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

Michael.Bomford@KYSU.edu

Learn more:

EnergyFarms.wordpress.com

Organic.KYSU.edu