pollutants There are two types of fossil fuel power plants: 1. Burn fuel to produce steam for steam turbines to produce electric power or 2. Burn oil or gas directly in combustion turbines (CTs) to produce electric power Power plants that burn coal produce the most emissions (lbs/mwh) Power plants that use natural gas in CTs produce the least emissions (lbs/mwh) 19

20 Emissions of Various Power Plants TIC Candidates Unit Type CHP/Cogeneration Combined-Cycle CT Simple-Cycle CT Prime Mover Frame CT Frame CT- STG Frame CT Fuel Natural Gas Natural Gas Natural Gas Plant Age (Yrs) < 5 < 5 < 5 CT Heat Rate (Btu/kWh) 10,750 7,000 10,750 Generation Capacity (MW) Hours of Operation Themal Energy Need, MMBtu Fuel Use, MMBtu Power Generation 1, ,075 Thermal Use (1) Total 1,075 1,247 1,622 Energy Efficiency, % Electric Power Generation Overall Energy Efficiency, % Carbon Emissions, Tons Existing Older Plants Boiler + Steam Turbine (STG) Condensing STG Natural Gas > 30 13, , , Notes 1. CHP provides thermal energy from the CT Exhaust without using additional; Other systems use 85% efficiency boilers for providing thermal energy needs. Source: EPA and Pasteris Energy, Inc. 20

21 Power Plant Priority of Use to Reduce Emissions The preferred order of operating fossil power plants using natural gas should be: 1. CT in combined-cycle system - lowest heat rate/highest energy efficiency 2. CT in simple-cycle system 3. Old steam turbine system - highest heat rate/ lowest energy efficiency 21

22 Preferred Dispatch Order for a Combined-Cycle System using TIC 73,394 8,440 Btu / kwh Supplementary Duct Firing 6,799 Btu / kwh Cooling to Dew Point 16,874 7,894 Btu / kwh Cooling to 50 F 452,183 6,371 Btu / kwh Base Case Dispatch Order at 95 F Basis: GT pro model at 95F DB/78F WB with inlet chilled 207FA. Source: TAS 22

23 TIC Reduces Regulated Pollutant Emissions 0.5 Environmental Impact Regulated Pollutants 0.4 CC NOx SCR = 3 ppm SC NOx SCR = 3 ppm 0.03 lbs per MWH Virtual TIC Peaker 0.10 New Aero Peaker HC CO NOx TIC Reduces Total Emissions (lbs/mwh) by Over 50% Basis: Total of all pollutants (lbs/mwh), LM6000PC-Sprint with hot SCR & TIC vs. incremental MWH from combined cycle 207FA with TIC added (Source: TAS) 23

24 Turbine Inlet Cooling Reduces CO 2 Emissions 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2,000 0 Heat Rate & CO2 Emissions F Class CC F Class CC Chilled SC Aero Thermal Plant 2,000 1,800 1,600 1,400 1,200 1, lb CO2/MWH Heat Rate (MMBTU/KWH) HHV lb CO2/MWH Basis: 95 o F DB and 78 o F WB Source: TAS 24

25 Turbine Inlet Cooling Environmental Benefits Reduces need to run less efficient peaking plants that have greater emissions than gas turbine plants Reduces carbon footprints for the grid Reduces emissions of greenhouse gases including carbon dioxide (CO2) and other pollutants Minimizes the need for new generation capacity Delays or avoids environmental impacts of siting and construction Delays or avoids a new source of emissions 25

26 Turbine Inlet Cooling Reduces Need for New Power Plants TIC used on CTs in combined-cycle (CC) systems reduces the need to operate CTs in simple-cycle (SC) systems For example, TIC used in a 500 MW CC plant eliminates the need for a MW SC peaking plant TIC eliminates costs associated with siting, construction and interconnection of a new plant 26

27 Turbine Inlet Cooling Economic Benefits Generates more MWhs during peak demand in hot weather Reduces the amount of fuel used per kwh by up to 15% Increases electric power output which reduces effective capital cost per unit of capacity as compared to constructing a new power plant Reduces use of peaking plants that are generally more costly to operate (due to lower efficiency) and produce more emissions than gas turbine systems using TIC Reduces ratepayer costs since lower capacity payments are required from independent system operators (ISOs) to power producers Increases baseload supply which enhances economic development 27

28 A Comparison of Turbine Inlet Cooling Economic Benefits $ per MWH $150 $140 $130 $120 $110 $100 $90 $80 $70 $60 $50 $40 $30 $20 $10 $0 off-peak power to recharge TES $40 per MWH amortized over peak hours $12.63 $1.94 $46.28 $- Virtual Peaker variable O&M $6 per MWH $4.43 gas = $8 per mmbtu MM Btu LTSA = $20 per ton $111, year capital recovery no interest charges $33.58 $6.29 $68.69 $6.00 Aero Peaker fixed O&M $250,000 Annualized Cost Of Electricity New Aero Peaker = $115 Virtual TIC Peaker = $ 65 Water Cost Off-Peak Power Variable O&M Fuel Cost Fixed O&M Capital Recovery Basis: LM6000PC-Sprint with hot SCR & TIC vs. incremental MWH from combined cycle 207FA with TIC added. (Source: TAS) 28

29 Monthly Incremental Electric Energy Provided by Some TIC Technologies (316 MW Cogeneration Plant Near Houston, TX) Evaporative Cooling is a Wetted Media system Single-Effect and Double-Effect Refer to Absorption Chillers Source: D.V. Punwani et. al. Presented at ASHARE

30 Overall Benefits of TIC TIC increases electric energy production during hot weather and reduces emissions of GHGs per unit of electricity produced. Plus TIC: Provides the grid with up to 31,000 MW more electric power by generating more electricity from combined heat & power (CHP), combined-cycle (CC) and simple-cycle (SC) plants Is readily implemented within 6-18 months Reduces generation costs saving money for producers and ratepayers 30

31 Suggested Regulatory and Policy Positions Regulators should recognize TIC is a valuable solution to their supply problem during hot weather and Use the full potential of existing combustion turbines plants Require TIC use before allowing construction of new capacity Ensure capacity payments provide appropriate returns for systems using TIC Policymakers should recognize the value of TIC and Exempt plants that retrofit with TIC from environmental re-permitting since TIC results in plant emissions similar to those in winter (TIC yields winter performance in summer) so no permit changes should be necessary Create incentives for plant owners to use TIC technology 31

32 Conclusions TIC is a valuable tool to increase electric energy production during hot weather TIC provides regulators an important, easy to implement tool that quickly adds supply to meet demand TIC provides economic and environmental benefits TIC is a useful tool for ratepayers, the environment, plant owners and regulators Cooling the air to gas turbines makes good sense 32