A flurry of conferences have been springing up on the Africa circuit lately, touting renewable energy as a potential solution to the continent's well known energy deficits.
The continent is home to 15 percent of the world's total population but, once traditional biomass is excluded, its per capita energy consumption is just one-sixth of the global average.
The number of Africans without access to electricity reached 589 million in 2008. Those in rural communities are in greatest need, living several hours or even days from large towns and ready consignments of fossil fuels. Renewables currently provide 17 percent of Africa's power. Can this be scaled up to position them at the heart of the region's energy mix?
Thembani Bukula, director of South Africa's national energy regulator, says Kenya stands out as one of the few countries in the region to make significant progress in adopting renewable energy. While other nations' plans are "still at the implementation stage, Kenya's wind farms are generating power and injecting it into the grid," he explains.
"Kenya was one of the first - if not the first - African country to start a project using feed-in tariffs." South Africa's efforts have taken longer, explains Mr Bukula, because it aimed not only to produce electricity but also to build new infrastructure around renewable energy to create jobs. To that end, the government's ambition is that over the next 30 years some 40 percent of the additional 40,000MW of electricity to be generated will come from renewables.
South Africa, responsible for just over one-fifth of the continent's primary energy use, is a relatively mature model for its peers to draw upon. However, its public investment driven strategy - though it carries tremendous benefits - will be difficult to replicate for many other African countries due to high capital requirements. The International Renewable Energy Agency envisages a scenario where every African country, through the careful exploitation of renewable energy resources, will have electricity access by 2030, but this would cost around $32bn per year over the next 20 years or so.
Adnan Amin, Irena's director general, says financing is one of the two inhibitors to the development of Africa's renewable energy sector.
The other is infrastructure, which one of his peers believes will have distinct characteristics in the region. "More and more in Africa you hear from key decision-makers about 'jumping a stage', and missing out the centralised grid altogether," says Jeremy Leggett, the founder and non-executive chairman of Solarcentury.
"But the challenge of getting energy to hundreds of millions of people is just too great, and so you'll get disaggregated use of renewables; both at the levels of households and communities, and I think microgrids as well, as you might have in a town or district."
Like Mr Amin and colleagues at IRENA, Mr Leggett considers solar energy vital to Africa's future: along with wind, it is the continent's most abundant renewable resource, and currently supplies less than 1 percent of Africa's electricity.
This area is exciting for two reasons. First, the costs of technology are falling.
According to McKinsey, the cost of solar photovoltaic modules has dropped by more than a quarter in the last seven years. Pointing to the potential, Blue Energy, the UK-based renewable energy investor, just announced plans to build Africa's biggest solar PV plant in Ghana, under the government's feed-in tariff scheme. Secondly, Africa does not have the same "entrenched incumbency" of oil and gas powers as the more mature energy markets of the US and Europe, and so the barriers are appreciably lower.
Research from Frost and Sullivan estimates that investment levels into renewable energy across Africa are set to soar to $57.7bn by 2020, up from just $3.6bn in 2010. While this sounds promising, it is too soon for celebration, cautions Cornelis van der Waal, an analyst with the firm. The development of the sector will be slow and uneven, he argues.
"The African energy story, or electricity story, is very much a South Africa and North Africa story," he says, identifying Algeria, Kenya, Morocco, South Africa and Tunisia as leaders. "The bits in between, unfortunately, are falling behind in terms of investment, both overall and in renewable energy in particular." Even in North Africa, the Desertec solar initiative seems to have stalled, with big industrialists Siemens and Bosch both recently pulling out.
Mr van der Waal considers the role of government, through the provision of subsidies and the introduction of new legislation, to be crucial; although he remains skeptical about this sector's potential for transformative change. "Renewables are not necessarily the answer for Africa in the next 20 years," he explains. "The reality is that something like 58 percent of Africa's population still do not have access to electricity. I think that although renewables, in terms of sustainability and long-term thinking, are definitely the way that we need to go, the first priority is to get those people in rural communities some access.
The cost of renewable energy remains prohibitively high for most Africans, whose necessary focus is on survival rather than the environment. "I can tell you," says Mr van der Waal, "they don't care whether they're burning cow dung, coal, or gas. The whole concept of sustainability is very much a European concept, which does not necessarily resonate quite as strongly in Africa."
Perhaps most compellingly, he points out that "less than 1 percent of global renewable energy investment last year was invested in Africa. If you look at the realities, the money is not flowing in just yet."
The Democratic Republic of Congo provides one of the more frustrating symbols of the continent's unrealised potential. The Inga Dams in the country's south west could theoretically outproduce China's Three Gorges Dam, making it the world's largest potential source of hydro power. Were the initiative to take flight, as part of a proposed collaboration with South Africa, it could power most of the south of the continent. Yet work on the projects has been plagued by delays, with no clear timeline for completion. As Dolf Gielen, the director of Irena's innovation and technology centre, explains, ambition is one thing, implementation quite another.
Asked to highlight other success stories for renewable energy within Africa, Mr Gielen points to Ethiopia, which has exceptional hydropower resources, and Kenya, where there is "significant geothermal potential in the Rift Valley".
The problem with geothermal development is the drilling. "It's the bulk of the cost...but they've now built up their own drilling capacity, so they don't have to depend on outsiders coming in to find and develop the resources. And that development is going quite well now."
If there is to be a green energy revolution in Africa, we are only seeing its earliest turns. Despite the continent's rapid urbanisation, a considerable number of its inhabitants will remain rural for decades to come, and so it is helpful to view renewable energy as a long-term complement to a centralised grid, with wind, solar, hydro and other sources forming part of the portfolio of African energy supply.