The rural requirement for sustainable economic growth and an ever-increasing supply of energy is perhaps most pronounced in Africa. Are renewable energy technologies mature enough to meet the demand?
Life without electricity might feel like an apocalyptic scenario in the developed world, but for those living in rural Africa it is a fact of everyday life. According to figures from the International Energy Agency, 59 per cent of the population of Africa has no access to electricity.
Outside the urban centres that figure rockets to 85 per cent. In order to improve living standards and increase the average life expectancy, which currently sits at a lowly 49 years, the provision of sustainable energy sources to isolated communities is essential.
Current development trends suggest that by 2030 almost 600 million people will still lack access to electricity across rural Africa. However, International Renewable Energy Agency (IRENA) and European Commission Joint Research Centre (JRC) experts believe the continent's renewable energy resources have the potential to support future national economic growth and local development.
Power grids in rural Africa currently tend to be powered by diesel generator sets often running 24 hours every day. While relatively cheap to buy, speedy to install and simple to use, diesel gensets burn a lot of fuel, push out CO2 and require a lot of refuelling and maintenance. Rising diesel prices and environmental concerns are therefore driving grid operators to reconsider their offering and reduce emissions.
A report published in 2011 (JRC 67752) assessed in detail the renewable energy options for rural electricity production. It looked at the economic viability of decentralised off-grid renewable technologies against conventional grid extension and transport costs of conventional fuel while taking both population density and transport infrastructure into account. While further investigation and analysis is required, the report recognised that throughout sub-Saharan areas in particular – where transport infrastructure is immature, fossil fuels are unsubsidised and, according to IEA data, 99.6 per cent of the African population without electricity access is concentrated – renewable energy technologies (RETs) 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.
Benefits of solar power
Historically used for drying crops and animal skins, preserving meat, and extracting salt, solar energy is widely recognised as an abundant energy resource.
Solar photovoltaic (PV) and thermal technologies have been promoted across sub-Saharan Africa, with most countries having undergone a major industrial-scale project. 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.
Disease, pandemics and child and maternal mortality are all reduced, while gender equality is arguably supported by relieving women of fuel- and water-collecting tasks. Because of these improvements, young people are encouraged to remain in rural areas, making local economies more stable. Lastly, if access to energy is implemented with environmentally sound technologies, it contributes directly to global environmental sustainability.
Characterised by low population densities with limited financial resources, most rural communities in Africa face high grid connection costs. Remote rural renewable energy development often requires mini-grids or standalone off-grid solutions supported by dedicated public policies, as the set-up is unsuited to the large-scale power plants used in urban environments.
With demand focused more on household and agricultural use, these smaller-scale solutions offer rural entrepreneurs and small power producers investment potential. But, to ensure sustainability, the infrastructure must overcome the barriers associated with remote locations, lack of public awareness and limited affordability while offering long-term compatibility and potential integration with the central grid.
In 2003, the South African Department of Minerals and Energy (DME) ran a project to test the viability of renewable energy for grid-inaccessible locations. The project delivered energy costs that escalated to 0.16 Rand per kWh (some 50 times higher than public utility figures) in 2007, and resulted in energy conversion losses of around 30 per cent between the electricity source and consumer, compared with the 10 per cent experienced by public utility supplies.
In-depth analysis by the Council of Scientific and Industrial Research (CSIR) showed that the renewable energy system was unsustainable in terms of both social demand and stability of supply. The conversion losses were determined to be a result of battery storage and conversion from DC generation to AC distribution. Making up 70 per cent of the capital and running costs, capital costs of lead acid DC storage and DC to AC conversion also led to high energy prices.
The International Off-Grid Renewable Energy Conference (IOREC), held in Accra, Ghana, in November 2012, illustrated that several innovative business models have been successfully adapted to the off-grid market.
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 RETs such as solar PV. 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 RET implementation.
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 RET 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 enabled this energy supplier to deliver electricity to 500,000 people at a cost of less than £4 per connected person.
In order to meet a growing demand for low-cost, reliable power solutions with reduced environmental impact, manufacturers have developed hybrid technologies integrating 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 genset runtime by around four hours per day, typically delivering a reduction in operating costs of between 50 to 85 per cent, a reduction in carbon emissions of between 48 and 80 per cent, and increased refuelling and maintenance intervals.
Hybrid power systems are ideally suited to applications in the developing world, where they ensure continuous, energy-efficient operation and are used widely to power mobile basestations, 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.
In renewable energy projects, solar panels or a wind turbine can be included as part of a scheme alongside diesel generators to supply the recharge current. Francois Linck of battery manufacturer Saft explains: "The battery can also be combined with solar PV and wind power, discharging at night or in times of low wind-speeds and of course recharging in sunlight hours or windy periods. If it is dark or not windy then you would run the genset, of course." It is feasible that RETs might completely replace the diesel generator. Although installers must ensure they are capable of supplying the continuity of power needed to handle the load.
Madagascar leads the way
One ground-breaking solar PV energy solution is being deployed in the coastal village of Marovato, a village on Madagascar's east coast. The new facility offers an alternative source of energy to the kerosene and hand-gathered wood traditionally used by the villagers. It provides Marovato's 120 residents with clean, safe energy for around six hours per day and generates peak power of 1,400W of which the village currently uses 490W.
A specialised 24V battery system, comprising 18,920 Ah cells, stores energy generated during daylight hours by 24 solar PV panels with an average output of 7kWh. The pocket plate Ni-Cd batteries are optimised for use in PV solar and wind applications, performing beyond conventional limits and offer good cycling capability to withstand variable states of charge and discharge rates. The batteries combine an optimised electrode with an internal gas recombination process that significantly extends the interval for topping up with water.
The first solutions to be deployed use nickel-cadmium batteries. However, in future they will also use smaller, lighter and maintenance-free Li-ion batteries that offer round-trip efficiency of more than 95 per cent, that is, 95 per cent of energy stored in the battery is released. Linck is confident that lithium-ion has the edge over sodium nickel chloride and nickel cadmium in terms of cycling, if not performance degradation at extreme temperatures.
"Every time you increase the temperature by 10°C the performance of lead acid batteries is reduced by half. Also, the weight of lead acid batteries is greater than lithium-ion by a factor of ten."
Renewable energy technologies do offer opportunity for private investors to develop remote rural off-grid power supplies. Whilst sustainable development requires business models that support a much broader outlook, beyond simple technology provision, RET systems seem set to increase the electrification of Africa, particularly in sub-Saharan regions. With careful implementation, entrepreneurial suppliers can not only bring power to the people but, by doing so, empower people themselves.
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