Ghana was in hurry to develop after it got independence in 1957. The President at the time, wanted to build factories, hospitals, schools, roads, new homes etc.. All this needs energy. The solution to this problem was to build a dam on the River Volta to give the country hydroelectricity.
Back in those days, Dams cost a fortune and Ghana had no money to fund the building of this new dam. The President(Kwame Nkrumah) came up with the idea of getting loans from the World Bank and a large loan from the USA. As part of this deal, an American company called Valco got the right to produce aluminium in Ghana, using electricity from the dam. Agreements were signed and the building of the Akosombo Dam was completed in 1965
This is how Ghana got the Akosombo Dam.