For more than a decade, one 48-year-old entrepreneur in Ghana has been quietly building up a multimillion-dollar oil and gas outfit called UBI Group. Salma Okonkwo is a rare woman to head up an energy company in Africa.

“I don’t stop when the door is being shut. I find a way to make it work,” Okonkwo told Forbes. “That’s what propelled my success.”

She’s now expanding her reach across Ghana’s energy industry, working on an independent side project that may become the biggest in her career. Okonkwo is building Ghana’s biggest solar farm, called Blue Power Energy, slated to open in March 2019 with 100 megawatts of energy. It’s set to be one of the largest in Africa.

“Most of the multinational companies that come to Ghana don't put in infrastructure. They operate a system where they invest very little and they take it away. They sell their products and leave,” Okonkwo says. “I’m hoping to provide employment and add to Ghana’s economy.”

Okonkwo grew up in Accra, one of 14 children born to a real estate agent and developer mother and a cattle dealer father. She often visited her grandmother in her family’s ancestral village. She's a member of the Akan clan, whose women often sell products they make, like sandwiches or smoked fish, to make sure their children are provided for—and that left an indelible mark on Okonkwo. “The women didn’t know how to read and write, but they knew how to make a margin,” Okonkwo says.

After graduating from an all-girls boarding school with little running water, Okonkwo moved to Los Angeles for college at Loyola Marymount University. (Her family was able to pay her tuition.) She graduated in 1994 and briefly worked in California for a food brokerage company. Then oil and gas company Sahara Energy Group recruited her; Okonkwo returned to Accra in 2003 for the job.

Within a few years, Okonkwo realized that the firm could grow by opening up retail gas stations. She presented the idea several times over the years, but each time she was rebuked. Executives told her they wouldn’t change their business plan because it would be too political and would require too much of an investment in infrastructure.

At 36 years old in 2006, Okonkwo decided she’d heard “no” too many times and quit to try it herself, focusing on bringing liquified petroleum gas to the hard-to-reach region of northern Ghana, where many families still rely on burning firewood for energy. Because Okonkwo's father was from northern Ghana, she knew firsthand how the business could change lives there. “It was just too hard to pass up the opportunity,” Okonkwo recalls. “It looked quite lucrative.”

But Okonkwo hit an early snag when she realized that she didn’t take into account a complicating factor: The North had few storage facilities for the liquified gas. To get it to the remote region, she’d have to build the storage herself, and she was already struggling to secure funding. So Okonkwo pivoted and started trading diesel and petroleum wholesale. A contract to supply fuel to Dallas-based Kosmos Energy came in 2007, followed by one with Hess in 2008. In the early days, she financed the operation by mortgaging some properties that her family and husband had inherited.

By 2008, UBI opened its first retail gas station. It soon owned 8 outright and managed another 20 through partnerships. That caught the eye of Singapore-based multinational firm Puma Energy, which had 2017 sales of $15 billion from operations in 49 countries. Puma acquired a 49% stake in two of UBI Group’s subsidiaries (retail gas stations and wholesale fuel distribution) in 2013 for about $150 million.

After the partial acquisition in 2013, Okonkwo says, she started developing her solar company. She estimates the company will spend about $100 million—financed by roughly $30 million in loans—to create 100 megawatts of solar power by early next year. Construction started earlier this summer. The plan is to add another 100 megawatts by the end of 2020.

Despite all the sunshine in Africa, solar power isn’t a prominent energy source on the continent. Most farms are concentrated in South Africa and Kenya. In 2009, Morocco announced plans to build one of the biggest solar farms in the world. The first of the project’s three phases opened in 2016. “I don't know of another large-scale project like this in Africa that’s led by a woman,” says Arne Jacobson, who has been studying renewable energy with a focus on Africa since 1998 and is now the director of Humboldt State University’s Schatz Energy Research Center. “Power is fairly expensive in countries like Ghana. If they can keep costs low, this is will be a profitable venture.”

The project is also personal for Okonkwo. Half of the solar farm will be located in her father’s village in northern Ghana. The rest will be spread out throughout the North, which is Ghana’s poorest region, according to Unicef. The organization says the area has seen the smallest progress in terms of poverty reduction since the 1990s.

There are so few employment opportunities in the north of Ghana besides farming that most women migrate to Accra looking for work. Many can only find jobs as “kayayo”—working in markets carrying goods for customers, sometimes known as “living shopping baskets.” They live in slums and regularly endure harassment, theft and even rape. Okonkwo, aiming to create a better alternative for some of these women, says Blue Power Energy has already created hundreds of jobs in northern Ghana and that more than 650 will be created upon completion.

Okonkwo’s ultimate goal is to bring cheap energy to northern Ghana through the solar farm, which she hopes will incentivize companies to create lasting jobs there. In the meantime, she is opening a day-care center in Accra for children born to kayayo women, where, as she explains, they can “get educated and hopefully break the cycle.”

“I want to bring support to my people in the north,” Okonkwo says. “Then there will be more Salma’s all over the place.”