Bioenergy Greenhouse Gas Bioenergy Greenhouse Gas Balances for Distributed PowerBalances for Distributed Power

Bioenergy and Northern Communities in Canada Workshop, Saskatoon, Nov 16-17, 2004

Dr. Eric BibeauDr. Eric BibeauMechanical & Industrial Engineering DeptMechanical & Industrial Engineering Dept

Doug SmithDoug SmithInnovative Dynamics Ltd., Vancouver BCInnovative Dynamics Ltd., Vancouver BC

Martin TampierMartin TampierEnvirochem Services Inc., Vancouver BCEnvirochem Services Inc., Vancouver BC

Arctic Climate Impact Assessment ReportArctic Climate Impact Assessment Report

““Arctic will lose 50Arctic will lose 50--60 per cent of its ice distribution by 2100”60 per cent of its ice distribution by 2100”

“one model predicts that the North Pole in summer will be comple“one model predicts that the North Pole in summer will be completely tely iceice--free by 2070”free by 2070”

“Projections made by the Intergovernmental Panel on Climate Chan“Projections made by the Intergovernmental Panel on Climate Change ge estimates that if global greenhouse gas emissions double their pestimates that if global greenhouse gas emissions double their prere--industrial levels, melting ice will raise sea levels between 10 industrial levels, melting ice will raise sea levels between 10 and 90 cm and 90 cm in this century”in this century”

Human Activity Affects Dynamic SystemAdds 30 Billion tonnes of new CO2 per year

OUTLINEOUTLINEDistributed BioPower systems backgroundHow do we calculate greenhouse gas displacements – distributed systems under development– efficiency: scaling effect/cost constraints

Efficiency calculations: How?50% MC CHP conversion chart 50% MC greenhouse gas chart Conclusions

Distributed BioPower BackgroundDistributed BioPower Background

Biomass Life Cycle Analysis (LCA)– Identifying environmentally preferable

uses for biomass resources–Life-cycle emission reduction benefits of

selected feedstock-to product treads–Reports CEC website

Commission for Environmental Cooperationwww.cec.orgAuthors: Tampier, Smith, Bibeau, Beauchemin

Distributed BioPower BackgroundDistributed BioPower BackgroundBarriers to distributed BioPower– need low capital cost + low O&M costs– need CHP economics

Low Canadian power rates– Residential/Commercial/Industrial: 4.3 / 3.6 / 2.5 cents US

Industrial users– convert waste to power incentive

Biomass: low HHV fuel + distributed– transportation cost limitation– biopower considered to be 20 MW and up

Decentralized power– when will it come?

Distributed BioPower Distributed BioPower ApplicationsApplicationsApplications

• forestry waste• OSB plants• diesel communities• greenhouses • forest thinning• bugwood• wildfire control• agricultural wastes • animal wastes • municipal wastes

Bio-Energy Drivers

• GHG• Energy supply• Innovation• Rural development• Air quality

How Does One Calculate GHG for How Does One Calculate GHG for Distributed Power Systems?Distributed Power Systems?

Effect of feedstock?Effect of Conversion Efficiency?Accounting for small scale?Compare conversion technology?Factors affecting actual implementation and getting actual GHG displacement

Example:

New Hampshire experience studying bio-oil• What was learned?

• What information was missing?

Technologies Used to Calculate GHG Technologies Used to Calculate GHG Displacement for Distributed SystemsDisplacement for Distributed Systems

BioBio--oil (fast and slow pyrolysis)oil (fast and slow pyrolysis)Gasifier (syngas)Gasifier (syngas)Steam with no CHPSteam with no CHPSteam with CHPSteam with CHPOrganic Rankine Cycle (ORC)Organic Rankine Cycle (ORC)Entropic Hybrid Cycle (Entropic Hybrid Cycle (EHCEHC))Air Brayton CycleAir Brayton CycleLarge steam (for reference)Large steam (for reference)

What are the GHG emissions displacements opportunities for each technology?

FEEDSTOCKFEEDSTOCK

Volume

(dry) (wet) FractionCarbon, C 50.0% 25.0% 29.50%

Hydrogen, H2 6.0% 3.0% 21.20%Oxygen, O2 42.0% 21.0% 9.30%

Nitrogen, N2 2.0% 1.0% 0.60%Water, H2O 0.0% 50.0% 39.40%

Feed Analysis

Mass Fraction

Biomass feedstock = natures solar energy storage system

HHV = 20.5 MJ/BDkgfuel & 50% MC

Modeling ApproachModeling ApproachRealistic systems for small size– limit cycle improvement opportunities

cost effective for technology for small size– limit external heat/power to system– adapt component efficiencies to scale

Model system as if building system today– design actual conversion energy system – some components of parasitic power for bio-oil

& gasifier not accounted for– mass and energy balances

Account for every step in conversionExclude use of specialized materials

11-- BioBio--OilOilLiquid: condense pyrolysis gases – add heat; no oxygen – organic vapor + pyrolysis gases + charcoal

Advantages for distributed BioPower– increases HHV – lessens cost of energy transport – produces “value-added” chemicals

Disadvantages for distributed BioPower– energy left in the char– fuel: dry + sized

BIOBIO--OILOIL

Rotating Cone (fast pyrolysis)

Travelling Bed (fast pyrolysis)

Bubbling Bed (fast pyrolysis)

Slow pyrolysis

BioBio--OilOilJF Bioenergy ROI Dynamotive Ensyn

Bio-oil (% by weight) 25% 60% 60% – 75% 60% – 80%Non-cond. gas (% by weight) 42% 15% 10% – 20% 8% – 17%Char (% by weight) 33% 25% 15% – 25% 12% – 28%Fuel feed moisture Not published

BioBio--oil Overall Energy Balanceoil Overall Energy Balance

Biomass Feed 50% moisture

Drying/Sizing to 10% / 2 mm Pyrolysis

21.5% energy loss 32% energy

Char 45.6%

energy loss

Engine/ Generator

6.4% Electricity

60% energy Bio-oil

8% energy loss

18.5%

3%

3%

5%

N2 Sand

Electricity: 363 kWhr/BDtonne

Pyrolysis heat: non-condensable gas + some char (no NG)Pyrolysis power: 220 – 450 kWhr/BDtonne (335 or 5%)Engine efficiency: 28% (lower HHV fuel; larger engine; water in oil lowers LHV)

Other parasitic power neglected (conservative)Limited useable cogeneration heat

PowerPower

2 2 -- Gasifier Gasifier -- Producer GasProducer GasSub-stoichiometric combustion – syngas: CO, CH4, H2, H2O– contains particles, ash, tars

Advantages for distributed BioPower– engines and turbines (Brayton Cycle)– less particulate emission

Disadvantages for distributed BioPower– syngas gas cleaning– cool syngas – fuel: dry + sized – quality of gas fluctuates with feed

GasifierGasifier

Assume require 25% MC and no sizing requirements (conservative)Ignore parasitic loads: dryer, gas cooler, gas cleaning, tar removal, fans (conservative)Heat to dry fuel comes from process (3.8 MJ/BDkgfuel)100% conversion of char to gas (conservative)HHV of syngas = 5.5 MJ/m3 dry gas (16% of natural gas)

Syngas Vol Dry vol Dry wgtfraction fraction kg/kgfeed

CO 0.1907 0.2994 0.461CO2 0.0365 0.0573 0.139CH4 0.0143 0.0224 0.02H2O 0.363 0 0

H2 0.1043 0.1638 0.018N2 0.2911 0.457 0.703

5.5 MJ/m3 dry gasHHV (dry gas)

Gasification Overall Energy BalanceGasification Overall Energy Balance

Biomass Feed 50% moisture

Drying to 25%

40% energy Producer Gas

7.75% Electricity

Engine/ Generator Gasification

15%

15% energy loss

60% energy loss

17.25% energy loss

Electricity: 440 kWhr/BDtonne

Low HHV of gas affects efficiency of engineAssume ICE operates at 75% of design efficiency15% heat from producer gas dries fuelNo heat lost across gasifier boundaryLimited useable cogeneration heat

33--Small Steam CycleSmall Steam Cycle(no CHP)(no CHP)

Steam Rankine Cycle– common approach – water boiled, superheated, expanded, condensed and

compressed

Advantages distributed BioPower– well known technology – commercially available equipment

Disadvantages distributed BioPower – costly in small power sizes – large equipment and particulate removal from flue gas– high operator qualification

Superheater

Economizer

Boiler

Feed Pump

Deaerator

Attemporator

Condenser

8% steam

Ejector

Turbine

2% blowdown makeup

10

9

76

4

3

2

1

8

Small Steam Overall Energy BalanceSmall Steam Overall Energy Balance

Biomass Feed 50% moisture Heat Recovery Steam Cycle

9.9% Electricity

40.5% energy loss

49.6% energy loss

Electricity: 563 kWhr/BDtonne

Limit steam to 4.6 MPa and 400oC (keep material costs low)Use available turbines for that size: low efficiency (50%)No economizer4% parasitic loadFlue gas temperature limited to 1000oC for NOxAll major heat losses and parasitic loads accounted

4% power

4 4 -- Small Steam CycleSmall Steam Cycle(with CHP)(with CHP)

CHP– limit pressure drop across turbine

use back pressure turbine rather than condensing turbine

– steam from turbine contains useful heat

Advantages distributed BioPower– CHP economics – reduces volumetric flow– heat + power increases overall efficiency of system

Disadvantages distributed BioPower – reduced power production– high operator qualification

Superheater

Economizer

Boiler

Feed Pump

Deaerator

Attemporator

Turbine

2%blowdown

Condensate returnand makeup

10

9

6

4

3

18

7

Co-generation process

5

Small Steam CHP Overall Energy BalanceSmall Steam CHP Overall Energy Balance

Electricity: 324 kWhr/BDtonne Heat: 2936 kWhr/BDtonne

Limit steam to 4.6 MPa and 400oC (keep material costs low)Could use economizer to pre-heat combustion airMany ways to improve efficiency

Biomass Feed50% moisture

Steam Cycle5.7%

Electricity

Heat Recovery

115°C steamcogeneration

40.5%energy loss

53.8%energy loss

5 5 -- ORC ORC (Organic Rankine Cycle)(Organic Rankine Cycle)Advantages distributed BioPower– smaller condenser and turbine as high

turbine exhaust pressure– higher conversion efficiency– no chemical treatment or vacuum– no government certified operators– CHP – Dry air cooling can reject unused heat

Disadvantage for distributed BioPower– organic fluid ¼ of water enthalpy– binary system– systems are expensive – particulate removal from flue gas

ORCORC

Biomass Feed50% moisture Turboden CycleHeat Recovery

80°C liquidcogeneration

10.2% Electricity

40.1%energy loss

49.7%energy loss

Electricity: 580 kWhr/BDtonne Heat: 2713 kWhr/BDtonne

Flue gas temperature limited to 1000oC for NOxCool flue gas down to 310oCCHP heat at 80oCAll major heat losses and parasitic loads accounted

EHCEHC (Entropic Hybrid Cycle)(Entropic Hybrid Cycle)Advantages for small BioPower– vapour heater - no boiler – small turbine and equipment – no chemical treatment, de-aeration or vacuums – no registered steam operators – ideal for CHP: 90°C to 115°C – dry air cooling can reject unused heat

Disadvantages for small BioPower– restricted to small power sizes (< 5 MW)– system has not been demonstrated commercially– special design of turbine– particulate removal from flue gas

EHCEHC

Biomass Feed 50% moisture Entropic CycleHeat Recovery

90°C liquidcogeneration

12.0% Electricity

56.2%energy loss

31.8%energy loss

Electricity: 682 kWhr/BDtonneHeat: 3066 kWhr/BDtonne

Flue gas temperature limited to 1000oC for NOx

Cool flue gas down to 215°CCHP heat at 90oC

Fluid limited to 400°CAll major heat losses and parasitic loads accounted

NonNon--Steam Base SystemsSteam Base SystemsORC & ERCORC & ERC

Thermal Oil Heat Transfer

TURBODEN srl

synthetic oil ORC

Conversion

1000°C 310°C

250°C 300°C

60°C

80°C Liquid Coolant

Air heat dump

17%

Input Heater 59.9% recovery

Entropic Fluid Heat

Transfer

ENTROPICpower cycleConversion

1000°C 215°C

170°C400°C

60°C

90°C Liquid Coolant

Air heat dump

17.6%

Input Heater 68.2% recovery

Cycle efficiency Cycle efficiency

Air Brayton CycleAir Brayton CycleAdvantages – simple– use air at relatively low pressures– off the shelf turbine/compressor– many ways to optimize cycle

Disadvantages – increased cycle pressures limits

heat recovery from indirect heat exchanger

– air specific volume large– significant compression work– air has low enthalpy

650°C 315°C

367 kPa258 °C

111 kPa315 °C 336 kPa

483 °C

377 kPa127 °C

13.1% cycle eff. 58.3%

cycle energy

108 kPa185 °C

101 kPa15.6 °C

Air Heater

7.4% overall eff.

Compressor Turbine / Expander

Recuperator

combustion air

56.7% recovery

Air Brayton CycleAir Brayton Cycle

Electricity: 420 kWhr/BDtonne

Flue gas temperature inlet to heater limited to 650oC for material requirementsRecuperator with single-stage turbineNo preheat of combustion air (34% increase in efficiency)Tube metal temperatures limited to 565oCTurbine thermal efficiency 85%

Biomass Feed50% moisture Heat Recovery Brayton Cycle

7.4% Electricity

34.4%energy loss

14.9%58.2%energy loss

Biomass Feed50% moisture Heat Recovery Brayton Cycle

7.4% Electricity

34.4%energy loss

14.9%58.2%energy loss

LARGE STEAM BIOMASS LARGE STEAM BIOMASS

Largest independent biomass power plant in

North America

Quoted overall efficiency 29%• note: efficiency may be over estimated• MC less than 50%

1

Distributed BioPowerDistributed BioPowerCHP Conversion ChartCHP Conversion Chart

Note: Results are for 50% moistures content

Bio-oil GasificationSyngas

AirBrayton

Large Steam

Overall Power Efficiency 6.6% 7.8% 7.4% 25.0%Electricity (kWhr/Bdtonne) 363 440 420 1420Heat (kWhr/Bdtonne) - - - -Overall Cogen Efficiency 6.4% 7.8% 7.4% 25.0%

SmallSteam

SmallSteam CHP

OrganicRankine Entropic

Overall Power Efficiency 9.9% 5.7% 10.2% 12.0%Electricity (kWhr/Bdtonne) 563 324 580 682Heat (kWhr/Bdtonne) - 2,936 2,713 3,066Overall Cogen Efficiency 9.9% 53.9% 54.5% 67.5%

GHG DisplacementsGHG DisplacementsBiomass Emissions– CO2 neutral– CH4

active use can be better or worse than natural decay– Paticulate

can be addressed– Sulfur

biomass (except for MSW) has low S– NOx

important in collection and final combustion

Fossil Fuel Used: COFossil Fuel Used: CO22 CostCostWaste biomass application (residues)– often no fuel usage attributed to biomass– transportation (wood chips 35% MC)

0.0249 kgfuel/km/BDtonne 3.2 kgCO2 released for 40 km

– from emissions point transportation of biomassvery positive on CO2 displaced (< 1% CO2 cost per 100 km)economic limitation ($65/BDtonne for 125 km)

GHG DisplacementGHG DisplacementElectricity (kWe- hr)– displace electricity from various sources– look at (1) location, (2) average electricity

on the grid, (3) additional load– favorable to displace fossil fuels generation

only

(tonnes/MWh) (tonnes/TJ) (tonnes/MWh) (tonnes/TJ)Newfoundland and Labrador 0.02 6.2 0.000 0.0Prince Edward Island 0.50 137.9 0.807 224.2Nova Scotia 0.74 204.5 0.542 150.5New Brunswick 0.50 137.9 0.807 224.2Quebec 0.01 2.5 0.000 0.0Ontario 0.23 65.2 0.542 150.5Manitoba 0.03 8.2 0.000 0.0Saskatchewan 0.83 231.7 0.542 150.5Alberta 0.91 252.1 0.542 150.5British Columbia 0.03 7.4 0.000 0.0Territories 0.35 98.5 0.909 252.5Marginal Canadian Emission Factor 0.22 61.3 0.426 118.4

CO2, CH4, N2O

Electricity Emissions Average Marginal Provincial Emission

CO2

Example:

Manitoba versus Wha Ti diesel

remote community

GHG DisplacementGHG DisplacementHeat (kWth- hr)– integrated areas

displace oil, natural gas, electricity

– non-integrated areadisplace oil

Northern Community: special case– off-grid power from transported diesel– off grid heat from transported oil– very favorable to CHP

ORC, EHC, and small steam CHP

GHG Displacement by BiomassGHG Displacement by BiomassScenario Description Emissions

per kWe-hrTypical Regions

1 Low carbon intensity power generation: 90% of nuclear or large hydropower; 10% natural gas

CO2: 52 g Québec, British Columbia, Manitoba; France; Norway; Sweden

2 Moderate carbon intensity power mix:65% nuclear/large hydro, 25% coal, 10% natural gas

CO2: 288 g Canadian average; Ontario; Atlantic Canada; Austria; Belgium

3 High coal/oil content in power production (50%); nuclear/large hydro: 25%; natural gas: 25%

CO2: 588 g United States average, Denmark; Germany; Mexico; Spain; U.K.

4 Very high coal/oil content 75%, nuclear/large hydro 15%, natural gas 10%

CO2: 761 g Alberta, Saskatchewan, central U.S.; Greece; Ireland; Netherlands

-900-800-700-600-500-400-300-200-100

0

CHP SYSTEMSSmall Steam Turboden Entropic

GH

G E

MIS

SIO

N

(kgC

O2/

BD

tonn

e)

Heating OilNatural Gas

Power

Heat

Comparison of Biomass OptionsComparison of Biomass Options(Distributed and 50% MC)(Distributed and 50% MC)

-1400

-1200

-1000

-800-600

-400

-200

0

EMISSION REDUCTIONS for CHP SYSTEMS

GH

G E

MIS

SIO

N(k

g CO

2/BD

tonn

e)

Scenario 1Scenario 2Scenario 3Scenario 4

LargeSteamPow er

SmallSteamPow er

BraytonCycle

Pow er

Bio-oilConver.Pow er

Gasif.Conver.Pow er

SmallSteam

CHP

TurbodenCycleCHP

EntropicCycleCHP

Displacing oil for heat

Bioenergy in Northern Communities

2 MWe Community Subsidized Power System BioPower SystemPower (2 MWe) tonne CO2 0 tonne CO2Heat (10 MWth) tonne CO2 0 tonne CO2Total tonne CO2 0 tonne CO2

115532305534,608

Power: Diesel Fuel Turbion™ CHPNorthern Community

Heat: Oil Biomass (local or pellets)2 BD tonne/MWe-hr

Power

Heat

~233 liters/ MWe-hr~2.83 Kg CO2/ liter

~93 liters/ MWth-hr~2.83 Kg CO2/ liter

~1 MWe-hr~No GHG

~5 MWth-hr~No GHG

BioPower SystemSubsidized Power System

(Biomass district heat already installed)

CHOICES?

$0.060 per kWhr$0.025 per kWhr

Canadian DollarsPower (85% use) Heat (40% use) Total

Bio-oil $19 $19Gasification Syngas $22 $22Air Brayton $21 $21Large Steam $72 $72Small Steam $29 $29Small Steam CHP $17 $29 $46Organic Rankine $30 $27 $57Entropic Hybrid $35 $31 $65

Revenue per BDTon Biomass

Electical PowerNartural Gas

*Revenue for distributed biopower systems using 50% MC biomass

1

Distributed BioPowerDistributed BioPowerCHP Revenue Chart CHP Revenue Chart

Technical complexity

25%

Manitoba Hydro: Chair in Alternative Energy

Natural Resources Canada

Commission for Environmental Cooperation

National Research Council

ACKNOWLEDGEMENTACKNOWLEDGEMENT