Mohammed Mahgoub used to spend more than $12 a day on gasoline to pump Nile waters onto his farm in Sudan.
That changed when he made the switch to solar.
"The comparison with solar energy is now I spend nothing. The only difference is that you pay for the cost once, with a guarantee of being able to use it for years to come."
Mahgoub's farm is one of many small businesses and households turning to sustainable energy in Sudan.
That's because, though the water may be flowing, petrol is not.
The country's lack of foreign reserves has caused an unstable supply, leading to frequent lines at gas stations, power cuts and protests.
The reduction of subsidies, part of reforms aimed at unlocking badly needed foreign finance, has also made energy more expensive.
At the same time, banks are providing financing that allows farmers to pay for solar panels in instalments and businesses receive exemptions on their customs when importing them.
One such company is Saruest Investment.
It estimates that investment in Sudan's solar energy sector has reached $500 million, producing nearly 500 megawatts annually.
"This country I think is projected to look at over the next ten years maybe 2.4 gigawatts"
Business development manager Rushdi Hamid says Sudan is an important emerging market.
"Some of that will be in the production of large power-generating plants using solar power, but there is a lot of small domestic use that is required and a significant agricultural requirement."
Back among his crops, Maghoub urges others to follow his example.
If you can afford it, you should not hesitate, he says.
And anyone who doesn't believe him, can come to his farm to see for themselves.