the engineers had in mind. Sometimes, they
don’t use them at all.
Our experiences throughout many of villages across africa, asia, and the americas
confirm the largely anecdotal evidence that
improved stoves are underutilized. Users tend
to adopt improved cookstoves as additional
cooking devices rather than replacing open
fires. 3 This practice, commonly referred to as
“stove stacking,” occurs when users retain
multiple cookstoves, each for a specific
purpose. Much the way that a Western family
might have a gas stove, a microwave oven,
a toaster, a waffle iron, and a slow cooker
and use each for different, specific tasks, a
family in the developing world might see an
improved cookstove not as a replacement for
an open fire but a supplement to it.
The developers and philanthropists who
provide well engineered clean-burning stoves
often overlook such cultural considerations.
designing a fuel-efficient, low-emission stove
is an engineering challenge, but engineers
must also understand local needs and preferences. No matter how efficient an improved
stove may be, it won’t reduce fuel consumption or improve public health if it’s not used.
a growing body of research indicates that
cookstove use and impact are shaped by many
factors, from culture and demographics to
climate, diet and local infrastructure. yet most
cookstove studies have focused narrowly on
the effect of materials and construction on
stove performance and emissions. comparatively little attention has been paid to developing design criteria and constraints informed
by local needs and preferences.
The place of cookstoves in routines of
everyday life—that is, the experiences of
cookstove users—is generally overlooked yet it
is essential to understand the design needs.
cookstove technologies shouldn’t just be engineered for efficiency, but also for impact.
addressing this challenge begins with in-
depth field study. For our part, we traveled to
an isolated rural village in sub-Saharan africa
to examine how people there use various
cooking technologies. We discovered that the
impact of improved cookstoves in this village
was minimal, but we also developed some
guidelines that might improve the penetration
of introduced cooking technology in the future.
Further, we tested and measured fuel use.
We discovered that 98 percent of all energy
used in the village goes to domestic needs,
particularly cooking and space heating. Of
that energy, 94 percent comes from wood, of
which three-quarters is burned in domestic
cookstoves. The village annually consumes
234 metric tons of wood. 4
We made four visits to Nana Kenieba, a village
in southern Mali, between May 2009 and
december 2010 to examine the human, natural,
and infrastructural factors that characterize the
dynamics of village energy supply and use. 5 Nana
Kenieba is located within the Sahel, a transition
region bet ween the Sahara desert and africa’s
mid-continental forests. Mali ranks 160th out
of 169 countries on the United Nation’s Human
development Index, which measures life expec-
tancy, educational attainment and income. 6 Mali
also has the world’s sixth-worst mortality rate
for children under five years old attributed to
water and air pollution. 7
all 60 families in the village live on subsis-
tence agriculture. Seasons define rural life
and economics, including agricultural activi-
ties, wood harvesting and other duties. during
the rainy season, for instance, 10 percent of
the village’s 770 residents live outside the vil-
lage proper, in small camps adjacent to their
farmland, see Figure 1.
connection to the world beyond the village
is difficult. There is no access to the electrical
grid and travel along the dirt roads is by foot,
bicycle or the small bus that departs daily
for the market town 35 kilometers away.
any goods not available in the village can be
sourced from the market, however, many of
the goods used in the village are supplied by
local artisans, including blacksmiths, bakers,
tailors, carpenters, furniture makers, brick
makers, potters and basket makers.
Homes are commonly built from uncompressed earthen blocks and thatch roofs.
Kitchens, which are constructed from mud-daubed wood lattice, are separate structures
from the main living space. Families are often
polygamous, with several women exchanging
familial cooking duties every fe w days. It’s
common for women within the same family to
have separate kitchens and cookstoves.
We visited five families, ranging from
small (fewer than seven members) to large
(more than 22 members). Our study encom-
passed several different methods, from
direct observation and participation with the
shouldn’t just be
engineered for efficiency,
but also for impact.
0 3. 5
Plant ( 8) Weed ( 12) Harvest ( 12)
(trips per week)
FARM AC TIVIT Y
(hours per day)
Hot & Dry temperate & rainy Cold & Dry
3. 5 0 5
Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan
FIG 1: Farming activity and wood collections by season8