The company said the power failures forced the refinery to shut down for three days and restart of the first of two crude distillation and cracking trains was completed by 3 May.
The second production train came online towards the end of May, and it has had limited upgrading economics due to technical and operational issues particularly in one catalytic cracker and one train of the residue hydrotreating unit.
BP spokesman Scott Dean said that due to the impact of the emergency shutdown and restart, the company is continuing to have operational issues associated with some key downstream units.
"This has meant that we have only been able to economically utilise about half of the plant’s capacity on average over the quarter but we expect to return the last of the impacted units to full capacity during August," Dean said.
