I woke up to a front page story in the Otago Daily Times a couple of days ago about our worryingly low hydro lake levels, and the plans being put in place by the authorities to make sure we have enough electricity to get us through the winter. 

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These dry years happen, on average, every 4-5 years and this one has had a significant impact on the wholesale price of electricity. 

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Other articles tell me that it’s also been quite calm, so we haven’t had as much wind generation as we would normally have. That doesn’t exactly help the situation, and is leading to even higher prices.

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At Rewiring Aotearoa, we believe more rooftop solar is essential as we electrify all the fossil fuel machines in our economy  - and not just because it reduces emissions, but because it’s the cheapest form of delivered electricity available to New Zealanders and can help bring down the price of electricity for everyone. 

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And it turns out it’s even more sensible in a dry year. 

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We looked at NIWA’s data on sunshine hours in Auckland and Christchurch since 2000.

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We know that there isn’t as much sun in winter than there is in summer. But over April-August, sunshine hours are, on average, 5% higher in a dry year compared to the average. 

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And they are 10% higher in April/May/June, which is actually critical so that we can go into winter with higher lake levels. 

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Our hydro lakes are basically like big batteries and we need to save them for when they are most needed. Currently it's the job of coal to help keep this big battery charged and that's expensive and polluting.

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More solar on our homes, businesses and farms - and more batteries to store that cheap solar energy and help manage our peaks - can help do that. If 1.5 million Kiwi homes got an average sized solar installation (9-10Kw), just the additional 10% kick from solar in Apr/May/June in dry years would reduce the need for one of those big Huntly coal units by 50%!

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This will also generate about 23kWh per day in August, which is the equivalent of burning a 20 kilogram sack of Indonesian coal at Huntly every 1.5 days. The house with solar would stop about one metric tonne of coal from being burned in June, July and August.
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We need to start thinking about customers as part of the electricity system and fairly rewarding those who have invested in solar and batteries. And we need to reward customers fairly for their contribution.

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