Cooking with Plant Oil

Overview - Characteristics of Plant Oil

Plant oil for cooking can be generated from coconut, soybeans, jatropha, rapeseed, etc., and has an average calorific value of around 33 MJ/l, comparable to the calorific value of kerosene of around 35MJ/l . Plant oil differs from other liquids when used for cooking. They pose a challenge because 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 required. Pressurising enhances the performance and power-output, but adds more challenges and increases the cost of the stove. Given that plant oil can be supplied in a sustainable and reliable way at affordable market prices, it may become a suitable option for cooking, especially in regions where households already rely on purchasable fuels. However, the use of plant oil for cooking can have an impact on issues such as land use, food market prices and availability, as well as on agricultural practices, e.g. the production of plant oil plants in monoculture practice.

Advantages

• Plant oil is made from renewable primary products
• Safety: Plant oil has a high viscosity and a higher flame point when compared to kerosene. For the user this is a safety advantage, as it does not ignite spontaneously and is not so explosive when spilled.
• Fast cooking: Plant oil has a high energy content (only 5% less than kerosene). Therefore, it produces a powerful flame if used in a pressurised stove, and cooking large quantities can be done quickly.
• Smell: Although not as strong as the smell of burning kerosene, most plant oils emit an undesirable odour when burnt.

Disadvantages

• Pre-heating: Plant oils usually need to be preheated with another fuel (e.g. ethanol or methanol) in order to be ignited. This pre-heating is another cost factor and consumes time.
• Production of plant oil is labor-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, the production of fuelwood is much easier and much cheaper than production of plant oil

Please see as well further information on plant oil stoves.

Further Information

• 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.
• Website on plant oil cookers

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 “GIZ HERA Cooking Energy Compendium” in the Imprint - GIZ HERA Cooking Energy Compendium.