Net profit fell from $69.3m to a loss of $16.6m in the latest year, while revenue dropped 3 per cent to $1.83b, reflecting lower wholesale electricity prices and reduced electricity sales to industry.
Genesis chairwoman Dame Jenny Shipley said market conditions had been challenging.
Warm and wet weather suppressed demand for power produced by Genesis' thermal generation assets, and the company faced fierce competition for electricity and gas customers, she said.
Total customer numbers rose 3 per cent to 661,500, on the back of customer gains in the South Island - where subscribers rose to 42,500 at the end of June from 16,000 at the start of the financial year.
Buying the Tekapo assets would help with the Genesis strategy of increasing its lower-cost renewable asset base and expanding its presence in the South Island, Genesis chief executive Albert Brantley said.
A revaluation of generation assets as at June 30 saw a net increase of $297m to $2.6b, despite the Tekapo assets decrease of $96.8m against the $821m acquisition valuation.
The company made the adjustment against Tekapo because it considered the cost of Tekapo remedial work, including capital expenditure associated with canal repairs planned for the 2013 financial year, and the costs of the related generation outages was greater than the contingency provided in the acquisition price.
- NZPA