Improved biomass institutional stoves

Improved biomass institutional stoves have been disseminated in several Eastern and Southern African countries. In most institutions in the region, especially schools, firewood is used for cooking in an inefficient manner such as three stone fires or using traditional stoves or models which are only marginally better than the three stone fire. Consequently, a significant amount of live trees are cut down at a rate that is faster than they are planted to provide wood energy for institutions.

In response to this problem, in the 1980s, development agencies and NGOs in the region embarked on developing efficient institutional stoves largely targeting schools that used inefficient forms of biomass energy. Perhaps the most well know developer of institutional stoves was Bellerive Foundation - an NGO based in Kenya. Bellerive institutional stoves were designed in various sizes ranging from 12 to 200 litres. Investment costs ranged from US$1,250 to US$ 1,500, including installation costs, supplementary equipment, training of cooks and maintenance contracts.

Key Technical Characteristics and Basic Principles of Operation of Biomass Institutional Stoves

Improved biomass institutional stoves are carefully designed to be more efficient in burning wood and getting as much heat as possible to the cooking pots, and so reduce the amount of wood required to cook a meal. A good institutional cook stove must ensure maximum heat retention and economic fuel wood consumption. Well built institutional stoves are easy to use with locally available fuel wood, economically viable, robust and easy to maintain.

The efficiency of wood combustion depends on adequate supply of air reaching all the areas where the wood is burning. Hot gases tend to rise, creating a draught that draws in more air. Adding a chimney improves draught thus enhancing combustion. Improved combustion also reduces the amount of smoke that is produced. Many designs of institutional stoves include a chimney that removes smoke from the cooking area. Careful direction of the hot gas flow, and insulation around the flow paths, ensures that the hot gases heat only the cooking pots or hot plates and heat losses are significantly reduced.

Uses of Biomass Institutional Stoves

• Used for cooking needs in institutions such as schools, hospitals, prisons, etc

• Water heating

Benefits and Best Practices of Improved Biomass Institutional Stoves

• The technology is environment friendly, indoor air pollution is reduced significantly as is firewood consumption.

• Because of its efficiency, firewood savings are realized hence reducing operating costs and fuel bills.

The feedstock of improved biomass institutional stoves is biomass - a domestic resource that can be grown locally in low-cost small-scale tree plantations. As domestic fuel source, it is not subject to change in price or availability according to world price fluctuations on imported fuels.

Improved Biomass Institutional Stoves - Common Problems and Response Options

• Poor design of institutional stoves can result in high oxygen levels, it could result in the stove corroding thus constituting a safety threat. Routine checkup of the stove and regulation of air flow must be maintained.

• In contrast to household improved cookstoves, institutional biomass stoves consume much larger volumes of wood. Even if improved institutional stoves are more fuel- efficient than the traditional three-stone fire, the amount of wood consumed can contribute to deforestation. As mentioned earlier, it is important to encourage institutions to establish tree/wood lots that can provide the wood needed by the improved biomass cookstove on a sustainable basis.

What to Consider When Installing Small Scale Biomass Institutional Stoves

• Consider the availability of the amount of wood fuel required by the improved biomass institutional stove.

• Ensure that the size of the stove is adequate to cook the quantity of food required.

• Maintain high quality of the material used in the construction of the institutional stove by using high performance materials such as stainless steel pots and heat resistant bricks for the fire box which ensures high performance and increases durability of the stove.

• Insist on high quality of workmanship for the fabrication of the stove’s components as well as for installation to increase the durability of the institutional stove.

• Ensure all expenses are catered for including installation costs, supplementary equipment, training for cooks and maintenance contracts (if necessary) and avoid unwise cost-cutting that can lead to poor long-term performance

Case Study – Experiences of Rural Schools in Uganda with Institutional Biomass Cookstoves

This case study presents the transformation that two schools in rural Uganda experienced after the installation of institutional biomass cookstoves.

One of the schools is Iganga High School - a mixed day and boarding “A” level secondary school. It was started as a Primary school in 1967 by the Asian community living in Uganda. The School has been steadily growing for the last 5 years. Presently, the students’ enrolment stands at 1500.

In the past, the Scholl faced the following challenges with regard to meeting the meal requirements of its students:

• Ensuring a steady fuelwood supply

• Rising students enrolment which increased woodfuel needs

• Occasional delays in serving meals due to firewood shortages

• Complaints by kitchen staff about smoke and heat of the traditional institutional stoves and three-stone fires.

Following the installation of an institutional biomass cookstove in early 2010, the school realized a significant range of benefits which include:

• Reduction in fuelwood consumption and expenditure. Previously 2 lorries (about 14-16 tonnes) of fuelwood were consumed per month at a cost of about Ugshs 370,000 (approx. US$ 185). With the installation of the stove, the fuelwood consumption/expenditure has been reduced to almost a third of the previous amounts.

• Less heat and smoke in the kitchen

• Better kitchen conditions for cooks as there is less heat and smoke in the kitchen.

• Minimized risk of accidents e.g. students or cooks getting burnt.

• Eased the time and work burden of cooking which has, in turn, boosted the morale of the cooks

• Increased interest of school community in biomass improved stoves. Some teachers got convinced enough to buy the efficient household charcoal stove for their homes.

Increase in the length of time food is kept warm for consumption later and reducing the number of cooking sessions for certain meals (food prepared for lunch sufficient for later meals)

Based on the experience of the aforementioned school, the only drawback identified is the difficulty in lighting the institutional stove during wet days. To address this challenge, the fuelwood has to be split into small pieces in order to dry properly - a demanding and costly task which has compelled the school to employ someone for this purpose

In another school – St. Stephen Budondo, two modern improved institutional biomass stoves were installed. According to the School, the benefits accrued to the school include:

Decreased Fuel Consumption: before installing the institutional biomass stoves, the School consumed an average of three lorries (about 21- 24 tonnes) of fuelwood per school term. Being a relatively young rural secondary school, the high rate of fuelwood consumption stretched the School’s limited financial resources. However, after the installation of the improved institutional biomass stove, the School’s consumption dropped to just one lorry-load (about 7-8 tonnes) of firewood per term

Decreased smoke and heat in the kitchen: Previously, the School kitchen had a lot of smoke. This made the cooks almost permanently red-eyed and constantly sneezing as well as exposed them to several respiratory diseases. The installation of the improved institutional biomass cookstoves led to a relatively smoke free environment. In addition there was no more excessive heat in the kitchen as it was transformed into an acceptably warm environment.

Reduced time taken to prepare lunch: In the past, food preparation would take a very long time. For example, lunch for the students would be ready by 1.40pm instead of the required 1.00pm. With the improved institutional biomass stove, lunch for the students would be ready by 12.50p.m.

Enhanced quality of food: Prior to the installation of the improved institutional biomass stove, food smelt of smoke and had a bitter taste. This is attributed to the fact that, with a lot of smoke and heat in the kitchen, food would not be monitored closely enough and would in some cases, get burnt. Therefore, the elimination of excessive smoke and heat from the kitchen led to better cooked and palatable food for the students.

In summary, according to the Administration of St. Stephen School, the institution is now saving a lot of wood which translates to reduced school expenditure on fuelwood and the quality of the food has improved with meals being served on time. The improved institutional biomass cookstoves have transformed the kitchen environment and the cooks now enjoy better working conditions.

References and Links

1. Karekezi, S. and Ranja, T. 1997. Renewable Energy Technologies in Africa. African Energy Policy Research Network, Nairobi and ZED Books, London.

2. http://www.bioenergylists.org/stoves

3. http://www.arecop.org/zip/sushil-ppr.pdf

4. http://www.afrepren.org/caburesatraining/Casestudy-PresentationonIgangaHighSchool.pdf

5. http://www.afrepren.org/caburesatraining/casestudypresentantions-StStephenS.SBudondo.pdf

6. http://www.ashdenawards.org/wood-stoves

7. http://www.ashdenawards.org/winners/nishant

8. http://www.arecop.org/zip/sushil-ppr.pdf

9. http://www.hedon.info/CEC:ProductionOfWoodfuelStoves#TypesOfWoodfuelStoves

10. http://practicalaction.org/docs/technical_information_service/stoves_institutional.pdf