Tag Archives: solar cooking

Solar Cooking and Energy Service Companies: An Unexplored Market Opportunity?

Solar cooking, as a technology and group of products, has existed for many decades, with examples being used in the 1970s. The technology in its simplest form has remained relatively unchanged since then, with the basic premise being either a flat or parabolic reflecting surface, placed in the sun, reflecting sunlight onto a cooking chamber. This can be either below the flat-plate reflector, or at the focal point of the parabolic collector. These types of devices are easy to manufacture and can be extremely cost-effective, with little more than a reflecting surface (for example, foil-backed card) and a cooking vessel needed for a minimum setup. These features give this technology particular applicability for targeting bottom-of-pyramid consumers with sustainability interventions: typical prices for simple designs (such as the flat-plate reflector shown below) range from US$3-5.

Solar box cooker made from carboard boxes and aluminium foil. Image: https://nakazora.files.wordpress.com/2011/06/solar-cooker1.jpg

Parabolic solar cooker in use at an informal settlement in Barcelona. Image: Brinerustle / Wikimedia Commons / CC BY-SA 3.0


A number of companies currently distribute simple kits for creating solar cookers from scratch, usually in the form of a reflective card template for the reflecting surface. However, these pre-packed kits are often more expensive than locally-sourcing materials for manufacture, ranging up to US$30-40, without offering meaningful benefits to the consumer aside from convenience. There are also a number of companies in developing countries that distribute full solar cookers to consumers using a direct-purchase business model, such as SunFire in South Africa and L’Obel Solar Power in India. Prices for these designs, commonly higher-quality parabolic mirror cookers, range up to US$200.

As such, it appears there is an opportunity for low-cost solar cooking business to develop markets for cheap, reliable solar cookers for bottom-of-pyramid consumers. In addition, through using alternative payment models for business, higher-cost designs can become more accessible to a greater number of consumers. Offering micro-credit products for deferred purchasing of solar cookers, or engaging with consumers on a fee-for-service basis with consumers paying a monthly fee for their product, would allow mid-range technologies to become accessible to consumers with lower incomes.

Other opportunities exist in the solar cooking market space for complimentary technologies, in particular heat-retention bags such as the Wonderbag from South Africa. This is designed to fit around the cooking vessel to retain heat and slow-cook the contents, after it has already been heated, reducing the overall energy requirement for cooking. Whilst this technology is perhaps most applicable to wood or charcoal-fired stoves, it can also help improve convenience when using solar cooking products. For example, rather than leaving a cooking vessel in the solar cooker for up to six hours, it can be left there for 1.5-2 hours, then transferred to the Wonderbag for further cooking.

For more information on the Wonderbag and use-case studies, please refer to https://samsetproject.wordpress.com/2017/04/10/energy-poverty-in-peri-urban-communities-in-polokwane-south-africa-part-1-identifying-the-issues/

— Daniel Kerr, UCL Energy Institute


Teach A Man To Fish (2009) Solar Cooker Business Guide. Available at: http://www.teachamantofish.org.uk/resources/incomegeneration/Solar-Cooker-Business-Guide.pdf

Gautam (2011) Microfinance Intervention for Financing Solar Cooking Technologies – Financing With Savings. Available at: http://www.microfinancegateway.org/sites/default/files/mfg-en-paper-microfinance-intervention-for-financing-solar-cooking-technologies-financing-with-savings-mar-2011.pdf

Solar Cookers International: CooKit. https://shop.solarcookers.org/?pn=CooKit&cn=Solar+Cookers&p=621&c=27

L’Obel Solar Power Systems: Solar Thermal Products: http://www.lobelpower.com/solar_thermal_product.htm

SunFire Solutions: http://www.sunfire.co.za/wp/

Wonderbag World: http://www.wonderbagworld.com/


What Could the Energy Transition Be for Thermal Energy Services in the Global South

The STEPs project (Sustainable Thermal Energy Service Partnerships) funded by Dfid-DECC-EPSRC is about the design of public private partnerships for the provision of thermal energy services targeting the poorest in developing countries.  The STEPs research focuses on thermal energy services for households and small producers.  The following posts describe what the main needs are in terms of thermal energy services, and with which technologies they could be provided.

Households and small producers in developing countries have needs in terms of cooking, heating/cooling, refrigeration and drying which vary according to the geographical, socio-economic and cultural conditions found in their locations, and can be satisfied in a very different manner than in industrial countries.  Not only can the technologies used be different, but the entrepreneurial model which can help to disseminate these technologies is particular to the Global South: social entrepreneurs, cooperatives, informal groups or established small rural companies acting like utilities have to be involved.

The sustainability of their business models implies the need to find the right mix between different technologies and services provision adapted to the context they evolve in.


Currently cooking in developing countries is mainly done using non-efficient cook stoves using traditional biomass (wood, charcoal) or fuels like coal or paraffin. More infrequently efficient cook stoves, bio-digesters or more rarely LPG (Liquefied Petroleum Gas) are used for cooking in rural areas.

Improved cook stoves have been tried to be disseminated for several decades now with mixed results. It seems cook stoves of all kind of shapes and made of all kind of materials have been conceived without being able to reach their intended market. Improved cook stoves fall broadly into two categories – cook stoves that use traditional wood fuels more efficiently, or cook stoves that use improved fuels such as unprocessed charcoal, briquettes or pelletised fuelwood.


A small selection of the diverse design options for clean cookstoves. Image credit: GIZ 

One of the aims of the STEPs project is to understand if public-private partnerships similar to the ones established for rural electrification could facilitate the dissemination on a very large scale of improved cook stoves. This is done by reviewing the (few) successful experiences of large-scale dissemination of improved cook stoves, for example the National Biogas Cookstoves Program (NBCP) in India (http://www.mnre.gov.in/schemes/decentralized-systems/national-biomass-cookstoves-initiative/), and determining how private business can take charge of the distribution and the marketing of improved cook stoves.

Another way of facilitating the energy transition in terms of cooking facilities is to encourage the use of LPG (Liquefied Petroleum Gas). LPG may not be a very low-carbon energy but it is considered a lot cleaner/less damaging for the environment and efficient than the use of traditional fuels. Unfortunately, the logistics of distribution in remote places makes it unaffordable for the poorest unless a program of subsidies is also implemented, which experiences show are difficult to target. For example, the Ghanaian LPG distribution and promotion program started in the 1990s, and continuing today, has experienced difficulties through cross-subsidising LPG, intended for cooking, through gasoline sales. This led to a rise in LPG transport use and conversions, particularly in urban taxis, skewing sales towards transport use and not rural cooking use as intended by the government program.

Bio-digesters can produce methane for cooking. This technology is widely disseminated in few countries like China or India, but not so much in sub-Saharan African countries. Various reasons have been invoked to explain this situation – low density of population/small size of holdings notably. It seems nevertheless than even if conditions may be less favourable in African countries than Asian countries, there could be specific services organised around collective use of bio-digesters (e.g. cooking in a school by collecting waste from a community).

There are two main approaches to household biodigester construction. The traditional technology is a dome-type biodigester, with the digesting chamber constructed from compacted earth or brick. These are cheap and easy to construct, but are prone to failure and require significant maintenance for good efficiencies. Modern household biodigesters are made from prefabricated plastic digesting chambers, which only require maintenance to maintain the digestion process, and are significantly more durable than the traditional type.

biodigester in cantonment

Biogas construction in cantonment (4971874669)” by SuSanA Secretariat – https://www.flickr.com/photos/gtzecosan/4971874669/. Licensed under CC BY 2.0 via Wikimedia Commons

africa biodigester

Prefabricated biodigester being installed in South Africa. Image: popularmechanics.co.za

agama biogas

Prefabricated biogas digester being constructed by AGAMA Bioenergy worker in South Africa. Image: Agama Biogas PRO via Youtube

Solar cooking and solar ovens are another technology that can be used for cooking in rural areas of developing countries. The Global South, and Sub-Saharan Africa in particular, generally has a good level of insolation for the use of solar technologies. Solar cooking technology however has struggled to find a foothold in Sub-Saharan African markets, and is at a low level of dissemination despite the maturity of the technology. A number of factors could be behind this, most notably the lack of convenience associated with solar cooking and the long cooking times and forward planning associated with using the technology.

ikiwaner solar oven 2008

A solar oven being demonstrated in Ghana. Credit: Ikiwaner / Licensed under CC BY 2.0 by Wikimedia Commons

– Xavier Lemaire & Daniel Kerr – UCL