Combined Heat and Power Applications and Guidelines Jeffrey Ihnen, P.E.
Portions of this Presentation Brought to you by: Views, opinions and bad ideas are mine alone 2
Content CHP Perspectives Status Quo CHP Types Examples Best fits / Considerations Questions 3
Combined Heat and Power Orientation, as in perspective, not introduction CHP Swans? CHP Elephants? 4
What is CHP? It s power generation with heat recovery for other uses. That s easy; But: 1. Is it electricity generation with free recovered heat, or 2. Is it taking advantage of thermodynamics to convert low cost thermal / natural gas energy to valuable electrical energy? 5
I argue #2 because without the ~ constant need for heat, the cost effectiveness is lost. 6
Another View of CHP Inexpensive thermal energy from natural gas converts to valuable electricity with virtually no energy loss (conversion but not loss) 7
CHP in a Nutshell Value of 1,000,000 Btus of: Natural Gas Electricity $3.87 $19.63 EIA Industrial Recent 12 month average costs Nationwide 8
Power Plant Cycle Boiler Loss 35% Power To Grid 5-10% Line Loss 32% Electricity t Customer Heat Rejected (Wasted) Turbine Line Loss Power to Customer 45% Rejected 20% Loss Coal Cooling Tower Pump 9
Iowa Electrical Energy (kwh) Generation 2009 Iowa Electric Fuel Sources 2% 9% 15% Coal Wind Natural Gas Nuclear 74% 10
Customer Site 20% Loss Steam/Heat to Plant Natural Gas Power @ 32% 11
Considerations Hours of use Design for minimum thermal load Thermal requirements: steam, hot water, temperature Tradeoff between power generation and heat quality Summer peak 12
Case #1: Gas Turbine CHP Gas Turbine 75% Turbine Exhaust Heat 35% Loss 25% Power $1.25 Electricity 40% Steam Steam At current electric and gas rates: CHP with a gas turbine produces $1.25 of electricity per dollar of fuel input PLUS Steam 13
Case #2: Internal Combustion CHP $2 Electricity $1 In Generator Cold Feed Water 15% Exhaust Internal Combustion Engine 45% to 180F Water to Process Similar to gas turbine Heat is delivered at lower temperature ~ 1/3 can be steam Not as useful High volume of low temp heat 14
Case #3 Topping Cycle Make higher pressure steam to extract power Slightly less steam generation efficiency Much more valuable electricity, in addition to steam 15
Case #4 Backpressure Turbines Some plants generate high pressure steam all times Status quo: throttle valve lost opportunity Backpressure turbine packaged unit 16
Case #5 Waste Heat Power Generation Organic (refrigerant) Rankine Cycle power generation Cement Glass Steel NG compressor stations 17
Medium Capacity Gas Turbine 6.7 /kwh, $3.87/MMBtu Natural Gas Solar Turbine 1.2 MW Gas Turbine Qty Units Cost/ Value Percent of NG Value Percent of NG Energy (Efficiency) Gas Consumption 168 therm/hr ($65.02) Electrical Production 1200 kw = kwh/hr $ 80.40 124% 24% Steam Production 8.7 MMBtu/hr $42.09 65% 52% Total 188% 76% 18
Small Capacity Gas Turbine 6.7 /kwh, $3.87/MMBtu Natural Gas Capstone 60 kw Gas Turbine Qty Units Cost/ Value Percent of NG Value Percent of NG Energy (Efficiency) Gas Consumption 7.80 therm/hr $ (3.02) Electrical Production 65 kw = kwh/hr $ 4.35 144% 28% Steam Production 0.30 MMBtu/hr $1.44 48% 38% Total 192% 67% 19
Medium Capacity IC Engine 6.7 /kwh, $3.87/MMBtu Natural Gas 400 kw Agenator IC Engine Qty Units Cost/ Value Percent NG Value Percent of Energy (Efficiency) Gas Consumption 34.13 therm/hr $ (13.21) Electrical Production 400.00 kw = kwh/hr $ 26.80 203% 40% Thermal Production 1.52 MMBtu/hr $7.35 56% 45% 259% 85% 20
Backpressure Turbine 6.7 /kwh, $3.87/MMBtu Natural Gas Back Pressure Turbine Qty Units Cost/ Value Percent NG Value Percent of Energy (Efficiency) Gas Consumption 1.00 therm/hr $ (0.39) Electrical Production 23.43 kw = kwh/hr $ 1.57 406% 80% Steam Production - MMBtu/hr $0.00 0% 0% 406% 80% 21
Waste Heat Power Generation 6.7 /kwh, $3.87/MMBtu Natural Gas Glass Plant Example: $1,147,000 per year, No fuel Ormat Recovered Energy Generation Qty Units Cost/ Value Percent NG Value Percent of Energy (Efficiency) Gas Consumption - therm/hr $ - Electrical Production 1,955 kw = kwh/hr $ 130.97 #DIV/0! #DIV/0! Thermal Production MMBtu/hr $0.00 #DIV/0! #DIV/0! 22
CHP Barriers To big Interconnection rules Standby rates T&D (majority) Generation (minority) Unfavorable policy Fuel switching (utility incentive perspective) Renewable energy goodies Cross-subsidization 23
Attacking Barriers Policy: End users must use all electricity and heat (most cost effective anyway) Mechanisms for fuel switching Allow REG (recovered energy generation) Addressing standby rates 24
Considerations Hours of use Design for minimum thermal load Thermal requirements: steam, hot water, temperature Tradeoff between power generation and heat quality Summer peak 25
ALL ENERGY [RELEASED] ENDS UP AS HEAT ELECTRICITY IS ALWAYS MORE VALUABLE THAN GENERATING FUEL OR HEAT 26
Remaining Questions Jeff Ihnen JLI@MichaelsEnergy.com 608.785.1900 27