This paper contains and combines two main components: (1) practical experiences, developments and literature with regards to clean(er) cooking solutions; and (2) current experiences with approaches to bring initially successful technologies to scale, in particular in the context of emerging economies. As stated before, we will only lightly touch upon but not discuss in depth the implications for the broader household energy landscape. The two components that we do focus on create a large enough scope as it is. We discuss these two components in a logically intertwined sequence: the current state of clean cooking, among others reflected upon through the lens of a range of sustainability aspects (
Section 2.1) and a relevant development in that respect (
Section 2.3), intertwined with current experiences with (cooking) scaling strategies (
Section 2.2) and a new approach in that respect (
Section 2.4). This together provides the academic grounding that sets the scene for the steps that we describe next, in the second half of the paper. The discussion on scaling strategies and barriers (
Section 2.2) is a relevant basis to explore whether the new approach (
Section 2.4) could alleviate these barriers.
2.1. Current State of Cooking and Relation to Sustainability
The introduction of Improved Cook Stoves (ICSs) has become influential to ensure sustainable energy access for all [
4,
5,
6]. Worldwide, initiatives regarding cleaner cook stoves are numerous and such initiatives have been going on for several decades [
4,
7]. The reasons to promote cleaner cooking are not difficult to guess. Besides the aforementioned health-related effects, see e.g., [
1,
8,
9], socio-economic consequences of unsustainable cooking methods include time spent on collecting (fire) wood, most relevant in rural areas, or high costs for purchasing fuels, depending on circumstances potentially relevant in urban and rural areas. On top of that the direct ecological effects are substantial: biomass-based cooking methods cause 3% of global CO
2 emissions, 25% of global black carbon emissions and over 1.3 billion tons of wood fuel consumption, contributing to deforestation [
2]. The effects on the sustainability-spheres often are interconnected. For example, abundance of free firewood or cheap charcoal keeps people with little disposable income in rural areas locked into old cooking methods: economic arguments (free availability and low cost stoves) join forces with social arguments (habits, ease of use, familiarity) creating serious social effects (health) and ecological degradation which is exacerbated by social-economic lock-in (livelihood dependence). This also makes it difficult to pinpoint exactly which intervention (technology-focused or broader) has which effect exactly [
10]. In addition, while the exact levels of different presumed benefits are not certain and vary per evaluation, the benefits are there [
5], just not always assessable with the level of precision that policy makers hope for [
5,
10].
For now it seems to be justified to conclude that a long period of initiatives has not resulted in real breakthroughs on a meaningful scale relative to the size of the population that suffers from the effects [
9]. In urban areas, cleaner fuels like LPG suffer from a lack of infrastructure and in rural areas freely available biomass and inefficient but very familiar cook stoves are difficult to compete with. One might say that on a micro scale (developing better cook stoves) the problem is relatively simple, but when considering the cooking eco-system (affordability, supply chains, alternatives, habits, time vs. money), many of these elements are interdependent, and as such, the system as a whole is complex.
Decades of clean cooking projects now slowly start to pay off. The cumulative achievement of all members of the Global Alliance for Clean Cook stoves surmounts to 82 million cook stoves distributed, of which 53 million are labeled as “clean and/or efficient” [
7] but only 23 million both clean and efficient. While these numbers look substantial, on a total of three billion people who are affected, there still is much ground to cover. This can be shown by a quick calculation: three billion people, in families of for example 5 people on average would require 600 million clean and efficient cook stoves. 23 million implies less than 4% of that target has been achieved.
This number is even too high because of two reasons. Firstly, as the GACC itself acknowledges, “distributed”, often funded by donors, is not the same as accepted and adopted by the actual end users. Whether that will happen is still a question mark. Secondly, the threshold to be labeled as “clean and efficient” is set at tier-2 for efficiency and tier-3 for emissions, on a scale from 0 to 4 with 4 representing the best performance [
11]. It is doubtful for many technical testing protocols whether they lead to relevant results, since they are based more on laboratory tests than real life situations, which means they are likely to overestimate the positive health effects, e.g., [
7,
10]. This implies that there is still much room for improvement in the realm of cleaner cooking.
The slow progress in achieving impact on a substantial scale is in part due to the underestimation of the value that for many people is hidden in the current system [
3], like entrenched jobs in current value chains, or underestimation of the relevance of human behavior as opposed to technical features [
5]. Indeed, many studies found similar reasons like user-insensitive design [
12], focusing on technical functionality but discounting socio-cultural fits [
13], focus on just technology [
14], technological efficiency without much consideration for affordability for end-users after a donor-funded phase [
15] or a focus on getting “anything” out there to capture market share and then expand quickly [
16]. In the end, the effectiveness of interventions needs to be assessed based on the combination of the incidence of technology adoption (extensive margin), and the way the technology is actually used (intensive margin) [
17].
While current cooking technologies and their value chains have detrimental effects in terms of deforestation and health, they are in fact sometimes efficiently organized and many people depend on them for their livelihood, as such just making people aware of cleaner alternatives is certainly not enough. Many researchers, e.g., [
18,
19,
20], found that simply stating the beneficial effects on health and environment compared with for example (char)coal-powered cooking is not sufficient for the uptake of these new technologies. This conclusion leaves aside the magnitude of these effects and under which conditions these occur in real life [
10]. The experiences so far do seem to present a case for inclusion of more socially and eco-system related aspects to consider, even if these would not be as easily measurable as some technical aspects.
To summarize this section: dirty cooking is a large-scale issue affecting billions of people. Many initiatives so far focused on one technology and considered only one context at a time. This resulted in a specific product for a specific target group in some cases followed by incremental improvements. This has not been helpful in creating change on a meaningful scale across cultures, regions and segments, i.e., contexts. This development may have been exacerbated by the focus of stove developers and donors on seemingly objective metrics, which however now seem to have created a false sense of certainty [
7]. To understand this issue better we now look closer at current approaches to scale and challenges that have been encountered in doing so.
2.2. Current Approaches to Scale Proven Technologies: Gaps to Address
Approaches that aim to reduce the negative social, environmental and economic effects of cooking need to take into account contextual specifics [
21]. To create substantial change, we however also need to ask how such a contextual focus can be combined with an outlook of scalability. After all, with an issue affecting as many and widely dispersed people as cooking does, we will need to serve people in different contexts (e.g., urban/rural, income segments, countries). Therefore, contextually optimized solutions will not be sufficient. The continuing cycle of redesign that so far is required to achieve meaningful scale across multiple segments is undesirable for an issue with suffering on this scale [
22]. It seems necessary to recognize that maximization of relevance on micro scale, i.e., a specific context, is counterproductive to the desired level of uptake [
23,
24] even if the former is the approach that is currently most commonly used in practice.
The explanation for this context-by-context approach is not difficult. Historically, scaling up the sales of products consisted of little more than producing more and expanding market outreach. In case of products for emerging markets, this often resulted in stripped versions of the offerings for more developed markets [
25]. Such expansion strategies do however not satisfy the needs in these new segments, which is more problematic if serious social problems need to be addressed. Strong dependency on one initial product points at downplaying the differences in actual needs as well as abilities of people [
26,
27]. At first sight therefore, it seems justified to avoid “universal” solutions and use approaches that build on context-specific intelligence [
28].
However, the case of for example ICSs clearly shows the downside of this context-specific strategy. In many cases, initiatives focus mostly on rural areas, with solution directions not adequately aligned with urban end-users [
29], or vice versa [
30]. The initial focus on either rural or urban segments puts the characteristics of one of these center stage. With different starting points regarding time, availability of fuel and perception of costs, a solution design process would be pushed in a very different direction. When one context is the leading one and the context-specific solution is then in next phases adjusted to next contexts, the later ones may suffer from the initially chosen path or solutions need to be redesigned to a large extent, thereby reducing the chance and/or severely speeding down economies of scale and thus affordability advantages. Besides, possible connections between the contexts are not made, or only much later than necessary. This neglect of possible connections occurs even more often if the different “contexts” are in fact different countries.
Such path dependency [
31] is a typical phenomenon when complex, interconnected large scale issues have been broken down into seemingly more manageable chunks, e.g., markets that are subsequently entered. As a managerial response to get more grip on a messy or complex problem it is not uncommon [
32]. However this breakdown in manageable sequential chunks (e.g., country or segment) can also result in too much “heads down design” [
33], which then becomes a cause for scaling problems. This is what we see happening for clean cooking: initial success cannot be repeated elsewhere without partial or full, time-consuming and costly redesign of the physical product and/or (parts of) the business model.
We therefore seem to be in need of approaches that on the one hand do acknowledge that one cannot design immediate full-scale solutions to complex challenges [
32], but also acknowledge that decomposition in small chunks like single segments is not the solution either. The dual challenge of taking into account
supply chains for cook stoves as well as
fuels does not make the effort easier [
34], but all experiences demonstrate that an integrated approach is necessary nevertheless. Possibly this requires cooperation with governments [
35] and other stakeholders to allow solutions on systemic level to materialize faster.
In order to work with the contemporary complexity in design challenges the problem analysis can be enriched by including views from more contexts rather than contracting the scope. Using a diversity of contexts to frame the problem [
36] looks daunting to many people but more accurately represents the reality of a diverse and complex landscape, in our case the cooking eco-system. Combining diverse contextual views is likely to create some friction in the solution search process but such friction is rather a sign that one is actually dealing with reality instead of a simple but fictitious vacuum [
37]. While keeping an open mind as to where relevant information can come from may introduce (the perception of) a risk of a “loss of control” [
37], in complex environments this control is illusionary anyway. The proponents of this approach expect that using an intentional multi-contextual attitude is more likely to be an enriching rather than an endangering experience. Acting on that expectation, it seems justified to explore to move from the focus on contextual intelligence [
28] to one of collective intelligence that does not disregard the contextual specifics.
To repeat our observation: the number and dispersion of households that are affected shows the necessity of solution directions that cater for a larger diversity of (end-user) needs, which would be conducive for adoption of clean cook stoves on a larger scale. To achieve this goal, looking beyond the initial scope at the very start following this logic reduces the risk of path-dependencies and lock in. As case in point, even in outlining a seemingly advanced method to design cook stoves based on decades of lessons and failures authors propose [
38] to incorporate views from multiple angles, but still from within one context. Interpretations from beyond that contextual boundary are left out. This level of diversity does not seem to be sufficient anymore.
2.3. A Technological Promise: Gasifier Stoves
Before we continue in
Section 2.4 with the analysis on design approaches leading up to a development (/design) approach that addresses the current gap, in this sub-section we first discuss a relevant development in terms of clean cooking technology.
A technology that, for reasons explained below, seems to be promising regarding reduction of the negative effects of household cooking is micro biomass gasification. The core principle is that biomass is burnt under oxygen-lacking conditions to create syngas (a mixture of various non-combustible gases) from volatile matter in biomass and then burnt, generating biochar as non-volatile by-product. This process is carbon efficient and potentially carbon negative under perfect conditions when about 20% of short cycle carbon is trapped in biochar. It is also a cleaner way of burning the biomass, as it creates less black carbon, particulate matter and smell. The magnitude of all these benefits however depends on the exact use, i.e., human handling [
5].
Biomass gasification can potentially achieve high thermal efficiencies (bringing down the fuel demand and thus costs), scoring in tier-3 for efficiency. As stated before care should be taken to not attach too much value to technical measurements (alone) [
7]. In addition it generates a range of related benefits which touch all spheres of sustainability: gasifier stoves can use many fuel types thereby reducing dependence and vulnerability to market fluctuations and they produce fewer incompletely combusted gasses, i.e., fewer harmful emissions. The latter will require more robust and verified testing but is reported to go as far as 90% depending on which stoves are compared [
8]. As additional potential positive economic and environmental effect the residue biochar can be used as fertilizer. This effect itself is real, but estimating the magnitude would still require more rigorous testing in different environments. Putting such effects in only one box (social, environmental or economic) would not do justice to their integrated nature. Many of the (potential) benefits of gasification for households are self-enforcing and integrated, covering a large part of the sustainability spectrum.
A step towards gasification, which is easier to develop and therefore currently more common for applications like cooking, is semi-gasification. The main difference with full gasification is the fact that the syngas creation and syngas burning zones are not physically separated. These semi-gasifier stoves potentially still provide sizable gains compared with other cooking methods in terms of thermal efficiency, therefore fuel cost efficiency, level of air pollution and greenhouse gasses. While gasifier stoves show good results in a technical sense [
39], with too little or too context specific attention to end-users or costs this will still not lead to a breakthrough on substantial scale [
5]. Some technology oriented initiatives may dig their own grave by pushing for measurement methods that prove their alleged technical superiority, instead of spending time on getting their solution convincingly used in real life [
40].
In summary, even though the technologically promising gasifier technology is available it has not yet been adopted on a large scale. We turn next to an approach that might be conducive to achieve scale by taking into account fulfillment of user needs across multiple contexts from the start.
2.4. An Approach Promise: Context Variation by Design
We consider the technological promise of gasification for cooking purposes as a given for now, despite the magnitude of this promise also depending on human behavior. Then the next question becomes: which approach should be followed in order to develop a gasifier stove in such a way that it fits the broader complex cooking eco-system, both on micro level (product and product-user interaction) and higher systemic level (fitting needs and abilities of multiple target groups and the value chains these are a part of). In other words, we are looking for an approach that can appropriately address the complexity of this holistic design challenge.
Previously, [
41] a design approach has been presented that at least explicitly takes into account multiple contexts from the start, called Context Variation by Design (CVD). First results based on practical experiences were reported as well [
42,
43]. For the purpose of this paper, not primarily being written for a design-audience, we only highlight the following aspects to create a basic understanding of this approach. It will not be discussed in depth after that:
the CVD-approach presents four principles (systematic variation, hierarchical decomposition, satisficing and discursiveness) to approach a (complex) design challenge. Together these create the conditions for a design space where one can work with complexity (e.g., multiple target groups simultaneously) instead of being tempted to immediately over-simplify the design challenge.
A resulting working principle is to gather perspectives from multiple contexts from the very beginning of the design process, ideally even before the exact design challenge has been decided upon: different contextual views regarding the topic can and will influence the overarching formulation of the design challenge.
Such a collective instead of merely contextual intelligence creates a design solution space that reflects reality better than one that is based on premature simplification, e.g., immediate focus on one context. The rich design space facilitates revealing connections and patterns between elements from different contexts. This richness is a welcome basis to derive solution variations that address the diversity of requirements that are typically encountered when solutions are confronted with reality, especially if driven by the necessity to scale.
Taking diverse requirements into account, and letting them interact in an early stage before final paths are determined, allows for more adaptable solution platforms.
From all experiences so far it is clear that this approach has logical appeal, while it is based on time-honored design principles [
44] and was inspired by extensive practice-based literature from organizational sciences, e.g., [
45,
46,
47]. It is however good to realize that this approach is an evolution rather than a revolution, and based on first experiences, it rather seems to tie together and bring to a next level a number of other existing design methods.