The disease burden related to air pollution from traditional solid-fuel cooking practices in low- and middle-income countries impacts millions of people globally. Although the use of liquefied petroleum gas (LPG) fuel for cooking can meaningfully reduce household air pollution concentrations, major barriers, including affordability and accessibility, have limited widespread adoption. Using a randomized controlled trial, our objective was to evaluate the association between the cost and use of LPG among 23 rural Rwandan households. We provided a 2-burner LPG stove with accessories and incorporated a "pay-as-you-go" (PAYG) LPG service model that included fuel delivery. PAYG services remove the large up-front cost of cylinder refills by integrating "smart meter" technology that allows participants to pay in incremental amounts, as needed. We assigned three randomized discounted prices for LPG to each household at ~4-week intervals over a 12-week period. We modeled the relationship between randomized PAYG LPG price and use (standardized to monthly periods), analyzing effect modification by relative household wealth. A 1000 Rwandan Franc (about 1 USD at the time of the study) increase in LPG price/kg was associated with a 4.1 kg/month decrease in use (95% confidence interval [CI]: -6.7, -1.6; n=69 observations). Wealth modified this association; we observed a 9.7 kg/month reduction (95% CI: -14.8, -4.5) among wealthier households and a 2.5 kg/month reduction (95% CI: -5.3, 0.3) among lower-wealth households (p-interaction=0.01). The difference in price sensitivity was driven by higher LPG use among wealthier households at more heavily discounted prices; from an 80% to 10% discount, wealthy households used 17.5 to 5.3 kg/month and less wealthy households used 6.2 to 3.1 kg/month. Our pilot-level experimental evidence of PAYG LPG in a rural low-resource setting suggests that further exploration of subsidized pricing varied by household wealth is needed to ensure future policy initiatives can achieve targets without exacerbating inequities.

Household air pollution due to the burning of solid fuels is one of the leading risk factors for disease and mortality worldwide, resulting in an estimated three million deaths annually. Peru's national LPG access program, FISE, aims to reduce the use of biomass fuels and increase access to cleaner fuels for cooking in low-income Peruvian households through public-private partnerships. Perspectives from front-end program implementers are needed to better understand barriers and facilitators to program implementation and to identify strategies to strengthen program reach, uptake, and health impact.

Increased residential energy consumption and reduced income caused by the lockdown measures invoked to combat the COVID-19 pandemic have deepened energy poverty, particularly in vulnerable communities. In this context, the pathway through which COVID-19 impacts energy poverty is constructed, and six relief measures are proposed: consistent financing of energy suppliers and consumers, developing various forms of socio-economic aids, leveraging fiscal stimuli to promote renewable energy transition, identifying vulnerable populations to improve policy effectiveness, designing equitable resource allocation mechanisms, and rethinking socio-economic transition in the post-pandemic era.

Decades of government subsidies for LPG and electricity have facilitated near-universal clean cooking access and use in Ecuador, placing the nation ahead of most other peer low- and middle-income countries. The widespread socio-economic impacts of the COVID-19 pandemic has threatened the resilience of clean cooking systems globally, including by altering households' ability to purchase clean fuels and policymakers' considerations about continuing subsidy programs. As such, assessing the resilience of clean cooking in Ecuador during the pandemic can offer important lessons for the international community, especially other countries looking to ensure resilient transitions to clean cooking. We study household energy use patterns using interviews, newspaper reports, government data on household electricity and LPG consumption, and household surveys [ = 200 across two rounds]. The LPG and electricity distribution systems experienced occasional disruptions to cylinder refill delivery and meter reading processes, respectively, which were associated with pandemic-related mobility restrictions. However, for the most part, supply and distribution activities by private and public companies continued without fundamental change. Survey participants reported increases in unemployment and reductions in household income as well as increased use of polluting biomass as a secondary fuel. Ecuador's LPG and electricity distribution systems were resilient throughout the pandemic, with only minimal interruption of the widespread provision of low-cost clean cooking fuels. Our findings inform the global audience concerned about the resilience of clean household energy use on the potential for clean fuel subsidies to facilitate continued clean cooking even during the COVID-19 pandemic.

Existing efforts to promote cleaner fuels have not achieved exclusive use. We investigated whether receiving 12 months of free liquefied petroleum gas (LPG) and behavioral support could motivate continued purchase and use.

Access to clean energy for cooking is central to achieving Sustainable Development Goal 7. Latest predictions suggest that this goal will not be met by 2030, with further setbacks due to the COVID-19 pandemic. We investigated the impacts of COVID-19 restrictions on household cooking fuel, practices and dietary behaviours in a peri-urban community in Central Cameroon. Using surveys (n = 333) and qualitative semi-structured interviews (n = 12), we found negative financial impacts and high levels of food insecurity, with 83 % and 56 % of households reporting reduced income and insufficient food, respectively. Households reduced food intake and cooking frequency and relied more heavily on local sources (e.g., farmland) to feed their families. Changes in primary cooking fuel were less pronounced and fuel choice was inherently linked to cooking behaviours, with some households utilising LPG more often for simple tasks, such as reheating food. Local systems were key in sustaining food and fuel access and households demonstrated resilience by employing numerous mechanisms to overcome challenges. Our findings underline the vulnerability of households in maintaining sufficient food intake and sustaining clean cooking, highlighting how policy needs to take a nuanced approach considering food-energy dynamics and strengthening local systems to ensure access to clean energy is resistant to system shocks.

Since the World Health Organization announced the COVID-19 pandemic, indoor airflows became a synonym for virus super-spreaders and the focus point for the scientific community and professional associations across the globe, disrupting all daily life dimensions. Europe's quick response to control the disease led the REHVA board to address mitigation guidelines, reassessed by each member association's following national specifics. The present study aims to quantify the energy consumption and CO emissions of "large office" buildings in top-five European economies under the COVID-19 guidelines under the post-pandemic telework forecast. Methodology resorted to a standard model under Building Energy Simulation assessment to compare prior and posterior scenarios. The latter displays a tendency to increase energy and CO emissions in all locations, in the first form 10.18% (Rome) to 69.48% (Paris); and second 5.80% (Rome) and 120.61% (Paris), which will affect national energy production and imports, urban pollution and business competitiveness. On a different scope, future HVAC guidelines need to address the incoming figures, particularly in highly dense urban areas. Also, to comply with the goals set by the Paris Accord.

The COVID-19 pandemic has introduced opportunities for more research in resilience as globally cities experienced lock-down, causing change to conventional energy consumption pattern especially in the residential sector. This study aims to quantify the increased energy demand during work-from-home arrangement, using high-rise public residential buildings in Hong Kong, where its government announced work-from-home arrangement four times in 2020. Building energy modellings were conducted to compare the total energy demand of residential units during normal and work-from-home arrangements, followed by validation against peer models and empirical data. A 9% residential energy demand increase was demonstrated, hence additional energy supply became desirable for the sake of resilience. This study assesses the possibility to leverage photovoltaic rooftop to supplement the increased energy demand. The photovoltaics' potential contribution was estimated by solar energy simulation and evaluated in terms of the capability to utilize its generation output to supplement the additional energy demand. During the four work-from-home periods, it was shown that a photovoltaic system could have supplemented 6.8% - 11% of the increased energy demand, mainly subject to the air-conditioning operation and solar generation. These findings are valuable to safeguard energy resilience in upcoming grid planning and operation.

This paper investigates the factors affecting access to clean cooking fuel among rural Indian households during the COVID-19 outbreak, based on World Bank's rural impact survey, covering 2731 rural households. Our analysis shows a significant decline in access to clean fuel among rural households from 35% in 2018 i.e. before COVID-19 to 19.7% during the COVID-19 pandemic. This implies that in order to meet their cooking needs, many rural households have switched from conventional fuels, which have numerous health and environmental concerns. The association between states and socio-demographic profiles of rural households with access to sources of cooking fuel shows a significant difference. The analysis results further indicate that socio-demographic characteristics and asset holdings of the rural households are the key factors that determine access to clean cooking fuel during COVID-19. Among the socio-demographic variables, age, gender, family size, social category, and income level are estimated to be significant factors that affect the access to clean fuel for cooking. Similarly, ownership of assets such as exclusive kitchen room, refrigerator, pressure cooker, television, and furniture are significant factors affecting access to clean cooking fuel among Indian rural households. Additionally, this study provides policy insights on developing mechanisms to ensure that rural households have an access to clean cooking fuel during crisis situations such as COVID-19.

The COVID-19 pandemic continues to wreak havoc on global operations and economies. Inadvertently, lock-downs and working from home have reduced the daily carbon footprints of inter alia transport and office buildings. A beneficial consequence of carbon footprint reductions is the ability to measure the differential demand of occupants, to benchmark the base load of buildings, and identify opportunities for efficiency improvements. In this paper we evaluate the change in energy demand in five public schools in South Africa with changes in occupancy due to the COVID-19-imposed lockdowns. We make recommendations to carry these savings into the everyday operation of the schools, and estimate the savings for forthcoming closures.

If hydrokinetic turbines are to make a significant contribution to small scale off-grid power supply, they will need to be affordable, reliable and easily deployed at many sites, not just a few with exceptional combinations of depth and high flow velocity. Few if any products currently on the market meet these criteria. This paper addresses the challenge of providing small scale electrical power and pumping from rivers, in particular for villages in high rainfall tropical areas where there is no mains power, not much wind or sunny weather in the wet season, and not enough elevation for conventional micro-hydro. Hydrokinetic power is proposed, and candidate turbines are evaluated, including multiple small axial flow turbines, various forms of horizontal axis Darrieus turbines, water wheels, and belt turbines. The importance of channel blockage in enhancing turbine power output is discussed.

Reducing the burden of household air pollution could be achieved with exclusive adoption of cleaner fuels such as liquefied petroleum gas (LPG). However, we lack understanding of how much LPG is required to support exclusive use and how household characteristics affect this quantity. This paper used data from 90 participants in the Cardiopulmonary outcomes and Household Air Pollution (CHAP) trial in Puno, Peru who received free LPG deliveries for one year. Households with a mean of four members that cooked nearly exclusively (>98%) with LPG used an average of 19.1 kg (95% CI 18.5 to 19.6) of LPG per month for tasks similar to those done with the traditional biomass stove. LPG use per month was 0.5 kg higher for each additional pig or dog owned (p=0.003), 0.7 kg higher for each additional household member (p<0.001), 0.3 kg higher for households in the second-lowest compared to the lowest wealth quintile (p=0.01), and 1.1 kg higher if the household had previously received subsidized LPG (p=0.05). LPG use per month was 1.1 kg lower during the rainy season (p<0.001) and 1.7 kg lower during the planting season (p<0.001) compared to the cold and harvest seasons, despite the fact that LPG was not typically used for space heating. LPG use decreased by 0.05 kg per month over the course of one year after receiving the LPG stove (p=0.02). These results suggest that achieving exclusive LPG use in Puno, Peru requires that rural residents have affordable access to an average of two 10 kg LPG tanks per month. Conducting similar investigations in other countries could help policymakers set and target LPG subsidies to ensure that households have access to enough LPG to achieve exclusive LPG use and the potential health benefits.

Widespread adoption of clean cooking fuels is a necessary step toward reducing household air pollution and improving population health. Here we use large-scale surveys (10,000 households) from two Indian states, Kerala and Rajasthan, to examine how education and attitudes toward cooking associate with the adoption of liquefied petroleum gas (LPG), India's most popular clean cooking fuel. We report three main results. First, education is a strong predictor of LPG adoption. Second, perceptions that LPG is good and affordable and progressive health-related perceptions are associated with LPG ownership. Third, and surprisingly, education does not predict positive attitudes toward clean cooking fuels. These results suggest that education leads to LPG adoption, but not through attitudinal changes. Further research should examine the mediators of the observed robust education-adoption association.

Household air pollution generated using solid-fuel cookstoves is a leading risk factor for morbidity and mortality worldwide. Many studies have quantified cookstove emissions with respect to the main fuels used (e.g., wood, charcoal and other biomass fuels). Anecdotal evidence suggests a variety of fuels are used to ignite cookstoves, however quantitative information on startup fuel types is lacking. Emissions from startup materials contribute to household air pollution. As such, understanding startup practices and the choices of startup materials is integral to understanding the full burden of household air pollution from cookstoves on health and the environment. We conducted an expert elicitation style survey to gather information about startup practices worldwide. Twenty-three respondents from academic and private sectors responded to a survey instrument on cookstove startup, providing information that covered 48 geographic locations across 22 countries. Responses to the open-ended questions were analyzed to quantify how startup materials vary according to factors such as location, seasonality, and the main cooking fuel/stove type. A wide variety of materials were reportedly used to ignite cookstoves, including many non-biomass materials that may have toxic combustion byproducts. Paper, plastic, agricultural wastes, waxes and other petroleum fuels (e.g., kerosene), and rubber-like materials (e.g., tires, footwear) were the most commonly indicated startup materials. Additional materials mentioned included fabrics, plastic packaging, soda bottles, snack food wrappers, and trash. Results from this survey can be used to direct future research on the impacts of startup materials on health and the environment, such as justifying the choice of materials to test in the laboratory.

This paper reviews the experience of a for-profit firm in Rwanda promoting biomass pellets and a fan micro-gasification improved cookstove as a clean cooking alternative to charcoal. Consumers purchase locally produced biomass pellets and receive the improved cookstove on a lease basis. The cost of the pellets and stove(s) is lower than the cost of cooking with charcoal in the urban setting where our study takes place. Inyenyeri has been piloting its business model since 2012. Using data from an ongoing quantitative impact evaluation study, focus group discussions, and a series of key informant interviews, we chronicle the firm's experience with stove choice, pellet production, and marketing, highlighting lessons for the design of private sector led clean cooking interventions We find that 38% of households marketed to as part of our ongoing impact evaluation study adopted the pellet and stove system, but that approximately 45% of those who adopted suspended contracts after signing up. The firm's experience with stove choice, pellet production, pricing structures, and customer service strategies have influenced implementation, adoption rates, and scale-up. Customer preferences for specific stove attributes and willingness of stove manufacturers to modify stoves for local conditions have influenced both the firm's choice of stove and customer satisfaction. In 2015 the firm transitioned customers from the Philips stove to the Mimi Moto, a decision which created confusion among consumers, and affected adoption rates. Despite the challenge of establishing and scaling-up pellet production in central Africa, the firm increased production 400% between 2014 and 2017 to reach 800,000 kg/year. Importing and maintaining pelletizing equipment in Rwanda is costly, the supply of feedstock, and undercapitalization of the firm have affected production. With respect to marketing, after experimenting with a sign-up fee and a minimum monthly purchase of pellets, the firm has decided to transition to a pay-as-you-go system to reduce perceived risk by consumers. A high-level of customer service including in home visits, free in-home repair, and home delivery of pellets are major innovations. The long pilot phase and the evolutionary nature of the firm's activities illustrate both the complexity of building a market for clean cooking, and the time required to understand nascent markets and consumer demand.

Approximately 3 billion people, most of whom live in Asia, Africa, and the Americas, rely on solid fuels (i.e. wood, crop wastes, dung, charcoal) and kerosene for their cooking needs. Exposure to household air pollution from burning these fuels is estimated to account for approximately 3 million premature deaths a year. Cleaner fuels - such as liquefied petroleum gas, biogas, electricity, and certain compressed biomass fuels - have the potential to alleviate much of this significant health burden. A wide variety of clean cooking intervention programs are being implemented around the world, but very few of these efforts have been analyzed to enable global learning. The Clean Cooking Implementation Science Network (ISN), supported by the U.S. National Institutes of Health (NIH) and partners, identified the need to augment the publicly available literature concerning what has worked well and in what context. The ISN has supported the development of a systematic set of case studies, contained in this Special Issue, examining clean cooking program rollouts in a variety of low- and middle-income settings around the world. We used the RE-AIM (reach, effectiveness, adaptation, implementation, maintenance) framework to coordinate and evaluate the case studies. This paper describes the clean cooking case studies project, introduces the individual studies contained herein, and proposes a general conceptual model to support future planning and evaluation of household energy programs.

A recently completed randomized controlled study in Nigeria that transitioned pregnant women from traditional fuels to ethanol in their cook stoves demonstrated improved pregnancy outcomes in mothers and children. We subsequently conducted a pilot study of 30 households in Lagos, Nigeria, to determine the acceptability of blended ethanol/methanol as cooking fuel and willingness to pay for the Clean Cook stove. A third of the pilot participants expressed a willingness to purchase the stove for the minimum price of 42 USD or more. Fuel sales data suggest sustained, but non-exclusive, use of the CleanCook stove. These results will influence the final design and implementation of a planned 2500 stove commercial pilot that is scheduled to start in Nigeria in August 2018.

Approximately 80% of Ethiopia's energy consumption is dominated by woody biomass fuel use, resulting in 91.2 million tons of firewood and 4.2 million tons of charcoal consumed annually. Ethiopia's dependency on non-sustainable energy, especially for cooking, has been a major concern for the nation for the past 30 years, contributing to deforestation, climate change, and adverse human health impacts.

This paper analyses the Africa Biogas Partnership Program (ABPP) in Kenya, Tanzania and Uganda. ABPP was established in 2009 to promote adoption of biodigesters by rural households in sub-Saharan Africa. We use the RE-AIM framework (Reach, Effectiveness, Implementation, Adoption, Maintenance) with information from literature, internal documents, primary data from user surveys and interviews with sector stakeholders. ABPP was implemented with the primary objective of establishing viable biodigester markets. By 2017, Kenya made most progress toward commercial viability, evidenced by market entry of companies offering prefabricated digesters and establishment of 22 marketing hubs, which link rural organizations with local construction enterprises and finance institutions. In Uganda 5 marketing hubs were established and in Tanzania 7. Between 2009 and 2017 over 27,000 households installed a biodigester, half of them in Kenya. Additional objectives include improving agricultural productivity by using bioslurry, improving health, reducing deforestation, and improving livelihoods. Households perceive higher crop yields (84%-91% of users), reduced fuel consumption (84%-94% of users), reduced eye problems and respiratory symptoms (45%-91% of users). Benefits most appreciated are "easy cooking" and "saving time and money". Fuel consumption tests show households with biodigesters use 2.1 to 3.3 fewer tons of wood per year than similar households without biodigesters. The ABPP case study suggests that the program has created a nascent biodigester market in East Africa. The country programs have been dynamic and adaptive, moving along the cycle of market development; however, many challenges remain. For example, while half of the adopters in Kenya exclusively use biogas for cooking, in Uganda and Tanzania fuel stacking is more prevalent, making it more difficult to achieve health and environmental objectives. In addition, high upfront cost, limited access to credit, and lack of maintenance present challenges. In 2016, 27% of biodigesters constructed between 2009 and 2013 were not working. In response, ABPP implemented call centers and launched campaigns to repair non-functioning plants. To ensure long-term viability and increase the likelihood of achieving environmental and health goals, we suggest deeper engagement with governmental and non-governmental stakeholders and a targeted campaign promoting exclusive use.

The National Biodigester Program (NBP) was established in 2006 to build and maintain household biodigesters in Cambodia. In its first six years, the program installed almost 20,000 biodigesters and established an in-country network of local financiers, construction companies, skilled masons, bioslurry specialists and after-care technicians accessible to rural users in 14 of 24 Cambodian provinces. Since its initial success, the program's adoption rates have stalled despite increasing government support and high rates of user satisfaction. Building on an initial evaluation of the NBP in 2013, this updated assessment identifies multiple changes in its second implementation phase that have undermined the initial momentum of the program. Abrupt interruptions in institutional support, deteriorating supply side services (access to construction agents, masons, repair services) and reduced access to credit for farmers have eroded the service network that the first implementation phase established. Structural changes in the rural economy may also contribute to declining demand. Government support to another biodigester program which offers a lower investment price, but does not provide after-sales services has also undercut the long-term implementation strategy of the NBP. The paper finds that despite these programmatic changes, the installed biodigesters continue to perform according to expectation and to be maintained and valued by their users, but the future viability of the program remains uncertain.

In 2016, the government of Cameroon, a central African country heavily reliant on wood fuel for cooking, published a Masterplan for increasing primary use of LPG from 20% to 58% of households by 2035. Developed via a multi-sectoral committee with support from the Global LPG Partnership, the plan envisages a 400 million Euro investment program to 2030, focused on increasing LPG cylinder numbers, key infrastructure, and enhanced regulation. This case study describes the Masterplan process and investment proposals and draws on community studies and stakeholder interviews to identify factors likely to impact on the planned expansion of LPG use.