Cooking with Coal

Introduction

Coal is among the most important fossil fuels, accounting for 25% of total energy consumption and 40% of worldwide electricity generation. It is not to be confused with charcoal. Coal is a black, solid, carbon-rich mineral, which is mined underground, while charcoal is the ultimate form of burnt wood.

Coal for Cooking

Coal is not so often found as a cooking fuel on its own, it is rather utilized in regions where cooking and space heating are combined. Due to its regional availability, coal is used for cooking e.g. in China and India. The World Health Organization does not recommend the use of unprocessed coal in households due to carcinogenic emissions and toxic elements such as fluorine, arsenic, lead, selenium, and mercury, which are not destroyed by combustion.

Coals are formed in processes of decomposition and chemical conversion of immense masses of organic matter. This process is also known as coalification and means 'the gain in carbon content'. The process begins with peat as a parent material, is supported by increasing temperature and depth of burial, and ends with anthracite.

Coals are classified according to their degrees of coalification: the major ones are lignite (brown coal), bituminous (black coal), and anthracite. The most geological reserves of non-renewable energy forms consist of coal. The United States (31.4%) followed by China (25%), and India (10%) have the highest shares of black coal reserves in the world. Due to the higher energy content of black coal it is often exported, whereas brown coal is a regionally used energy source.

Type	Lignite (Brown Coal)	Bituminous (Black coal)	Anthracite
	Lignite	Bituminous	Anthracite
	1.) Center for Applied Energy Research University of Kentucky	2.) Chemical Engineering	3.) United States Geological Survey
Carbon content [%]	60 – 75	75 – 91	> 91.5
Energy content in MJ/kg	< 28.6	28.6 – 35.2	35.3

Coal used in households for cooking and heating varies in composition, form, and way of application. Coal is used in different forms such as “bee-nest coal briquettes” (also called “bee-hive”), “coal cakes”, “coal balls” and raw coal. Bee-nest coal briquettes, for example, are typically made of anthracite, semi-anthracite, and clay, which can be used as a binding material and burn-rate controller. The concept, which comes from China, assumes that the height and diameter of the stove burning chamber corresponds to the coal briquette. This type of coal briquette is primarily used for heating in China and South-Korea, but also for cooking, e.g. in Vietnam. In some areas, where coal is scarce, coal dust is used in a mixture with dung, formed to cakes and dried in the sun, as shown in the picture.

Further Information

• Improved Cooking Portal on energypedia
• Energypedia article coal cookstoves  
• Mineral coal in comparison to wood and charcoal – experience from Kiwira, Tanzania by HEDON (2010)
• Household use of solid fuels and high-temperature frying. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans by IARC (2010)
• Vietnam Household Energy Technical Assistance: Improved Coal Briquetting and Commercialized Dissemination of Higher Efficiency Biomass and Coal Stoves by UNDP and WB-ESMAP (1996)
• Greenhouse gases and other airborne pollutants from household stoves in China: A database for emission factors, by Zhang J. et al. (2000)
• Reserven, Ressourcen und Verfügbarkeit von Energierohstoffen, by BGR (2010) provides an overview of energy resources and its global distribution.