06 June 2013 – Though urbanisation is underway in Africa as it is in other parts of the world, the continent’s population remains more rural than urban. Figures from 2010 indicate that while Africa had an urban population of some 400 million people, over 620,000 people still live in rural areas. The projection for 2030 is that the continent will have an urban population of some 750 million people but a larger rural population of over 800 million.

Figures from the International Energy Agency indicate that 59% of Africa’s population has no access to electricity but the figures skew further in comparing urban to rural populations, with 85% of the latter without access to electricity. Based on current development trends, by 2030 almost 600 million of the rural population in Africa will remain without access to electricity.

According to Engineering and Technology magazine (http://eandt.theiet.org/magazine/2013/05/power-to-the-people.cfm) power grids in rural Africa currently tend to be powered by diesel generator sets that often run for 24 hours a day. While relatively cheap to buy, speedy to install and simple to use, diesel generator sets burn a lot of fuel, push out CO2 and require a lot of refuelling and maintenance. Rising diesel prices and environmental concerns are driving grid operators to reconsider this option.

While further investigation and analysis is required, it has been recognised that throughout sub-Saharan areas in particular – where transport infrastructure is immature, fossil fuels are unsubsidised and, according to IEA data, 99.6% of the African population without electricity access is concentrated – renewable energy technologies offer opportunities to improve access to energy for rural communities. However, to meet demand, investors will need to push energy production to high levels of sustainability.

Solar photovoltaic (PV) and thermal technologies have been promoted across sub-Saharan Africa. Solar energy is well established in many urban areas, and is used for: power generation, water heating, detoxification, telecommunications and transport at an industrial level; water pumping, purification, vaccine refrigeration, and electrification at a municipal level; and lighting, cooking, heating and to run modern appliances at a domestic level.

With the potential to enhance both social and economic aspects of village life in remote areas, rural solar electrification faces very different challenges to those faced by urban projects. Food preservation and pumping systems reduce hunger and improve access to safe drinking water. Recent solar-panel cost reductions have broadened the range of economical applications for solar water pumps, enabling farmers to irrigate crops.

Following successful implementation, solar-powered lighting enables shopkeepers to conduct business for longer without resorting to dangerous, naked-flame light sources. Schools and clinics can run refrigeration and telecommunications. Rural electrification means that residents can safely gather during the hours of darkness and children can study longer. Communities can power perimeter security and support emergency medical care.

However, as recently as a decade ago, in-depth analysis by South Africa’s Council of Scientific and Industrial Research (CSIR) showed that renewable energy systems were unsustainable for rural areas in terms of both social demand and stability of supply. Some 70% of the capital and running costs were seen to relate to costs of lead acid DC storage and DC to AC conversion, which led to unaffordable high energy prices.

In addition, electrical technologies are more difficult to understand than mechanical power generation solutions. Rural areas are particularly susceptible to technical skill gaps that hamper the uptake of electrical renewable energy technologies such as solar photovoltaics. Projects that see experts depart following initial installation can fail in the longer term. Retaining local levels of technical expertise is a prerequisite for sustainable renewable energy technology implementation.

However, there are successes. A market development approach is enabling a member of the Alliance for Rural Electrification (ARE) to bring renewable energy to thousands in sub-Saharan Africa. The organisation forms sustainable supply-chains by providing training and finance to renewable electrical technology entrepreneurs, technicians and support staff. Large-scale marketing campaigns and local demonstrations promote public awareness and incite demand. Credit and carbon schemes improve product affordability. This approach has reportedly enabled this energy supplier to deliver electricity to 500,000 people at a cost of less than US$6 per connected person.

Manufacturers have developed hybrid technologies that integrate a variable-speed diesel DC generator with a battery pack. The generator charges the battery as it powers the site load. Once fully charged, the battery takes over and the generator shuts down. By becoming the primary power source, the battery reduces generator runtime by about four hours a day, typically delivering a reduction in operating costs of between 50% and 85%.

Hybrid power systems are suited to applications in the developing world, where they are widely used to power mobile base stations, due to the widespread use of mobile phones. Designed for fast handling and deployment, a typical model comprises power generator, battery packs, a low-cost cooling unit and fuel tank where required. Easily transportable, adaptable and scalable to site needs, modular hybrid power systems eliminate AC/DC rectifiers and use batteries capable of operating in extreme temperatures without the need for complex air-conditioning systems. Four to six battery modules can be connected in parallel according to the site load. Battery manufacturers claim a lifetime expectation of five or more years, with payback between 12 and 18 months.

Solar panels or a wind turbine can be included as part of a scheme alongside diesel generators to supply the recharge current. The battery can also be combined with solar PV and wind power, discharging at night or in times of low wind-speeds and recharging in sunlight hours or windy periods. It is feasible that renewable energy technologies might completely replace the diesel generator.