With winter approaching, people in rural areas of the developed world are thinking about heating and cooking. And firewood. And stoves. Around the globe, in the developing world, it isn’t a seasonal thought – it’s a daily thought. “More than half of the world’s population cook their food and heat their homes by burning coal and biomass, including wood, dung and crop residues, over open fires or in rudimentary stoves.” (World Summit on Sustainable Development, 2002)
Whether you use a woodstove for winter heat or you cook over a fire for every meal, the efficiency of your stove and the emissions it puts out are important, for your own health, and to the health of the planet. In 2002, the World Summit on Sustainable Development (somewhat belatedly?) branded smoke inhalation of indoor smoke from cooking/heating as a “major health hazard.” International organizations came together as a result of the summit, forming the Partnership for Clean Indoor Air (PCIA, www.pciaonline.org/ )to address the challenge.
As a result of that effort, Aprovecho Research Center – a non-profit 501(c)3 organization devoted to improving cookstove efficiency and emissions (www.aprovecho.org and www.aprovecho.net ) – tested 18 different cook stoves in use around the world and published Test Results of Cook Stove Performance in 2011 in partnership with the US-EPA and the PCIA. The categories tested include wood-burning stoves with and without chimneys, wood-burning stoves with electric fans, charcoal-burning stoves, liquid-fuel stoves, and a solar cooker. The stoves are rated on seven performance categories: time to boil water, amount of fuel and energy it takes to cook, carbon monoxide emissions, particulate matter emissions, safety, cost, and monthly fuel use.
In the first section of the book, each stove is given two pages, with a photo, a drawing with dimensions, written description of the stove’s origin, performance features and manufacturer contact information. The second section compares stoves by performance category. The third section asks questions about the performance features and answers them with graphs and charts. The book also includes appendices with a glossary and greater detail on testing methods and testing data.
It is evident that a great deal of time and care were taken in designing and carrying out these tests. However, the authors point out that this is a work in progress, a starting place to be improved on over time as these stoves (and others) are used in the home and/or tested in the lab.
This research is an invaluable practical resource for those seeking to improve their sustainability and lower the health risks involved in burning fuel for heat or cooking. On average, each person in the developing world where wood stoves are used burns 1,000 pounds of dry wood annually. To sustainably harvest this amount of firewood, a 40,000 square foot forest is required for each person – something that is simply not available for most people. If the most effective stove can be chosen for each application, less wood may be needed, increasing sustainability, and decreasing the health and environmental impacts of burning wood.
But more can be done! When this stove information is combined with heritage coppicing/pollarding woodland management techniques, the results for sustainability are truly wonderful. Coppiced and pollarded trees are managed so that they regrow after cutting, taking less time to grow more wood than if you planted new trees (the difference between the two is that coppiced trees are cut at ground level, while pollarded trees are cut further up the trunk).
For more information on sustainable coppicing, including a comparison of suitable tree species with yield and uses listed, see Ecology Action’s article Coppicing, available for download from: www.growbiointensive.org/ePubs under the “eInformation Sheets/Articles” tab.
Here’s the punchline:
If tree species are selected that will coppice successfully on a 16-year cycle, and if you use only the wood from significant branches for fuel and compost the bark and smaller branches, then 95% of the trace minerals from the fuel harvested can be captured and returned to the soil in the form of cured compost.
Combine coppicing with the use of a modified lorena stove (permanent cookstoves made of sand and clay) or an effective rocket stove (build of brick/cement www.rocketstoves.com/) and the 1000 lbs. of wood needed annually can be grown using biologically intensive methods in as little as 625 square feet. It’s a gigantic reduction of the 40,000 square feet it takes to grow the fuel for a regular stove. Imagine all that forest staying wild!
This makes sustainable soil fertility AND sustainable forestry AND heat generation possible!
You can download the Test Results of Cook Stove Performance for free at http://www.pciaonline.org/resources/test-results-cook-stove-performance
If you want to learn more about what goes into building efficient cookstoves, Aprovecho has published a new book, Clean-Burning Biomass Cookstoves which you can download for free at http://aprovecho.org/
Coppicing is also used in the creation of hedges, which I posted about earlier this year https://johnjeavons.org/2018/06/19/hedgerows/ For a brief and entertaining visual intro to coppicing, watch this video: (https://www.youtube.com/watch?v=FkRuMqVuJDE).
Happy growing, cooking and heating!