Battle of the manufactured stoves

One thing we’ve learned is that stoves are a bit like dogs: they come in every shape, size, and specs.

From the scrappy mongrel that’s hardwired for survival, to the pedigreed hound that’s bred for speed, they all have traits their fans will swear by.

So, when a report evaluating the performance of various mass-produced stoves landed on our desk(top), we pounced on it!

The evaluation was conducted in the Dadaab Refugee Camps in Kenya under the auspices of USAID and the UNHCR.

Five different models of wood-burning stoves were tested for performance in various aspects, including, fuel efficiency, fastest cooking time, acceptability of stove to end users, and ease of use.

Perhaps the most illuminating aspect of this evaluation were some of the counter-intuitive conclusions.

For example, the report suggests that “fuel efficiency is not the sole determinant of user preference. Ease of use, safety, level
of smoke, and taste of food are also key factors in the choice, assuming all models are equally available and affordable.“

Another interesting conclusion is that none of these stoves offered noteworthy savings in cooking time.

The report also states that a stove’s design may also plays a critical role in its adoption. Specifically, “familiar stove technologies and designs may be more readily accepted by potential beneficiaries, and therefore easier to introduce in humanitarian situations, where time and security constraints may limit extensive training. Technologies that require more behavior change on the part of the end user will also require more significant training on proper use than those that are more similar to current practices.”

Finally, the report concludes that “addressing fuel requirements is critical to successful adoption as users are not necessarily willing or able to chop fuel to accommodate improved stove requirements.” We kind of knew this but it’s always useful to see this corroborated.

Here are the highlights of the contest:

Contest: Evaluation of Manufactured Wood Stoves in Dadaab Refugee Camps, Kenya.

Date: February 2010

Judge: Berkeley Air Monitoring Group (Berkeley Air)

Sponsor: US-AID, UNHCR

Overview:

The purpose of this study was to obtain information on the potential suitability of a new generation of manufactured biomass cooking stoves for refugee and Internally Displaced Person (IDP) environments as well as disaster relief situations. Berkeley Air Monitoring Group (Berkeley Air) was asked to combine rigorous quantitative stove performance testing using the Controlled Cooking Test protocol with as much qualitative assessment of the acceptability and usability of each stove as feasible during a time-limited visit to a refugee camp designated by USAID. At USAID’s request, UNHCR agreed to host and facilitate the stove performance testing at the Dadaab refugee camp, located in northeastern Kenya.

Contestants:

· Envirofit G-3300 Stove
· StoveTec Wood Stove (26 cm)
· Philips Natural Draft Stove
· Save80 Stove
· Vesto – The Variable Energy Stove

Qualification requirements:

To qualify for the study, all of these stoves had to:

* perform well in laboratory tests

* must be centrally manufactured

* required no assembly

* be easily transported

* designed to burn wood.

A “three-stone fire” or (“open fire”) was tested as the comparison baseline.

Test objectives and methods

The stove’s were tested for:

* Fuel efficiency

* Fastest cooking time

* Acceptability of stove to end users

* Ease of use

And the winner are… all! (sort of)

All five of the manufactured stoves had significantly lower fuel use than the open fire, with
savings ranging from 32 – 65%.  The first table below shows that the Save80 was the most fuel
efficient stove tested, followed by the StoveTec and Envirofit rocket stoves.  In contrast, the time
savings, also summarized below, were minimal.  Only the Vesto and Envirofit stoves had
significantly faster cooking times than the open fire, and they saved only 7 and 5 minutes
respectively.  The other three stoves had cooking times that were not statistically different from
the open fire.

Table 1. Ranking of the manufactured stoves on fuel efficiency and cooking speed.  Percent
differences compared to the open fire are shown in parentheses.

Conclusions
• All five tested stoves outperformed the open fire, requiring significantly less fuel to cook
the test meal.  This result is not a foregone conclusion, as a skilled operator can cook very
efficiently on an open fire.   
• The study’s strong consistent results demonstrate the quality of these five stoves and
suggest it is likely that this performance differential would continue to be measurable
across various operators and situations.   
• Fuel efficiency is not the sole determinant of user preferences.  Ease of use, safety, level
of smoke, and taste of food are also key factors in the choice, assuming all models are
equally available and affordable.   
• None of these stoves offered noteworthy savings in cooking time.
• Familiar stove technologies and designs may be more readily accepted by potential
beneficiaries, and therefore easier to introduce in humanitarian situations, where time and
security constraints may limit extensive training.
• Technologies that require more behavior change on the part of the end user will also
require more significant training on proper use than those that are more similar to current
practices.
• Addressing fuel requirements is critical to successful adoption as users are not necessarily
willing or able to chop fuel to accommodate improved stove requirements.

To see the full report, please clip or copy the following address:

http://www.usaid.gov/our_work/humanitarian_assistance/disaster_assistance/sectors/files/uganda_final_summary.pdf