The huge rise in the price of cooking fuel is costing Indonesia
millions of trees it can ill afford to lose. Desperate families
are turning to wood, cutting down trees or spending precious
money on firewood and charcoal. All too often this is
burned in an open fire, wasting most of the heat and using
much more wood than a simple closed stove would consume. And
the deforested hillsides become vulnerable to floods and mud
slides.
A solution to this dilemma is right overhead. Solar cooking,
once considered a fringe technology, has proved to deliver
enormous environmental and economic benefits in countries
where it has been adopted. IDEP volunteer Ashley, whose
thesis was on the introduction, training, efficiency and cost
of this technology in developing communities, is in Bali for
3 months. She will be studying local conditions and
customizing solar ovens to Indonesian materials and cuisines.
“Often new energy technologies are just ‘dropped
off’ in a developing community without training or support.
Sometimes they are not even culturally appropriate,”
she states. “My research in Port au Prince, Haiti,
showed that an urban situation wasn’t the best place
for solar stoves, because few families had garden or roof
access. But the conditions in Bali seem ideal.”
A solar cooker uses the same basic principle as a greenhouse.
It is typically an insulted box with a glass top, sometimes
with reflecting panels. The solar rays pass through
the glass and are converted to heat, which is trapped in the
box. Food is mixed in a dark, covered pot and placed
in the box, which is then placed outside for optimal solar
exposure. On a cloudless day, a meal can be cooked in
three hours and drinking water can be pasteurized in about
an hour (a temperature of 65C kills all bacteria harmful to
humans). Wet clothes and towels can also be dried in these
boxes.
This healthy method of cooking, similar to a slow cooker,
retains more vitamins in the food and renders meat more tender
andflavourful. Vegetables can be cooked in their own
vapour. Solar cookers can be designed to hold several
pots so the whole meal can be cooked at once.
Ashley will be working from IDEP’s Bali Permaculture
Project, a working farm in Pengosekan that is becoming a demonstration
centre for organic gardening, rice field restoration, wastewater
gardens and community waste management. “I’ll
design one or more cookers which can be made from easily obtainable
local materials,” Ashley explains. “With
support from IDEP staff and volunteers, I can develop prototypes
that are appropriate for the local foods.”
The cheapest solar cooker consists of a cardboard box covered
in foil or reflecting metal, a plastic bag and a dark pot
with a lid. A more sophisticated model is an insulated
box larger than the pot, which should be dark, and a glass
lid. Extra reflectors are optional; they increase the
rays entering the box but don’t actually increase the
heat. The lid must be kept tightly shut in order to
retain the trapped heat.
These more sophisticated ovens can reach 260C under optimum
conditions, hot enough to bake bread. Lower temperatures
are sufficient to cook meat or chicken, vegetables, eggs,
rice and stews or curries.
“Solar cookers not only save money that would otherwise
be spent on fuel, but are non-polluting and also have the
potential to reduce the cutting of forests for wood or charcoal.
Another huge bonus is the amount of time and energy that women
save by using solar cookers. It takes a bit of a shift
in how they organize their days, but instead of spending several
hours seeking fuel and cooking the daily meal, the meal can
be prepared in the morning in one or more pots, placed in
the cooker and left to cook. The food doesn’t even need
to be stirred because it can’t burn. The only attention
required is to occasionally realign the cooker to capture
the most sunlight.”
As always, people are suspicious of change and slow to adopt
new technologies. Ashley found that in Haiti, the women were
reluctant to try the cookers until they had witnessed their
use. While Ashley was talking about the technology, she would
also be cooking a local meal in the solar cooker. The
group of women would then share the meal and could immediately
appreciate the benefits. “You won’t believe
what these cookers can do until you see it for yourself,”
Ashley enthuses. “Once one person starts using it successfully,
others quickly follow.”
Ashley’s goal is to perfect a local model and then train
villagers to make solar cookers for sale within their communities.
The technology will be valuable in the hot, dry provinces
of NTT. She will also be working on a design for a simple,
closed stove that can burn wood or alternative fuels efficiently
during the rainy season when solar cookers can’t be
used.
In 1992 solar cooking was introduced in Nepal, where it has
been widely adopted. The government subsidizes the cost of
village-level manufacturing and encourages the use of the
cookers. Even large-scale solar cookers are used at an institutional
level. One school has a 9 meter mirrored reflector angled
to a hole in the kitchen wall, which directs rays to a bank
of solar ovens feeding 150 students. Nepal’s sunny
climate and highly reflective snowfields allow meals to be
prepared up to three times a day.
An Austrian engineer who promotes solar cooking throughout
Asia tells me that he and his wife have cooked 90% of their
food in solar ovens for the past 15 years at their home in
California. He describes how he carries a sheet of reflective
Mylar with him when trekking in Nepal. He rolls this
into a cone, sits it in a funnel in the snow angled to the
sun and places a black metal jar in it containing soup.
“It is boiling hot in less than 20 minutes,” he
attests. He claims that the best way to clarify
water is using glass bottles painted black.
Ashley will soon be looking for villages in Bali’s poorer
north and northeastern regencies to pilot the solar ovens.
If you know of any communities that might be interested in
learning about this technology, please contact me.
