First-half operating profit for the six months ended September was $173 million against the Forsyth Barr forecast of $175 million, but up 13.1% on the previous corresponding period profit of $153.2 million.
Total revenue was up 20.6% to $504.9 million but costs increased nearly 25% to $331.5 million in the period.
The profit before tax was up 11% to $110 million and the reported profit was $89.2 million, up 15.6% from the $77.2 million in the pcp.
Mr Rooney expressed a note of concern about the New Zealand operating profit falling from $143 million in the pcp to $131 million, due to a combination of factors.
Wholesale market conditions were difficult and increased competition in the retail market had eroded margins.
''Trustpower had tried to counter this with increased investment in its retail segment which has had an impact on the company's cost base.''
New Zealand sales revenue was better than expected but gas sales were slower than forecast.
Trustpower, which is controlled by listed Infratil, had been increasingly leveraged as it invested in the Australian market, where it is anticipating the federal government's repeal of its carbon tax would boost demand for renewable energy, likely to be favoured under that nation's Renewable Energy Targets scheme.
Its 270MW Snowtown Stage 2 wind farm was officially opened on Sunday, adding to the hydro power stations and wind farm assets of Green State Power it acquired from the New South Wales state government this year for $A72.2 million.
The Snowtown Wind Farm in South Australia produced 578GWh of electricity in the first half, up from 193GWh a year earlier, helped by the contribution from Snowtown Stage 2 starting in July.
Trustpower said it had applications for almost 1300MW over four wind projects in Victoria, New South Wales and South Australia awaiting regulatory approvals.
''The outcome of the Australian Government's review of the renewable energy target remains uncertain but there appears to be growing support for the view that a bipartisan agreement may be successfully concluded,'' chairman Bruce Harker said in the statement.
''Trustpower continued to experience lower levels of customer churn than the market overall.''
Trustpower would pay a first-half dividend of 20c ashare on December 12, with a record date of November 28.
Mr Rooney said Trustpower was Forsyth Barr's preferred stock in the electricity sector.
''The things we like about the Trustpower story are its Australian wind development potential and the bold retail offering which is gathering traction.''
Forsyth Barr had a neutral rating on the company with a target share price of $7.85.
