Biogas Casebook: NY On-Farm Anaerobic Digesters

63 Pages·2011·2.29 MB·English

Biogas Casebook:
NYS On-farm Anaerobic Digesters

Decommissioned
Operational
Planned
Under Construction

Prepared by:
Norm Scott, Ph.D
Jennifer Pronto
Curt Gooch, P.E.

Department of Biological and Environmental Engineering
Cornell University
Ithaca, NY
July 2010
www.manuremanagement.cornell.edu

Last updated: July 2010 v1
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Table of Contents

Glossary & Abbreviations………………………………………………………………………….
Chapter 1. Background…………………………………………………………………………
Chapter 2. Summary charts…………………………………………………………………
Chapter 3. Case Studies: New York…………………………………………………………..
3.1. Operating AD‟s ……………………………………………………………………
AA Dairy
Aurora Ridge Dairy
Corwin Duck Farm
El-Vi Farms
Emerling Farm
New Hope View Farm
Noblehurst Farms
Patterson Farms
Ridgeline Farm
Roach Dairy
Sheland Farms
SUNY Morrisville
Sunny Knoll Farm
Sunnyside Farms
Twin Birch Farms
3.2 Design/Planning Stage AD‟s ……………………………………………………..
3.3 Decommissioned AD‟s……………………………………………………………
Farber Farm
Spring Valley Dairy
Cooperstown Holsteins
Agway
Millbrook Farm
Curtain Brothers
Chapter 4. Lessons learned & Common problems…………………………………………………
Appendices…………………………………………………………………………………………
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Abbreviations
AD Anaerobic digester
HRT Hydraulic retention time
kW Kilowatt
kWh Kilowatt hour
TS Total solids
TVS Total volatile solids
NYSERDA New York State Energy Research and Development Authority
ASERTTI Association of State Energy Research and Technology Transfer Institutions
Btu British thermal unit
SLS Solid-liquid separator
CH Methane
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CO Carbon dioxide
2
H S Hydrogen sulfide
2
ppm parts per million
Eng-gen set Engine-generator set
NYS New York State
GHG Greenhouse gases
MC Milking center

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Glossary

Anaerobic bacteria
Microorganisms that live and reproduce in an environment containing no “free” or
dissolved oxygen.

Anaerobic digester
A vessel and associated heating and gas collection systems designed specifically to
contain biomass undergoing digestion and its associated microbially produced biogas.
Conditions provided by the digester include: an oxygen-free environment, a constant
temperature, and sufficient biomass retention time.

Anaerobic digestion
A biological process in which microbes break down organic material while producing
biogas as a by-product.

Anaerobic lagoon
A holding pond for livestock manure that is designed to anaerobically stabilize manure,
and may be designed to capture biogas with the use of an impermeable, floating cover.

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Annual capital cost
The equivalent annual capital cost converts the total capital costs into an annual charge.
The equivalent annual capital cost is calculated according to the formula
EAC= pv/(1/r - 1/(r*(1+r)^n)) where “pv” is the present value or total capital investment
in today's dollars, r is the discount rate, and n is the life of the capital investment.

Barn effluent
Material exiting a barn structure, generally consisting of animal excrement (urine and
feces) and used bedding material, and may contain milking center washwater.

Biogas
For the purposes of this document, the raw and un-cleaned gas produced by an AD,
consisting of mainly methane CH (~60%), carbon dioxide CO (~40%), water vapor, and
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hydrogen sulfide.

British Thermal Unit (Btu)
The English System standard measure of heat energy. It takes one Btu to raise the
temperature of one pound of water by one degree Fahrenheit at sea level.

Capital cost
A one-time fixed cost incurred on the purchase of buildings and equipment. A digester‟s
capital cost includes the purchase of land the system is on, permitting and legal costs, the
equipment needed to run the digester, cost of digester construction, the cost of financing,
and the cost of commissioning the digester prior to steady-state operation of the digester.

Centralized digester
An anaerobic vessel which uses feedstocks from several farms and/or other biomass
sources, within a relatively proximate distance to the digester location.

Co-generation
The sequential use of energy for the production of electrical and useful thermal energy.
The sequence can be thermal use followed by power production or the reverse, subject to
the following standards: (a) At least 5% of the co-generation project‟s total annual energy
output shall be in the form of useful thermal energy. (b) Where useful thermal energy
follows power production, the useful annual power output plus one-half the useful annual
thermal energy output equals not less than 42.5% of any natural gas and oil energy input.

Combined Heat and Power (CHP)
The sequential or simultaneous generation of two different forms of useful energy –
mechanical/electrical and thermal – from a single primary energy source in a single,
integrated system. CHP systems usually consist of a prime mover, a generator, a heat
recovery system, and electrical interconnections configured into an integrated whole.

Complete mix digester
An anaerobic vessel that is mixed with one or more mixing techniques.

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Dewater
To drain or remove water from an enclosure. Dewater also means draining or removing
water from sludge to increase the solids concentration.

Digestate
Effluent; Material remaining after the anaerobic digestion of a biodegradable feedstock.
Digestate is produced both by acidogenesis and methanogenesis, and each has different
characteristics.

Discount rate
The interest rate used in discounting future cash flows.

Distributed generation
A distributed generation system involves small amounts of generation located on a
utility‟s distribution system for the purpose of meeting local (substation level) peak loads.

Distribution system (electric utility)
The substations, transformers and lines that convey electricity from power plant via
transmission lines to consumers.

Effluent
Digestate; Material exiting the AD vessel.

Emission
The release or discharge of a substance into the environment; generally refers to the
release of gases or particulates into the air.

End-use sectors
The residential, commercial, transportation and industrial sectors of the economy.

Engine-Generator set
The combination of an internal combustion engine and a generator to produce electricity;
may be single or dual fueled depending on the location and set up.

Flare
A device used to safely combust surplus or unused biogas.

Greenhouse Gas (GHG)
A gas, such as carbon dioxide or methane, which contributes to a warming action in the
atmosphere.

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Grid
The electric utility companies‟ transmission and distribution system that links power
plants to customers through high power transmission line service; high voltage primary
service for industrial applications; medium voltage primary service for commercial and
industrial applications; and secondary service for commercial and residential customers.
Grid can also refer to the layout of gas distribution system of a city or town.

Hydraulic retention time (HRT)
The length of time material remains in the AD.

Hydrogen sulfide (H S)
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A toxic, colorless gas that has an offensive odor of rotten eggs. Hydrogen sulfide has
serious negative implications for the wear of gas handling equipment for an anaerobic
digester system.

Hydrolysis
A biological decomposition process involved in the anaerobic digestion of organic
material.

Influent
Biomass on the in-flow side of a treatment, storage, or transfer device.

Installed capacity
The total capacity of electrical generation devices in a power station or system.

Kilowatt-hour (kWh)
The most commonly used unit of measure of the amount of electric power consumed over
time. The stand-alone unit indicates one kilowatt of electricity supplied for one hour.

Lagoon
In wastewater treatment or livestock facilities, a shallow pond used to store wastewater
where biological activity decomposes the waste.

Lost capital
The portion of a capital investment that cannot be recovered after the investment is made,
usually used to express the immediate loss in value of a purchased or constructed item.

Main tier
Distributed renewable energy systems where the electrical power produced is not used
on-site but rather transported to the grid for use elsewhere. Wind generation generally
falls into this category.

Manure
The combination of urine and feces.

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Methane (CH )
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A flammable, explosive, colorless, odorless, gas. Methane is the major constituent of
natural gas, and also usually makes up the largest concentration of biogas produced in an
anaerobic digester.

Methanogens
Active in phase 3 of the digestion process (methanogenesis), acids (mainly acetic and
propionic acids) produced in phase 2 are converted into biogas by methane-forming
bacteria.

Microturbine
A small combustion turbine with a power output ranging from 25- to 500-kW.
Microturbines are composed of a compressor, combustor, turbine, alternator, recuperator,
and generator.

Net generation
Gross generation minus the energy consumed at the generation site for use in maintaining
energy needs (heat or electric).

Net metering
A billing practice used by utilities for certain customers who generate electricity. “Net”
refers to the difference between the electricity sold to the customer-generator by the
utility and the electricity purchased by the utility from that customer-generator.

Net Present Value (NPV)
The present value of an investment‟s future net cash flow minus the initial investment.
Generally, if the NPV of an investment is positive, the investment should be made.

Operation and Maintenance (O&M) costs
Operating expenses are associated with running a facility. Maintenance expenses are the
portion of expenses consisting of labor, materials, and other direct and indirect expenses
incurred for preserving the operating efficiency or physical condition of a facility.

Plug-flow digester
A design for an anaerobic digester in which the material enters at one end and is
theoretically pushed in plugs towards the other end, where the material exits the digester
after being digested over the design HRT.

Present value
The current value of one or more future cash payments, discounted at some appropriate
interest rate.

Rate of return
The annual return on an investment, expressed as a percentage of the total amount
invested.

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Siloxane
Any of a class of organic or inorganic chemical compounds of silicon, oxygen, and
usually carbon and hydrogen, based on the structural unit R SiO where R is an alkyl
2
group, usually methyl.

Tipping fees
Monies that are paid to a site that is accepting outside sources of organic material (non-
farm biomass).

Ton
US short ton equals 2,000 lbs

Tonne
Metric ton equals 1,000 kg

Treatment volume
Inside volume of an anaerobic digester that, under normal operating conditions would be
occupied with material undergoing anaerobic decomposition.

Turbine
A device for converting the flow of a fluid (air, steam, water, or hot gases) into
mechanical motion.

Volatile solids
Those solids in water or other liquids that are lost on ignition of the dry solids at 550
degrees Centigrade.

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