Reducing Energy Costs on
Vegetable Farms
Michael Bomford, PhD
Kentucky State University
College of Agriculture, Food
Science & Sustainable Systems
Fertilizers and
pesticides
Gasoline
Diesel
LP gasNatural gas
0
1
2
3
1965 1970 1975 1980 1985 1990 1995 2000
Qu
ad
rill
ion
BT
Us
Electricity
Total Energy Consumed on US Farms, 1965-2002
John Miranowski, Iowa State University
Low input farming
techniques • Conservation tillage
• Cover cropping
• Organic
• Integrated Pest Management
Changes that are (almost) free
• Gear up, throttle down
– Lower RPM is more fuel efficient
– Don’t overload the engine
• Routine machinery maintenance
– Tire pressure
– Lubrication
– Clean filters and fluids
• Appropriate ballast to reduce slipping
• Machinery sized for the job
Inexpensive changes (<$100)
• Insulate water heater
– Only necessary for older (>5 years)
water heaters. Does it feel warm to
touch?
– Costs $15-$35
– Payback less than a year
• Replace incandescent bulbs with
compact fluorescent
– Cuts energy for lighting by 75%
– Cuts lighting cost in half
Inexpensive changes (<$100)
• Weatherize buildings
– Homes, barns, sheds,
greenhouses
– Caulking, weather
stripping
• Can reduce heat loss by
one-third
• See www.eere.energy.gov/weatherization
– Caution! Air flow / ventilation is crucial to
animal and plant health
Energy Efficient Fans
• Install energy efficient fans
– High volume, low speed fans more
efficient than high speed fans
– Large diameter more efficient than
small diameter
– Straight blades more efficient than
cloverleaf
– Discharge cone increases efficiency
• Clean and lubricate fans
• Open doors, windows & vents when
fans operating
Walk-in Cooler
• CoolBot costs $300 and allows use of off-
the-shelf air conditioner and well-insulated
room for walk-in cooler.
– Cut up-front installation costs by 75%
– Cut energy costs in half
– Not suitable for cooler that
is opened frequently…
Cools more slowly than
conventional cooler.
Replace Greenhouse Thermostats
with Environmental Controllers
• Controls heating, cooling and
humidity control systems
– Avoids simultaneous heating
and cooling
• Allows night set back and
temperature flexibility to work
with outdoor environment
• Less energy, better crops
• Controllers cost $250+
Energy Efficient Heating
• Radiant heat for homes, workshops
– In-floor warm water pipes
– Heat surfaces, not air
– Comfort at lower temperature
– Heat more evenly distributed
– System costs $3-$4 per square foot
– New construction less expensive than
retrofitting
– Possible to integrate with solar hot water heat
Greenhouse Heating – Efficient
Furnaces Pay Back Quickly Gravity-
vented
Power-
vented
Separated
combustion
Condensing
Combustion
MSRP ($) 2083 2169 3131 5743
Extra cost ($) 0 86 1048 3660
Thermal efficiency 80% 80% 82% 93%
Seasonal efficiency 65% 78% 80% 91%
Fuel (gallons) 2499 2082 2030 1785
Fuel saving (%) 0 16 19 29
Cost saving ($)* 0 1209 1360 2070
Payback (months) 0 1 9 21
*Assumes liquid propane fuel at $2.90 per gallon
All other cost, efficiency, and consumption estimates from:
Sanford, Scott. 2006. Greenhouse Unit Heaters: Types, Placement, and Efficiency.
University of Wisconsin Extension Bulletin A3784-15
Alternative Heating
Fuels Can Save $
Online calculator at Hearth.com
Wood Boiler for Greenhouse
and Home Heat
Passive solar -- High tunnels and
row covers instead of heated
greenhouses
Dec. 15, 2009, Smiths Grove, KY.
Paul and Alison Wieidger
March 24, 2009, Shelbyville, KY.
Ken Waters
Tomato season
J M A M J J A S O N D
Spring
high tunnel
Fall high
tunnel
Field
Green-
house
Transplant production
Growth
Harvest
D F
Sanjun Gu. 1998
Chinese-style solar greenhouse
Zhang & Boris, 2007. University
of Manitoba & Manitoba Hydro.
• Eighteen raised
beds, 6’ x 36’
• Five mulch
treatments in four
replicate blocks:
– Bare control
– Black Plastic
– Silver Plastic
– Black Landscape
Fabric
(2 reps only)
– Hay
Varieties tested
• Six heirloom varieties randomly
assigned to six 6’ sub-plots in
each bed
– Green Zebra
– Pruden’s Purple
– Red Pear
– Rose de Berne
– Yellow Pear
– Yellow Perfection
• Transplanted at 6 weeks
on June 22, 2011
• Plants spaced 18” apart
Monitoring • Soil moisture
– June 22 – Sept. 29
– Field Scout TDR-300
• Soil temperature
– June 30 – Aug. 10
– Temp. recorded hourly 2 cm
below soil surface
– Probes attached to CR-1000
datalogger
• Yield
– All fruit harvested Sept. 16 and
Sept. 29
– Counted, graded & weighed
Results – Soil Temperature
• Temperature lowest
at sunrise; highest
mid-afternoon
• Hay moderates daily
temperature flux
• Black plastic
maintains warmer
temperature
throughout day
24
26
28
30
32
34
36
Temp. ( ° C)
Bare Black Fabric Hay Silver
Results – Soil Moisture
• Higher soil moisture
under landscape
fabric than other
mulches
Results - Yield
• Yields higher with hay
mulch than with no
mulch or landscape
fabric
Resources
• A Farmer’s Guide to Energy
Self Reliance (Vermont Law School Institute
for Energy and the Environment, 2008)
– Handbook: How to Decrease
Consumption and Increase Profits
– Report: A Guide to Using Energy
Efficiency, Biomass, and
Renewable Energy on the Farm
• eXtension.org
– Sustainable Ag Energy
Community of Practice
(www.extension.org/ag_energy)
Thanks to
• Tony Silvernail
• Jon Cambron
• Joni Thompson
• Mike Ward
• KSU Farm crew
• CASS & SEED programs
• Post Carbon Institute
• Teferi Tsegaye
• Kimberley Holmes
Contact:
Michael Bomford
502-597-5752
Learn more:
EnergyFarms.wordpress.com
Organic.KYSU.edu