04 “[For energy], people burn wood. Wood
and trees are very important to their sur-
vival,” Bielenberg explains.
For everything that wood cannot fuel,
people rely on diesel engines and generators
or human muscle power.
Diesel machines are expensive in places
where income earning opportunities are scarce.
Running a small, 2.5-kilowatt diesel generator
for a full day can incur about $10 in fuel costs.
Thus, people try to minimize fuel use to save
cash for inevitable expenses like medicine,
clothing and school fees; they do this by relying
on their own labor as much as possible.
“In villages that have diesel-powered grain
mills, a significant portion of women prefer
to hand pound their corn to avoid the cost of
mechanized milling,” Bielenberg explains. “This
indicates that, for low-income women, manual
labor can be cheaper than diesel power.”
Bielenberg stresses the need for accessible,
low-cost types of power, as well as solutions
that can provide income-earning opportunities
within communities—especially for women.
THE SMALLER S TEAM ENGINE THAT COULD
The opportunity to harness biomass as an
energy source for under-developed areas
came to Bielenberg through 40 years of work
in West Africa and a long career in power
generation in the United States. In the U.S.,
he has earned his living representing what he
calls a “mission-based company” that makes
commercial scale biomass boiler plants.
“The principal market for those plants is
New England, where the winters are long and
the growing seasons are short and we have
lots of wood. We put them in schools and in
hospitals, and they produce very cheap heat
and hot water for large buildings,” he says.
“This is a technology that [is] very exciting
and cost-effective when reduced in scale.”
The VIP’s useable energy output takes
three forms: mechanical, electrical and
heat. Mechanical power can be used to drive
machinery or be converted to electrical power
through the machine’s generator. The original
7-k W prototype steam engine absorbs 60
percent of the heat from the biomass-fueled
fire—about eight percent of which can be
used for power or electricity.
The latest version of the VIP is a 10-k W
machine that can capture 70 percent of the
fire’s heat—roughly 10 percent of which can
be converted to electricity. Running for eight
hours a day, it can produce 80 k W-hours,
which is enough power to provide 100 to
200 homes with electricity for low-wattage
lighting and basic appliances, like a small
refrigerator. It also replaces $32 to $40 in
diesel costs each day.
The remaining 60 percent of captured
energy can be used as heat for applications
such as public bathing, cooking, crop processing or drying, or healthcare sterilization.
“It sounds like a bad deal that we're
getting more heat than power, but in the
applications we're looking at, [such as] crop
processing and healthcare, the demand for
heat is actually greater than the demand for
electricity or power, so it’s essentially a very
good balance,” Bielenberg says.
One key advantage of the VIP over other
technologies is that its power can be readily
dispatched at any time. Photovoltaic solar,
for example, requires back-up batteries to
run at night or in poor weather conditions.
Making steam-powered energy available
to resource-scarce communities required
Bielenberg and his team to make significant
design modifications to their inspirational
model. Traditional steam engines had compli-
cated linkages and mechanisms for operating
their valves, which added to the machine’s
complexity and cost. But the VIP had to be sim-
ple in its design, with minimal moving parts,
because of the difficulty finding experts to
perform maintenance in remote communities.
The solution Bielenberg’s team devised
was to install self-acting inlet valves. “These
are pressurized, operate all by themselves
CASE STUDY | REINVENTING THE STEAM ENGINE
Heat Transfer Loss
Traditional Open Fire
FIG 2A: Efficiency of simple biomass energy sources
Available Thermal Energy