The May average price was $247 a MWh, well above the three-year May average of $68 a MWh.
The current supply risk had been caused by low hydro storage levels and high winter electricity demand, he said.
The 330MW New Plymouth gas-fired steam turbine power station was closed in December 2007 following the discovery of asbestos in areas not detailed on the asbestos register.
Decommissioning staff were working on the asbestos-removal programme under strict safety guidelines, Mr McIntyre said.
In order to recommission and run the plant operations, staff would take the same asbestos safety precautions as those currently in place.
"We expect the recommissioned plant to operate only over the high-demand and high-price winter period."
Contact was 51.4% owned by Origin Energy, the Australian energy company subject to a takeover bid by BG Group (British Gas).
The Australian Financial Review reported yesterday BG had improved its takeover offer for Origin Energy.
The two companies were understood to be discussing an offer of between $A15 and $A16 a share via a scheme of arrangement, the newspaper reported.
The deal would value Origin at more than $A13 billion ($NZ15.9 billion).
The all-cash bid would represent a premium of more than 40% against Origin's value before the original bid.
BG initially approached Origin last month with a $A14.70 per share proposal.
Origin's share price was at $A14.60 when it called a trading halt on Wednesday.
Contact was put on a trading halt yesterday pending an announcement today by BG.
Earlier this month, the Takeovers Panel ruled that if BG succeeded in taking over Origin, it must make a cash bid for the Contact shares it did not own within a month of its Origin offer going unconditional.
The bid would have to be at the value per share attributed to Contact by BG in the price payable for Origin, the panel said.
However, BG said at the time its $A14.70 a share bid for Origin did not attribute any premium to the market price of Contact's shares.
ABN values Contact on a merger and acquisition price of $12.95 a share.
The catalysts for rerating the company remained unchanged, Mr McIntyre said.
"We maintain our current earnings forecast and we expect any contribution from New Zealand and high wholesale price benefits to offset an expected reduced hydro output due to existing low hydrology.
"We reiterate our view that Contact has potential operational merger and acquisition valuation up from current levels, especially as Origin is in a trading halt indicating progressing discus-sions with BG," he said.
Contact last traded at $9.10.
