In 2015 the UN general assembly agreed on an ambitious set of 17 Sustainable Development Goals (SDGs). Amongst them is target 7.1, universal access to energy, including electricity and clean cooking, by 20301. This target is closely related to many other SDG-targets, either through synergies or trade-offs2. Progress towards the universal clean cooking target has proven particularly difficult. As of 2020, roughly 2.6 billion people still lacked access to clean cooking globally and relied on traditional fuels to reach their daily cooking needs3. Such practices are estimated to cause approximately 4 million pre-mature deaths annually and impede progress on gender equality and environmental quality goals4,5. The lack of clean cooking is especially pronounced in sub-Saharan Africa (SSA), where the number of people without access to clean cooking increased by almost 50% between 2000 and 20203.
The slow transition to clean cooking has received ample attention in the literature, and much work highlights the wide variation in the pace and outcomes of this transition across regions1,6−8. To support efforts towards achieving universal access to modern fuels for cooking, here we present the first open-source, scalable and reproducible spatial tool comparing cooking solutions (OnStove), as well as its first application for SSA. In terms of methodological novelty, while Geographic Information Systems (GIS) have been widely used to support electricity access strategies and least-cost electrification planning9,10, GIS has not been used to date to systematically assess and compare the relative potentials of clean cooking solutions. OnStove can help increase understanding of how fuel availability, access to infrastructure, and relative fuel prices change across a study area, which in turn influences investment opportunities, and then inform the most appropriate promotion strategies. For policy-makers in SSA, the use of GIS can help to clarify where transitions to improved technology are currently lagging relative to their potentials, and thereby facilitate prioritization of greater policy and investment supports.
Here, we estimate and describe the costs and benefits of implementing universal clean cooking in SSA by comparing cooking solutions over every sq. km in the region. Furthermore, we identify factors that may inhibit or catalyze the adoption of clean cooking, such as lack of economic opportunity, issues in supply chains or low availability of specific technologies (e.g. no access to electricity). We also discuss the technical and political options that can speed up achievement of universal access to clean cooking.
Cooking in SSA – a market failure
Our results serve to highlight the important role that critical market failures and behavioral obstacles would appear to play in the current choice and distribution of cooking technologies across SSA. Most people in the region still rely on traditional stoves for cooking, as externalities connected to stove-switching (e.g. many of their health effects, the value of time saved, and environmental damages) do not appear to be properly quantified, understood, or internalized. We model two perspectives, one social and one private. The social perspective accounts for all private benefits – health costs avoided and the value of time saved, plus externalities such as greenhouse gas (GHG) emissions and health spillovers avoided. It applies a discount rate of 3% to account for the value of all expenditures and benefits over time. Results from the analysis indicate that the social optimum based on current infrastructure corresponds to a cooking energy situation with 771 million people primarily using LPG stoves, 350 million using electrical stoves, 13 million using biogas stoves and around 20,000 primarily using improved cookstoves (charcoal ICS or biomass ICS) (Fig. 1a). When evaluated from a social perspective, the OnStove cost-benefit analysis shows that traditional biomass and charcoal stoves would not deliver the highest net-benefit in anywhere in the region (Fig. 1). This is in stark contrast with the current situation in SSA, where 84% of the population relies primarily on such traditional technology3. This indicates the extreme disconnect between the cooking options that are ideal for social well-being, and those that people are actually using.
When taking into account private benefits only, i.e. reduced morbidity, mortality and time spent collecting fuels and cooking within stove-adopting households, and applying a discount rate of 15% that is more consistent with individual time preferences, results continue to show a large disconnect between current decisions and optimal outcomes. This supports further a claim of substantial market failure, in that markets are not delivering solutions that would benefit many people, as well as highlighting the severity of behavioral obstacles to cleaner cooking. Even in this model framing, most people in the region (~78%) should use clean cooking solutions (Fig 22), simply for the private benefits that these technologies deliver. The remaining 22% would use transitional stoves such as charcoal ICS or biomass ICS. LPG is again the most prevalent technology in the stove mix as the primary stove for around 830 million people, followed by charcoal ICS (232 million), electricity (45 million), improved biomass cookstoves (20 million), and biogas (8 million) (Fig 22a). The larger presence of transitional stoves in the private scenario highlights the reality that a large share of the population in SSA would not achieve positive net-benefits themselves from switching to clean solutions. Major contributors to reducing benefits include the relatively low value of time (i.e. low minimum wage and (or) unequal distribution of wealth) and low Value of Statistical Life (VSL) across many countries in SSA. Equally striking, however, is the fact that many households in SSA who would appear to benefit privately from using improved or clean technology are still primarily reliant on traditional cookstoves. The fact that they do not adopt such technologies is clear evidence that other barriers – discussed further below – remain determinant.
ICS as transition
We included two ICS options in our analysis (biomass and charcoal) which have been classified as “improved” or transitional11. ICS have lower benefits than clean stoves in terms of health, emissions avoided and time saved, but are nonetheless more efficient than their traditional counterparts. Furthermore, their costs are typically lower than those of clean stoves and their operation tends to be more similar to that of traditional stoves, which limits the learning effort needed for their operation6. These factors contribute to ICS potentially playing an important role as transitional stoves on the path to more widespread use of clean options.
In the optimal social benefits scenario, ICS would only be used in the Democratic republic of Congo, Mali, Niger and Rwanda, by a very limited number of people (~20,000). Their low share is partly due to GHG-emissions and the fraction of non-renewable biomass. The production of charcoal is an emission-intensive process12 and larger shares of non-renewable biomass have an impact on the costs of biomass. The role of these factors is further highlighted by the fact that charcoal ICS become much more prevalent in the private benefits scenario, in which emissions reductions are the largest category of benefits (or for charcoal, costs) omitted from the net-benefit equation. Indeed, charcoal ICS become the second most used stove option across SSA under this private perspective. In general, charcoal ICS is also primarily used in countries with lower VSLs (i.e., where health benefits are valued less). Similarly, the prevalence of biomass ICS in the optimal stove mix increases in the private scenario as well. Two countries, Burundi and Malawi, have a majority of their population benefiting the most from biomass ICS (81 and 54% respectively). For Burundi, this is a result of the country having the lowest VSL and minimum wage amongst the full set of countries studied. As a result, the value of reduced mortality and the opportunity cost gained from using more efficient technologies are comparatively low. For Malawi, the primary reason for high shares of biomass ICS is the low fuel collection time (on average the travel time to woody biomass is less than 6 minutes).
Overall, these results illustrate that including a more restricted set of benefits, or applying lower valuations to them, tend to result in the cheaper ICS technologies becoming more attractive. Furthermore, time savings and health benefits may not always be salient to households, and particularly among household decision-makers. Those individuals – typically male head of households – are rarely the same people who bear the majority of the burdens of fuel collection and exposure to pollution from combustion in the kitchen environment – who tend to be women13. Thus, clarifying how such household “internalities” can be reduced with use of more efficient stoves may increase the incentive for adopting ICS. Prior work suggests that this can be challenging, however, and that financial aspects – and liquidity constraints in particular – often dominate the household decision calculus14,15.
Achieving the potential of clean stoves requires multi-pronged interventions
Markets alone are falling dramatically to deliver on the promise and myriad benefits of clean cooking. Achieving enhanced alignment between household cooking technology use and the socially, or even privately, optimal technology use will require concerted, coordinated policy action. In the optimal social benefits scenario, virtually everyone in SSA would use clean cooking solutions, with LPG as the most important stove option (for 68% of the population), followed by electrical stoves (31%). The latter, share of electrical cooking, is significant as the current electricity access rate in SSA is estimated to be 47.9%,16 and OnStove does not account for future improvements in electricity access. Thus, electricity is more often the preferred solution over LPG, from a social net-benefits perspective, where it is available. Indeed, integrated planning efforts that consider expanded access to universal electricity and clean cooking would likely substantially increase the optimal share of electric cooking.
In the scenario maximizing private benefits, meanwhile, LPG stoves become more competitive than electric ones, largely because of the lack of accounting for GHG emissions, where electricity has a relative advantage given the considerable reliance on renewable power generation in SSA. At the same time, the total share of clean stoves decrease, as charcoal cooking is privately attractive in a number of locations. Thus, omission of social benefits (i.e. spillover effects from kitchen emissions, avoided GHG-emissions and the social costs of illness borne by the public health system) renders the benefit of adopting clean stoves too small to offset their higher costs for a sizeable share of the population. Externalities are a classic example of market failure; achieving the social optimum in their presence requires either a) subsidies that would reduce the private user costs of clean technology, or alternatively, b) taxes that would raise the private user costs of polluting solutions. Given that the latter policy would be hard to implement for traditional stoves and fuels that are rarely purchased, the former approach is recommended.
As noted above, household cooking technology choices in SSA at this time are highly divergent even from the privately optimal technology mix. This is likely due to underdeveloped supply chains for improved and appropriate technology17, household internalities that create a discrepancy between the benefits that decision-makers perceive and the real benefits to household members18, liquidity constraints that inhibit adoption of new solutions14,15, and even social influences whereby many people simply mimic the behaviors of others around them, even when those behaviors are costly19. Fuel-stacking also play a role in the challenge20,21. Addressing this complex web of factors and barriers will require coordinated policies, interventions, and cooperation between governments and the private sector suppliers of clean solutions17. Besides subsidies, the actions needed include information provision, social marketing that especially targets influential sub-groups, empowerment of marginalized populations (particularly women), and supply chain and market strengthening.
The urgency of correcting the market failure
The use of traditional stoves carries with it numerous disadvantages. People forced to rely on traditional fuels often spend considerable time collecting fuel from the environment, and preparing their food. For example, it is estimated that rural households using traditional stoves spend approximately 1.3 hours daily on collecting biomass fuels22. This burden often falls on women and children. Much of the biomass collected is collected in a non-sustainable manner, contributing to forest degradation, which increases net GHG-emissions23. Furthermore, around 700,000 deaths in Africa in 2019 where attributed to HAP24. OnStove captures these aspects of traditional cooking by monetizing the benefits of time saved, avoided emissions, and reduced morbidity and mortality from transitions to cleaner options.
When the optimal technology is used (based on a social benefits accounting), the impacts of adopting the technologies with the highest net-benefits in SSA amount to 463,000 averted deaths per year. Furthermore, health costs of 66 billion USD are avoided annually. This decrease in deaths and health costs can be attributed to the very high shares of LPG and electrical stoves, which dramatically reduce exposures to harmful particulate emissions, and therefore result in fewer cases of disease and deaths. With optimal technology selected solely based on a private accounting of costs and benefits, the number of deaths and health costs avoided would sum up to 330,000 and 44 billion USD respectively. While this is a significant improvement from the current situation, it is considerably lower than that which is optimal under the full social perspective. This can be attributed to the significantly higher share of transitional options that would be selected when spillover benefits are ignored.
The total time saved in both scenarios averages around an hour per household and day. This similarity is expected as cooking times are comparable among the clean stoves modeled. Furthermore, fuel-types requiring substantial collection time (biomass and biogas) are not widely used in either scenario. This is important as the time spent collecting fuel contributes the most to the total time used. The emissions avoided in the social scenario amount to 315 billion MT of CO2-eq. The private scenario, while not explicitly considering stove emissions, still leads to a decrease of emissions (210 billion MT of CO2-eq), simply because households would still shift to much more efficient technology under those assumptions.
In conclusion, both perspectives suggest that considerable benefits – health improvements, emissions reductions and lower time spent on collecting fuels and cooking food – would result from a shift to more efficient technology, and these benefits well outweigh the resulting stove and fuel costs (Fig 3). In the social benefits scenario, the benefits are higher across all categories, because the technologies favored under that perspective are the cleanest and most efficient.
The costs of correcting market failures
The costs of the two scenarios differ considerably. While the net-investments of adopting the stove mix delivering the highest private net-benefits would reach 3 billion USD per year, the net-investments of the social perspective would amount to 7.5 billion USD per year. These costs include the costs of investing in new stoves as well as capacity upgrades needed to allow the existing grid to sustain electrical cooking. This can be contrasted to the annual investments needed to reach universal residential electrification, estimated at 41 billion USD3.
The largest share of costs is associated with buying fuel needed for cooking (either electricity, LPG or charcoal). The fuel costs for the technology mix selected under the optimal private benefits framing amount to 11.8 billion USD per year, which rises to approximately 14.5 billion USD for the optimal social benefits technology mix. Here it is important to consider that all costs (and benefits) are relative to the baseline stove situation. Therefore, if the stove with the highest net benefits in a given settlement has a lower fuel-cost than the baseline, the fuel cost in that specific settlement will be negative. This occurs with adoption of biomass ICS, biogas and, in some countries, charcoal ICS and electricity. In the case of biomass ICS and biogas this is because these stoves do not require fuel purchases, and fuel collection costs decline relative to the traditional stoves which are less efficient. In the case of charcoal ICS it occurs in regions were traditional charcoal is currently frequently used, thus fuel costs are saved by switching to more efficient ICS stoves. In the case of electricity, it is due to low electricity costs in specific countries that lead to savings relative to other purchased baseline fuels with higher costs (LPG).
Uncertainty regarding the specific value of the many model parameters across the SSA region is substantial, and may influence the results. To assess the sensitivity of results to major assumptions, a screening of different variables was conducted. We ran 580 scenarios to assess the effects of 28 different parameters using the method of Morris25,26. This approach assesses the relative impact of different parameters included in the full social accounting of the net-benefit equation with regards to optimal stove shares, and resulting benefits and costs. Across the different parameters assessed, several factors are indicated as especially important (see Fig 4). This is in line with the point raised previously; it is important to understand the benefits of switching to cleaner alternatives in order to correct current market failures. For example, if households underestimate the health costs, and especially the mortality losses, of polluting fuels use this will have a major impact on their stove choices. The parameters selected, as well as their ranges, the method of Morris and the detailed results of the screening exercise are described in Supplementary File C.
Ways forward to universal access to clean cooking in SSA
The divergence between private and social benefits of clean cooking, globally and in SSA, has been identified as a major policy challenge in previous studies, that requires concerted policy actions to address5–7,18. That work has also highlighted the substantial heterogeneity in outcomes that arises from different assumptions, based on empirical data, about the values of parameters that influence the costs and benefits of various cooking energy technologies27. However, neither spatial patterns of this divergence, nor the implications for targeted policies and interventions, have previously been characterized. Here, we presented the first spatially explicit clean cooking transition tool using a cost-benefit approach applied to SSA. Critically, the approach allows us to conclude that the economic rationale for strong policy action to supply clean cooking technology at low cost applies across all of SSA.
Indeed, a majority of people in the region currently use traditional biomass for cooking, but the socially optimal technologies across most locations are in fact clean stoves. Internalizing only private benefits, including non-monetary aspects related to health burdens and time losses, suggests some role for charcoal and biomass ICS cooking, but still no use of traditional stoves. The fact that existing technology use in SSA is so different from this private optimum serves to highlight the fact that markets alone are failing to provide technologies that would benefit many millions of people in the region.
Of course, so called transitional technologies, which are somewhat important in the privately optimal stove mix, still impose substantial health and environmental consequences relative to the cleanest technologies, i.e., biogas, LPG, and electric cooking. A different perspective that includes the full societal benefits yields an even higher share of clean technologies (mainly LPG and electricity), and almost completely removes transitional stoves from the set of optimal technologies. This further confirms the observation that the cooking market is not delivering on the promised benefits of a modern cooking transition. Instead, interventions – that address the myriad obstacles to dissemination of such technology, and especially address the affordability challenges – are needed across all countries of SSA in order to correct current behavioral challenges and market inefficiencies. This challenge is especially great in countries with low wages, severe wealth inequalities (and hence low health valuations), and lack of infrastructure such as effective LPG distribution networks, and access to electricity.
Education and decent employment options that raise the opportunity cost of time can also help overcome market inefficiencies related to time spent cooking with ineffective stoves and fuel collection. By strengthening the economy and providing access to quality education, time would be valued more by private individuals, who would see economic gains in finding work relative to the money saved from collecting fuels from the environment or using cheap, but highly inefficient, cooking technologies. Here, household internalities resulting from gender norms and lack of women’s empowerment and work opportunities must also be addressed. Private and public health costs can be partly internalized with information and behavior change interventions that raise awareness about the health effects of traditional fuels, but economic development is also highly correlated with health valuations28. With targeted investments and subsidies to support initial adoption, general knowledge about clean cooking technologies and their versatility can be increased, which would in turn reduce public expenditures needed for treating HAP-related diseases. Fully in the sphere of spillovers, there is a need to internalize the costs of GHG-emissions by implementing carbon markets and leveraging carbon financing at large scale to reduce use of polluting fuels and incentivize sustainable harvesting of biomass.
Even so, internalizing health, time and environmental benefits will likely not suffice to achieve a successful cooking energy transition. There is a strong need for investment in complementary infrastructure and supply chains for clean cooking solutions. In electrified locations, for example, we find that electric cooking is more often than not the preferred clean cooking technology from a social benefits perspective. Meanwhile, investments in cylinders, storage capacity, filling plants, road network improvement and expansions, and road and rail transport tankers are needed to scale-up the adoption of LPG29. The high cost of biogas digesters calls for targeted subsidies to increase the competitiveness of small-scale biogas use for cooking, at least among the rural households who can utilize that technology. The significant investment requirements to support such solutions make it imperative for energy planners to account for energy-for-cooking needs while developing their energy systems. The use of a spatially explicit model such as OnStove can aid in these developments by providing insights on how cooking technologies should be scaled-up to provide universal access to clean cooking solutions.