DUBAI, Jan 5 (Reuters) - Public utility Qatar Electricity and Water Company said on Wednesday its subsidiary signed an agreement to acquire 40% stake in energy investment company Nebras Power for $530 million. QEWC, which already owns 60% in Nebras Power, would get full control in the company through the deal. QEWC"s unit Raslaffan Operating Company made the offer to buy the stake from Qatar Holding, a unit of Qatar"s sovereign wealth fund, the Qatar Investment Authority, QEWC said in a bourse statement. The transaction, it said, is subject to a number of conditions precedent which includes regulatory approvals and notifications from other foreign jurisdictions where Nebras is present.