biomass energy: a crash course

Biomass Energy: A Crash Course

Peter Flynn

Poole Chair in Management for Engineers

Dept. of Mechanical Engineering

University of Alberta

U of A Energy Club: February 2009 2

Opening Thoughts Society will likely have limits on its

willingness to spend given that the problem is in the future.

What we get for the dollar spent varies widely.

The head needs to help the heart get the most environmental benefit per dollar spent.


1. Biomass is Carbon Neutral

The carbon it emits is taken up in regrowth of the plant.

If the biomass was not converted, it would rot and make CO2 anyway.

Hence, it displaces coal or oil.


2. Alberta Has Lots of It

Straw and forest harvest residues are annual crops.

Straw alone could supply the next 25% of Alberta’s total power usage.


2A. And May Have Much More


3. The Technology Exists Today: Power at Large Scale


3. The Technology Exists Today: Ethanol at Commercial Scale Grain to ethanol is long established:

WhiskeyCorn to fuel grade ethanolBarley and wheat in Alberta

Six commercial scale lignocellulosic ethanol plants announced in the US, including Iogen


3A. Whole Grain to Ethanol is a Poor Choice Competition

between food and fuel impacts the whole world.

Poor energy yield, high impact on soil and water quality.


3A. Lignocellulosic Ethanol

Lignocelluosic residues (straw/ stover and wood) are available waste products.

Purpose grown crops on marginal lands are also possible.


4. Research Isn’t the Correct Prime Focus Research can be misused as a tool to

postpone difficult choices.

Technologies exist today.

Alberta has a particular need for action.


5. Renewable Energy is not and never will be “Competitive” We have used fossil fuels because they

are cheaper. Competitiveness isn’t the key question: we

are paying more for an environmental gain. Someone must pay.

The key objective is to buy the most greenhouse gas out of the atmosphere

at the lowest extra cost.

The key objective is to buy the most greenhouse gas out of the atmosphere

at the lowest extra cost.


6. Technologies are Not Equal..

The cost per unit of energy output and per tonne of avoided CO2eq varies widely with technology and plant size.

Power from straw: ~$75 per MWh Power from manure: ~$200 per MWh

The minimum screen for any technology is “how much grant per tonne of CO2 avoided?

The minimum screen for any technology is “how much grant per tonne of CO2 avoided?


And Can Be Studied in Detail

For each technology:What is the appropriate size of plant?How much CO2 equivalent is avoided?

Life cycle analysis need not be the complicated barrier it has morphed into.

How much extra does someone pay compared to a business as usual case.

Minimizing extra $ per tonne of avoided emission is the right metric.

Minimizing extra $ per tonne of avoided emission is the right metric.


7. There is an Optimum Size; it is Large Three elements to producing useful

energy from biomass:Get the biomassMove it to siteProcess it

Processing cost decreases with size, transport cost increases.


Cost Per Unit Output

Plant Size, e.g. MW

Co

st

pe

r U

nit

Ou

tpu

t, e

.g.

$/M

Wh

First Cost of Biomass

Can be positive (purchased) or negative (avoided cost)

Can be positive (purchased) or negative (avoided cost)


Biomass Transportation by Truck

Costs include:Loading and unloading: distance fixed.Shipping: distance (scale) variable.

Typical values are $5 per tonne (distance fixed) and $0.09 per tonne km (one way) (distance variable).

Increases ~ with (scale)1/2.


Distance Fixed vs. Distance Variable Costs

Only DVC affects scale

Only DVC affects scale



Plant Size, e.g. MW

Co

st p

er U

nit

Ou

tpu

t, e

.g.

$/M

Wh

Field cost of biomass

Transportation cost

Total delivered cost of biomass


Other Modes are Available:

Pipeline (for liquid based processing only): high economy of scale, economic at sizes greater than 1 M Dry T/yr.

Rail: fixed cost of trans-shipment requires minimum economic shipping distance.


Trans-Shipment: the Concept


Trans-shipment: Alberta Based Straw Power Plant

c = 0.1309d + 4.76

c = 0.0277d + 26.901

0

5

10

15

20

25

30

35

40

0 50 100 150 200 250 300 350

Distance (km)

Tra

nsp

ort

atio

n C

ost

of

Bio

mas

s ($

/dry

to

nn

e)

Truck only

Truck plus rail

Minimum economic

rail shipping distance exceeds

draw area: rail is not economic.

Minimum economic

rail shipping distance exceeds

draw area: rail is not economic.


Biomass Processing: Use It

Economy of scale in capital equipment and operating costs, typical scale factors in the range of 0.6 to 0.8.

All evidence is that scale factor is valid up to very large processing sizes (>500 MW); road congestion limit is the prior constraint if delivery by truck.


Scale factor for Manure AD Plants

y = 147,870 x0.60

y = 360,280 x0.56

y = 323,862 x0.56

$0

$4,000

$8,000

$12,000

$16,000

0 200 400 600 800 1,000 1,200 1,400 1,600

Th

ou

san

ds

Biomass Input (m3/day)

Cap

ita

l Co

sts

(20

05

US

D)


$-

$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500

$4,000

0 100 200 300 400 500 600 700

Net Power Output (MWe)

Cap

ital C

ost (

$/kW

)

Biomass

US DOE Coal FacilitiesRadian Corporation

Castleman

Uddin & Barreto

US DOE

Caputo et al.

Kumar et al.

Alholmens Scrubbed New Coal

Subcritical Coal

Pulverized Supercritical Coal

Data Consistency VariesDirect Combustion to power has been widely

applied including very large scale plants.


Hence Good Fit for Processing Cost Estimate: Direct Combustion

y = 150 x-0.3

R2 = 0.78

$0

$10

$20

$30

$40

$50

$60

$70

$80

0 50 100 150 200 250 300 350 400 450

Capacity (MWe)

Pro

cess

ing

Cos

t (2

006U

SD

/M

Wh

)

Radian Corporation

Kumar et al.Castleman

Uddin and BarretoCaputo et al.


$-

$0.50

$1.00

$1.50

$2.00

$2.50

$3.00

$3.50

$4.00

$4.50

0 1000 2000 3000 4000 5000 6000 7000

Capacity (ML/yr)

Cap

ital C

ost (

2006

US

D/L

/yr)

$-

$0.20

$0.40

$0.60

$0.80

$1.00

$1.20

$1.40

$1.60

$1.80

$2.00

Cap

ital C

ost (

2006

US

D/b

bl /d

)

Coal

Biomass

Natural Gas, increased by60% (see Boerrigter 2006)

Wright & Brown

Boerrigter

ExxonBechtel & Mann

US DOE

Gray & Tomlinson

Gradassi

Syntroleum

US DOE

Choren

Yamashita et al.

Hamelinck et al.

Boerrigter & ZwartLarson et al.

Gray & Tomlinson

Boerrigter

US DOE

Boerrigter

Hamelinck et al.

Yamashita et al.

Wide Scatter in Other ProcessesFischer Tropsch estimates show wide scatter only

partly due to configuration options



Plant Size, e.g. MW

Co

st p

er U

nit

Ou

tpu

t, e

.g.

$/M

Wh


Transportation cost


Operating cost

Capital cost

Total plant processing cost



Plant Size, e.g. MW

Co

st p

er U

nit

Ou

tpu

t, e

.g.

$/M

Wh


Transportation cost


Operating cost

Capital cost

Total unit output cost

Total plant processing cost


Power from Field Sourced Biomass in Alberta

Plant Size vs Power Price

0

20

40

60

80

100

0 500 1000 1500 2000

Plant Size (MW)

Po

wer

Pri

ce (

year

200

0 U

SD

$ / M

WH

)

Whole ForestWood ResiduesStraw


Optimum Size

Increases with increasing processing cost

Increases with increasing biomass availability

Is neutral to the field cost of biomass


Optimum Size Depends on Biomass Gross Yield and Processing Cost


The Optimum is “Flat”A 3% relaxation in the criterion of minimum

cost drops plant size sharply.


50% of Optimum Size Has Minimal Impact, But the Cost Climbs Sharply Thereafter

Power from straw in Alberta: $75 per MWh at optimum (330 MW net) $77 per MWh at 50% of optimum $100 per MWh at 25% of optimum $125 per MWh at 10% of optimum $145 per MWh at 5% of optimum


Power from Field Sourced Biomass in Alberta Straw to Power: >150 MW

FHR to Power: >100 MW

Lignocellulosic Ethanol: >3000 TPD

Power from Manure: county wide plant.


8.Life Cycle Analysis of Emissions

For most biomass plants the replacement of fossil fuel is the overwhelming contributor.

Processing related emissions tend to equalize.

Transport and refining are relatively small and estimates vary widely.


LCA Values, CO2eq

Base load power vs. coal: 830 g/hWh, 1350 g/dry tonne of biomass.

Ethanol or diesel: 2000 – 2400 g/l, 600 g/dry tonne of biomass.

Power from manure (methane avoidance a factor): 900 g/kWh.


9. Put Cost and Avoided Emissions Together How much extra does someone (the

consumer or taxpayer) pay?

How much emission is avoided.

Pick the most cost effective process.


Two key technology questions

For a given end form of energy, e.g. power or transportation fuel, what is the most efficient technology. (This will depend on the abundance of biomass, since low availability = higher delivered cost).

Between two end forms of energy, what should I pick.


Gasification vs. Direct Combustion

-$100

-$80

-$60

-$40

-$20

$0

$20

$40

$60

$80

$100

$0 $20 $40 $60 $80 $100 $120 $140 $160

Power Price ($ MWh-1)

Ca

rbo

n C

red

it ($

t-1

CO

2 e) Direct Combustion

BIGCC

As straw availability drops, the required carbon credit increases faster for direct combustion than BIGCC. The crossover

is beyond any point of real interest.

~ Current power price in Alberta


Ethanol vs. FT Diesel

-$300

-$200

-$100

$-

$100

$200

$40 $60 $80 $100 $120 $140 $160 $180

Crude Oil Price ($ bbl-1)

Car

bon

Cre

dit R

equi

red

($

t CO

2 e-1

) Ethanol

FT using best fit

FT using fitted model

Oil price range, 2008 to 2009

As straw availability drops, the required carbon credit increases faster for ethanol than FT diesel.


Picking the End Energy Form

$-

$20

$40

$60

$80

$100

$120

$140

$- $10 $20 $30 $40 $50 $60 $70 $80 $90 $100

Power Price (2006 USD MWh-1)

Oil

Pirc

e (2

006

US

D b

bl-1

)

Power Production via Direct Combustion Favored

Ethanol Production Favored

June 2008

October 2005

June 2002

Above an oil price of $80.3 per bbl, no carbon

credit is required for a 12% return

Above a power price of $73.9 per MWh, no carbon credit is required for a 12% return


Some Cautions

Some technologies are far better demonstrated than others, hence more confidence in cost.

All cost estimates rely on pre 2006 references, and hence miss the upswing in equipment and labor cost. The future of these costs is uncertain.


10. Policy Comes in Good and Bad Flavors Jurisdictions around the world are

wrestling with how to integrate a more expensive form of energy into an existing energy economy.

Some do it better than others.


Bad Policy

“Man on the moon” targets obscure social costs.

Short term “up front” payments. Higher payment to small scale projects. Doing everything with every source

(makes as much sense as making electricity from gasoline).


Good Policy

Does not, for a global warming target, specify the end product of bioenergy.

Is long term Allows competition between projects to

meet a social goal at the lowest cost. Identifies the cost per tonne of avoided

CO2eq.


For Biomass Energy to Grow:

Drayton Valley, AB: 12 MW

Alholmens, Finland: 240 MW

biomass energy: a crash course

Documents

energy club

biomass energy

useful energy

renewable energy

unit of energy output

poor energy yield

cost of biomasscan

lowest extra cost