Power is back on in most areas of Timaru after a major blackout when a substation caught fire this morning.

Contact Energy and TrustPower have been given formal warnings over a 2002 bid-rigging attempt during negotiations over buying a power station.

A fire at a Timaru power substation has caused a city-wide power outage.

Barack Obama has a vision of a fundamental US energy makeover, moving from fossil fuels such as coal and oil to renewable sources including solar and wind.

Transpower is contemplating a domestic bond issue of around $200m early next year as it gears up for $5 billion of capital expenditure on national grid upgrades over the next decade.

TrustPower has reported a 23 per cent rise in interim profit on a 13 per cent fall in operating revenue.

A $540m power cable which will prevent outages such as today's in North Auckland and Northland won't be available until 2013.