New Zealand’s set an ambitious target of reaching 100 percent renewable electricity generation by 2030.
The Government’s first emissions reduction plan, released earlier this month, gave an indication of the roadmap to this aspirational goal, with a plan to ban electricity companies from investing in new generation from fossil fuels.
In 2021, according to Ministry of Business, Innovation and Employment data, 82 percent of all electricity generation in Aotearoa was from renewable sources.
To break total generation down further: 56 percent was hydro, 18 percent geothermal, six percent wind – the rest being gas or coal-fired fossil fuel.
As energy analyst and consultant Greg Sise explains to The Detail, each of these generation methods has strengths and weaknesses.
Geothermal activity generates a stable baseload of electricity, but it’s difficult to scale output up or down according to demand. This method of producing electricity also causes emissions, though significantly less than fossil fuels.
Wind almost always blows – it isn’t confined to a certain time of the day or year. But this strength is also a weakness: wind is unpredictable, and it can rise or drop away at a moment’s notice, sometimes without explanation. And reliability is key.
Hydro power – which is the most important form of electricity generation in New Zealand, with more than half our production coming from hydro – is efficient and scalable, but also at the mercy of the elements: dry years happen, lake levels can fluctuate, and if things turn pear-shaped there isn’t much you can do about it.
Aotearoa doesn’t produce much solar energy, even though there’s a lot of interest in the idea. There are the obvious pitfalls – we aren’t the sunniest country on the planet, after all – but Sise says solar also has the issue of when peak demand tends to land in Aotearoa.
“The downside is you don’t get much output at night – in fact, you don’t get any.
“The thing about New Zealand is our highest electricity demand, consumption [is] in the winter, but that’s when solar output is at its lowest.”
This explains why New Zealand’s solar power industry lags behind, for example, Australia’s, where demand in many places peaks during summer.
Fossil fuels, on the other hand, are good for generating electricity: they store a lot of potential energy in a dense space, and coal and gas plants are nimble and can be fired up at short notice. During periods of peak demand, fossil fuels are invaluable in filling the gaps when renewables can’t provide enough electricity to meet demand.
But, of course, the downsides are obvious: fossil fuels are dreadful pollutants, and their continued use poses an existential threat, not just to the country, but to the planet. Sooner or later, they must go.
Asked whether the 100 percent renewable goal by 2030 is realistic, Sise is undecided.
“In the long-term, we can absolutely get rid of fossil fuels. We won’t need them for electricity generation.
“That’s technically feasible now, and has been for some time. The issues are around the economics of the transition and the speed at which you can manage it.
“It’s a great thing to have out there as a challenge…[but] I think it’s probably not realistically achievable. If we were in a real emergency and our lives depended on getting to 100 percent…we could probably do it.
“But we’re not in that situation. It’s important to consider things like the cost of making the transition, and what’s the best mix of renewable electricity generation, storage, and other technologies.”
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