Nigeria has a growing technology scene, full of ambitious young entrepreneurs looking for ways to overcome various social challenges.

Thirty of them recently competed for a chance to pitch their business ideas directly to the president of Nigeria. Three of them made the final cut, including a Nigerian American:

Angel Adelaja is the CEO of Fresh Direct Nigeria, which specializes in urban farming to meet the needs of Nigerians who have been dependent on importing food products.

“We take a 20-foot [6.1-meter] container that you would put a car in to ship, and we fit it with hydroponic farming technology and we farm vertically, so we’re using as much space as we can in the system,” she said.

Adelaja is a Nigerian American who recently returned to Nigeria to cater to the expanding class of nutrition-conscious urbanites.

Ifedayo Oladapo is the founder of GRIT Systems Engineering. He is trying to amass data on electricity consumption and production. GRIT Systems manufactures an energy device for users to monitor their various energy sources.

“There’s an incredible amount of waste,” Oladapo said. “We spend $11 billion each year fueling generators. That’s 4 percent of our GDP, and that doesn’t even cover the cost of maintenance.”

Emmanuel Okena is the CEO of Tracology. He and his team created a barcode that will be posted on people’s front gates, so garbagemen know whether a customer has paid for the trash to be picked up.

“Once the utility provider comes to the house, all he has to do is scan this barcode and he knows in real time whether you have paid for that waste or whatever service he wants to offer you,” Okena said.

Meeting some high-powered people

Tracology’s Okena, along with the two others, got the chance to meet President Muhammadu Buhari and Vice President Yemi Osinbajo.

Okena won a cash prize of more than $8,000 from telecommunications company Airtel, an event sponsor.

“It has been humbling, and we are very grateful,” Okena said. “The president was so impressed that Nigerians are thinking out of the current crisis, economic recession, we have, making sure that we can generate revenue.”

The pitch event kicked off with a lot of fanfare, and with tech celebrity Mark Zuckerberg of Facebook.

Zuckerberg listened to the winning pitches from the startup owners and said he was reminded of when he first started building Facebook.

“This trip has really blown me away by the talent of the entrepreneurs and developers in this country, and by the focus on building something that is going to make a difference and going to make a change,” Zuckerberg said while on stage at the presidential banquet hall.

“I think if you keep on doing this, you are not only going to change Nigeria or Africa, but the whole world,” Zuckerberg said.