The Technology Radar's examination of the solar lantern encompasses a wide range of lighting solutions that integrate power source, power storage and lamps. These solutions have been developed with the specific objective of meeting the basic lighting needs of people who either have no access to electricity or whose electricity supply is unreliable.
From a global perspective, the main role of solar lanterns is to provide the "off-grid“ population (more than 1.4 billion people) with basic lighting services. This technology is generally inexpensive for the consumer and incurs virtually no running costs, making it an appropriate option for the off-grid population.
Solar lanterns are expected to replace traditional lighting in off-grid regions. In these regions, the major source of energy for traditional lighting is fossil fuel (kerosene). Therefore, if solar technology is widely adopted it has the potential to make a considerable reduction in levels of greenhouse gas – and other hazardous – emissions.
Solar lanterns are becoming the preferred option for the provision of basic lighting services to the off-grid population. Solar lanterns provide light that is more effective, cleaner and of better quality than light from any of the traditional sources (e.g. candles or kerosene lamps). The provision of lighting services is linked to a number of development priorities, such as reducing exposure to the hazard of indoor air pollution and increasing the possibilities for education and productive work by enabling people to pursue these activities during the hours of darkness.
By replacing traditional kerosene lamps, the solar lantern offers a number of environmental improvements. Notable examples include the reduction of indoor air pollution and the contribution to climate change mitigation.
Kerosene combustion produces hazardous air pollution. Kerosene lamps are often used in enclosed spaces (e.g. in the home or in a small business premises). The concentration of toxic particles can reach high levels and considerably increases the probability of the development of chronic bronchial diseases. Solar lanterns do not produce toxic emissions during operation.
The operation of the solar lantern does not produce greenhouse gas emissions. From a lifecycle perspective, the production and distribution phases of the product are the major source of emissions. There appear to be few, if any, sound lifecycle assessments of the technology. However, the quality and effectiveness of light from solar lanterns is several times better than that produced from kerosene lamps and the energy and resource efficiency of the production processes of the relevant technologies (e.g. solar PV and LED lamps) is continually improving. The expectation is, therefore, that even from a lifecycle perspective the use of solar lanterns will generate far lower levels of greenhouse gas emissions than the use of kerosene lamps or other traditional lighting options.
The practices for the end-of-life of the components of solar lanterns may become a controversial issue. In particular, establishing appropriate systems for the collection of used batteries may be crucial in order to avoid negative environmental impacts and also to recover valuable (scarce) materials, thereby improving the overall resource efficiency of the technology.
Setting financial mechanisms
Populations that lack access to electricity traditionally also lack access to other infrastructure and services (e.g. roads and markets). Potential consumers are generally dispersed across rural regions rather than concentrated in urban or semi-urban centres. Building cost-efficient distribution networks to reach this population may require the involvement of various local players (e.g. distributors and small retailers). Establishing new local businesses along the supply chain may also necessitate special financial schemes.
Additionally, after-sales maintenance and repair services are crucial for ensuring the long-term adoption of the technologies. The provision of technical training for local service suppliers, as well as clear channels for warranty enforcement, may need to be part of the strategy for growing the solar lantern market.
The market for basic lighting products is very diverse. However, a considerable proportion of commercial products are of poor quality. Consumer dissatisfaction and discredited products may damage the market's reputation. The enforcement of quality standards and certification, as well as the provision of appropriate information channels for the consumer and research into their experience of different products, may help to avoid the wrong purchases being made (i.e. avoid consumers losing money they can ill-afford). This, in turn, may protect against potential damage to the solar lantern market.
Different concepts for solar lanterns are already penetrating the market for basic lighting solutions and the diversity of designs is still growing. A wide variety of models are being developed in order to better respond to the very different requirements of users. However, assuring quality is still a crucial issue in order to further develop the technologies.
Technical tests carried out on behalf of the German Agency for International Cooperation discovered that most of the commercially available solar lanterns are of very low quality. A wide range of potential improvements have been identified, e.g., amongst others, the mechanical and electrical design, the actual light output of the products, the recharging control of batteries, the efficiency of the ballast for the lamps, more accurate labelling of the products (the technical data given is often "too optimistic“). 1
Users' expectations are very diverse. A striking example is the quality of light, which includes the light intensity and the size of the light cone, i.e. whether it is for ambient lighting or is a more direct light for specific tasks such as reading or weaving. Some users would prefer to have a switch and a (relatively) fixed lamp rather than a portable device. The option for additional functions (e.g. mobile phone charging, radios etc.) is perceived as particularly useful. Other features, such as the means to easily supervise the charging/discharging process of the battery or the ease of access to maintenance and repair services, may be crucial for ensuring the long-term adoption of solar lanterns.2
Due to the fact that the users' expectations are so diverse, the most likely future market scenario is one in which a range of product concepts become established as preferred solutions to meet the various end-user requirements, as opposed to a single option emerging as the overall best design.
Solar lanterns integrate components from technological fields that are still in a dynamic and innovative phase, such as solar photovoltaic, LED lamps and rechargeable batteries. It is anticipated that within the next few years the further development of these technologies will result in significant improvements in performance, as well as in cost reductions.
The solar modules account for around 30% of the total cost of the solar lantern. Since 2008 the cost of photovoltaic modules has been rapidly declining. Continued technological innovation and growth in global production capacities may lead to further price reductions. This dynamic may help to make solar lanterns more affordable.
In the field of LED lamps, considerable improvements in performance and in cost reduction have already been achieved. Further increases in the effectiveness of the light produced will translate into lower power demand and allow for the use of smaller solar modules and lighter batteries. Further significant cost reductions are also expected over the next few years: a drop in the cost of LEDs by 75% may be achieved by 2015. 3
In the field of rechargeable batteries, the development of the Lithium-Ion (Li-Ion) battery is, in particular, driving technological innovation and cost reductions. The share of Li-Ion batteries in the solar lantern market is still small, around 5% according to Lighting Africa 2010. However, due to the expected cost reductions and technical advantages (such as longer life-cycle, higher energy density and greater durability), it is predicted that solar lanterns will increasingly use Li-Ion batteries.
The market price for a solar lantern ranges from around $17 to over $120.4 Lighting Africa, 2010 estimates the average manufacturing costs of portable lanterns to be around $20. Cost reductions of 40% are expected during the next few years, meaning that manufacturing costs may fall to $12 by 2015. The actual price for the consumer can be twice as high as the manufacturing costs, or even higher.
By providing an alternative to the use of kerosene lamps and other traditional lighting options such as candles, the investment in a solar lantern can translate into savings in terms of fuel for lighting. Taking into account the current average price of kerosene in Africa, the payback period for an investment in an average portable solar lantern is around eight months.3 Furthermore, considering the expected reduction in manufacturing costs combined with other optimistic assumptions about the development of the solar lantern market, set against the increase in kerosene prices, Lighting Africa estimates that the theoretical payback period could reduce to five months – or even less – by as early as 2015.