NSW could reap a windfall of up to $15 billion under new models being considered for the partial sale of the state's ''poles and wires'' electricity business before crucial party room meetings next week.

The funds, which could be used to pay for priority projects including a second harbour rail crossing ($8 billion) and infrastructure for a second Sydney airport, would be more than double previous estimates, which have hovered around the $7 billion mark.

Power sale: Infrastructure would be the big winner from a partial sale of the state's "poles and wires". Credit:Jessica Shapiro

These estimates have been based on a potential gross sale price for the entire network of $30 billion, from which would be taken debt and transaction costs.

But it is understood the strategy to propose a partial sale is in part based on the belief this would increase the number of potential bidders, driving up competitive tension and therefore the price.