Bioenergy: Development Challenges

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Bioenergy Development Challenges ACRE Seminar
Sustainability of Renewables Policy and
Practice UNSW, 26 July 2001
Dr Stephen Schuck Bioenergy Australia
Manager Email sschuck_at_bigpond.net.au Tel/Fax
[phone] www.users.bigpond.net.
au/bioenergyaustralia
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• Presentation Outline
• Biomass as a sustainable energy source
• Bioenergy technology options
• Barriers and Drivers
• Plant and project examples

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• What is Biomass?
• Product of photosynthesis
• solar energy atmospheric carbon dioxide ?
  biomass
• i.e. stored solar energy
• World-wide photosynthesis produces about 220
  billion dry tonnes/a (as an energy source about
  ten times worlds current energy usage)
• Globally biomass accounts for 14 energy
  supply
• Sweden and Austria 14 of energy
• Australia lt 5 of energy.

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Life Cycle Emissions in Practice

• 95 - 135 carbon dioxide loop closure
• or
• -410g/kWh to 50 g/kWh carbon dioxide emission on
  a life cycle basis for typical bioenergy systems
• or
• 1 J fossil fuel produces between 16 and 28 J
  electrical energy via bioenergy path.

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Source IEA Bioenergy Task 38
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Life Cycle Emissions of Various Technologies
g/kWh CO2 SO2 NOx

• Black Coal 955 11.8 4.3
• Gas CCGT 446 0.0 0.5
• Bioenergy
• Straw - steam cycle 13 0.88 1.55
• Forestry residues steam cycle 29 0.11 1.95
• Forestry residues gasification 24 0.06 0.57
• Poultry litter gasification 8 1.67 2.68
• Animal slurries anaerobic digestion
  31 1.12 2.38
• Landfill gas 49 0.34 2.60
• Sewage gas 4 1.13 2.01
• MSW incineration 364 2.54 3.30
• Other renewables
• Decentralised PV new homes 178 2.03 0.70
• Wind on shore 9 0.06 0.02
• Hydro existing large 32 0.04 0.02
• Source IEA

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Biomass Conversion Technologies

• Combustion (full oxidation)
• - 90 of bioenergy plants
• Gasification (partial oxidation)
• - combustible gas of CO, H2, CH4,
• - gas engines, gas turbines, BIGCC, Stirling
  engines,
• fuel cells.
• - chemical feedstock for methanol, ethanol
• Pyrolysis (starved oxygen)
• - bio-oils, gaseous products and char
• Anaerobic digestion
• - landfill, covered ponds, plug flow reactors
  for combustible gas of methane and CO2
• Biodiesel for powering generators.

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Tracy Biomass Plant, California
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Co-firing trial at Delta Electricitys
Wallerawang Power Station
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Gasification

• Range of technologies, manufacturers, size plants
• Air blown, oxygen blown, steam gasification
• Directly heated and indirectly heated processes
• Atmospheric pressure and pressurised systems
• Move towards Biomass Integrated Gasification
  Combined Cycle (BIGCC plants)
• Local examples Brightstar Environmental,
  Waterwide close coupled gasifier
• Overseas examples Varnamo, ARBRE, FERCO/Battelle

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AMER Centraal gasifier co-firing adjacent 900 MW
unit
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AMER Centraal FBC gasifier - Netherlands
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ARBRE 10 MWe BIGCC Plant, York, UK.
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• Model of ARBRE plant
• 8 MW export to grid
• Fuel coppiced willow
• Gas 5.4 MJ/m3
• Atmospheric FB gasifier
• Overall thermal efficiency 31
• GT shaft speed 17000 rpm
• Steam turbine 8500 rpm
• Four pole generator

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Short rotation willow
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ARBRE Gasifier Ash disposal
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Small scale biomass gasifier and generator set
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Pyrolysis of Biomass

• Flash pyrolysis 70 wt liquid products (char
  lt5)
• Combustible bio-oil substitution for
  conventional fuels
• Heating value approx. 40 of fuel oil or diesel
  on weight basis and 60 on a volume basis
• Does not mix with hydrocarbon fuels
• Not as stable as fossil fuels
• pH 2.5
• HHV as produced 16-19 MJ/kg
• 2.5 MWe Orenda gas turbine has run on bio-oil
• 20 MW of NFFO projects based on pyrolysis oil

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Anaerobic Digestion

• Landfill gas
• Bioreactor cells
• Plug flow reactors
• Covered lagoons
• Project Examples
• Earthpower Technologies, Camellia NSW
• Werribee sewage treatment plant
• Berrybank pig farm
• Combustible gas 45-70 CH4, balance mainly CO2

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Anaerobic Digestion

• Breakdown of organic matter by bacteria in
  absence of air
• Net producer of renewable energy
  (biogas/electricity)
• Composting net user of energy
• Biogas energy 21-27 MJ/m3

Biogas 2-4
7-25 Fibre (Conditioner)
100
AD process
96-98
Separator
Digestate
Feedstock
75-93 liquor fertigation
AD Mass Balance
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Example of Centralised Biogas Plant (Denmark)
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Eligible Bioenergy Sources Under MRET

• Bagasse co-generation
• Black liquor
• Wood waste
• Energy crops
• Crop waste
• Food and agricultural wet waste
• Landfill gas
• Municipal solid waste combustion
• Sewage gas
• Co-firing
• Fuel cells
• Waste products derived from fossil fuels
  ineligible

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Bioenergy Drivers

• Greenhouse gas mitigation
• Management and use of wastes
• Industry development and export opportunities
• Jobs and income from a new industry
• Local source of dispatchable energy (import
  replayment)
• Local environment (e.g. odour control)
• Co-values (Landcare, biodiversity, co-products)
• New market for residues
• Opens way for energy crops (carbohydrate economy)
• Improved efficiency with new technologies (e.g.
  gasifiers)

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• Development Challenges for Biomass Energy
• Resource security
• Use of native forest residues and restriction on
  plantations
• Perceptions (thermal processing incineration)
• Capturing all the values (e.g. waste processing,
  co-products, co-values, green pricing)
• Adequate return on investment
• Low energy density of fuel (50 energy cost can
  be in fuel)
• Low calorific value of fuels
• Wet fuels (need for drying)
• Need for and effect on water
• Ash (way better than coal)
• Seasonality and storage of biofuels
• Need for ongoing development of technologies
• RD funding and support.

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Project examples in Australia (1)
Brightstar Environmental's green and
municipal waste projects Rocky Point Sugar
Mill and other Stanwell Corporation
projects Envirostar Energys projects
including 21 MW at Stapylton, Gold
Coast Delta Electricity's 100 MW wood/bagasse
in NSW Co-firing wood at Liddell, Muja and
Wallerawang Power Stations Co-firing
biogas at Swanbank Power Station, Qld Clean
Green Energy Cos studies for 30 MW bioenergy
plants Western Power Corporations oil mallee
project (1MW initially) RECL project at
Dormit, Victoria
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Project examples (2) Visys 17 MW
co-generation plant at Tumut 30 MW
waste-to-energy plant at Brighton, Tasmania
Auspines 60 MW bioenergy plant at Tarpeena,
S.A. Stanwell/Ricegrowers Cooperatives 10 MW
rice husk project at Deniliquin NSW
Thiess 7 MWrice fired gas turbine at Leeton,
NSW 10 MW Blair Fox chicken litter project in
WA 3 MW sewage gas at Malabar, Sydney
Microturbine project at Wagga Wagga using
digester gas
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Bioenergy Development Challenges ACRE Seminar
Sustainability of Renewables Policy and
Practice UNSW, 26 July 2001
Dr Stephen Schuck Bioenergy Australia
Manager Email sschuck_at_bigpond.net.au Tel/Fax
[phone] www.users.bigpond.net.
au/bioenergyaustralia