Thursday, April 20, 2017

100% renewable electricity is achieveable

The Greens have launched a new electricity policy today, and the key component is a target for 100% renewable electricity generation (under average hydrological conditions) by 2030. The obvious question is "is it achieveable"? The good news is that the answer is "yes".

That answer is in MBIE's Electricity Demand and Supply Generation Scenarios 2016 (see sheet 13), which show that almost all of our current thermal generation capacity is scheduled to be decommissioned due to age between 2020 and 2027 (the exception is the relatively new Huntly E3P plant, but that seems fine as a dry year backup). The challenge for meeting the target then isn't how to shut the existing generation down, but how to ensure that it is replaced by renewables rather than thermal generation. The Greens don't actually say how, but the obvious answer is to restore the thermal ban passed in 2008. With flat demand, plenty of already-consented wind waiting to be built, and untapped geothermal resources, it seems perfectly achieveable, at minimal cost. We're going to be replacing this generation anyway, so we might as well be clean rather than dirty.

What if demand isn't flat? The long-term risk here is electric cars, which will mean that the energy they currently get from burning petrol will have to come from the electricity grid. Over the term of this policy that's not a big effect - there are currently only 2000 electric vehicles in New Zealand and while the government wants that to double every year, we'd just build extra wind. In the long run, we seem to be heading for cheaper photovoltaics and battery storage which will allow them to be charged from daytime peak, so policy is a matter of positioning to enable that future. On the other side, if Tiwai Point shuts down, then those thermal plants will close earlier, and we'll chieve the target that much faster.

Basicly, its do-able, and with climate change getting worse, seems like its worth doing. we're not going to make things better by continuing to burn coal and gas.

(There's also some other stuff in the policy: a "winter warm up" payment for low-income households to ease winter electricity costs. Funded by government electricity SOE dividends, but should have significant health benefits. And the usual tinkering with electricity market structures and regulation, but that's less interesting than the headline target).