Pertamina New and Renewable Energy (Pertamina NRE), a unit of Indonesian state energy firm Pertamina, has signed a joint study agreement with Guma Africa Group to cooperate on a natural gas and power project, the company said on Tuesday. The agreement was signed by Pertamina NRE's CEO John Anis and Guma Group's executive chairperson Robert Gumede on the sidelines of Indonesia-Africa Forum being held in the resort island of Bali, Pertamina NRE said in a statement.