Ethiopia’s Prime Minister Abiy Ahmed has said a multibillion-dollar mega dam on the Blue Nile, which has caused deep consternation to downstream neighbours Egypt and Sudan over its effect on their water supply, is complete and will be officially inaugurated in September.

Of that regional concern over the Grand Ethiopian Renaissance Dam (GERD), Abiy said on Thursday in an address to parliament: “To our neighbours downstream – Egypt and Sudan – our message is clear: the Renaissance Dam is not a threat, but a shared opportunity … The energy and development it will generate stand to uplift not just Ethiopia.”

Egypt and Sudan have expressed concerns about GERD’s operation, fearing it could threaten their access to vital Nile waters. Negotiations to reach a three-way agreement with Ethiopia have failed to make a breakthrough.

Egypt, which is already suffering from severe water scarcity, sees the dam as an existential threat, as the country relies on the Nile for 97 percent of its water needs.

The GERD, launched in 2011 with a $4bn budget, is considered Africa’s largest hydroelectric project, stretching 1.8km (about one mile) wide and 145 metres (475ft) high.

Ethiopia says the dam, located on the Blue Nile, a major tributary of the Nile River, is vital for its electrification programme.

Ethiopia first began generating electricity at the project, located in the northwest of the country, about 30km (20 miles) from the border with Sudan, in February 2022.

At full capacity, the huge dam can hold as much as 74 billion cubic metres (2,590 cubic feet) of water and could generate more than 5,000 megawatts of power – more than double Ethiopia’s current output.

The east African nation is the second most populous on the continent, with a rapidly growing population estimated at 130 million, and has growing electricity needs.

About half of its people live without electricity, according to estimates released this year by the World Bank.

Earlier this week, Egyptian President Abdel Fattah el-Sisi and Sudan’s leader Abdel Fattah al-Burhan met and “stressed their rejection of any unilateral measures in the Blue Nile Basin”.

According to a statement by Sisi’s spokesman, the two are committed to “safeguard water security” in the region.

But Abiy said Ethiopia is “willing to engage constructively”, adding that the project will “not come at the expense” of either Egypt or Sudan.

“We believe in shared progress, shared energy, and shared water,” he said. “Prosperity for one should mean prosperity for all.”