Clean Cooking

Project Drawdown defines clean cookstoves as solar-powered or fuel-burning household stoves that reduce greenhouse gas emissions by increasing thermal efficiency, reducing specific emissions, or increasing ventilation. This solution replaces traditional cookstoves that burn wood and/or charcoal inefficiently and without ventilation.

Currently, about one-third of world’s population (2.7 billion people) depends on solid fuels including fuelwood and crop residue, for cooking. This is projected to increase by 8 percent by 2030. These traditional cooking practices impact not only global carbon dioxide-equivalent emissions from fuel combustion, but also the health of rural populations of the developing world due to household air pollution. Traditional stoves can be improved in three different ways, as named above. The type of cookstove is determined by the International Organization for Standardization tier based on thermal efficiency and emissions. Tiers 0 and 1 constitute the basic, traditional, solid-fuel-based stoves. Tiers 2–4 are considered improved clean cookstoves.[1]

This analysis evaluates the growth of improved clean cookstoves as a replacement for traditional cookstoves around the world.[2]

Methodology

Total Addressable Market[3]

The total addressable market is defined as the total terawatt-hour therms final energy used for cooking in all regions except OECD90 and Eastern Europe (that is, Middle East & Africa, Asian sans Japan, and Latin America). From the literature review, assumptions were derived for population growth, average population per household, average household useful energy use for cooking per capita, a weighted average energy efficiency factor for stove and fuel type mix, and the percentage of the population using solid fuels. These values, along with global data from the International Energy Agency (IEA, 2006 and 2012), were used to develop a composite global market for the period 2014–2050.

Current adoption[4] of clean cookstoves was estimated at 53 percent of families in the regions selected for this analysis. This figure was derived, in part, from data on clean cooking as guided by the UN Sustainable Development Goals (SDG’s) which call for universal access to clean energy by 2030 which would have significant health and societal benefits for the families involved.

Adoption Scenarios[5]

Impacts of increased adoption of clean cookstoves from 2020 to 2050 were generated based on two growth scenarios. These were assessed in comparison to a Reference Scenario, in which the solution’s market share was fixed at the current levels.

With the UN goal of 100 percent access to clean cooking by 2030, this was the main guide in identifying and using data for developing scenarios, considering its humanitarian significance that aligns with the climate objectives of Project Drawdown. The IEA has developed a Sustainable Energy Scenario (SES) which matches the UN goal.

For clean cookstoves, two scenarios were developed:

• Scenario 1: Aligned growth that matches the IEA New Policies Scenario (NPS)
• Scenario 2: full achievement of the UN SDG of 100 percent access to clean cooking by 2030 using linear projections of adoption in each region included in the analysis (aligned with the IEA Sustainable Energy Scenario (SES).

Emissions Model

Emissions mitigation variables were based on several peer-reviewed sources and weighting, calculating an estimated 43 percent of fuel saved from the clean cookstoves compared to the traditional stoves.

In addition to carbon dioxide emissions, black carbon is also an important factor to consider for the clean cookstoves solution. There is wide consensus on the impact of black carbon, but its magnitude is still under study—mainly because of the impacts of other components emitted with it during open combustion, such as organic carbon. Organic carbon consists of scattering particles and aerosols that are considered to have a global cooling effect. Black carbon data from 12 sources were included, and this contributed a significant portion of the emissions reduction.

Financial Model

Financial variables (the costs of traditional and improved stoves) have largely been obtained from sources such as the World Bank (2010) and US EPA (2015). Weighting based on cooking fuel mix was applied where possible. The average first cost of a conventional stove was found to be US$1.28 since these are simple devices often consisting of nothing more than three stones arranged on the ground to hold up a pot. However, the average first cost of an improved clean cookstove was found to be US$45.[6] Operating cost data was less available. Much of the fuel required for traditional wood-burning stoves is not purchased but collected by women in rural parts of the developing world, so the cost of fuel is weighted appropriately.

Integration[7]

Integration of cooking solutions was mainly to avoid double counting, and a prioritization was applied where the other cooking solution, Biogas for Cooking was seen as one with a more limited scope so was considered of higher priority for the applicable locations. Clean Cookstoves therefore were limited in adoption if total functional units adopted between Biogas for Cooking and Clean Cookstoves exceeded the cooking energy TAM.

Results

The total carbon dioxide-equivalent reductions that can be achieved from 2020–2050 in Scenario 1 are 31 gigatons carbon dioxide equivalent (including an attribution of 8 gigatons from black carbon). This scenario would cost an additional US$136 billion and would raise lifetime operating costs by US$2.0 trillion since families would now have to pay for something that used to be free (if their time for collecting firewood was discounted). Still only 84 percent of families in the three developing regions selected would have access to clean cooking, with Africa being the furthest behind, considering its slow adoption of clean cooking technologies.

Scenario 2 of achieving the UN SDG for universal access by 2030 would see a reduction of 73 gigatons of carbon dioxide equivalents inclusive of 20 gigatons from black carbon reduction. This would cost an additional US$291 billion in stove costs and US$4.2 trillion in lifetime fuel and operating costs.

Discussion

Clean cookstoves are an important solution to consider for drawdown. It should be noted that 17 percent of the world’s black carbon comes from biomass-based cooking, and reducing this value to almost zero by replacing solid fuel-burning stoves with renewable fuel stoves is a huge step towards drawdown. The source of solid-wood fuel is not considered in this model, but the nature of clean cookstoves enables solid fuel of size and density that could come from regenerative forest management and not subsistence clear-cutting.

In addition to climate impacts, the health impacts of this solution are significant. Our model estimates that in the Scenario 1, over 3 billion tons of carbon monoxide, 180 million tons of fine particulate matter (PM2.5) and 28 million tons of nitrous oxide can be avoided through clean cookstove adoption.  In India, it was estimated that the dissemination of 150 million clean cookstoves over 10 years could help avoid 2.2 million premature deaths due to household air pollution in the country, and that the reduction in health burden in 2020 (measured in lost healthy life years) would be equivalent to about half the total national cancer burden projected that year. The potential rebound effects of improved health outcome on fertility rates, consumption rates, and emissions are hard to predict and are not studied in the literature.