Ethiopia’s biggest obstacle to finishing the dam is not geopolitics — it is money. The project is overseen by Ethiopian Electric Power, a state-owned utility that is helping finance the project with its own revenue and loans from state-owned banks. Though the government may raise more money by selling bonds on global markets in the coming years, the current tactic of borrowing from state banks is draining available credit. That could squeeze private enterprise in a country that already has the world’s sixth-lowest rate of private investment as a percentage of G.D.P., said Lars C. Moller, the World Bank’s lead economist in Ethiopia.

“For every dollar of credit and every dollar of foreign exchange the project gets, there’s less for the rest of the economy, including the private sector,” he said.

“But in the long term, the investment is likely to pay off well,” Mr. Moller added, noting that Ethiopia’s plan to sell excess energy to neighboring counties could bring in about $1 billion in annual export revenue starting in 2021, four years after the dam is scheduled to be completed.

Ethiopia’s state finance minister, Abraham Tekeste, said it was a price worth paying. “We know that we are sacrificing in the short term, but this is for a long-term objective,” he said. “We don’t see any contradiction.”

More than $357 million spent so far has come from Ethiopians, both domestically and abroad, who have been encouraged to donate money or purchase bonds, according to Mr. Zadig.

Workers on the government payroll, some of whom make as little as $32.68 per month, have been pushed to buy bonds worth a full month’s salary every year through a system that deducts straight from their paychecks.