Above the sacks of seeds and coal, three kerosene lamps gather dust in the tiny shed that Kenyan chicken farmer Bernard calls home. He prefers to use solar energy to light up his evenings, listen to the radio or watch television, after abandoning a diesel generator he said was expensive to maintain and burned fuel too quickly.

"Solar panels are a good, cheap solution," he told AFP.

Across the continent, consumers are opting for their own off-grid solar solutions to power homes and small businesses, even as African governments unveil massive new solar projects seemingly every month to expand their grids.

According to International Energy Agency projections, almost one billion people in sub-Saharan Africa will gain access to the grid by 2040, but by that time 530 million will remain off-grid, almost comparable with the 600 million who cannot access power today.

Governments have ramped up their efforts: on Africa's Atlantic coast, Senegal last month inaugurated a massive 20 megawatt (MW) project that will deliver energy to 160,000 people, which President Macky Sall saluted as ushering in "a new, clean-energy era".

But Mouhamadou Makhtar Cisse, director-general of national utility Senelec, underlined upcoming problems in an interview with AFP.

"We actually have an excess of 100MW of power," he said. "But we have a distribution problem. We have been thinking in terms of roads and railways... but not about electricity highways."

With around 55 to 65 percent of homes receiving electricity, Senegal's grid strength is above average for sub-Saharan Africa, whereas in South Sudan and Liberia this hovers between one and two percent.

But even in Senegal, neighbouring Mauritania and Rwanda, which have all invested in large-scale solar projects as the cost of panels tumble, the twin challenges of limited grids and Africa's demographics remain.

Power Africa, which identifies governments and businesses requiring sustainable and affordable energy and offers funding and expertise in more than 15 countries, has taken a particular interest in solar.