anaerobic digestion overview hawaii and guam energy technology demonstration project

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Anaerobic Digestion OverviewHawaii and Guam Energy Technology Demonstration Project

Jerry Davis

Senior Engineer

Project Development &

Finance Section

20 Sep 2011

Anaerobic Digestion Overview

Current Projects

WWTP Project Characterization

Potential Navy Applications

Presentation Outline

National Renewable Energy Laboratory Innovation for Our Energy Future

Thermal Biochemical

CombustionGasification/

PlasmaPyrolysis

Heat Fuel Gases (producer gas)

(CO + H2+CH4)Char, gases, aerosols

(syn gas)

Pretreatment

Fermentation

Transesterification

Ethanol

Biodiesel

No OxygenPartial OxygenExcess Oxygen Digestion

CH4

Energy Pathways


Process Overview


In feed

Reactor

End User

Feed Stock

Organic Food Waste

Human Waste

Oils/Fats

Wood/Paper

Agricultural Wastes

Food Processing Waste

Biogas

Engine/generator

Boiler

Heater

Liquids

Nutrients/Fertilizer

Low Solids .05-3% total solids by weight Little or no suspended solids Single phase liquid system, readily mixed

Medium Solids 3% to 12% total solids by weight Contains suspended solids Slurry system, can still be mixed

High Solids 12 to 25% total solids by weight “Solids-processing” system Requires mixing

General Categories of Digesters


Potential Yield


Beef c

attle

manure

Hog m

anure

: grow

er to

finish

er

Dairy m

anure

Poultry

man

ure

Animal

fat

Animal

carca

ss (h

omog

enize

d-bov

ine)

Munici

pal w

astew

ater s

ludge

House

hold

waste

Total s

traw an

d othe

r roug

hage

s

Thin st

illage

(etha

nol b

y-prod

uct)

0

100

200

300

400

500

600

700

800

900

Biogas yield (m3/tonne)

Biogas yield (m3/tonne)

Source: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex11397

Thermophilic: Decomposition and biogas

generation is more rapid More sensitive to upsets and

disturbances Results in more complete

destruction of pathogen

Mesophilic: Tend to be larger vessels More “forgiving” More common

Psychrophilic Lagoons and swamps Slower process

Temperature Range


Thermophilic

(122ºF - 135ºF)

Mesophilic

(77ºF - 100ºF)

Psychrophilic

(65-70ºF)


Current Projects

WWTP Project Characterization




Total farm-scale projects: 156 Total regional/centralized projects: 11

Farm Based AD


Source: EPA AgStar Website

Wastewater Treatment Plant Projects


>200 MGD

100 to 200 MGD

75 to 100 MGD

50 to 75 MGD

20 to 50 MGD

10 to 20 MGD

5 to 10 MGD

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

% WWTPs with AD% WWTPs with AD and Biogas Utiliza-tion

1,066 WWTPs in CONUS

544 with AD

106 with AD and biogas utilization

Declining trend of biogas utilization at smaller sizes


Current Projects

WWTP Project characterization




Key site attributes: At least 3 million gallons per day (MGD) intake for energy recovery Per EPA, >6.8 MGD for a CHP application

WWTP: Project Characterization


Project Economics


For a 6.8 MGD facility with 130 KW microturbine

Equipment costs for biogas treatment and electrical generation: $390,500

Installed cost: $564,953

Operating costs: $.022/kWh

Total electricity costs: $.03 to $.065 per kWh (depending on assumptions used to calculate avoided costs)


Current Projects

WWTP Project characterization




WWTP facilities

Per ORNL study, about 140 WWTPs with >3 M GPD within 5 miles of federal facilities

Per NREL study, 3 Navy sites have ~3M GPD on site Fort Kam, ~ 5.2 MGD Puget Sound NSY, ~ 6 MGD Apra Harbor, Guam, ~ 2.9M GPD



Jerry DavisSenior EngineerProject Development and FinanceDeployment & Market TransformationNational Renewable Energy Laboratory1617 Cole Blvd, MS-302Golden, CO [email protected]

Contact Info


mailto:[email protected]

anaerobic digestion overview hawaii and guam energy technology demonstration project

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