Nigeria signed a memorandum of understanding with a U.S.-Nigerian joint venture to build six modular refineries with a combined capacity of 180,000 barrels a day, the country’s Trade and Investment Ministry said.

The joint venture group, comprising Vulcan Energy Corp. and Petroleum Refining and Strategic Reserve Ltd., signed a $4.5 billion deal to build the refineries in collaboration with state-owned Nigerian National Petroleum Corp., or NNPC, Trade and Investment Minister Olusegun Aganga said today in an e- mailed statement from Abuja, the capital. Two of the refineries are expected to be completed within a year.

“We are working in collaboration with the Ministry of Petroleum Resources and the NNPC; we are working together as a team to ensure that in 12 months’ time, we witness the commissioning of the refineries,” Aganga said.

Nigeria, Africa’s largest oil producer, plans to boost foreign investment in industries by making it easier to do business in the country. The government is focusing on changes that can improve the investment climate and on the overhaul of industries.

The continent’s most populous nation, with more than 160 million inhabitants, relies on foreign fuel supplies for 70 percent of its requirements because of inadequate refining capacity, Petroleum Minister Diezani Alison-Madueke said in November. It exchanges 60,000 barrels a day of crude for products with Trafigura Beheer BV and a similar amount with Societe Ivoirienne de Raffinage’s refinery in Ivory Coast, according to NNPC.