The use of coal to produce electricity soared in the first three months of the year as dry weather conditions put the squeeze on hydro generation, new figures show. That pushed CO2 equivalent emissions from electricity generation up by almost a third from a year earlier. Renewable generation accounted for 65 per cent of electricity in the March quarter, down from 72 per cent a year earlier, the Ministry of Economic Development's New Zealand Energy Quarterly shows. The amount of electricity generation from renewable sources was "unseasonably low", while low inflows into hydro lakes towards the end of 2007 and the beginning of 2008 resulted in significant increases in the amount of electricity generated from thermal sources. The 3566 gigawatt hours (GWh) of thermal generation in the March quarter - 35 per cent of the total - included 1020 GWh from coal, compared to 727 GWh a year earlier and just 589 GWh in the December quarter.

Hydro generated 52 per cent of the total in the March quarter, 5275 GWh compared to 6035 GWh a year earlier. Wind produced 260 GWh, up from 148 GWh in the March 2007 quarter but down from 294 GWh in the December quarter. The country's diesel-fired reserve generator at Whirinaki had run at record levels during the quarter, generating 26 GWh, or 0.3 per cent of the total, according to the report which was published today. A total of 10,130 GWh of electricity was generated in the March quarter, up 3 per cent from a year earlier. The rise in the use of coal was the key factor in a rise of almost a third from a year earlier in this country's production of CO2 equivalent emissions from electricity generation. During the March quarter the figure was 1845 thousand tonnes of CO2 equivalent emissions, compared to 1405 a year earlier.

Efforts to reduce emissions had received a boost in the second half of 2007 after Genesis Energy's combined cycle gas turbine at Huntly went into full operation. That reduced the need to use coal, which produces more emissions per unit of electricity than gas does. Meanwhile, New Zealand production of crude oil and condensate continued at near record levels during the March quarter, as a result of output from the Tui field which started production last July. A total of 35.4 petajoules (PJ) of crude oil and condensate was produced in the March quarter, from 36.1 PJ in the previous three months. Imports were up to 57.4PJ from 50.1PJ, while exports eased to 32.5PJ from 35.1PJ.