Tag Archives: solar

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/


Kitonyoni Solar Mini-grid and Integration of Thermal Energy Services

Binu Parthan from SEA writes on his recent visit to the Kitonyoni Solar Mini-Grid project, part of the University of Southampton’s efforts for the Energy for Development (E4D) project they lead.

The solar mini-grid at Kitonyoni near Machakos in Makueni County was financed by the UK government and commissioned in 2012 by the STEPs partner The Sustainable Energy Research Group at University of Southampton. The Kitonyoni Solar mini-grid is managed by Makueni County Solar Energy Co-op Society Ltd which is owned and managed by the community.


Management of the Solar Electric Cooperative and manager of the mini-grid business. Image: Sustainable Energy Associates

In July 2016, I travelled to Kitonyoni to visit the solar min-grid and meet with the community. While at Kitonyoni, I met with Joseph, Monicah, William and Shadrack from the management Makueni County Solar Energy Co-op Society Ltd and also with Stephen, the manager of the mini-grid and energy service business. With the community leaders and the manager of the mini-grid, I visited several businesses and households that were consuming electricity from the cooperative to understand the business model. The solar electric cooperative seems to be professionally managed and financially sustainable. They operate on a for-profit business basis and the financial accounts reveal that the operation is financially sustainable. The electricity cooperative uses a pre-paid card system for electricity sales and payments which seems to be working well. The electricity consumers are more conscious of energy use and payments and the cooperative is also happy with the upfront collections. The number of shops in the Kitonyoni market has significantly increased since the solar mini-grid was commissioned and the value of the land in the area has also almost tripled. However, the tariff charged by the solar electric cooperative is considerably higher than the public electricity utility but the community has been willing to pay a higher tariff due to better availability and reliability.


One of the new businesses established in the Kitonyoni market powered by the solar mini-grid. Image: Sustainable Energy Associates/span>

STEPs project team at University of Southampton had carried out a survey to examine the possibility of integrating thermal energy services into the existing electrical energy service business model. The results showed that 90% of the households in Kitonyoni use firewood for cooking which is available without cost to the community (Bahaj and Kanani, 2016). While the households spends over 5 hours to gather firewood, there is limited interest in switching to cleaner cooking options such as LPG which involve additional financial expenditure. The opportunity to integrate a solar thermal energy service along with the electricity service seems rather limited due to limited scope and demand for commercial fuels. The firewood is available freely in the area and LPG distribution networks are not available in the village.  Therefore currently, there does not seem to be a business case for introduction of an LPG franchise model and integrate the model into the solar electricity business. However some thoughts that I shared with the community were:

Since households and restaurants are cooking in separate rooms than their houses and as there is a preference for community schemes, will a community electric cooking scheme succeed? This may be relevant as on most days the battery bank of the solar mini-grid seems to be fully charged in the early afternoon and this could provide an opportunity for a central cluster of electric induction cookers which people can use to cook on a pay per use basis(similar to battery charging) to the cooperative.

It is possible that people may opt for efficient Cookstoves/Jikos if available on a hire-purchase/PAYG basis and reduce the amount of firewood to be collected resulting in time savings. An efficient Jiko will cost 45 $ which could be offered on a loan basis with daily/weekly/monthly payments to people by the cooperative for 6 months to 1 year tenure. These funds could be revolved over the time period to reach other members.

A differential tariff with a lower tier-tariff for the shops and establishments that use electricity during the day will likely improve the revenue model of the cooperative and can increase the utilisation levels. Such a tariff regime could allow the use of induction electric cookers at households during the day. Such a development could result in increasing sales and revenue and improving the business viability.


Cooking using firewood and a metallic stove in Kitonyoni. Image: Sustainable Energy Associates

Therefore the technology options for thermal energy and cooking in Kitonyoni is electric cooking or efficient Cookstoves with the possible business models of pay-per-use or hire-purchase respectively. A differential tariff with lower off-peak tariff could also allow electric cooking during the day time and improve the business model. These options are not entirely obvious and needs to be investigated and defined. This approach will certainly face stiff competition from free biomass availability and availability of free time for fire-wood collection.

Dr. Binu Parthan

What Could The Energy Transition Be For Thermal Energy Services in the Global South – Part 3

Following our previous post on heating, this last post will investigate other energy service needs linked notably to farming activities.


Refrigeration in developing countries in remote areas is rarely found except for specific needs like to keep vaccines for health centres. A number of possibilities exist to provide refrigeration with LPG, with passive solar, and again using ground-source heat pumps, but it seems solar PV is the most economical one. Various attempts have been made at renewable refrigeration over the past 30 years, predominantly focusing on solar collector designs, although photovoltaic vapour compression systems are the most commonly found for vaccine refrigeration. The high cost of these systems can often be justified by the importance of the application.

Larger refrigeration systems based on solar collection/kerosene/LPG power using different absorption refrigeration cycles (for example the Platen-Munters ammonia-water-hydrogen continuous diffusion absorption cycle) have been tested for ice-making in developing countries, but the lack of constant heat sources in renewably-powered systems has made reliability and efficiency a concern. Alternatives do exist to LPG-powered refrigeration in the form of solar refrigeration however, and with the current global lowering of photovoltaic and other solar components, the technology is becoming more cost-effective and viable to small entrepreneurs.


Platen-Munters absorption refrigeration system and cycle. Image – centrogalileo.it

Drying is to be found in agriculture, but not at a small scale for individual households. Tray design solar dryers can be useful for small agricultural businesses to increase productivity, and are often easy to construct from locally-sourced materials. Updraft-style solar dryers are more complex from a design perspective, requiring specific attention to be paid to air flows and moisture extraction from the heating areas.


Solar drying for chilli pepper crop in Peru, with locally-produced equipment. Image: Carlos Bertello, GIZ EnDev Peru.

Other Agricultural Uses

Milk pasteurisation is a critical issue for dairy farmers in the developing world. It has been estimated that over 50% of an average rural dairy farmer’s milk crop in Kenya will spoil before it has been sold, which has a severely detrimental effect on their livelihood and income generation. Modern pasteurisation equipment using steam boilers and batch-type pasteurisers can significantly increase output and income from a rural dairy farm in the developing world.

These steam boilers can be renewably powered, for example through biomass from animal/crop waste. Low-temperature (70-80°C) water can be substituted for steam in the pasteurisation process with only slight plant modifications, and this allows the potential for greater renewable energy use in the process, for example through flat-plate solar collector water heating, or cogeneration/recuperation from electricity generation or refrigeration equipment condensers. Whilst renewable pasteurisation technology has not been a focus of many organisations, the FAO have produced a report on the potential uses and processes for the technology, which is available here (http://www.fao.org/docrep/004/t0515e/T0515E03.htm).


Potential for novel pasteurisation technologies in the developing world, to be powered by renewable electricity from solar or biomass digesters. Image: Openideo, Sarah Rizk, Stanford University.

In conclusion of this series of three posts, there exists vast potential over the wide range of available thermal energy services for the residential, industry and commercial sectors, notably in the Global South in general, and Sub-Saharan Africa specifically. The STEPs project will specifically be working most on the services that appear most viable in the Sub-Saharan African context: cooking/heating services for household needs, and low-temperature hot water production for households. The need for sustainable cooking and household thermal energy is a pressing one, and the STEPs project, through investigating a technology-neutral approach to thermal energy services and business, hopes to address this need.

– Xavier Lemaire & Daniel Kerr – UCL

South Africa’s Renewable Energy Procurement Program

Robert Aitken from Restio Energy offers his thoughts on South Africa’s renewable energy procurement program to date.

South Africa has undertaken a very ambitious renewable energy programme which has the world watching with great interest. It has been said that the current programme to secure 3720MW of renewable energy is the largest in the world at this point in time. The approach used by the government is a competitive bid scheme (IPP Procurement Programme) where the private sector is invited to submit proposals against a stipulated amount of renewable energy required. Each of the identified renewable energy technologies has an associated tariff cap beneath which the bid must sit. The renewable energy technologies involved include; on-shore wind, solar PV, concentrated solar as well as a small amount of biomass, biogas and small-hydro.

It is an innovative and effective scheme which has thus far has been heavily over-subscribed in each of the three rounds assessed. It represents an important step for South Africa for a number of reasons;

  • This is the first large scale utility based renewable energy project in the country.
  • It will provide security of supply by diversifying the generational mix (previously predominantly coal) of electricity in the country
  • It has an increasingly demanding ‘local content’ or localisation component which is intended to stimulate the local renewable energy technology industry
  • It also has a strong community component aimed at ensuring local communities in and around these utilities benefit in a meaningful way.

It is these sorts of parallel requirements that will contribute towards the long-term operations and imbedding of renewable energy in the country. However, one of the service gaps this initiative will not address is access to electricity. The REIPPPP is a powerful grid security initiative which demonstrates the country’s willingness to engage with the private sector, promote renewables etc. Despite this 3.4 million households within the country remain without a grid connection and many households that are electrified cannot afford to use electricity particularly for thermal applications. While security of supply is crucial, the South African government needs to ensure a mixed approach (grid/off-grid, rural energy service delivery, small scale distributed initiatives, etc.) if access for all is to be achieved.

– Robert Aitken, Restio Energy