WOOD 120
Bio-energy
1
The “Bio-Buzzwords”
• Bio-energy
• Bio-mass
• Bio-fuels
• Bio-diesel
2
Past practice in BC
Beehive burners
Sawmill waste (hog fuel) was burned without
capturing heat value.
Now sawmill waste is burned to heat the dry kilns.
3
Forms of Energy
• Electricity
• Transportation fuel
• Heat
4
Forms of Energy
• Solid
• Liquid
• Gas
Fossil fuels (the simple slide)
CO2
Fossil Fuels
6
Bioenergy (the simple slide)
CO2
Biomass
Fossil Fuels
reduce
7
Bioenergy (the more complicated slide)
8
Bioenergy – drivers
• Climate change
• Shortages of traditional energy sources
• Costs of traditional energy sources
• Energy security
• Landfill reduction
• Mountain Pine Beetle (BC-specific)
9
Biomass – sources
• Grain
• Straw
• Grass
• Sugar cane (bagasse)
• Wood (lignocellulose)
10
Wood vs. other cellulosic biomasses
• Longer storage life and lower storage costs
• Higher bulk density
• Less intensive use of water and fertilizer in its
growth
• Established collection system exists
11
Transportation
12
GJ per unit
Energy density of materials
13
Bioenergy – technology platforms
•
•
•
•
Wood pellets
Gasification
Bio-ethanol
Direct combustion
14
Bio-fuel status in BC
www.energyplan.gov.bc.ca
15
Wood Pellets
• Sawmill waste extruded
into small pellets.
• Either burned directly for
heat value or for
generation of electricity
• Used domestically (N.A.)
and industrially (Europe)
16
Wood Pellets
• Waste may be ground to
consistent, fine size.
• Pressed through pelletizer
to consolidate.
• Pellets are held together
by natural “adhesive” in
wood (lignin).
• Pellets are denser than
starting material.
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Wood Pellet Stove
1 – Hopper
2 – Convection fan
3 – Auger
4 – Ash pan
5 – Igniter
6 – Heat exchange tubes
7 – Burn chamber
www.pelprostoves.com/images/pelpro-cutaway.jpg
18
Pellet plants in BC (2011)
• 8 plants
• 787,000 tonnes
production
• Plant capacity
56-186,000 tonnes
• Used 2.2 million m3 of
wood residues
• 10% of global market
Liquid biofuels
• Bio-ethanol (one example)
• Currently produced from grain (in NA)
• Blended with gasoline
• Gasoline:ethanol 90:10
• Reduces carbon monoxide emissions
20
Wood Chemistry
WOOD
Holocellulose
Cellulose
Lignin(s)
Extractives
Ash
Hemicellulose(s)
21
Bioethanol from wood waste
Burn
Solid
material
Wood
Enzymes
Solid
residue
New
products?
Pretreatment
Sugars in
solution
Fermentation
Alcohol
22
Comparsion of bio-fuel feedstocks
23
Conversion of biomass sources
LIGNOCELLULOSE
Pretreatment
Fractionation
Fractionation
Fractionation
Enzymatic
Hydrolysis
Enzymatic
Hydrolysis
Hexoses
Hexoses
Hemicellulose
Pretreatment
Cellulose
Pretreatment
Hexoses
Pentoses
Fermentation
Fermentation
Fermentation
Recovery
Recovery
Recovery
BIOFUELS
BIOENERGY
BIOPRODUCTS
Extractives
STARCH
Lignin
SUGAR
Bio-ethanol from wood
• Wood is hard to break down
into chemical components
• High cost of enzymes
• Products need to be
developed utilizing solid residue (lignin)
• Rate of development of technology is
influenced by price of oil
25
Gasification
• Burns biomass with
controlled amount of
oxygen
• Converts biomass into
carbon monoxide and
hydrogen
• Results in “syngas” which is
itself a fuel
www.nexterra.ca/i_mages2/Gasifier.jpg
26
Gasification
• Cleaner and more efficient
technology than direct
conversion of biomass
• Syngas can be burned on
site (for production of
electricity) or transported
(increase in energy density)
http://www.sc.edu/usctimes/articles/2005-02/images/gasification.jpg
27
Gasification plant at UBC
• Opened in September 2012
• 25,000 tonnes of urban wood waste per year from
Metro Vancouver
• Generation of steam and electricity
• Low pressure steam (15% reduction of natural gas
used for heating on UBC campus)
• Electricity generation (2MW, demonstration scale)
• GHG reduction of 5,000 tonnes/year*
28
Gasification plant at UBC
Photo credits: Don Erhardt
29
Gasification plant at UBC
(Nexterra)
30
Electricity generation
Raw
material ?
31
Cogeneration plant
•
•
•
•
William’s Lake, BC
Established in 1993
60 MW capacity
Electricity feeds into
BC Hydro grid
• Burns wood waste
(600,000 tonnes/year)
• 4-5 local sawmills provide wood waste
(combined capacity of 1 billion fbm)
• High efficiency combustion
32
Looking back and forward…??
log (primary energy use) by category
Hydrocarbon
economy
Biomass
& renewables
2020
2000
1980
1940
Oil & Gas
1920
1900
1860
1820
1780
1740
1700
Coal
2100
Industrial
revolution
2080
Agricultural-based
1990-21??
2060
1800-2050
2040
??-1800
Carbohydrate
economy
1960
Carbohydrate
economy
Current Status of Bio-Energy Technologies
Gasification
34
Bio-energy - issues
• Government policies (e.g., tax
credits? R&D incentives?)
• Competing green technologies
(e.g., wind, wave, geothermal)
• Competing bio-energy
technology platforms still being
developed
• Competing new fosil fuel
capcaity in North America
• Food vs. Fuel vs. Fibre