New report explores uses of natural heat for food production and processing
Rome—Geothermal energy, the flow of heat
energy radiating from the earth’s core, provides unique opportunities for cost
efficient, sustainable food production and processing in developing countries,
says a new report published by FAO today.
In
some developing economies, as much as half of all food produced is lost
post-harvest – that's due in part to a lack of affordable energy for food
processing, according to “Uses of Geothermal Energy in Food and Agriculture”.
This
makes the use of heat energy for drying foods, pasteurizing milk and
sterilizing produce especially interesting for developing countries, where
increased food processing can give a boost to food security.
Food
drying can prolong the shelf life of nutritious foods like fish and vegetables
and make them available year-round, including in times of drought.
Geothermal
energy is also a prime source for heating greenhouses, soils, and water for
fish farming, the report says.
Developing
countries that have much to gain from harnessing heat energy for agriculture
include those in the so-called Ring of Fire along the Pacific Plate, such as
Mexico, Indonesia, the Philippines and various countries along the Pacific
Coast of South America. So do Ethiopia and Kenya in Africa’s Rift Valley, and
transitioning economies in Eastern Europe, including Romania and Macedonia.
The
case for geothermal
“It’s an energy source that’s renewable, clean and low-cost once
you’ve made the initial investment to harness it,” says Carlos da Silva, Senior
Agribusiness Economist in FAO’s Rural Infrastructure and Agro-Industries Division.
“By
using a clean energy source, you’re not only addressing cost but also the
environmental impacts of food production and processing,” according to da
Silva.
Agriculture
both consumes energy and emits greenhouse gases that contribute to global
warming.
Research
suggests that using geothermal heating for greenhouses decreases fungus
infections and cuts fuel costs by up to 80 percent, providing significant
savings to operating budgets.
And
while oil and gas can be costly and scarcely available in parts of the world,
the estimated 42 million megawatts (MW) of power that radiates from the earth’s
5000-degrees-celsius core won’t run out for billions of years.
“Geothermal
energy for agriculture can be done even at small-scales and can significantly
contribute to income generation, providing employment and improving food and
nutrition security in developing countries,” adds Divine Njie, AGS Deputy
Director and co-editor of the report.
From
electricity to agriculture
Worldwide, 38 countries currently use geothermal energy for direct
application in agricultural production and some 24 countries harness it to
generate electricity, with Iceland, Costa Rica, El Salvador, Kenya, New Zealand
and the Philippines deriving more than 10 percent of their electricity needs
from natural heat sources.
Of
the 23 developing countries that are using geothermal, the majority currently
apply it to space heating and recreational purposes like bathing only, leaving
its significant potential for agricultural uses untapped.
Still,
successful geothermal agricultural projects are underway in just under half of
those countries, including in aquaculture, farming and processing.
Success
stories
A
government-funded project in Algeria is supporting the building of fish farms
that utilize hot water from drill holes to heat Tilapia ponds. The three farms
built so far produce an average 1700 tons of Tilapia per year.
Iceland—which
derives most of its heating and electricity from geothermal power—has been a
leader in the use of geothermal power for agriculture since the 1920s. In
addition to greenhouse heating, some 20 companies across Iceland dry between
2000 and 4000 tons of fish each year, while an emerging industry for geothermal
pet food drying is currently producing 500 tons of animal feed annually.
Challenges
Start-up costs remain the main barrier to developing countries’
exploring geothermal energy uses on a larger scale, making it all the more
necessary for governments to take a leading role in attracting investment and
creating policy environments that support the sector, according to FAO.
“You
can invest in ground proofs and not find any economically viable heat sources,”
says da Silva, adding that even in successful cases, selling energy at a low
cost can be a challenge when having to recover start-up costs.
Nevertheless,
various projects outlined in the FAO report show that these obstacles are not
insurmountable and investments worth exploring in the larger effort of making
agriculture more sustainable. Indeed, “the FAO report also shows that
there are direct-use opportunities which do not require high-cost exploration
and exploitation”, says Njie.
An
example of geothermal energy use: Drying chilies and garlic in Thailand
Chillies and garlic are highly popular in Thailand, where people eat
them both fresh and dried. In one project there, waste heat from a geothermal
power plant is being used to dry these important food products in compartments
that can hold 450 kg of chillies or 220 kg of garlic at a time. The required
air temperatures are 70 °C for chillies and 50 °C for garlic. The total energy
consumed is just 13.3 megajoules per kilogram of water evaporated for chillies,
and 1.5 mj/kg of water for garlic. This type of dryer has relatively low
running costs and can be used in any weather conditions. (FAO)
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