[Stoves] Laboratory Comparison of the Global-Warming Potential of Six Categories of Biomass Cooking Stoves

[Tom Miles]

Laboratory Comparison of the Global-Warming Potential of Six Categories of
Biomass Cooking StovesNordica MacCarty, Damon Ogle, Dean Still, Dr. Tami
Bond, Christoph Roden, Dr. Bryan Willson, September 2007

Abstract
Improved cooking stoves have been shown to reduce the amount of fuel used to
cook food and the air pollution produced in kitchens. Reducing deforestation
and smoke inhalation have been the primary motivating factors for the
dissemination of improved cook stoves. Recently, the potential of improved
stoves to reduce the effects of biomass combustion on global warming has
become a major interest, as well.

Gaseous and particle emissions from six cooking stoves were analyzed: a
three-stone fire, a rocket stove, a fan stove, a gasifier stove, a charcoal
stove, and a rice-hull burning stove. These stoves were chosen to highlight
different methods of combustion. Results indicated a significant difference
in emissions between the stoves when the overall climate-forcing effects
were calculated as CO2 equivalents on a 100-year timeframe, known as Global
Warming Potential, or GWPi
<http://www.bioenergylists.org/en/taxonomy/term/1287> .

Overall data showed that as much as a 50% reduction of fuel use, air
pollution and GWPi <http://www.bioenergylists.org/en/taxonomy/term/1287>
can be achieved by three of the wood-burning stoves in comparison to a
carefully-tended laboratory three-stone fire. The rocket and fan stoves
produced 39%, a gasifier stove 56%, and a charcoal stove 84% of the three
stone fire's global warming potential when CO2 is included. If the fuel is
harvested sustainably, then the CO2 is reabsorbed by the replacement
biomass, and can be carbon neutral. In this case, only the products of
incomplete combustion (PICi
<http://www.bioenergylists.org/en/taxonomy/term/322> ) are considered.

When fuel is harvested sustainably the rocket stove produced 41% of the
warming potential of the three stone fire, the gasifier 29%, and the fan
stove a remarkable 4%. The burning of charcoal produced 61% more warming
emissions than the three stone fire, not counting the energy loss or
emissions made when making the charcoal. Products of incomplete combustion
(PICi <http://www.bioenergylists.org/en/taxonomy/term/322> ) contributed
from 26% to 51% to the overall Global Warming Potential produced by the
direct burning natural draft stoves. Estimates of carbon reductions based on
fuel use alone may not be accurate if PICs are not measured, especially if
the fuel is harvested sustainably.

Measurements were based on the specific emissions, or grams of emissions
produced per liter of water boiled and simmered. In this way, heat transfer
efficiency is taken into account along with the combustion efficiency. It is
important to consider that these results were from laboratory testing field
results will differ and be highly variable. The intent of the investigation
was to assess the performance of the stoves when operator-influence was
minimized in order to better understand the capability of each type of stove
technology.

See articles at: http://www.bioenergylists.org/en/gwpapro0907

 

Tom Miles