Renewable power climbs in 2018 despite increased coal burn

Friday 15th March 2019

Renewable generation delivered almost 84 percent of the country’s electricity last year, despite the biggest annual coal burn by the sector in three years.

The share of renewables climbed to 83.9 percent from 81.9 percent in 2017, according to the latest data from the Ministry of Business, Innovation and Employment. The 84.9 percent achieved in 2016 was the highest since 1981.

Above-average hydro storage for much of the year helped offset a 19 percent drop in gas-fired generation due to two lengthy outages at the Pohokura gas field. Gas-fired plants run by Contact Energy, Genesis Energy and Nova Energy contributed just 5,374 gigawatt-hours of generation last year – the least since 1995.

Genesis Energy ramped up coal imports and generation from its coal- and gas-fired Rankine units at Huntly in the December quarter as hydro storage fell in September and a series of planned and unplanned gas field outages cut production. Coal-fired generation in the fourth quarter was 656 GWh, more than twice that of the preceding three months and the most for any quarter since early 2015.

Daniel Griffiths, MBIE’s manager of markets, evidence and insights, noted that the 84.5 percent renewables achieved in the December quarter was despite wind generation also being the lowest for that period since 2011.

“While the jump in coal-fired generation pushed it to the highest quarterly volume since March 2015 it contributed only 6.3 per cent of the generation mix as both hydro and geothermal generation rose,” Griffiths said.

The data released yesterday reflects both the sector’s resilience to sharp swings in hydrology, but also its reliance on gas to cover variations in wind and hydro availability and maintenance shutdowns across the generation fleet. Nor does it show the increased emissions that would have resulted from using coal to offset reduced gas-fired generation. Coal has roughly twice the emissions of natural gas.

The Labour-led government wants power generation to be 100 renewable by 2035 in a year of normal hydrology.

In a presentation to iwi leaders earlier this month, the Interim Climate Change Committee noted that the electricity system is on track to be 93 percent renewable by 2035.

It said getting to 100 percent renewable would be “prohibitively expensive” unless new technologies emerge to deal with dry-year risk. Emission reductions to be gained “from pursuing ever higher levels of renewability are relatively small.”

Hydro accounted for almost 61 percent of the country’s generation last year, up from 58 percent in 2017.

Geothermal production was 1 percent lower at 7,377 GWh. Wind production was 4 percent lower at 2,026 GWh due to weak wind conditions and maintenance work at some sites.

Solar’s estimated contribution was 30 percent higher at 97 GWh.

Even with reduced fuel supplies, gas-fired plants still accounted for 12 percent of total generation last year, down from 15.6 percent in 2017.

MBIE’s data shows the country’s gas production fell 11 percent to 167.6 petajoules last year, a seven-year low.

Net production from Pohokura, the country’s biggest field, fell 27 percent to 52.7 PJ, its lowest annual contribution since production began in 2006.

Production from the next three largest fields – Mangahewa, Maui and Kupe – was also down marginally.

(BusinessDesk)

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