Difference between revisions of "Alcohol Stoves"

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Revision as of 09:15, 14 August 2015

GIZ HERA Cooking Energy Compendium small.png


Basics | Policy Advice | Planning | Designing and Implementing (ICS Supply)| Technologies and Practices | Designing and Implementing (Woodfuel Supply)| Climate Change



Cooking with Alcohol Fuels

A stove to burn alcohol fuels can be very simple. The main components of the burner are shown here[1]:

RTENOTITLE



Cooking with Ethanol

Advantages of cooking with ethanol:

  • Very clean combustion with negligible emissions and no soot
  • Can safely be used indoors; eliminates Household Air Pollution (HAP)
  • Heat available instantly after ignition
  • Provides a safe alternative to LPG when not pressurized
  • Produced from a variety of feedstocks, many of which are sustainable
  • Intrinsically cheap


Disadvantages of cooking with ethanol:

  • Low heating value when further diluted with water to make gel-fuel
  • High flammability, burns at low temperatures
  • Currently weak supply chains for household use


Experiences of Cooking with Ethanol

At present, ethanol stoves and fuel are consumed for household energy use in areas where they have been fostered and promoted by studies and commercial projects. Nations worldwide have invested in large and medium-scale biofuel production to cut the use of costly, unsustainable petroleum-based fuels. As worldwide production capacity increases, so does the potential for ethanol to meet cooking and lighting energy demands worldwide. Alcohol fuels are increasingly recognized by the international community as a clean liquid fuel solution of the future. Ethanol projects, along with LPG and solar groups, lead the clean fuel advocacy efforts of the Global Alliance for Clean Cookstoves since its inception in 2010.

Ethanol and ethanol-based gel-fuel are quite common in niche applications, where clean combustion, safety and convenience are required: e.g. marine markets, camping, catering services and restaurants. Because ethanol can be made from a variety of low-cost, simple feedstocks, it is an intrinsically cheap fuel. Ethanol fuel can be produced at a scale which suits the community in demand. For example, In Ethiopia ethanol is sourced from the government-owned Sugar Corporation to meet the cooking demand of several thousand households and ethanol for household energy use is recognized an official priority of the National Biofuels Policy.

In humanitarian interventions where energy for cooking is in large and urgent demand and resources are extremely scarce, ethanol stoves and fuel have shown considerable success.

The most documented ethanol stove model is the CleanCook Stove by CleanCook Sweden AB, which is produced in South Africa and promoted mainly by Project Gaia.


CleanCook Ethanol Stove

The "CleanCook" Stove is available as a single or double-burner model for households and institutions. It is made from aluminium or stainless steel. The CleanCook is a non-pressurized alcohol stove with a refillable fuel canister of a capacity of 1,2 liters.[2] The canister contains a porous fiber that adsorbs alcohol and retains it in a manner that prevents spills, leaks, fires and explosions.[3] The power output per burner is rated at 1.8 kW at maximum heat, allowing for a cooking time of 4-5 hours. It can burn ethanol and methanol.[2]

Up to now, 55,000 cleancook stoves have been provided, mainly in Africa.[4]

Project Gaia and Gaia Associations have achieved an excellent history of safety by employing stringent training protocols for staff and end users. The cost of the CleanCook stove models range from $57-110 USD[5]. Project Gaia employs various financing schemes including sustainable loan programs and carbon finance to deliver affordable alcohol stoves and fuel to energy poor households.[6]


Hedon1.JPG

Project Gaia and its Ethiopian sister organization, Gaia Association, have lab and field tested alcohol stoves since 2005. To date, alcohol stoves have been used by households in Ethiopia, Nigeria, South Africa, Malawi, Madagascar, Mozambique, Vietnam, Brazil and Haiti. Click here to access country study/project reports. The largest number of households using alcohol stoves is in the UNHCR refugee camps near Jijiga, Eastern Ethiopia where more than 4,000 households rely on the CleanCook stove and ethanol fuel as their main source of energy. The UNHCR now aims to scale up to provide ethanol cookstoves and fuel to up to 27,678 households by 2017.[7]

Project Gaia currently leads four community-based, small-scale ethanol distillation projects in Ethiopia. Also in Brazil and Haiti microdistillery projects are being implemented. These projects aim to allow communities to produce clean cooking fuel using local feedstocks, simultaneously adding value to agricultural markets by taking advantage of co-products of the distillation process[8].



Cooking with Methanol

Methanol-use for cooking is still in its infancy. This is partially due to the fear of the potentially damaging health effects should the fuel be accidentally ingested. Project Gaia had a pilot study in Nigeria with Methanol (made from fossil flare gases): people were mainly satisfied with the stove, but complained that the fuel was not regularly available.[9]



Further Information



References




Cooking with Plant Oils

Plant oil fuels pose the challenge that they have a high viscosity and only ignite at temperatures above 200° Celsius. Depending on the oil type, simple wick-stoves are not suitable and sometimes preheating of the oil with another fuel that burns at lower temperatures is needed. Pressurizing enhances the performance and power-output, but adds more challenges and cost to the stove.

Plant oil differs from other liquids when used for cooking. Below are some advantages and disadvantages.

Advantages:

  • Safety: Plant oil is has a high viscosity and a higher flame point as compared to kerosene. For the user, this has the advantage of safety (it does not ignite spontaneously and is not so explosive when spilled).
  • Smell: Most plant oils also do not emit undesirable odours (it does not smell as intensive as kerosene).
  • Fast cooking: Plant oil has a high energy content (only 5% less than kerosene). Hence it produces a powerful flame if used in a pressurized stove. Cooking large quantities can be done quickly.


Disadvantages:

  • Pre-heating: The advantages on safety and smell come at the expense that it usually needs to be preheated with another fuel (e.g. ethanol or methanol) in order to be ignited. This pre-heating is another cost factor and it consumes time.
  • Simmering: The linked disadvantage is that it is difficult to simmer: in a pressurized regulating the plant-oil supply down for small heat poses a challenge.
  • Cleaning: Plant oils contain fiber, the amount of which depends on the kind of oil and the quality of the filter method applied. As the oil is burned as gas, the fiber remains behind and tends to clog the burner (depending on the type of stove). This requires regular cleaning of stove and nozzles.
  • Noise: if burned in a pressurized system, cooking on plant oil can be quite noisy. It requires muffling of the sound.


Experiences of Cooking with Plant Oil

During the last decades, projects have sought to design household appliances for cooking and heating that use plant oil.

Until recently, none of them got beyond the test phase. Some of the reasons for the past failure of plant oil cookers are:

  • Plant oil cookers have a rather complicated design which is not easy to construct
  • They may require ongoing maintenance
  • Production of plant oil is labour-intensive and expensive
  • The use of some plant oils as fuels competes with other uses, such as food crops, soap production etc., which are more profitable
  • In most cases, production of fuelwood is much easier and much cheaper than production of plant oil



Protos the Plant Oil Stove

The University Hohenheim (Germany), in cooperation with Bosch and Siemens Home Appliances Group (BSH), developed protos the plantoilcooker. The basic idea was to develop a cookstove that can use a variety of plant oils; even recycled and filtered oil previously used for frying.

Field tests in the Philippines and in Tanzania have shown that households and small enterprises such as restaurants, that were previously cooking on 3-stone fires, can handle the Protos-stove. People stated that they enjoyed the comfort of cooking and said it was like cooking on gas, even if LPG was not available. Based on observations from the field tests, BSH developed a 'second generation' of the protos plantoilstove technology to increase efficiency, reducing noise, cleaning time and the cost of production.[1] The serial production was launched in May 2010 in Indonesia. Initial costs were considered to be around  US$40 - 42, at a production rate of around 25,000-50,000 units in 2010.[2]

However, in 2012, BSH decided to conclude the Protos plant oil cooker project and to discontinue series production of the stove in Indonesia. The main reasons were as follows:[3]

  • The stove was required to be of a high quality, safe and as easy as possible to use. Equally, however, it had to be cheap enough for people in developing countries to be able to afford it. The low purchasing power of the potential users had limited the use of the stove to a few individual projects.
  • Plant oil cookers require a lot more cleaningn and maintenance than kerosene stoves as plant oil leaves residue in the burner when it evaporates.
  • Due to the physical properties of plant oil the stove is technically complex. All varieties of plant oil have an extremely high flash point, which means that plant oil stoves require much higher operating temperatures and a longer pre-heating process than conventional stoves burning fossil fuel.
  • No established market for sustainably cultivated plant oil in Indonesia.
  • BSH faced serious difficulties in setting up a supply chain for sustainable cultivated plant oil.


BSH has freed all patents associated with the plant oil cooker technology. Construction plans, introduction guidelines and other technical information is available at: http://www.bsh-group.com/index.php?127656



Further Information



References







Further Information on Plantoil

  • Jatropha curcas L. in Africa. Assessment of the impact of the dissemination of “the Jatropha System” on the ecology of the rural area and the social and economic situation of the rural population (target group) in selected countries in Africa, by Reinhard K. Henning (2006).
    This paper gives a good overview on production of the Physic Nut in Africa and the variety of its use. Special attention is paid the use of plant oil as a fuel. An overview of existing cooker models is given including technical details.
  • Jatropha System.htm The Jatropha System- An Integrated Approach of Rural Development in Tropical & Subtropical Countries.
    The very comprehensive homepage provides a good overview of the role of Jatropha in different countries, technical aspects of oil extraction, different cooker models developed so far, a selection of projects working in the field of Jatropha use as well as a large amount of literature on the issue.





References

This article was originally published by GIZ HERA. It is basically based on experiences, lessons learned and information gathered by GIZ cook stove projects. You can find more information about the authors and experts of the original “Cooking Energy Compendium” in the Imprint.



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