Jacqueline Novogratz’s impact investing group closed an almost $70-million fund to back companies delivering affordable and renewable energy to mostly poor consumers in East Africa.

KawiSafi Ventures seeks to bring clean energy to ten-million people with investments in fast-growing companies while also making competitive returns, according to a statement Tuesday from Acumen, a New York-based nonprofit founded by Novogratz. Early investors in the fund include TED curator Chris Anderson, the Skoll Foundation, venture capitalist Steve Jurvetson and the Green Climate Fund.

Impact investing has been accelerating, fueled by the interests of Millennials and the threat of climate change. In the US, assets dedicated to the social good reached $12-trillion at the start of 2018, up 38% from 2016, according to a report from the Forum for Sustainable and Responsible Investment.

In Africa, millions of people don’t have electricity and typically resort to dirty sources of power. The Acumen fund will supply early-growth capital to help companies gain scale and reach more consumers with energy from solar panels. Some of the outfits had earlier backing from Acumen’s “patient” capital, which sets long time-horizons for investment returns.

“We began to see the potential for off-grid solar as a major thrust for Africa to solve its electricity challenge,” Novogratz said in an interview. “That’s where we got the insight that, based on ten years of energy investing experience and using patient capital, now we could help really grow those companies.”

KawiSafi, which started fundraising in 2016, invests $750 000 to $10-million in the energy companies. So far the fund has approved five investments, one of which is d.light, which manufactures and distributes solar products.

The fund, which expects to exit all of its investments in 12 years, is seeking returns in the low-teens.

“What’s important to us is to show that it’s absolutely possible within more mature sectors like off-grid energy to build a vehicle that brings financial returns and social impact," Novogratz said.

Novogratz started Acumen in 2001, after co-founding Rwanda’s first micro-finance institution in 1986. She began her career at Chase Manhattan Bank, focusing on international banking and credit analysis for three years.