JANESVILLE’S ROAD TO CNG
Presented by:
Joe Zakovec
BIOGAS TO ENERGY SYSTEM
Digester upgrades
High Strength Waste unloading place
Gas Storage System
Gas conditioning and compressor system
(4) 65 kW microturbines with integral heat
recovery
(1) 200 kW microturbine with heat exchanger
Bio CNG Option
HIGH STRENGTH WASTE
GAS STORAGE SYSTEM
• Capacity is 107,000
cubic feet of gas
• Allows for
maximizing on peak
power production
• Delays or prevents
flaring of gas
GAS CONDITIONING SYSTEM
• Began operation
November 2010
• Removes moisture,
particulates, and
siloxane from digester
gas
• Compresses gas to
pressure required by
the turbines
(4) 65 KW MICROTURBINES
• Recovered
thermal energy
heats water that
is used to heat
the digesters
• Electricity is sold
to Alliant Energy
• Low maintenance
due to one
moving part
200 KW MICROTURBINE AND HEAT
EXCHANGER
• Microturbine started
up in January 2012
• Heat exchanger was
added in December
2013
CO2 REMOVAL SYSTEM
• Required to make
digester gas
suitable for
vehicle fuel
• Concentrates
methane from
60% to 90% by
removing Carbon
Dioxide and other
gases
CNG STORAGE AND FUELING STATION
• 100 gallons gasoline
equivalent storage
spheres
• Includes further
drying and
compression of the
gas before the
entering the storage
spheres
• Fast-fill system
CNG VEHICLE
• Handles the same as a conventional vehicle
• Uses the same engine with a few modifications
• Can switch from gasoline to CNG on the move
CNG LAWNMOWER
METHANE PRODUCED
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
180,000
200,000
C
U
B
I
C
F
E
E
T
/
D
A
Y
Last 6 months daily average
CNG PRODUCED AND USED
0
50
100
150
200
250
G
a
l
l
o
n
s
Last 6 months
COST TO PRODUCE BIO-CNG
Cost to produce Bio-CNG $0.88/gallon
Current cost of Gasoline $3.15/gallon
On vehicles that use the roads the City pays
$0.247/gallon in road tax.
Savings is $2.02/gallon
Exploring options to add more CNG vehicles to
fleet.