Gasfields showing surplus

Todd Energy estimates the Pohokura and Kapuni gasfields, which it partly owns, could hold another 880 petajoules (PJ) of gas.

As a guide, the energy from about just 5.8 petajoules of gas is estimated to equate to the output of one million barrels of crude oil, so the Todd statement is significant.

A petajoule is equal to one million gigajoules - a joule being the single metric unit of measure in the gas industry.

Pohokura's joint venture owners, Shell, Todd and OMV, are soon to start commercial gas production from the offshore Pohokura field, discovered in 2000.

The field's gas reserves are estimated to be 700PJ.

The owners have said the field will have a life of up to 20 years. New Zealand's yearly consumption of gas is 135PJ to 150PJ.

The average household might consume around 50 gigajoules of gas in a year.