Ross Salawitch

Class Web Site: http://www.atmos.umd.edu/~rjs/class/spr2011

Topic for today:

• A discussion of the pros and cons of various aspects of meeting

the energy needs of society by means of combustion of biomass,

biofuels, and biowaste

Renewable Energy II:Biofuels, Ethanol, Methanol, and Algae

Lecture 22

28 April 2011

1Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Course Logistics

• Problem Set #5 posted− Due Thursday, 28 April (best to not wait until Wed night to start)

• Problem Set #6 posted

− Assigned only to undergraduate students; due Thurs, 5 May

− 10 point per day penalty for late receipt, with hard cut off of noon, Mon, 9 May

− Evaluated by not knowing name of student (i.e., anonymously)

• Course evaluation now open:

− Everyone encouraged to participate in evaluation of this course at:https://www.courseevalum.umd.edu/portal (open now to 11 May)

− Info about this system at:https://www.irpa.umd.edu/Assessment/CourseEval/fac_faq.shtml

• Problem Set #5 posted− Due Thursday, 28 April (best to not wait until Wed night to start)

• Problem Set #6 posted

− Assigned only to undergraduate students; due Thurs, 5 May

− 10 point per day penalty for late receipt, with hard cut off of noon, Mon, 9 May

− Evaluated by not knowing name of student (i.e., anonymously)

• Course evaluation now open:

− Everyone encouraged to participate in evaluation of this course at:https://www.courseevalum.umd.edu/portal (open now to 11 May)

− Info about this system at:https://www.irpa.umd.edu/Assessment/CourseEval/fac_faq.shtml

• Final Exam

− Monday, 16 May, 10:30 am to 12:30 pm

− This room− Format similar to prior exams− Closed book, no notes− Perhaps slight emphasis on material covered since last exam, but

entire course will be covered on the final exam

− We’ll be present to answer any questions

− Have scheduled an evening review for Monday, 9 May

Three of the responses to Problem Set #6 will be presentedat this evening review (by student if present or by instructor)

2Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Nevada Solar One

Nevada Solar One

Output: 64 MW capacity / 134,000 MW-hr / year

Could supply all US electricity needsif built over a ~ 130 mile × 130 mile area

Construction cost: ~$2 / kW-hr for one yr’s prod

Size of Nevada Solar One:

Project site is ~ 0.6 mi² (0.77×0.77 mi); solar collectors cover 0.45 mi²

http://en.wikipedia.org/wiki/Nevada_Solar_One

US Electricity Consumption, 2011 = 3,741,485,000 MW-hrhttp://en.wikipedia.org/wiki/List_of_countries_by_electric_energy_consumption

To meet US Electricity Consumption, need a site size of:3,741,485,000 MW-hr /134,000 MW-hr × 0.6 mi² = 16,752.9 mi2 or 130×130 mi

3Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

4Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Nuclear

6.8% Nuclear

14.5%

Olah et al., Beyond Oil and Gas: The Methanol Economy, 2006.

World Energy World Electricity

Nuclear

6.8% Nuclear

14.5%

Olah et al., Beyond Oil and Gas: The Methanol Economy, 2006.

World Energy World Electricity

Nuclear

6.8% Nuclear

14.5%

Olah et al., Beyond Oil and Gas: The Methanol Economy, 2006.

World Energy World Electricity

Nuclear

6.8% Nuclear

14.5%

Olah et al., Beyond Oil and Gas: The Methanol Economy, 2006.

World Energy World Electricity

SURYA – Sanskrit for Sun

• 65 villages (6500 homes) covering 1500 km2, where mostresidents use wood for cooking, will be provided with eithersolar and/or biogas burners

• Air quality, soot, and particulates will be monitored for 6 months priorto installation of alternate cookers and for at least 1 year subsequent

• Indoor air quality will be measured in selected homes

• Outdoor air quality will also be monitored using NASA satellite instruments

• PI: V. Ramanathan, Scripps

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http://www.projectsurya.org

http://www.nytimes.com/2009/04/16/science/earth/16degrees.html?_r=3&ref=earth

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Electricity from Biomass

Olah et al., Beyond Oil and Gas: The Methanol Economy, 2006.

7Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Electricity from Biomass: Overview

• Plant size average 20 MW

• Efficiencies range from 15 to 30% (electricity only) to 60% (electricity + heat)− co-firing uses biomass to supplement fossil fuel

• Use wood, agricultural residues, and municipal waste

• ~140 plants in U.S.: emissions generally fine

• Addresses energy need and growing “mountain of waste”:− waste converted to CO2 and water; unburned residue about 10% of initial volume− iron-containing metals often recovered and recycled

Chemistry in Context

8Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Electricity from Waste: Pyrolysis

Dvirka and Harrington, Proceeding National Waste Processing Conf, ASME, 1980.

• Opened in 1975

• Waste shredded and separated into organic and inorganic components

• Inorganic material separated and recycled

• Organic material heated in a controlled, oxygen deficient environment (preventscombustion) initiating conversion to various substances, including fuel

• Closed Feb 1977

See “The Search for the Good in Garbage: A Look at Wichita’s Own Pyrolysis Pilot Plant and the History of the

Resource Recovery Movement …” , Angela Gumm, Masters Dissertation, Wichita State Univ, 2006.

http://soar.wichita.edu/dspace/pdfpreview/bitstream/handle/10057/647/t06124.pdf

9Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Electricity from Waste

• Opened in 1984

• Site of old pyrolysis plant

• Burns 2,250 tons of trash per day

• Metals recovered; volume of trash reduced by factor of 10

• Can generate 60,000 kW of electricity 60 MW (2700 × size of UP solar array &6% capacity nuclear plant)

• Heat used for direct steam heating / cooling downtown Baltimore

• One of 16 such plants in the U.S.

Baltimore RESCO (Refuse Energy Systems Company) Plant

Russell Street & U.S Interstate 95 (shadow of Ravens Stadium)

http://yeroc.us/wte-db

http://www.eia.doe.gov/kids/energy.cfm?page=RESCOE_Plant

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Ethanol

• Ethanol : C2H5OH

• Alcohol

• C6H12O6 → 2 C2H5OH + 2 CO2 ( Hf = 228 kJ/mol or 5 kJ/g)

• Reaction catalyzed by enzymes; theoretically, can be close to carbon neutral

• Ethanol combustion:

C2H5OH + 3 O2 → 2 CO2 + 2 H2O + 29.7 kJ/g

Heat release less than combustion of C8H18 (47.8 kJ/g) because C2H5OH

is already partially oxidized

• However … ethanol has a higher octane than gasoline

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Ethanol Production

• U.S.: Ethanol produced from corn

• Brazil: Ethanol produced from sugar cane, which thrives in tropical climate

Olah et al., Beyond Oil and Gas:

The Methanol Economy, 2006.

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Ethanol Production: Good News

http://www.eoearth.org/article/Energy_profile_of_Brazil

• Brazil: Ethanol produced from sugar cane, which thrives in tropical climate− energy to convert sugar to ethanol supplied by burning bagasse (sugar cane husk)

• About half cars in Brazil are “flex fuel vehicles (FFV)”− can run on 100 percent ethanol or any ethanol-gasoline mixture.

• Ethanol accounts for ~40% of non-diesel fuel use

Bad News: Annual Brazil ethanol production < 1 day world petroleum consumption

13Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Ethanol Production: Really Bad News

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Ethanol Production

• McElroy article suggests considering refinement cost, transportation cost, andenergy content of ethanol, “the energy captured in the ethanol exceeds the fossilenergy consumed in its production by no more than ~25 %”

• McElroy did not consider ______________

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Ethanol Production

• Raging debate over “green” aspects of both sugar and corn based biofuels:

Excellent point/counterpoint: http://pubs.acs.org/cen/coverstory/85/8551cover.html

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Ethanol Production

• Raging debate over “green” aspects of both sugar and corn based biofuels:

Excellent point/counterpoint: http://pubs.acs.org/cen/coverstory/85/8551cover.html

17Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Ethanol Production

• Raging debate over “green” aspects of both sugar and corn based biofuels:

Excellent point/counterpoint: http://pubs.acs.org/cen/coverstory/85/8551cover.html

Biofuels Threaten Fertilizer

By KEITH BRADSHER and ANDREW MARTINPublished: April 30, 2008

The squeeze on the supply of fertilizer has been building for roughly five years. Rising demand for food and biofuels prompted farmers everywhere to plant more crops. As demand grew, the fertilizer mines and factories of the world proved unable to keep up.

Some dealers in the Midwest ran out of fertilizer last fall, and they continue to restrict sales this spring because of a limited supply.

“If you want 10,000 tons, they’ll sell you 5,000 today, maybe 3,000,” said W. Scott Tinsman Jr., a fertilizer dealer in Davenport, Iowa. “The rubber band is stretched really far.

• Ammonium leached as nitrite or nitrate, contaminating water supply• Ammonia converted to NO, increasing acidity of atmosphere and soils• N2O produced by NO and fertilizer production

Chemistry in Context

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Ethanol Production: US

• Despite these debates the “show goes on”

− US produced 14 × 109 gallons of ethanol in 2011

− 73.4 million acres (23% of cultivated land area) harvested for corn− ~25% of US corn produced goes to ethanol production− ethanol production presently subsidized by US govt at rate of $0.45/gallon

http://www.ethanolproducer.com/articles/7714/corn-ethanol-policy-under-attack-in-california

http://frontpagemag.com/2011/04/26/are-ethanols-days-numbered/

Chemistry

in Context

McElroy, Ethanol Illusion,

Harvard Magazine,

Nov-Dec 2006.

http://www-scf.usc.edu/~kallos/Files/Biofuel%20presentation.pdf

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Biofuels and Diesel

• Fuels made from recycled restaurant waste have a CH ratio conducive for usein diesel engines and not gasoline engines

• Gasoline engine: spark plug ignites fuel/air mixture (Otto cycle)

• Diesel engine: compression ignites fuel in combustion chamber (Diesel cycle)

• Gasoline: C8H18

• Diesel fuel: C10H20 to C15H28 (average C12H23)

• Main advantage of diesel: better fuel economy due to higher engine efficiency• Disadvantages:

past fuel has contained high amounts of sulfurpast engines have released large amounts of NOx

fuel gels in cold weather!

• Diesel cars much more common in Europe than the U.S. but:diesel cars making a comeback in the U.S.

http://www.practicalenvironmentalist.com/automobiles/2011-diesel-cars-usa.htm

Sources:

http://en.wikipedia.org/wiki/Diesel_engine

http://en.wikipedia.org/wiki/Diesel_fuel

$mart Power by William H. Kemp, Hushion House Publishing

http://www.scientificamerican.com/article.cfm?id=why-european-diesel-cars

20Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Biofuels and Diesel

• Fuels made from recycled restaurant waste have a CH ratio conducive for usein diesel engines and not gasoline engines

Advantages of biodiesel:

• Low sulfur• Biodegradable• Climate friendly (C that is combusted recently pulled from atmosphere!)• Can be “brewed” at home

Disadvantage of biodiesel:

• Weak solvent that could soften rubber hoses, seals, and gaskets over time• Supposedly, B20 blends (20% biodiesel) combined with modern use of

synthetic materials minimize risk … nonetheless, vehicle warranty could

be compromised by use of biofuels For more info see:

21Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

http://www.makebiodiesel.com

http://www.biodiesel.org

http://www.biodiesel-canada.org

FuelMeister II™

Personal Biodiesel Processor!

Azure Biodiesel Company

Sully, Iowa 50251

http://www.azurebiodiesel.com/contact.shtml

The Methanol Economy ®

• Methanol: CH3OH

• Alcohol

• Methanol combustion:

2 CH3OH + 3 O2 → 2 CO2 + 4 H2O + 41.4 kJ/g

Heat release considerable more than ethanol (29.7 kJ/g) and close to

that of C8H18 (47.8 kJ/g)

• Octane of 107

• Very clean burning: little or no CO, NOx, or particulates

• Can be used in “clean diesels”

• Presently used in Indy 500 race cars !

22Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

The Methanol Economy ®

• Methanol production from atmospheric CO2:

− CO2 + 3 H2 → CH3OH + H2O

− Exothermic by 49.3 kJ/mol ; nonetheless, need a catalyst

− Need to capture CO2 out of atmosphere (tall order!)

− Need supply of H2 that is “carbon neutral” (i.e., not from CH4 !)

http://www.hydrogenassociation.org/general/factSheet_production.pdf

23Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

The Methanol Economy ®

• Methanol production from atmospheric CO2:

− CO2 + 3 H2 → CH3OH + H2O

− Exothermic by 49.3 kJ/mol ; nonetheless, need a catalyst

− Need to capture CO2 out of atmosphere (tall order!)

− Need supply of H2 that is “carbon neutral” (i.e., not from CH4 !)

− If electrolysis of seawater to yield H2 could be powered by solar energy,

and an energy efficient way to capture and concentrate atmospheric CO2 could

be devised (i.e., using KOH or MEA-monoethanolamine (CH2CH2OH)NH2 ,

then CO2+3 H2 → CH3OH+H2O would simulate photosynthesis and could

provide a fuel that could be used in cars without major changes to present

infrastructure

NOTE: methanol is corrosive to aluminum, zinc, and magnesium, and

reactive with some plastics and rubber, so some systems specific

to methanol would be needed

24Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Switchgrass

Cl

O

http://www.sciencedaily.com/releases/2008/03/080310164901.htm

• Schmer et al. (PNAS, 2008) recorded the amount of diesel, fertilizer, herbicide,and seed used to grow and harvest switchgrass on 10 working farms. Theydetermined switchgrass produced 540% more energy than used.

• Chesapeake Bay marsh grass bacterium (S. degradans) has enzyme thatquickly breaks down plant lignin into glucose

• UMd Professors Steve Hutcheson and Ron Weiner discovered how to produce this enzyme (ethazyme). Can break down a variety of plant products (paper, brewer's mash, etc.)

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Switchgrass

Cl Cl

O

Pros• unlike corn, is planted once and grows every year

− decreased fossil fuel use

• can be grown in marginal crop land

− will not compete with food crops for available land

• carbon negative (deep roots bury fixed carbon)

− study shows that switchgrass sequesters 4.42 Mg C ha-1 y-1

• does not require intensive fertilization or irrigation

Cons

• technology is not mature

− unlike other crops (i.e., corn) which have been studied for

decades, switchgrass has only recently been tested

• conversion of cellulose into glucose requires enzymatic reactions

− extra step needed before glucose to ethanol conversioncompared to sugar cane

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Area per MW

• Sugar Cane: 650 gal/acre http://www.earth-policy.org/Books/PB2/PB2ch10_ss7.htm

650 gal/acre × 3785.1 cm3/acre × 0.789 g/cm3 ×29.7 kJ/g = 5.8×107 kJ/acre

5.8×107 kJ/acre/year = 1.83 kW/acre = 2,211,393 m2/MW !!!

• Corn: 350 gal/acre → 4,106,872 m2/MW YIKES !!!!

• Switchgrass: 350 to 1100 gal/acre → 1,306,716 m2/MW to 4,106,872 m2/MW to

• Switchgrass is still very land intensive

− limited ultimately by efficiency of photosynthesis

• US gasoline consumption 140 to 150 billion gallons per year

− Hutcheson & Weiner claim plants (primarily switchgrass) can yield

up to 75 billion gallons per year

− For 1100 gal/acre yield, would require:

3% of total U.S. land area

21% of U.S. cultivated land (as much as presently being used for corn)

27Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Algae as a Biofuel

Pros:• High oil content• Absorbs atmospheric CO2

• Can use waste as fertilizer• Not a food staple

Cons:• Need sunny, warm conditions; certain areas preferred• Growth limited by “self shading” effect; challenge to exploit entire volume of pond• Water intensive (rules out many warm, sunny environs for large scale production)• Efficient processing method still being researched• Fertilizer intensive• Like all organisms, algae susceptible to disease

The promise of algae as an economically viable clean source of fuel is leadingmany groups to research the large scale viability of this potential resource.

http://www3.signonsandiego.com/stories/2009/apr/29/1n29biofuels005337-new-center-focus-algae-biofuels

http://cosmiclog.msnbc.msn.com/_news/2011/04/14/6471719-is-algae-biofuel-too-thirsty

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Algae as a BiofuelWigmosta et al., Water Resources Res, 13 April 2011 conclude:

Using current technology, 48% of petroleum needed for US transportation can be produced using:• 5.5% of U.S. land area (lower 48)• 3 times the total amount of water used for irrigation

Optimal placement of algae production facility in the humid Gulf Coast, southeastern seaboard,and Great Lakes regions would considerably reduce the water needed

High yield: 8000 L/ha/year:

U.S. uses 4.6×1011 L/year

Hence, need 5.75 ×107 ha

or 2.22 ×105 mi2

471 x 471 miles

(7% land area, lower 48)

29Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty

Nuclear

6.8% Nuclear

14.5%

World Energy World Electricity

Nuclear

6.8% Nuclear

14.5%

World Energy World Electricity

Olah et al., Beyond Oil and Gas: The Methanol Economy, 2006.

30Copyright © 2011 University of MarylandThis material may not be reproduced or redistributed, in whole or in part, without written permission from Ross Salawitch or Tim Canty