A natural gas storage venture backed by Origin Energy has boosted the size of its proposed plant off Victoria’s coast by 50 per cent amid keen appetite from customers increasingly worried about the availability of gas during peak-demand winter days.

The larger capacity of the Golden Beach storage system to be developed in a depleted gas field will increase the cost of the project to between $900 million and $1 billion, according to Tim Baldwin, the chief executive of the private firm behind the project, GB Energy.