Ali Jalalzadeh-Azar

Genevieve Saur

Anthony Lopez

National Renewable 

Energy Laboratory

2010 Hydrogen 

Program Annual 

Merit Review

June 8, 2010

Project ID: AN005

NREL/PR-560-48057

Biogas Resources Characterization

This presentation does not contain any proprietary, confidential, or otherwise restricted information

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC
Overview

 Project start: August 2009

 Project finish: September 2010

 Percent complete: ~ 80% 

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 Stove-piped/Siloed Analytical 

Capability (4.5.B)

 Inconsistent Data, Assumptions 

and Guidelines (4.5.C)

 Suite of Models and Tools (4.5.D)

 Total project funding: $326K

(100% DOE-funded)

 Funding in FY2009: $326K

 Funding in FY2010: None

 None

Timeline

Budget

Barriers

Partners

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 Develop a cost-analysis tool for bio-methane production from biogas based on the 

H2A Production model.

 Gather GIS data on biogas resources in California and cost data on biogas 

purification systems.

 Perform techno-economic analyses for various scenarios involving production and 

utilization of bio-methane. 

Relevance

Objectives

Drivers / Benefits

 Fuel cells operating on bio-methane or on hydrogen derived from bio-methane can 

mitigate energy and environmental issues and provide an opportunity for their 

commercialization.

 The availability of incentives and requirements for renewables such as:

 California RPS requirements: 20% by 2010 and 33% by 2020

 SB1505 renewable content requirement: 33% by 2020 (under review).

 SGIP (self-generation incentive program.) 

 The project can provide valuable insights and information to the stakeholders—

utilities, municipalities, and policy makers (at a macro-level) and producers of 

biogas (at a micro-level).

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Approach

 Develop a cost-analysis tool based on the H2A Production model that is 

transparent and vetted. The model focuses on biogas upgrading process with 

optional post compression. 

 Collect, qualify, and analyze GIS and cost data:

 Selected sources of biogas—landfills, dairy farms, and sewage treatment 

plants.

 GIS data—biogas potential in California, energy consumption, distances of 

biogas sites from the load centers and utility grids.

 Cost data—purification systems, pipeline extension, and fuel cells.

 Perform techno-economic analyses focusing on:

 Bio-methane production via biogas purification / upgrading.

 Bio-methane utilization via on-site fuel cell technologies and/or injection into 

natural gas pipeline for expanded market.

 Evaluate impact of federal and state incentives on the cost of bio-methane.

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Approach: Project Concept

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Water Treat. Plant

Animal Waste

Landfills

Dairy Waste

Anaerobic Digester

Clean-Up System Injection in NG 

Pipelines

Source Distribution & Utilization

Power Grid

Vehicle Fueling Station

Hydrogen

Electricity

Heat Stationary 

End-Use 

Biomethane

Biogas

Production & Cleanup 

Reformation / Fuel 

Cell Systems

Shaded areas represent the boundaries of the current project.

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Approach: Milestones

Milestone Title Date Status

2.11.1

Provide update on the 

collection of GIS, cost and 

technical biogas data and 

information.

2/26/2010 Complete

2.11.2 Complete Upstream H2A 

biogas model. May 2010 Complete

2.11.3 Hold Stakeholder workshop on 

biogas systems. Sept 2010 In Progress

National Renewable Energy Laboratory Innovation for Our Energy Future
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Progress: Cost Analysis Model (H2A) 

New feature: Input data tab characterizing biogas purification system.

Input Biogas Composition Notes Output Biomethane Requirement

Rate (Nm3/h) 1400 Rate (Nm3/hr) 857 634 kg/hr

Methane (CH4) (%) 60% by volume CH4 Recovery Factor 99%

CO2 (%) 38% by volume Methane (CH4) (%) 97% 595 kg/hr

Nitrogen (%) 2% by volume CO2 (%) 1% 17 kg/hr

H2S (ppm) 600-800 Nitrogen (%) 2% 21 kg/hr

Siloxane (mg/m3) 60-80 H2S (ppm) <4

Siloxane (ppb) <30

Biogas Density 1.201 kg/Nm3 Biomethane Density 0.739 kg/Nm3

Energy Content

Methane (CH4) LHV 0.052 GJ/kg methane Electricity Consumption 0.230

LHV Biogas 0.0223 GJ/Nm3 biogas

LHV Biomethane 0.0361 GJ/Nm3 biomethane

Energy Usage Units Notes

Total Electricity Usage 0.508 kWh/kg biomethane

Compression 0 kWh/kg biomethane

Process 0.508 kWh/kg biomethane

Biogas Usage 2.209 Nm3 biogas/kg biomethane

 Can facilitate quantification of capital cost as a 

function of purification requirements.

 Allows use of scaling factor.

Upgrading

Process*

Low HV High HV (High Wobbe Index)

Waste Stream(s)

Purity: 90% – 98% CH4

Biogas Bio-Methane

Purity: 50% – 65% CH4

Upgrading Techniques

Pressure swing adsorption

High-pressure water scrubbing

Cryogenic separation

Chemical absorption

Membrane separation

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Schematic of biogas upgrading process
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Progress: Sample Results of Model

Specific Item Cost 

Calculation $0.53/kg $10.86/GJ

Cost Component

Biomethane 

Production Cost 

Contribution ($/kg)

Percentage of Cost

Biomethane

Production Cost 

Contribution ($/GJ)

Capital Costs $0.11 21.22% $2.30

Decommissioning Costs $0.00 0.24% $0.03

Fixed O&M $0.05 9.13% $0.99

Feedstock Costs $0.34 64.03% $6.95

Other Raw Material 

Costs $0.00 0.00% $0.00

Byproduct Credits $0.00 0.00% $0.00

Other Variable Costs 

(including utilities) $0.03 5.37% $0.58

Total $0.53 $10.86

Key Results

Costs

Cost components and 

relative values

Total unit cost of biomethane

Energy

Process energy usage

Upstream energy usage

Process energy efficiency

Emissions

Process emissions

Upstream emissions

Sensitivity

Tornado chart depicting 

sensitivity of bio-methane 

cost to key variables.

Emissions Summary CO2 CH4 N2O Total GHG 

(CO2 eq)

Total upstream emissions

(kg/kg biomethane) -1.96 2.27E-03 2.47E-05 -1.898

Total process emissions

(kg/kg biomethane) 1.62 0.01 0.00 1.84

$6.00 $7.00 $8.00 $9.00 $10.00 $11.00 $12.00 $13.00 $14.00 $15.00

Electricity Usage (-/+ 5%)

Electricity Price (-/+ 10%)

Operating Capacity Factor (95%,90%,85%)

Total Direct Capital Cost (-/+ 10%)

Biogas Usage (-/+ 5%)

Biogas Price ($2.9/GJ,$7.6/GJ,$11/GJ)

Biomethane Cost ($/GJ)

Biomethane Cost Sensitivity

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Progress: Qualification of Cost Data

0

1

2

3

4

5

6

0

2

4

6

8

10

12

0 500 1,000 1,500 2,000

Relative Cost of Biomethane Production

Relative Capital Cost

Feed Biogas Capacity, Nm3/h

Vender A, Total Capital

Project I, Total Capital

Vender A, Biomethane Cost (calc.)

Project I, Biomethane Cost (calc.)

Bio-Methane Cost,

“Biomethane from Dairy Waste,”

Krich et al, July 2005

Assumptions:

Effective CF = 90%

Inflation rate = 1.9%

ROR = 10%

Life span = 20 yrs. Salvage 

value = 0.

Feed CH4 = 50% - 60%

Input pressure= 1 bar (abs.)

Output pressure = ~ 7 - 8 bar

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Note: Project “I” represents an actual installation in California.

The differences are in part due to the uncertainty in the estimated 

biogas capacity and in underlying assumptions of other sources of data. 
10

Progress: Preliminary / Exploratory Analysis

 Energy efficiency takes on greater 

importance at larger capacities.

 Clustering sources of biogas may 

be imperative to achieving 

economy of scale. 

 Impact of system life on product cost 

diminishes at higher biogas 

capacities.

 Significant uncertainty in life span is 

reflected in the literature and 

vendors’ data.

National Renewable Energy Laboratory Innovation for Our Energy Future

0%

20%

40%

60%

80%

100%

120%

150 350 700 1,400 2,800 6,000 12,000

Relative Contribution to Biomethane Cost 

Feed Biogas Capacity (Nm3/h)

Elec. Cost O&M Cost Total Capital Cost

0

1

2

3

4

5

6

0 2,000 4,000 6,000 8,000 10,000 12,000

Relative Cost of Biomethane Production

Feed Biogas Capacity, Nm3/h

20 years

15 years

10 years

Assumptions:

Effective CF = 90%

Inflation rate = 1.9%

ROR = 10%

Life span = varies

Salvage value = 0.

Feed CH4 = 60%

Input pressure: ~ 1 atm (abs.) 

Output pressure = 7 - 8 atm (abs.)

Life Span

Vender A

Exploratory / “what-if” analyses can be instrumental in strategic planning for 

the next steps in the analysis and provide valuable insights to stakeholders. 
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Progress: Preliminary Cost Estimates

Select 

AD Type

Reported 

elec. gen. 

costs*,

$ / GJ of 

elec.

Estimated 

biogas*,

cost, $/GJ 

Approx. 

Biometh. 

Cost = AD 

+ Upgrad. 

Cost, $/GJ

Remarks / Assumptions

The reported values are compilation of data from 

number of AD case studies with a wide range of 

biogas output capacities. 

Estimates are in 2010 USD. The reported cost 

data were adjusted for inflation. 

Upgrading cost of ~$1.5 per GJ of bio-methane 

was used for relatively large biogas capacities.

Estimates for total cost of bio-methane neglect 

cost of AD/upgrading system integration and other 

indirect costs. 

Covered 

AD—

Dairy

$12.59 $2.9 $4.4

Plugflow—

Dairy

$34.82 $7.6 $9.1

Mixed—

Dairy $52.39 $11.0 $12.5

* Source: “An Analysis of Energy Production Costs from Anaerobic Digestion Systems on U.S. Livestock Production 

Facilities,” Technical Note No. 1, Natural Resources Conservation Service, USDA, October 2007.

Upgrading biogas from dairy-farm anaerobic digesters.

Price of natural gas (residential) is approx. $9.5/GJ for CA and $11.7 for U.S. based on EIA data: 

http://tonto.eia.doe.gov/state/state_energy_profiles.cfm?sid=CA

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Progress: GIS Map for California

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 Select categories of biogas resources: 

Landfills, sewage treatment plants, and 

dairy farms.

 Landfills offer greater biogas potential.

 Transmission lines are reasonably 

accessible to most of biogas sources in 

select categories.

 Majority of GIS data are for the central 

valley due to systematic tracking. 

 GIS data for a number of counties, 

including Sacramento, San Joaquin, 

and Solano, have been verified. Data 

validation continues. 

 Data may be unavailable for a number 

of dairy farms in California.
National Renewable Energy Laboratory 13 Innovation for Our Energy Future

Progress: GIS Map for Select Counties

 Validated data for three counties: 

Sacramento, San Joaquin, and 

Solano.

 Select biogas resources: landfills, 

dairy farms, and sewage treatment 

plants.

 Aggregate potential of three biogas 

resources: Less than 3% of the NG 

consumption (~160 x 106 GJ/yr).

83.3%

14.7%

1.9%

Dairy Farms

Sewage T. Plants

Landfills

Of the select resources, landfills have the 

dominant share of the biogas potential in these 

counties.
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Progress: A Scenario Analysis / Clustering Dairy Farms

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 Bio-methane potentials: 

C1: 2,020,000 Nm3/yr (~ 80,200 GJ/yr.)

C2: 1,316,000 Nm3/yr (~ 52,200 GJ/yr.)

C3: 1,860,000 Nm3/yr (~ 73,800 GJ/yr.)

 Achieving economy of scale for biogas 

upgrading can be challenging for dairy farms.

C1

C1+C2+C3

C3

C2 Cost of Biogas Upgrading as a 

function of input biogas capacity

C3

C1

C2

NG Transmission Line

0

1

2

3

4

5

0 1,000 2,000 3,000 4,000

Cost of Biogas Upgrading, $/GJ

Feed Biogas Capacity, Nm3/h
National Renewable Energy Laboratory 15 Innovation for Our Energy Future

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

0 5 10 15 20 25

Total Construction Cost, $ / mile

Pipe Diameter, in.

Mean Total Construction Costs 

NG pipeline cost

 Pipeline costs are based on data 

reported in “Using Natural Gas 

Transmission Pipeline Costs to 

Estimate Hydrogen Pipeline Costs” 

(UCD-ITS-RR-04-35).

 Large scatters were reported for labor 

and right of way costs. 

Upgrading / Purification System Cost Evaluation

 A bio-methane production facility—anaerobic digester coupled with an upgrading 

process.

 Biogas capacity= 2,000 Nm3/h (17.5 x 106 Nm3 /year).

 Overall capacity factor= 85%.

 Length of pipeline from production site to nearest NG transmission line = 10 miles.

 H2A assumptions: Rate of return = 10% ; Inflation rate = 1.9%; Life span = 20yrs.

 Bio-methane pressure at the output of purification system= ~ 8 bar (abs.)

 NG transmission line pressure= ~ 40 bar.

Pipeline Cost

Progress: A Scenario Analysis / Bio-Methane Export to NG Grid
National Renewable Energy Laboratory 16 Innovation for Our Energy Future

Cost Items Cost Relative 

Capital Cost

Bio-methane

Cost, $/GJ

Biogas Feedstock 3 – 11 $/GJ of CH4 ------- 5.0

Upgrading System $4.0 M 40% 3.5

Pipeline—10 miles $5.8 M 58% -------

Compression $0.2 M 2% -------

Pipeline + Compression ------- ------- 4.6

Balance of Plant ------- ------- N/A

Total: ------- ------- ~ 13 $/GJ

Notes: 

1) The new cost-analysis model (H2A) was used in the scenario analysis.

2) Storage for 2-day worth bio-methane production will increase the cost by about $2/GJ—

based on estimates from “Bio-methane from Dairy Waste,” Krich et al, July 2005.

 Cost of biogas can play a critical role in the economics of bio-methane. 

 If permissible, injection of bio-methane into a distribution pipeline can reduce the 

transport cost (due to likely shorter pipeline and lower pressure).

 Incentives and policies, such as SGIP, RPS and SB1505 can render renewable 

biogas economically more attractive.

Progress: Bio-Methane Export to NG Grid (cont.)
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Collaboration

 As a strategy to acquire realistic data and to generate results that are 

beneficial to the stakeholders, efforts in communicating with 

equipment vendors, manufacturers, and municipalities are ongoing.

 Held a panel discussion, “Renewable Biogas: A Commercialization 

Opportunity for Fuel Cells,” at the 2009 Fuel Cell Seminar and 

Exposition. The event aimed to get feedbacks from the stakeholders 

on the objectives and facets of this project and to facilitate data 

collection for the analysis.

 A workshop for dissemination of the results and feedbacks from the 

industry and stakeholders may also be arranged prior to the 

conclusion of the current project. 

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 This project intends to develop a vetted cost-analysis tool based on the H2A Production 

model, collect GIS / cost data, and perform techno-economic analyses of upgrading 

biogas and utilizing the resulting bio-methane. 

 To facilitate realistic analyses and improve the usefulness of the results, inputs from 

industry and stakeholders are sought. The objectives and approach of this project lend 

themselves to overcoming the identified barriers (4.5.B, 4.5.C, and 4.5.D). 

 The preliminary analysis indicates that, by taking advantage of economy of scale, biomethane production via purification of biogas from dairy farms can be cost-effective . 

 Focusing on large dairy farms and/or clustered farms to facilitate use of a central 

AD/upgrading system is a key for realizing economy of scale, albeit it can be challenging. 

 Landfills can offer a greater potential due to the potentially lower cost of biogas, favorable 

economy of scale, and significance in emissions control. However, constant supply of 

biogas from landfills may not be sustainable. 

 The economics of producing and exporting bio-methane to natural gas grid is subject to 

variations in the costs of biogas and transport of bio-methane. 

Summary / Conclusions 

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Future Work

National Renewable Energy Laboratory Innovation for Our Energy Future

 Continue collection and validation of GIS and cost data.

 Perform additional techno-economic analyses to encompass on-site utilization 

of bio-methane in conjunction with fuel cell technologies.

Planned Work:

 Purging / sequestration of the waste stream(s) with high concentrations of 

impurities should also be addressed from the economic and environmental 

standpoints.

 An in-depth evaluation of the correlation between the cost of the biogas 

upgrading system and the purification requirements is recommended. The 

currently available cost data do not readily lend themselves to formulating 

such relationship.

Recommended Work: