On a personal level, Mr Moges, now 40, was also "very proud to be part of it".

"Watching the dam's progress day by day was deeply satisfying. I came seeking employment, but somewhere along the way, it stopped feeling like just a job. I grew attached to the project, worrying about its future as if it were my own."

There were challenges.

"Lengthy separation from family was difficult," he told the BBC. Mr Moges could only go home – a 400km-drive away in Bahir Dar – twice a year.

The dam site's remoteness and the at times extreme heat – with temperatures sometimes hitting 45C - also presented issues. Plus, the working hours were long.

"Our shifts ran from 7am to 7pm, with only an hour's break for lunch. Then we handed over to the night crew, because the work had to continue around the clock," Mr Moges said.

His job was to make sure the building work was structurally sound and construction standards were maintained.

The Gerd project was a rare unifying force as the Horn of Africa country has been rocked by political violence and ethnic strife in the past decade.

While some, like the engineer, worked directly on the dam, millions of other Ethiopians were, literally, invested in it.

People from all walks of life contributed to building the dam through donations and the purchase of government-issued bonds.

Despite claims by US President Donald Trump that Washington financially supported the dam's construction, Addis Ababa maintains it was fully funded domestically.

Several fundraising campaigns were held that saw members of the public contribute multiple times.

Clinical nurse Kiros Asfaw was one of those.

Despite being from the Tigray region, which was blighted by a two-year civil war, he contributed when he could to the dam's construction ever since the plans were first announced in 2011.

He says he bought government bonds more than 100 times – though he had to pause his purchases during the conflict, when basic services, including banking, were suspended in Tigray.

Mr Kiros' motivation was rooted in remarks made by Ethiopia's late Prime Minister Meles Zenawi, who oversaw the beginning of the project, that all Ethiopians must come together in backing the dam.

"I promised myself to do everything I could to help it through the finish line," the father-of-five told the BBC.

Now, with all the turbines working, thoughts turn to what difference the power can make to Ethiopia.

At full capacity it should generate 5,100MW of power - more than double what the country produces without the dam and enough to supply tens of millions more homes in the country. That is however dependent on the infrastructure being in place to carry the power to different parts of the country.

Water and Energy Minister Habtamu Ifeta told the BBC that nearly half of the country's 135 million people do not have access to electricity.

"That is what we want to reduce now in the coming five years. Our intention is by 2030 at least 90% of our nation should get access to electricity," he said.

Thirty-five-year-old Getenesh Gabiso, who lives in Alamura, a farming village just outside Hawassa, a major city in southern Ethiopia, is one of those who is imagining the difference it could make.

Her life mirrors that of millions of others in rural Ethiopia.

Despite her small, mud-walled thatched hut being just 10km from Hawassa, Ms Getenesh, her husband and her three children do not have access to electricity.

For cooking she collects firewood around their farm nearby.

And for light they use kerosene-powered lamps. Her husband, Germesa Galcha is concerned for the health of his family.

"[Getenesh] used to have big and beautiful eyes. But all these years of smoke is damaging them. They have become watery," he said.

"I worry what I would do if the fumes suffocate my children."

For Ms Getenesh, who, when it is dark, sometimes relies on the weak light from her husband's mobile phone, just being able to see at night is what she dreams of.

"I want to see light in my house. All the other electric goods don't matter now. Just light in the evening is all I want," she tells the BBC.

They are looking forward to the difference that the power from Gerd could make. But the government minister, Habtamu, admits that much more needs to be done to expand the infrastructure of the national power grid.

Tens of thousands of kilometres of cable still need to be laid to ensure that small towns and remote villages can be connected.

But for the engineer, Mr Moges, the power generated on the Blue Nile will eventually make a difference.

He has a son who was born while he was working on the dam.

"I hate the fact that I couldn't be there for him as much as I needed to," he says. "But I know his future is going to be bright because of something I have contributed, and I am so proud to tell him that when he grows up."

Additional reporting by Hanna Temuari