Microsoft co-founder and philanthropist Bill Gates has lauded African tech start-ups for the thousands of businesses they are creating as well as changing the daily lives of people across the continent.

Gates was speaking at the 14th Nelson Mandela Annual Lecture Series at the University of Pretoria's Mamelodi campus on Sunday.

This year's theme was "Living Together", with a special focus on those who gave their lives during the struggle for liberation.

The Nelson Mandela Annual Lecture is one of the foundation's flagship programmes to honour founder Nelson Mandela, and raise topical issues affecting SA, Africa and the rest of the world.

Previous speakers include former US president Bill Clinton, Nobel Peace Laureate archbishop emeritus Desmond Tutu, and former UN secretary-general Kofi Annan.

Silicon Savannahs

The multi-billionaire said for him, the most important thing about young people is the way their minds work. "Young people are better than old people at driving innovation, because they are not locked in by the limits of the past."

The African entrepreneurs driving start-up booms in the Silicon Savannahs from Johannesburg and Cape Town, to Lagos and Nairobi are just as young – in chronological age, but also in outlook. The thousands of businesses they're creating are already changing daily life across the continent, he said.

"When I started Microsoft in 1975 – at the age of 19 – computer science was a young field. We didn't feel beholden to old notions about what computers could or should do. We dreamed about the next big thing, and we scoured the world around us for the ideas and the tools that would help us create it.

"But it wasn't just at Microsoft. Steve Jobs was 21 when he started Apple. Mark Zuckerberg was only 19 when he created Facebook.

"In a few days, I'll be meeting with some of these young innovators. People like the 21-year-old who founded Kenya's first software coding school to provide other young people with computer programming skills. And like the 23-year-old social entrepreneur here in South Africa who manufactures schoolbags from recycled plastic shopping bags."

Speaking about education, Gates said: "A good education is the best lever we have for giving every young person a chance to make the most of their lives. In Africa, as in the US, we need new thinking and new educational tools to make sure that a high-quality education is available to every single child."

Foundational skills

He pointed out that with the high level of mobile phone penetration in Africa, technology using mobile phones connected to the Internet has the potential to help students build foundational skills while giving teachers better support and feedback.

Globally, he said, the education technology sector is innovating and growing rapidly, and it's exciting to see new tools and learning models emerging to meet the needs of educators and students that are not currently being met by existing systems.

"At the post-secondary level, we not only need to broaden access – we also have to ensure governments are investing in high-quality public universities to launch the next generation of scientists, entrepreneurs, educators and government leaders.

"South Africa is blessed with some of the best universities in Africa – universities that our foundation relies on as partners in important health and agricultural research. Maintaining the quality of this country's higher education system while expanding access to more students will not be easy. But it is critical to South Africa's future."

According to Gates, one way to create economic opportunity is to turn agriculture, which still employs more than half the people on the continent, from a struggle for survival into a thriving business.

Right now, he noted, most African smallholders suffer from an almost total lack of innovation. "They plant unproductive seeds in poor soils in order to produce just enough to feed their family. With climate change leading to more severe weather, doing more of the same is going to bring even more meagre harvests."

Agricultural transformations

He believes the key to breaking this cycle is a series of innovations at every step along the way from farm to market.

"Our foundation is also working with a young computer scientist from Makerere University who designed a mobile phone app that lets farmers upload a photo of their cassava plants and find out immediately whether it's infected or not.

"These are the innovators who can drive an agricultural transformation across the continent − if they have the support they need. For many decades, agriculture has suffered from dramatic underinvestment. Many governments didn't see the link between their farmers and economic growth."

He also pointed out that one of the most exciting prospects is the role African governments can play in accelerating the use of digital technology to leapfrog the traditional models and costly infrastructure associated with banking and delivery of government services.

Because so many people in developing countries have mobile phones, tens of millions of people are storing money digitally on their phones and using their phones to make purchases, as if they were debit cards, he said.

"Mobile money services like m-Pesa in Kenya don't just give people a better way to move money around. They give people a place to save cash to fund the start-up of a micro-enterprise or pay a child's school exam fee. They create informal insurance networks of family and friends who can help with unexpected financial shocks like a crop failure or a serious medical illness."

A digital financial connection can also help governments deliver services more efficiently, he said. "I've seen studies from India showing the government could save $22 billion a year by connecting households to a digital payment system and automating all government payments."