Renewable Energy. Geothermal Ocean energy II. Solar technologies. Other. Direct solar. Tidal Currents (partial) Salinity gradients

Transcription

1 Renewable Energy Solar technologies Direct solar Solar-electric (photovoltaic) Solar thermal Biomass Wind Hydroelectric Ocean energy I OTEC (partial) Wave Currents (partial) Geothermal Ocean energy II Tidal Currents (partial) Salinity gradients Other Planetary dynamo/atmospheric electricity Biomass 1

2 Renewable Energy Solar technologies Direct solar Solar-electric (photovoltaic) Solar thermal Biomass Wind Hydroelectric Ocean energy I OTEC (partial) Wave Currents (partial) Geothermal Ocean energy II Tidal Currents (partial) Salinity gradients Other Planetary dynamo/atmospheric electricity Biomass 2

3 What is biomass? Strict definition: living material Federal statute (7 USC ): Any organic matter that is available on a renewable or recurring basis, including agricultural crops and trees, wood and wood wastes and residues, plants (including aquatic plants), grasses, residues, fibers, and animal wastes, municipal wastes, and other waste materials. Biomass 3

4 Solar Power 175 PW (top of atmosphere) Solar Power Balance for Earth: Incoming 100% 175 PW Reflected 30% 53 PW Reradiated 47% 82 PW Water Cycle 23% 40 PW Wind, waves 0.2% 0.35 PW (350 TW) Photosynthesis 0.02% PW (35 TW) Biomass 4

5 Primary sources of biomass Agriculture Crop residues, animal manures, food processing residues Grains and other starch crops, sugar crops Forestry Logging slash, mill residues, forest thinning, shrubland management Urban Municipal solid wastes, biosolids, food wastes, green wastes, non-recyclable paper, waste oils and fats, sewage and other waste-water Dedicated energy crops (purpose-grown) Grasses, trees, algae, other aquatic species, microbes, conventional crops Biomass 5

6 California Residue and In-forest Biomass Resources Agriculture Forestry Technical Gross Municipal +90 BCF landfill gas and biogas Total Biomass (Million BDT/y) Landfill Gas, 61 TBtu, 11% Waste-water Treatment, 10 TBtu, 2% Agriculture, 137 TBtu, 24% Urban, 128 TBtu, 22% Source: California Biomass Collaborative, 2007 Potential Feedstock Energy in Biomass 507 Trillion Btu/year Forestry, 242 TBtu, 41% Biomass 6

7 Principal Biomass Conversion Pathways Production Collection Processing Storage Transportation Thermochemical Conversion Combustion Gasification Pyrolysis Bioconversion Anaerobic/Fermentation Aerobic Processing Biophotolysis Physicochemical Esters Alkanes Energy Heat Electricity Fuels Solids Liquids Gases Products Chemicals Materials Biomass 7

8 Biomass Structure and Composition Pine softwood Cellulose Hemicellulose Lignin Starch Sugar Extractives Birch hardwood Wheat straw Sugar cane Biomass 8

9 Crude Biomass Moisture Dry Matter (Total Solids) Volatile Solids Ash (Inorganic) Physical And Chemical Properties Fixed Carbon Structural Components Volatile Matter Extractives Salts Cellulose Simple Sugars Other Minerals Hemicellulose Lipids/Oils Metals Lignin Proteins Adventitious Material (e.g. soil) Elemental Composition

10 Carbohydrate units Source: Z. Fan Biomass 10

11 Plant cell

12 Starch Cellulose a-linked glucose units making up starch (amorphous) corn starch b-linked glucose units forming cellobiose, the repeating unit of cellulose (semi-crystalline) (Salisbury and Ross, 1992; Henriksson and Gatenholm, 2001) Biomass 12

13 Cell wall structure Pectic polysaccharides and proteins Source: C. Somerville, Imperatives in cell wall research, EBI

14 Hemicellulose J. VanderGheynst Partial structures of the principal hemicelluloses in wood (a) O-acetyl-4-O-methylglucuronoxylan from hardwood. (b) O-acetyl-galactoglucomannan from softwood. (Hon and Shiraishi, 2001). Ac=acetyl group. Biomass 14

15 Lignin Aromatic polymer of phenylpropane units Linked to carbohydrates in cell wall Recalcitrant to biological degradation Redeposition on biomass surfaces during pretreatment interferes with downstream processing Higher heating value compared with cellulose Often proposed for burning in biorefinery applications Higher value products may be feasible Phenolic subunits of lignin Partial lignin structure of softwood Biomass 15

16 Partial compositions (%) of biomass materials Biomass Constituent Populus Deltoides (rm #8492) Pinus Radiata (rm #8493) Sugarcane Bagasse (rm #8491) Wheat Straw (rm # 8494) Ash % ethanol extractives Acid soluble lignin Acid insoluble lignin Total lignin Glucuronic acid Arabinan Xylan Mannan Galactan Glucan Each value is mean from round-robin testing of 20 laboratories. For uncertainties of analysis, see NIST certificates, available from (NIST, 2003). Biomass 16

17 Biomass Composition Type Alfalfa Straw Rice Straw Wheat Straw Miscanthus Switch grass Jose Tall wheat grass Hybrid Poplar Nonrecyclable Water Willow Hyacinth Waste Paper Sugarcane Bagasse Municipal Digester Sludge (Class B Biosolids) Typical Harvest Moisture (% wet basis) Proximate Composition (% dry matter) Ash Organic Fraction Volatiles Fixed Carbon Higher Heating Value (MJ/kg) Moisture Free (dry) Moisture and Ash Free Wet Structural Composition (% dry matter) * Cellulose Hemicellulose Lignin *Structural data representative only and not necessarily from same sample used for elemental analysis and heating value. Biomass 17

18 Biomass Composition Type Alfalfa Straw Rice Straw Wheat Straw Miscanthus Switch grass Jose Tall wheat grass Hybrid Poplar Nonrecyclable Water Willow Hyacinth Waste Paper Sugarcane Bagasse Municipal Digester Sludge (Class B Biosolids) Ultimate Elemental Composition (% Moisture and Ash Free) Carbon Hydrogen Oxygen (by difference) Nitrogen Sulfur Chlorine Ash Analysis ( % ash) SiO Al2O TiO Fe2O CaO MgO Na2O K2O P2O SO Cl CO Biomass 18

19 Bioenergy Conversion Processes Combustion for heat and power Biofuels Biomass 19

20 Thermochemical Conversion Pyrolysis thermal decomposition of organic material through heating Gasification conversion of solids or liquids to fuelor synthesis-gases through gas-forming reactions Combustion (solids) exothermic oxidation involving pyrolysis, gasification, and heterogeneous and homogeneous oxidation reactions with fluid flow

21 Combustion Oxidation of the fuel for the generation of heat at elevated temperatures. Involves simultaneous process of heat and mass transport, chemical reaction through pyrolysis, gasification, ignition, and burning, frequently under turbulent fluid flow conditions Leads to the formation of oxidation products in addition to heat, as well as products of incomplete combustion

22 Combustion of biomass C x H y O z N a S b Cl c + n 1 H 2 O + Ash + n 2 (1+e)(O N 2 ) = = n 3 CO 2 + n 4 H 2 O + n 5 N 2 + n 6 O 2 + n 7 NO + n 8 NO 2 + n 9 SO 2 + n 10 HCl + n 11 CO + HC + Ash + Soot + Tar + Luminous soot radiation Ignition and burning C 2 radical emission Fuel evaporation and pyrolysis Fuel transport (wicking) Fuel melting Z916

23 Flame sheet

24 Simplified Global Combustion Reaction for Carbohydrate Solve for the values of the n i O N O H CO ) N e )(O ( O H O H C z y x n n n n n n n REACTANTS PRODUCTS

25 Simplified Global Combustion Reaction for Carbohydrate n C 1 x H y REACTANTS O z n H 2 2 PRODUCTS 79 O n 3( 1 e )(O2 N2 ) n 4CO2 n 5H2O n 6N2 n 7O 21 Let n 1 = 1. n 2 computed from moisture and ash. Compute n 3 assuming e, n 7 = 0 (theoretical air). Use C, H, O, N element balances for n 4 n 7 Let n n 2 W W f H M 2 O db Y o

26 Simplified Global Combustion Reaction for Carbohydrate n C 1 x H y REACTANTS O z n 2 n 3 n H W W x 2 f H O 2 M 2 y 4 PRODUCTS 79 O n 3( 1 e )(O2 N2 ) n 4CO2 n 5H2O n 6N2 n 7O 21 Let n 1 = 1. n 2 computed from moisture and ash. Compute n 3 assuming e, n 7 = 0 (theoretical air). Use C, H, O, N element balances for n 4 n 7 Let n 1 1 db Y o z 2 n 4 n 5 x y 2 2 n 79 n 6 n 3 ( 1 e ) 21 n 7 n 3 e 2

27 Air-Fuel Ratio AF Mass of Mass of For simplified global combustion reaction: AF Air Fuel 79 n 3( 1 e ) WO W 2 21 W f WH n 2O 2 Y o N 2 W O2 and W N2 are the molar masses of O 2 and N 2. The stoichiometric or theoretical air-fuel ratio is computed for e = 0. Conditions in which e 0, so that the air-fuel ratio is greater than or equal to the stoichiometric air fuel ratio, define the combustion regime. Conditions for which -1 e < 0 define the gasification and pyrolysis regimes, whereby the fuel is only partially or incompletely oxidized, and a larger number of reaction products are generated. Direct gasification reactions are carried out with something less than about 30% of theoretical air. The fuel equivalence ratio, f, the ratio of the stoichiometric air-fuel ratio to the actual airfuel ratio (or actual fuel-air to stoichiometric fuel-air), is sometimes used to define the operating conditions, in which case f < 1 defines the fuel lean combustion regime, and f > 1 defines the fuel rich combustion and gasification regimes. The air equivalence ratio, l = 1/f, is also sometimes used.

28 Additional elements n C 1 x H y O z N a S b n H 2 2 O n ( 1 e )( O 3... n CO n H 5 79 N 2 ) 21 O n N n O 7 2 n NO 8 2 n SO 9 2 More unknowns than constituent elements System is indeterminate Either constrain coefficients to yield determinate solution, or apply alternate solution technique, e.g. equilibrium Equilibrium does not apply to all species, e.g. NO, NO 2 formation which are kinetic limited Fuel N, S contribute to criteria pollutant formation and greenhouse gas emissions including NO, NO 2, N 2 O, SO 2, SO 3, Add other elements as needed: Cl (forms HCl, also dioxins and furans under appropriate conditions), Hg and other heavy metals, radionuclides, Excel spreadsheet to calculate stoichiometry

29 Higher and Lower Heating Values of Biomass Higher heating value of moist fuel at moisture content M wb Q h h, 0 Q 1 M wb Lower heating value at any moisture content Q l W H 2O 1 M Q u M H wb h, 0 fg db 2W u fg = latent internal energy of vaporization (2.3 MJ/kg at 25 C, 1 atm), use h fg for constant pressure case H = dry matter mass fraction (decimal) of hydrogen in the biomass from ultimate analysis W i = molar mass of species i H

30 Residual Energy (%) Sensible heat after evaporation of moisture Q residual M (%) 1001 ( 1 M vh,o wb u wb fg )Q Moisture Content (% wb)

31 Combustion Systems Power generation Combined Heat and Power (CHP) or Cogeneration Poly-generation Traditional uses Biomass 31

32 Rankine Cycle Power Plant Stack Exhaust Emission Control Superheated Steam Fly ash Boiler Steam Turbine Generator Electricity Fuel Air Water Condensor Bottom Ash Boiler Feedwater Pump Cooling Medium

33 Typical Boiler Design Steam Drum Combustion Gas Superheater Superheated Steam to Turbine Secondary Air Water Wall Evaporator Convection Pass Economizer Boiler Feedwater Air Heater Air from Forced Draft Fan Fuel Primary air Furnace Gas Duct to Emission Control, Induced Draft Fan, Stack Bottom Ash Detail through water wall

34 to convection pass to convection pass Furnace Designs Overfire air Air Fuel + Air Burner Burner flame Fuel Spreader flame Underfire air grate Bottom Ash Bottom Ash Traveling Grate S uspension Furnace to convection pass to convection pass Secondary air Secondary air Waste burning on grate Sand Bed Fuel Distributor Ash Fuel Fluidizing air Fluidizing air Bubbling Fluidized Bed Circulating Fluidized Bed

35 Wood-fired Boiler Babcock and Wilcox

36 Co-firing Firing biomass fuel with fossil fuel Coal Natural gas Reduced emissions Average tipping fee and locations of local biomass supply studies SO x NO x CO 2 Source: FEMP, 2004

37 Biofuels Thermochemical Conversion Biochemical Conversion Physicochemical Conversion Biomass 37

38 Biofuel (Billion BOE/year) US Biofuel Potential Conversion Efficiency (%) BBOE/year 78 BGY/year diesel equivalent US Billion ton study ,000 1,500 2,000 Quantity of Biomass (Million tons/year) Biomass 38

39 Annual Bioenergy (Billion Gallons of Gasoline Equivalent) Biofuel Potential in California 4 From In-state Biomass Resources 3 Hydrogen 2 Biofuels 1 Biomethane Electricity Year Biomass 39

40 Bioenergy/Biofuels Conversion Process Fuel Thermochemical Biochemical Physicochemical Solids Biomass/Chars/Charcoal Biosolids Liquids Gases Methanol Biomass-to-Liquids Renewable diesels, biogasolines, other hydrocarbons and oxygenated hydrocarbons Ethanol/Mixed Alcohols Dimethyl ether (pressurized) Bio-oils (pyrolysis oils) Bioparaffins Producer gas Synthesis gas (Syngas) Hydrogen Ethanol Butanol Other Alcohols Liquified- BioMethane (LNG) Biogas (incl. landfill gas, digester gas) Biomethane Compressed Biomethane (CNG) Hydrogen Biomass (incl. densified and other processed fuel) Biodiesel (esters) from Plant Oils, Yeast Oils, Algal Oils Alkanes (catalytic) Biomass 40

41 Biorefining Approaches for Lignocellulose Thermochemical Biochemical Thermolytic Solids Oils Gasification, Pyrolysis Pretreatment, Hydrolysis (cell wall deconstruction) Hydrolytic Cellulose Hemicellulose Synthesis gas (CO + H 2 + other) Sugar monomers, acids Catalytic Synthesis Syngas Fermentation Fermentation Hydrocarbons, mixed alcohols, hydrogen, ammonia, SNG, ethanol, higher alcohols Ethanol, butanol, other higher alcohols, biomethane, hydrogen, acids

42 Molar Mass (kg/kmol) 1,000, ,000 Photosynthesis Lignocellulose Starch Biomass Deconstruction/ Biofuel Synthesis 10,000 Pyrolysis Hydrolysis Air/Steam HTU Gasification 1,000 Lipids Esterification Hydrogenatio Biodieseln H Sugars Thermochemical 100 C Bio-oils Fermentation Anaerobic Ethanol DME Methanol Digestion Methane *Combustion 10 Charcoal Synthesis Plasma Gasification Syngas Hydrogen Biochemical Temperature (C) Biomass 42

43 Is there a definitive conversion technology for biomass? Miles per dry ton biomass Miles per dry ton of biomass Electricity Electricity (35% efficiency/igcc/cofiring) (25% efficiency/current) BTL-Syndiesel Ethanol Ethanol (63 gals/ton) (110 gals/ton) (80 gals/ton) Transport range for bioenergy Hydrogen Fuel Cell (62 kg/ton) Based on hybrid vehicle with 44 miles per gallon fuel economy on gasoline, 260 Wh/mile battery (source: B. Epstein, E2). Electricity includes generating efficiency, transmission, distribution, and battery charging losses. Ethanol, BTL- Syndiesel, and H 2 include fuel distribution transport energy. Biomass 43

44 Estimated costs of biofuel from lignocellulose Product Ethanol (biochemical) FT diesel (thermochemical) Mixed Alcohol (thermochemical) Pyrolytic Gasoline (thermochemical) Renewable Diesel (Hydrotreated Fats & Oils) Hydrogen (thermochemical) Capital + O&M Cost ($/gal) Feedstock Cost ($/gal) Total Cost ($/gge) (virgin oil) /kg 0.47/kg 1.04

45 Thermochemical Conversion Pyrolysis thermal decomposition of organic material through heating Gasification conversion of solids or liquids to fuelor synthesis-gases through gas-forming reactions Combustion (solids) exothermic oxidation involving pyrolysis, gasification, and heterogeneous and homogeneous oxidation reactions

46 Thermal Gasification Fuel + Oxidant/Heat Partial Oxidation/Air or Oxygen Steam/Carbon Dioxide/Hydrogen Indirect Heating CO + H 2 + HC + CO 2 + N 2 + H 2 O + Char + Tar + PM + H 2 S + NH 3 + Other + Heat

47 Gasification Prehistoric charcoal making 18 th Century development of gasification for heating and lighting Town gas WW II vehicle use due to limited petroleum supplies 1973 oil embargo stimulates development Harry LaFontaine s gasifier-fueled stretch Lincoln

48 Swedish design Imbert type downdraft gasifier (1977)

49 Classification by Reactor Type: Fixed/Moving (Stirred) Beds Updraft Countercurrent High moisture fuel (<60% wet basis) High tar production except with post-reactor catalytic cracking or dual stage air injection Low carbon ash Downdraft Cocurrent Moisture < 30% Lower tar than uncontrolled updraft Carbonaceous char Crossdraft Adaptation for high temperature charcoal gasification

50 Common (and not so common) gasifiers Air Ash Reaction front Updraft Gas and Smoke Gas Char and Smoke Reaction front Downdraft Air

51 Classification by Reactor Type: Fluidized Beds Freeboard Fluid Bed Plenum Williams, 2006 Ash Biomass Air/Steam Bubbling beds Lower velocity Low entrainment/elutriation Simple design Lower capacity and potentially less uniform reactor temperature distribution than circulating beds Product Gas Circulating beds Higher velocity Solids separation/recirculation More complex design Higher conversion rates and efficiencies

52 Classification by Reactor Type: Entrained Beds GE-Texaco Gasifier Solids or slurry entrained on gas flow Small particle size Entrained flow used as component in some developmental pyrolytic biomass reactor systems

53 Gasification: Indirect Heating Battelle/ FERCO gasifier Fast Internal Circulating Fluidized Bed (FICFB) gasifier, Güssing, Austria Mark Paisley, FERCO Bolhar-Nordenkampf, et al. (2002) Williams, 2006

54 Classification by Oxidation Medium Air gasification (partial oxidation in air) Generates Producer Gas with low heating value (~150 Btu ft -3 ) and high N 2 dilution. Oxygen gasification (partial oxidation using pure O 2 ) Generates synthesis gas (Syngas) with medium heating value (~350 Btu ft -3 ) and low N 2 in gas. Steam gasification Generates high H 2 concentration, medium heating value, low N 2 in gas. Can also use catalytic steam gasification with alkali carbonate or hydroxide Carbon dioxide Hydrogen Indirect heated--pyrolysis

55 Reactions and Products Oxidation Boudouard reaction Hydrogasification Water-gas reactions C + O 2 = CO 2 C + CO 2 = 2CO C + 2H 2 = CH 4 C + H 2 O = CO + H 2 Water-gas shift Methanation (reverse is the steam methane reforming reaction) C + 2H 2 O = CO 2 + 2H 2 CO + H 2 O = CO 2 + H 2 CO + 3H 2 = CH 4 + H 2 O

56 Gas Compositions (% by volume) Oxygen-blown H CO CO H 2 O 2-30 CH 4 (C1-C4) 0-5 N H 2 S NH 3 +HCN Air-blown High N 2 dilution 30-50% HHV: 3-6 MJ m -3 Steam-blown Composition of Raw Gas from Steam Gasification % by volume dry (except as noted) H 2 O (wet) CH C 2 H C3 fraction CO CO H N H 2 S ppmv NH ppmv Tar 2 5 g Nm -3 Particulate Matter g Nm -3 Lower Heating Value ~350 Btu ft -3 Concentrations approximate and depend on feedstock and reaction conditions

57 Imbert-type downdraft with hot gas filtration

58 Gasifier Boiler Application CONDENSATE option

59 CFB with gas conditioning Engine Gensets (Carbona Skive Project, Denmark) TAR CRACKER PRODUCT GAS FILTER GAS COOLER BOILER TO STACK BIOMASS Cyclone Separator FLY ASH GASIFIER PRODUCT GAS COOLING (Heat Recovery) Bed media and char return PRODUCT GAS SCRUBBING (Heat Recovery) DISTRICT HEATING 11.5 MW th PRODUCT GAS BUFFER TANK FLUE GAS HEAT RECOVERY AIR STEAM ASH WATER TREATMENT POWER 5.4 MW e GAS ENGINES Courtesy Carbona Corporation

60 Engine derating Reciprocating engines fueled with producer gas (from air blown reactors) are generally derated with respect to liquid hydrocarbon fuels High N 2 and CO 2 dilution leads to reduced air intake and fuel consumption per cycle, hence reduced power output

61 Integrated gasification combined cycle (IGCC) power generation CYCLONE STEAM TO HRSG GAS CLEAN-UP WATER FROM HRSG CLEAN PRODUCT GAS IGCC AIR GASIFIER GAS COOLER FLY ASH GAS TURBINE SOLID FUEL (MSW, Biomass, etc) BED MATERIAL AIR BOOSTER COMPRESSOR AIR Turbine Exhaust HEAT RECOVERY STEAM GENERATOR STEAM FROM GAS COOLER TO GAS COOLER STACK ASH AND BED MATERIAL STEAM TURBINE Varnamo IGCC, Sweden Source: Carbona Corporation CONDENSER Biomass 61

62 Värnamo IGCC, Sweden

63 Thermo-biorefining Syngas Direct use Fischer-Tropsch Isosynthesis Oxosynthesis Water-gas shift Alkali-doped Methanol synthesis adapted from Spath and Dayton, 2004 Methanation Ethanol synthesis Fe, Co, Ru ThO 2, ZrO 2 HCo(CO) 4 Fe, Cu/Zn Ni ZnO/Cr 2 O 3, Cu/ZnO/Al 2 O 3, MoS 2 Co, Rh Cu/ZnO Waxes, diesel Olefins, gasoline i-c 4 Aldehydes Alcohols Fe, FeO Hydrogen Ammonia SNG Mixed alcohols Ethanol Methanol Al 2 O 3 homol/co Ag isobutylene Co, Rh, Ni zeolites Direct use (M100, M85, DMFC) DME CH 3 OCH 3 (methanol dehydration) Ethanol Formaldehyde MTBE Acetic acid Olefins, gasoline

64 Liquid Synthesis GTL Gas to Liquids (commercial) Natural gas (or biomethane) reforming Steam reforming: CH 4 + H 2 O = CO + 3H 2 Partial oxidation: CH O 2 = CO + 2H 2 O Water-gas shift: CO + H 2 O = CO 2 + H 2 Example: Methane/Oxygen-fired autothermal reforming (Haldor Topsøe) Fischer-Tropsch Synthesis CO + 2H 2 = -(CH 2 )- + H 2 O Example: Sasol slurry phase reactor (gas fed liquid hydrocarbon-catalyst slurry) Product Upgrading Hydrotreating for olefin and oxygenate conversion Hydrocracking to naphtha and diesel Fractionation Yield: 3.5 bbl/1000 m 3 (4 bbld/1000 cows through biomethane)

65 BTL: Biomass To Liquids Fischer-Tropsch Synthesis Air/O 2 /Steam Gas Cleaning Gas Processing Wet/Cold Methane Reforming Dry/Hot CH 4 + H 2 O = 3H 2 + CO Gasification Water, Tar, PM, S Recycle Shift H 2 /CO adjust CO 2 removal Fe, Co Catalysts CO + 2H 2 = -(CH 2 )- + H 2 O DH 500K = kj/mol C/0.5-4 MPa CO 2 + 3H 2 = -(CH 2 )- + 2H 2 O DH 500K = kj/mol (Kölbel reaction) Ash, Char Pretreatment Drying Comminution Extraction Biomass FT Synthesis Off-gas Power Generation Liquid/Wax Products Refining Products (60-80 gals/ton) Power Heat/Steam h=33-56% LHV Overall

66 FT Product Distribution Fe catalyst source: Jager, 2003

67 Gas Cleaning Syngas contaminant concentration limits Particulate matter Tar Sulfur Halides ~0 (> 2 μm) ~0 ppm 60 ppb - 1 ppm 10 ppb Nitrogen 10 ppmv NH 3 ~0 ppmv NO x 10 ppb HCN (except for ammonia synthesis) Adapted from Dayton, 2005

68 Biomass FT Development Värnamo, Sweden pressurized fluidized bed gasifier steam/oxygen blown conversion of IGCC Choren, Germany 2-stage gasification VW and Daimler-Chrysler Güssing, Austria FT slurry reactor

69 Net CO 2 Emissions for Syndiesels 250 Gas-to-Liquids GTL Coal-to-Liquids CTL Biomass-to-Liquids BTL % CO 2 emitted compared to diesel Image: WELL-TO-WHEELS ANALYSIS OF FUTURE AUTOMOTIVE FUELS AND POWERTRAINS IN THE EUROPEAN CONTEXT (May, 2006) Biomass 69

70 Thermochemical Biofuel Lifecycle Energy Ratios Biomass to: Fossil Energy Ratio Primary Energy Ratio FT liquid Ethanol Mixed Alcohols Methanol Olefins via methanol Source: Spath and Dayton, 2003 Biomass 70

71 Capital Cost Basis for a 34,000 bbl/day Biofuel FT Refinery Cost (Million $) Air separation unit 207 Gasifier 138 H 2 manufacturing and syngas conditioning 46 Gas cleaning 161 Fischer-Tropsch synthesis 115 Product upgrading 69 Site and auxiliaries 735 Indirect costs and working capital 298 Total capital investment 1,768 adapted from Boerrigter, 2006 Biomass 71

72 Total Capital Cost ($/bbld) Total Capital Cost ($/bbld ), (Million $) Capital Cost Economy of Scale for FT Biorefinery 1,000, ,000 10,000 1, , , ,000 50, ,000 40,000 60,000 80,000 Capacity (bbld) ,000 10, ,000 Capacity (bbld) adapted from Boerrigter, 2006 Biomass 72

73 Production Cost ($/MMBtu) FT Biofuel Production Cost Conversion Pretreatment Transport Biomass 10 adapted from Boerrigter, MWth bbl/d Biomass (Million tons per year) ,800 4,100 8, ,125 15,300 34,849 72,248 Biomass 73

74 Diameter (miles) Comparative Area Requirements miles 3.1 million acres MWth 8,500 4,100 1, Ames tons/acre-year 5 tons/acre-y Des Moines Biomass (Million tons per year) Biomass 74

75 Comparative Area 72,000 bbl/d Arbuckle Requirements 35,000 15, miles 3.1 million acres 2,100 7 MWth ,500 4,100 1, Davis 33 Sacramento Average 5 tons/acre-year Fairfield ConocoPhilips Refinery, Rodeo, California: 76,000 bbl/d 1,100 million gallons/year Diesel equivalent Biomass 75

76 Small/distributed systems Significant opportunities for system integration CHP Fuels synthesis Cost? Policy effects Feed-in tariffs Net metering Lack of equity in California law Biomass 76

77 Biofuels Thermochemical Conversion Biochemical Conversion Physicochemical Conversion Biomass 77

78 Ethanol Fermentation Ethanol (C 2 H 5 OH) is widely produced by fermentation and is the predominant liquid fuel derived at present by biochemical means from biomass. The overall reaction for the fermentation of glucose to ethanol is C 6 H 12 O 6 = 2C 2 H 5 OH + 2CO 2 Cellulosic feedstocks (such as wood and herbaceous biomass) are less expensive to produce than corn grain and represent a large resource for fuel ethanol production with potentially better net energy yields and lower environmental impacts. They are more difficult to hydrolyze into monosaccharides and ferment, however, incurring more costly pretreatment. Current methods under development for cellulosic biomass hydrolysis and fermentation essentially fall into four categories: 1) concentrated acid hydrolysis, 2) dilute acid hydrolysis, 3) enzymatic hydrolysis, and 4) thermochemical conversion (gasification and pyrolysis) Biomass 78

79 Ethanol Fermentation: Starch Hydrolysis Known technology Basis for corn grainethanol industry Efficiency improvements continuing Uncertainties regarding sustainability Sugar feedstocks similarly fermented (e.g. sugar from sugar cane in Brazil) Biomass 79

80 Corn Grain Corn dry milling, fermentation, and distillation for anhydrous ethanol Water ph Adjust (lime) Water Grind Cook (Starch Solubilization) Cool ph Adjust (acid) Hydrolysis Enzyme (Glucoamylase) Cool Enzyme (a-amylase) Yeast Fermentation CO 2 Beer Steam Beer Still Stillage Drying Feed Steam Steam Rectifying Column Steam Solvent Stripper Anhydrous Tower Water Anhydrous Ethanol Make-up solvent Biomass 80

81 Million Gallons US Ethanol Production 16,000 14,000 12,000 Current and Under- Construction 10,000 8,000 6,000 4,000 2,000 US Demand US Production Capacity Imports Start of Year RFA, USDOE, USDA, US EPA

82 Fuel price volatility Ethanol price: Railcar/LA October 2007 $1.25/gallon June 2008: $2.50/gallon January 2009: $1.25/gallon

83 Cost of ethanol from corn and sugar Corn feedstock costs shown net of co-product credit. Without credit, corn feedstock cost ($5.00/bushel = $178.57/ton) is $2.00/gallon ethanol or $3.12/gge. Ethanol yield from sugar averages about 140 gallons/ton 2008 US sugar production: 8.5 million tons 1.2 billion gallons equivalent US imports = 2.2 million tons 0.3 billion gallons equivalent Sugar cost of $0.25/pound = $3.57/gallon ethanol or $5.58/gge Source: USDA, The economic feasibility of ethanol production from sugar in the United States, July, 2006,

84 50 MGY Corn Dry Mill Ethanol Refinery (Iowa) Biomass 84

85 50 MGY Corn Dry Mill Ethanol Refinery (Iowa) Biomass 85

86 25 MGY Ethanol Facility, Goshen, CA Biomass 86

87 Cellulosic Fermentation Pretreatment Size reduction/grinding Acid (dilute or concentrated) hemicellulose hydroylsis Heating Steam explosion/afex, others Hydrolysis (cellulose depolymerization--glucose release) Acid Enzymatic Fermentation of sugars (C5 and C6) Separate Simultaneous saccharification and co/fermentation (SSF; SSCF) Product Recovery and Purification Distillation and dehydration Lignin separation (unfermented) Biomass 87

88 Recycle acid + sugars Concentrated Feed acid Mill hydrolysis and fermentation of cellulose Solids Lime CO2 Neutralization/ Filter/Separation Fermentation Beer 9.5% H2SO4 10% glucose 5-10% C5 5-10% C6 Liquid Hemi Cellulose Reactor Press Cellulose Pretreatment Water Steam 100 C 1-6 h Steam Acid 20-30% H2SO4 1-2 h Dryer Distillation Cellulose Reactor Water Steam Stillage Steam Ethanol Press Solids (Lignin + unreacted cellulose) Acid recovery Sugar recovery Biomass 88

89 Theoretical energy balance Overall reaction of cellulose to glucose: C 6 H 10 O 5 + H 2 O = C 6 H 12 O 6 Fractional energy yields in the conversion of cellulose to ethanol: Compound Molecular Weight Higher Heating Value (MJ kg -1 ) Molal Energy (MJ) Fractional Energy (--) Cellulose , Glucose , Ethanol * , * 2 moles of ethanol produced per mole cellulose reacted Biomass 89

90 Ethanol yield from biomass Typical yields from lignocellulosic biomass: Volume Yield (Gallons/ton) VolumeYield (L/Mg) Mass Yield (kg/kg) Fractional Energy Yield (%) Biomass 90

91 Properties of ethanol and gasoline Property Ethanol Unleaded regular gasoline Specific gravity (15 C) Lower heating value (MJ kg -1 ) Lower heating value (MJ L -1 ) Octane Number ((R+M)/2) Stoichiometric air-fuel ratio Lower heating value of stoichiometric air-fuel mixture (MJ kg -1 ) Enthalpy of vaporization (kj kg 15 C) Reid vapor pressure (kpa)* *Reid vapor pressure of 10% ethanol in gasoline is 3-7 kpa higher than gasoline alone. Biomass 91

92 Butanol fermentation Butanol (CH 3 (CH 2 ) 3 OH) has higher heating value per gallon (energy content) than ethanol and is less hygroscopic Acetone-Butanol-Ethanol fermentation pathway Clostridium beijerinckii, C. acetobutylcium Gas stripping Biomass 92

93 Integrated Biorefinery (Advanced Biorefinery) 84 gal/ton Source: Spath, 2005; Bain, 2005 Biomass 93

94 Anaerobic Digestion Electricity Heat Biogas upgrading Pipeline quality CNG LNG Gas-To-Liquids (GTL) Other chemical synthesis Biogas for Power or Biofuel Upgrading Onsite And Grid Power, Fuels, Chemicals Biomass 94

95 Anaerobic Digestion Biogas Power Generation Upgrading/Pipelining Compression/CBG Reforming to H 2 Chemical synthesis CH 4 + CO 2 Biomass Methanogenesis Acetogenesis Hydrolysis Digested Effluent Organic Matter Anaerobic Digester Courtesy Prof. R. Zhang Biomass 95

96 Anaerobic digestion process Ahring, 2003 Hydrolyzing and fermenting microorganisms generate principally acetate and hydrogen along with volatile fatty acids (VFA), e.g. propionate, butyrate, also alcohols Obligate H 2 -producing acetogenic bacteria convert propionate and butyrate to acetate and H 2 Methanogenic Archaea generate methane from acetate or H 2 Biomass 96

97 Anaerobic digestion Biomass 97

98 Temperature regimes Psychrophilic (ambient) Mesophilic (30-40 C) Thermophilic (50-60 C) Extreme Biomass 98

99 Temperature phased anaerobic digestion (Thermophilic-Mesophilic) Increased pathogen destruction and potential for Class A biosolids production (thermophilic) Increased reaction rate Lower volatile fatty acid concentrations in biosolids (mesophilic) Sieger, et al., 2004 Biomass 99

100 Acid/Gas phased anaerobic digestion Biological hydrolysis (acid phase) Separate optimization of bacterial environments Increased gas production Sieger, et al., 2004 Biomass 100

101 Plug-flow dairy digester Biomass 101

102 Theoretical yields The overall reaction for anaerobic digestion of the organic portion of the feedstock is C x H y O x Cellulose: z y 4 z H 2 C 2 O x 2 y 8 z CO 4 6H10O5 H2O CO2 3 Theoretical methane yields: Mass = 29.6%, Energy = 93.0%, Methane volume =453 L kg -1 The actual concentration of CO 2 is generally reduced due to its solubility in water, and methane yield depends on substrate. Typical biogas yields are L kg -1, including CO 2, with energy efficiencies of 20-50% to biogas, 10-20% to electricity. CO 2 stripping used to produce biomethane for pipeline injection, CNG, LNG, and other uses. GTL for biomethane not yet practiced. 2 3 CH 4 x 2 y 8 z CH 4 4 Biomass 102

103 Biofuels Thermochemical Conversion Biochemical Conversion Physicochemical Conversion Biomass 103

104 Biodiesel (FAME, FAEE) Transesterification Reaction between lipid and alcohol using alkaline catalyst Reduced viscosity, improved atomization Soydiesel yield = 52 gallons per ton seed Soybean commodity prices through 2008 average $325 per ton ($9.75 per bushel) Feedstock cost adds $6.25 per gallon to the fuel production cost before co-product and federal tax credits ($6.75/gde) Yields for virgin oils and waste lipids range gallons/ton oil Non-feedstock production costs $ /gallon virgin oil $ /gallon waste grease 1 80 MGY/year capacity May 2008: Bay Area biodiesel price from local recycled oil: $4.74/gallon ($ /gallon, San Mateo County Times) 1.5 lb methanol (added in excess) Warm water wash 7.7 lbs soy oil React Methanol Flash 38.5 lbs Soybeans 30.5 lbs soybean meal Acid neutralization 1 gallon B100 biodiesel 0.6 lbs glycerine (52 gallons/ton) (32 lbs/ton) Salt

105 Renewable diesels: Biodiesel esters Hydrotreatment, hydrothermal upgrading of vegetable oils and animal fats, other lipids and esters (e.g. Shell, Neste, Petrobras) Fischer-Tropsch diesels from biomass FT diesels sulfur free Wide product spectrum including gasolines, diesels, alcohols, waxes, aviation fuels, higher value consumer products E-Diesels (ethanol-diesel blends) partially renewable if blending with petrodiesel Straight vegetable oils (engine warranty, coking, cold weather issues) Bio-oils (pyrolysis derived) Thermal depolymerization Differences in air emissions among fuels likely, limited data available on emerging fuels Biomass 105

106 Biodiesel (esters) Triacyglycerides (triglycerides) R 1, R 2, and R 3 represent the hydrocarbon chain of the fatty acid elements of the triglyceride. Biomass 106

107 Triglyceride and fatty acid structure Fatty acid chains extend from glycerol backbone Free fatty acids: Biomass 107

108 Fatty acid designation Fatty acids are designated by two numbers: the first number denotes the total number of carbon atoms in the fatty acid and the second is the number of double bonds. For example, 18:1 designates oleic acid which has 18 carbon atoms and one double bond. Biomass 108

109 Oil composition Oil or fat 14:0 16:0 18:0 18:1 18:2 18:3 20:0 22:1 Soybean Corn trace Peanut Olive trace Cottonseed trace Hi linoleic Safflower Hi Oleic Safflower Hi Oleic Rapeseed Hi Erucic Rapeseed Butter Lard Tallow Linseed Oil Tung Oil * Peterson, C.L., "Vegetable Oil as a Diesel Fuel: Status and Research Priorities," ASAE Transactions, V. 29, No. 5, Sep.-Oct. 1986, pp Linstromberg, W.W., Organic Chemistry, Second Edition, D.C. Heath and Company, Lexington, Mass., Biomass 109

110 Names of the fatty acids 14:0 Myristic Acid (tetradecanoic acid) 16:0 Palmitic Acid (hexadecanoic acid) 18:0 Stearic Acid (octadecanoic acid) 18:1 Oleic Acid 18:2 Linoleic Acid 18:3 Linolenic Acid 20:0 Arachidic Acid (eicosanoic acid) 22:1 Erucic Acid Biomass 110

111 Transesterification During transesterification, the triglyceride is reacted with alcohol in the presence of a catalyst, usually NaOH, KOH, or sodium silicate CH 2 OC=OR1 CHOC=OR2 + 3 CH 3OH CH 2 CO=OR3 (Triglyceride + methanol) CH 2 OH CH 3 COO -R1 CHOH + CH 3 COO -R2 CH 2 OH CH 3 COO -R3 (Glycerol + alkyl -esters) Biomass 111

112 Base-catalyzed reaction R1 backside attack RO > C=O O-CH2-CH-CH2-O-C=O O-C=O R3 KOH + ROH RO - + H 2 O Base + alcohol yields RO - The carbon on the ester of the triglyceride has a slight positive charge, and the oxygen has a slight negative charge, most of which is located on the oxygen in the double bond. This charge is what attracts the ROto the reaction site R2 Biomass 112

113 Base-catalyzed reaction R1 RO-C-O- (2e - ) O-CH2-CH-CH2-O-C=O Transition state has a pair of electrons from the C=O bond now located on the oxygen that was in the C=O bond O-C=O R3 R2 Biomass 113

114 Base-catalyzed reaction R1 RO-C=O + Ester formation and separation 2 additional RO - reactions at the other C=O groups -O-CH2-CH-CH2-O-C=O O-C=O R3 R2 Biomass 114

115 US Biodiesel Production Existing capacity 2.6 BGY Production = 460 MGY Planned capacity 850 MGY Source: NBB University of California, Davis

116 Supplemental Material Combustion Ash fouling and slagging Boilers Costs Emissions Standards Biomass 116

117 Problems in Biomass and Waste Combustion Inorganic transformations lead to rapid fouling of fireside surfaces in furnaces and boilers Slag formation on grates/agglomeration in Fluid Beds Increased corrosion/acid gas emission Increased maintenance, reduced capacity, reduced efficiency, reduced availability Alkali + silica + sulfur +chlorine + organics Complex Alkali-silicates, sulfates, chlorides, carbonates

118 Inorganic Material Behavior Potential for slagging, fouling, and agglomeration of fluid bed medium Higher risk with high-alkali herbaceous biomass Feedstock modification to reduce risk or use slagging reactors Back-scattered electron image Bleached zone Mullite Melt coating Mullite Slagging reactors developed specifically to slag the ash Slag viscosity important to slag removal...wayz Rice ash fragment Biomass 118

119 Fouling Deposits on Biomass Boiler Superheater Tubes

120 Rice Hull Slag

121 Straw-fired boilers Dust Collector 910 C European Cigar Burner Economizer Fuel 200 C Air Heater 690 C 640 C Primary Superheater Secondary Superheater Air Water-cooled Grate 650 C Ash Hopper

122 Maabjerg Plant, Denmark 28 MW electrical 68 MW thermal 135,000 tons/year of waste 28,000 tons/year of wood chips 35,000 tons/year of straw

123 COE (constant $/kwh) Cost of Electricity: Biomass Combined Heat and Power (CHP) California Natural Gas Price Range Value of Heat ($/MMBtu) CHP provides opportunities for low cost power Long utilized in forest products industry Matching generator to thermal host often difficult for large scale development

124 Straw-fired boiler modeling CHP Masnedø, Denmark 33 MWt/8MWe Wall heat fluxes (max -200 kw/m 2 ) Source: Kaer, S.K., Fuel 83: , 2004.

125 Oxygen Concentrations Source: Kaer, S.K., Fuel 83: , 2004.

126 Emissions Pollutant emission reductions for a 21.6 MW e (net) biomass power plant burning offset agricultural residue Species Power plant permit emission (Mg y -1 ) Power plant source test emissions (Mg y -1 ) Open burn emissions (Mg y -1 ) Reduction based on permit levels (Mg y -1 ) NMHC = non-methane hydrocarbons (reactive with NOx to form tropospheric ozone). Reduction based on source test (Mg y -1 ) PM10 = particulate matter in the respirable size range below 10 µm aerodynamic diameter. Reduction based on permit levels (%) Reduction based on source test (%) NMHC CO ,807 1,636 1, NOx SOx PM

127 Power Plant Virtual Tour

128 Air Quality, Siting, and Permitting Control of pollutants: Particulate Matter CO NOx SOx Hydrocarbons Lead and other metals Acid gases Hazardous air pollutants

129 Complete Hazardous Waste Combustion System Emission Control After-burners Quench tower Venturi scrubber (particulate matter) Packed column scrubber (acid gas) Ionizing wet scrubber (mist removal) Neutralization of acids

130 New Source Review NSR within AFC process following NOI Apply Best Available Control Technology (BACT) for emission control (CA BACT = Fed LAER, more stringent than Fed BACT) May require emission offsets Within 15 miles: Offset ratio of 1.3:1 (1.2:1 for CO, SOx, PM10) > 15 miles: 1.5:1 > 50 miles: > 1.5:1 Obtain Authority to Construct and Permit to Operate Also subject to CAA, NSPS and NESHAP* *Clean Air Act Amendments. New Source Performance Standards. National Emission Standards for Hazardous Air Pollutants

131 Ambient Air Quality Standards Pollutant Avg. Time California Federal Primary O 3 PM10 PM2.5 1 h 8 h Ann.Mean 24 h Ann.Mean 24 h 0.09 ppm 0.12 ppm 30 mg/m ppm 50 mg/m 3 50 mg/m mg/m 3 No separate standard 15 mg/m 3 65 mg/m 3 CO 1 h 20 ppm 35 ppm 8 h 9 ppm 9 ppm 8 h (Tahoe) 6 ppm NO 2 1 h 0.25 ppm Ann. Mean ppm

132 Ambient Air Quality Standards Pollutant Avg. Time California Federal Primary Pb SO 2 30 day Quarter 1 h 24 h Ann. Mean 1.5 mg/m mg/m ppm 0.04 ppm 0.14 ppm 0.03 ppm Vis. Red. PM 10 a.m. 6 p.m. 10 miles or more (<70% rh) none Sulfates 24 h 25 mg/m 3 none H 2 S 1 h 0.03 ppm none

133 Ozone Isopleth NO x (ppm as NO 2 ) Better to control ROG Better to control NO x Reactive Organic (ppmc)

134 BACT for Biomass (SJAPCD) 20.5 MW e /B&W on Ag Waste Pollutant Mass Emission Rate Destruction Efficiency (%) Method NOx 45 g/gj 75 Combustion air mgmt plus Thermal denox (no paper pulp, coffee grounds, MSW) SOx <0.069 kg S per 100 kg fuel 50 Limestone injection plus fuel mix controls PM g/nm 3 (99.9) Electrostatic Precipitator (ESP) VOC/ HC 21 g/gj Effective combustion CO 90 g/gj Effective Combustion

135 NOx control Combustion modifications Low-NOx burners Overfire air (staged air combustion) Reburning (staged fuel combustion, with or without promoter) Flue gas recirculation Operational modifications burners out of service (staged air combustion), low excess air, biased firing (staged fuel combustion)

136 NOx control Post-combustion treatment SCR: Selective catalytic reduction upstream ammonia injection with downstream catalyst bed up to 90% NOx reduction possible ammonia slip catalyst deactivation from fuel constituents, esp. sulfur SNCR: Selective Noncatalytic Reduction ammonia or urea injection into combustion products residence time and temperature are critical Hybrid systems Regenerative systems

137 Thermal DeNOx SNCR/Exxon Process NH 2 + NO = N 2 + OH NH 2 + NO = HN 2 + OH HN 2 + M = N 2 + H + M H + NH 3 = H 2 + NH 2 H + O 2 = OH + O O + NH 3 = OH + NH 2 OH + NH 3 = H 2 O + NH 2 Global reaction 6NO + 4NH 3 = 5N 2 + 6H 2 O Lyon, R.K., Exxon Research and Engineering/GE EER Temperature range C depends on H 2 injection (load following/lower temperature) Kohl and Nielsen, 1997, Gas Purification

138 SCR Selective Catalytic Reduction (SCR) Uses ammonia or urea injection into combustion gas as NOx reductant. Similar to selective non-catalytic reduction (SNCR, aka ammonia injection) except SCR employs a catalyst to increase reaction rate at lower temperatures. SCR is predominantly applied for stationary power generation, but is also considered for mobile applications. Chemistry: 4NO + 4NH 3 + O 2 = 4N 2 +6H 2 O 2NO 2 +4NH 3 + O 2 = 3N 2 + 6H 2 O Typically Uses Vanadium/Titanium Catalysts (titania stabilized vanadium oxide) or zeolites Undesirable sulfate reactions if sulfur present in fuel: SO 2 + ½O 2 = SO 3 2NH 3 + SO 3 + H 2 O = (NH 4 ) 2 SO 4 (ammonium sulfate) NH 3 + SO 3 + H 2 O = NH 4 HSO 4 (ammonium bisulfate) Urea (CH 2 CONH 2 ) is the principal nitrogenous reactant considered for mobile or vehicle applications but requires a new chemical supply infrastructure. Urea decomposes to ammonia and carbon dioxide in hot combustion gas before catalyst and reactions proceed as for ammonia above.

139 California BACT: Simple Cycle Gas Turbines

140 California BACT for Combined Cycles

141 2,3,7,8-tetrachlorinated dibenzo-p-dioxin Cl Cl O O Cl Cl

142 Dioxins and Dibenzofurans EPA estimates ambient concentrations of 0.04 pg/m3 California production rates Dioxins: 2 kg/year Furans: 28 kg/year Dioxins occur naturally due to forest fires and volcanoes, most produced from anthropogenic sources involving fuel burning Formed by combustion when Cl and complex mixtures containing C are present Many sources including wood stoves, municipal waste incinerators, combustion of PCB and chlorinated plastics

143 California Dioxin Emission Limits for Waste Incinerators Must reduce emissions by 99% Must reduce emission below 10 ng/kg waste burned Flue gas temperature at outlet of emission control equipment not higher than 149 C Single chamber combustor maintained above 982±93 C Multi-chamber: Primary chamber >760 C, secondary chamber > 982±93 C Residence time of at least 1 second

144 Power Plant Permitting: CEQA Processes CEQA Lead Agency Permitting 12-month Application For Certification (AFC) process produces EIR- equiv. doc Small Power Plant Exemption Mitigated Negative Declaration using Initial Study (with CEQA checklist) Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

145 California Environmental Quality Act Processes Local Lead Agency Permitting Initial Study (CEQA Checklist) by City or County Planning/Community Development staff Or air district Types of environmental documents Negative Declaration Mitigated Negative Declaration Environmental Impact Report (EIR) Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

146 Permitting Processes CEC Consolidated Local Agency Permit Process Permitting Power Plant Power Plant Roads Thermal Municipal Utility or > 50 megawatts CPUC Transmission Lines Transmission line Power plant to grid Gas Line Related Facilities Air District Water line Water Agency Wastewater line Water line Gas lines and roads Wastewater Agency Wastewater line Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

147 Small Power Plant Exemption Purpose Commission provides an Exemption from its process Projects 50 to 100 MW Project developer s option to seek this exemption rather than filing an AFC No significant adverse environmental impacts No significant adverse energy system impacts CEC approves Mitigated Negative Declaration Local, state, and federal agencies issue permits Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

148 Power Plant and Ethanol Facility Case Study Key issues Air quality Threatened and endangered (T&E) species habitat loss - Water supply/ groundwater depletion - Flood protection Noise Reliability of biomass (rice straw, etc.) emission reduction credits Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

149 Frequent Project Permitting Issues Air quality impacts - Availability of air emission offsets Public health and safety concerns Water supply (use of fresh or recycled water or dry/air cooling) Transmission system interconnection study for congestion or overload Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

150 Frequent Project Permitting Issues Biological resource impacts Land use plans / standards / zoning Adequate and reliable long-term fuel source Environmental justice Why in my community? Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

151 Recommendations Site Developer Agencies Have proper zoning Know project Know process Have "local" offsets Clear internal comm. Be flexible Use dry/air cooling Open communication Open communication Have site control Be flexible Solve problems Minimize linear facil. Accept responsibility Be consistent Avoid T&E species Know impacts Listen to public Avoid TL congestion Know community Be creative Source: Eileen Allen, Energy Facilities Siting Program Manager, California Energy Commission

152 Supplemental Material Gasification Advantages Constraints Predicting gas composition Equilibrium analysis Kinetics Biomass 152

153 Advantages of Gasification Produces fuel gas for more versatile application in power generation and chemical synthesis. Potential for higher efficiency conversion using integrated gasifier combined cycles compared with conventional Rankine steam cycle power systems. Typically lower reaction temperatures than direct combustion thus decreases potential alkali volatilization, fouling, slagging, and bed agglomeration (fluidized beds) although for high alkali, high ash fuels such as manure, slagging and bed agglomeration can be problems. Can also reduce heavy metal volatilization. Lower volume of gas requiring treatment to reduce NOx and SOx emissions compared to combustion flue gas. Fuel nitrogen evolved principally as NH 3 and sulfur as H 2 S, more readily removed than NOx and SO 2 in combustion systems. Applications for power generation at smaller scales than direct combustion systems although gas cleaning is primary concern and expense