There could be a sudden turn of events in the contest for the West Australian energy assets of Alinta Energy Pty Limited. Speculation is mounting that Macquarie Group Limited (ASX:MQG) is no longer in the final stages of the competition and is weighing options to partner with another contender. One suggestion is that it is looking to join forces with APA.

APA does not need Macquarie as its funding partner, but that is not to stop the Australian investment bank from trying. Final bids for Alinta are understood to be due in the middle of next month. About three weeks ago, Alinta was believed to have carried out management presentations to four parties in the second stage of the competition.

But now there is talk that only Fortescue Metals Group Limited (ASX:FMG) and APA Group (ASX:APA) are left in the race. Investment bank Citi is working with Fortescue Metals, while Barrenjoey and Morgan Stanley are advising APA Group. Alinta is selling a stake of 80% or more in a selection of assets.

These include its Newman Power Station and a remote energy grid in the Pilbara that includes a gas and distillate power station with a battery storage system. It provides energy via a 220 kilovolt transmission line to the Roy Hill mine site in the Pilbara. Also on offer is its Port Hedland Power Station with five 42 megawatt gas-fired turbine units providing electricity to the Pilbara.

Alinta is also selling its 11.8% stake in the 1380km Goldfields Gas Pipeline, which transports natural gas from Carnarvon basin producers in the northwest to Kalgoorlie in the Goldfields. APA owns the remainder of the pipeline and has pre-emptive rights in place to buy Alinta's interest. Macquarie Capital was said to be working on an acquisition with BP, through the pair's Asian Renewable Energy Hub, of which BP is a 40.5% owner.

The venture has a project in the Pilbara that it hopes can supply renewable power to local customers. It is working to support the development of 26 gigawatts of combined solar and wind power generating capacity. Sources say Fortescue was initially out of the running after round one, but re-entered when it adjusted its offer.

They add that should suitors bid what the company has outlined in the information memorandum, the price would be well above $1 billion.