Why are we asking this now?

Two hugely ambitious power-generating schemes have been launched in recent weeks, one offering to create the world's largest solar farm and the other to create the biggest hydroelectric dam on the planet. In both cases the location for the mega-projects is Africa: the solar-power scheme envisages harnessing the sun in the Moroccan and/or Algerian Sahara; while the hydroelectric plan centres on damming the mighty Congo River. What the two projects have in common is that they seek to export the majority of the power they intend to generate from impoverished countries to more developed economies. In the case of the Sahara to Southern Europe and in the case of Congo to South Africa, foreign mining interests inside the Democratic Republic of Congo and again, Europe. Even in the best-case scenario neither project will be up and running for 15 years.

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How would it work?

Planners behind the Desertec scheme point out that the solar energy that falls on the Sahara in six hours would power Europe for one year. Although the difficulty in harnessing, storing and transferring that electricity means that the eventual aim is to supply 15 per cent of Europe's power needs. The Inga Dam project in DRC aims to generate 40,000MW, meaning twice the capacity of the giant Three Gorges dam in China, which would be more than the output of South Africa's entire troubled national power industry. In terms of how it works, however sophisticated power stations become, they all do broadly the same thing as a bicycle dynamo – they either boil water or harness moving water to turn turbines that generate resistance and charge. In the Sahara it would be done by a new concentrated solar power (CSP) technology which is in effect a vast field of mirrors which collect heat, boil water and turn turbines. The electricity generated would be channelled through direct current cables under the Mediterranean and into Europe. In the case of the Congo it would involve absorbing the extraordinary power of the Inga Falls to power the turbines. The same cables would then transfer that electricity as far afield as South Africa, Nigeria, Egypt and southern Europe.

What would the cost be?

The Desertec plan has been costed at €400bn, while the Grand Inga Dam would weigh in at $80bn, always assuming that the projects are delivered on budget. The main backers of the Sahara scheme are a dozen finance and industrial firms, mainly from Germany, including household names such as Siemens. One of the biggest cost factors will be the direct current cables which will cost as much as $1bn each, even to cross from the Sahara to Southern Europe and at least 20 of them are needed. There are a host of risk factors involved in both that stretch from political and regional instability in the Maghreb to prolonged conflict in the DRC. Add to these Saharan sandstorms and the costs of providing the water necessary to clean solar panels and cool turbines in a desert.

Why are developed economies shopping for power in the third world?

The simplest answer is that there are no equivalents of the Saharan solar power or the roaring waters of the Inga Falls in southern England, or anywhere else in crowded Europe. But another aspect is the difficulty that governments and private investors have had in establishing large renewable energy projects in Europe. Some, such as Portugal, have forged ahead with widespread windfarms but others, such as the UK, have met with organised, local resistance to big projects that would transform the environment. By contrast, the Sahara offers proximity to Europe, a tiny population and intense sunlight.

How will Europe benefit?

In Europe the energy question is a strategic one. Most governments are looking for ways to reduce their reliance on Russian gas which some would argue has given too much power to Moscow. Many administrations are pursuing the nuclear option but often without being honest about the timescale involved in launching next-generation civilian reactors – at least 20 years from now in most cases. All of this is happening while the long-term goal is to reduce greenhouse gas emissions by 80 per cent below 1995 levels before 2050. In any case, many EU countries are behind on their commitments to switch at least 15 per cent of their energy needs to renewable resources by 2015.

How will Africa benefit?

According to the World Bank, The Grand Inga project has the potential to bring electricity to 500 million homes in Africa. It would solve at a stroke the electricity crisis in South Africa which has seen the continent's biggest economy plunged into darkness for days at a time. However, there are two previous Inga dams, which were costly and corrupt failures. If it worked, it could also deal with the energy needs of DRC's mining sector in Katanga, power Namibia and fill the shortfall in Nigeria's generating capacity. A quick look at satellite images of the Earth at night are sufficient to show that Africa remains in an electrical dark age. Fewer than 30 per cent of African households have access to electricity and that number plunges to one in 10 in many countries.

So why the controversy?

A new report by Usaid this week estimated that there are now one billion people living in Africa. Despite urbanisation, the majority of them live outside cities, or without access to basic services. Exporting African electricity to Europe's businesses and consumers strikes some as grotesquely wrong. Many development agencies favour a patchwork of smaller projects using existing solar technology – photovoltaic – which is cheaper and more suited to a dispersed population. In contrast, an open energy market would see Africans competing with far richer Europeans for electricity generated from their natural resources. Considering the scant benefits that have accrued to ordinary people from other natural boons such as oil and minerals, these projects can be seen as a power grab. Then there is climate change, to which Africa contributes least and suffers the worst consequences. In Kenya climate change is contributing to a drought that has crippled the hydropower the country relies on. A similar crisis in Uganda means the country is running on generators. Rich industrial nations are already committed to setting up global-warming adaptation funds and technology transfer through the UN climate talks. Critics of the mega-projects believe the billions would be better spent there than in indirect subsidies to Western multinationals under the guise of helping Africa.

Should Europe be allowed to continue its power-generating schemes in Africa?

Yes...

*Europe needs renewable energy and Africa needs massive investment, it's a win-win situation

*The Sahara is empty and barraged with more solar power every morning than Europe needs in a year

*A new grand dam on the Congo River would power up to 500 million African homes

No...

*These mega-schemes are huge indirect subsidies from rich nations to multinationals seeking mega-profits

*The centralised grand designs don't meet Africa's dispersed power needs and are a huge distraction

*Africa is full of Western-funded white elephants, two of them already on the Congo River

d.howden@independent.co.uk