Tanzania’s motor fuel revolution is gaining momentum, but a lack of refueling stations means it’s stuck in second gear.

Tanzania, like Nigeria and several other countries on the continent, has begun adopting compressed natural gas (CNG) as an alternative to gasoline and diesel.

It is considered cleaner and greener than fossil fuels, but its relatively cheap price is the biggest draw for the 5,000 or so motorists, especially commercial drivers, in the East African country who have embraced the change.

That’s only a small portion of Tanzania’s vehicles, but early adopters are paving the way for wider acceptance of CNG – with the government reportedly hoping to have almost all of it by mid-century.

There are vast reserves of natural gas under the sea in Tanzania, and the cost of bunkering with CNG is less than half that of gasoline equivalent.

The potential savings were enough to convince taxi owner Samuel Amos Irube to spend around 1.5 million Tanzanian shillings ($620; £495) to convert his three-wheeler, known locally as a bajaji, to CNG.

But now he has to refuel twice a day, often spending more time waiting at gas stations in Dar es Salaam, the largest city, than making money.

There are only four places in Tanzania’s commercial hub where he can refuel.

He was secretly frustrated, saying that every time he wanted to refuel, he had to wait at least three hours, but the savings made him feel it was worth it because he only spent 40% of the same amount of gas.

The queue of vehicles at the Ubengo CNG gas station winds along the road. Everything was in order – there were three clear lines, one for cars and two for Bajajs – but the irritating situation was obvious.

Medadi Kichungo Ngoma had been waiting in line for two hours next to a silver pickup truck, staring at the traffic ahead.

He told the BBC he was one of the first people in the city to modify his vehicle, which included installing a large cylinder in the back of a pickup truck, and recalled queues being short.

“Sometimes a waiter has to be called to serve us,” he said.

He complained that the infrastructure had not been expanded to meet the growing demand.

Such sounds were also heard at the largest CNG filling station near the city’s airport.

Sadiki Christian Mkumbuka and his bajaji have been waiting here for three hours.

“The lines are long,” he said, adding “we should have as many gas stations as possible”.

But the price factor will keep people coming back.

“I pay 15,000 shillings ($6; £5) to fill up an 11kg tank and travel about 180km,” said another motorist who gave his name as Juma, adding that this was less than the amount of petrol needed to cover the same distance. Half the cost.

Tanzania’s initiative to encourage motorists to adopt CNG-powered vehicles has been brewing for more than a decade, but it did not officially begin until 2018.

Project leaders admit they did not foresee the rapid increase in demand.

Aristides Kato, CNG project manager at state-owned oil company Tanzania Petroleum Development Company (TPDC), told the BBC there had been a “dramatic increase” in natural gas use by vehicle owners recently.

“We found ourselves without adequate infrastructure to support the demand for gas vehicles,” he admitted.

However, authorities want more people to switch to CNG because it is a relatively clean-burning fossil fuel that can reduce emissions of almost all types of air pollutants, according to the United Nations.

Additionally, locally available natural gas should be cheaper than gasoline. But the cost of modifying a vehicle coupled with the lower mileage a full tank of gas gives drivers compared to gasoline or diesel can be prohibitive for some.

However, the country manager of Taqa UAE, an Egyptian company that operates petrol stations near the airport, sees the growing demand as “a positive sign that the use of compressed natural gas is starting to develop in Tanzania”.

Amr Aboushady said his company plans to build more gas stations and hopes to “replicate our success story in Egypt by helping the (Tanzania) government best utilize natural gas as an affordable, reliable, clean energy source.” .

Egypt is a pioneer in the use of CNG on the African continent, with around 500,000 vehicles converted to dual-fuel systems since the 1990s.

Other African countries that have approved the use of CNG in vehicles include South Africa, Kenya, Mozambique and Ethiopia.

Tanzanian authorities are committed to rolling out more infrastructure and want to encourage more private investors to get involved.

TPDC is building a central CNG “mother station” in Dar es Salaam that will supply gas to small filling stations across the country.

In addition, TPDC will acquire five mobile CNG units, which will be located in Dar es Salaam and the capitals Dodoma and Morogoro.

In the medium term, these measures should reduce queue times, but the current lack of filling stations will continue to frustrate Tanzania’s CNG pioneers.