If we lose our coal and gas-fired power stations we will have blackouts in dry years.
Ever since Meremere power station was commissioned in the 1950s, New Zealand has relied on coal-fired power stations supplemented by gas and oil to provide the 10% of annual energy needed in a 1:20 dry year to replace the shortfall in hydropower generation. To make up for the shortfall we need to have an energy store that can be converted into electricity over a four month dry period.
As this winter demonstrated, the system is now close to its limits in a normal year. Transpower has already warned that the dry year risk is steadily increasing.
Many people believe that geothermal, hydro, wind and solar power can solve the dry year problem. Geothermal stations (which emit CO2) run flat out day and night so they cannot provide any extra energy when needed. Any new conventional hydropower stations commissioned to mitigate the dry year risk would need massive storage dams which, inevitably, the Green Party and its friends would oppose. Wind power is of little use because it produces power only when the wind blows and its output drops in the critical autumn/early winter period. New Zealand wind farms seem to be on the brink of biting the dust for just that reason.[1] Solar power is even more useless because shortages occur when the days are shorter.
Some people claim that batteries are the answer but they cannot store energy in a wet year and release it in a dry year because they self discharge by more than 3% per month. Anyway, they are prohibitively expensive and have a life of less than 20 years.
Nuclear power could do the job but it is prohibitively expensive to have a nuclear power station sitting idle and only used every few years when there is a shortage risk.
Whichever way you look at it, Huntly power station supplemented by stored gas is the only short-term option for keeping the lights on in a dry year.
We now have a government that, based on its unfounded belief that man-made CO2 causes dangerous global warming, wants to stop coal-fired generation at Huntly power station as soon as possible and is determined to rundown gas supplies. It also seems to believe that if New Zealand makes massively expensive efforts to reduce emissions of greenhouse gases the rest of the world will be inspired to follow our lead and global climatic disaster will be averted. Dream on! China alone plans to build 259,000 MW of new coal fired power plants. They will burn more than 1000 times as much coal as Huntly.[2]
The government also wants to ban log exports and process them here. But its policies will result in our power supply being constrained, expensive and unreliable.
The government should know that the IPCC’s own climate models show that if everyone abided by their Paris Agreement promises (so far, nobody has) and keeps it up until the end of the century, the world will be cooler by 0.17° – which you can’t even measure! The Paris Agreement is a hugely expensive exercise in futility.
In the short term, there is no alternative to keeping Huntly for dry year reserve with 1 million tons of coal available. In the longer term, gas storage would be an option but, as the government seems to be determined to shut down gas production in New Zealand, no one would contemplate investing in it.
A longer term option is to build a large dam in the hills above Roxburgh Hydro station to store the huge amount of water needed by a pumped storage scheme big enough to get us through a dry year. Preliminary investigations indicate that it will be much more expensive than storing coal or gas. Engineering studies, RMA approval and construction would probably take 15 – 20 years at a cost of at least $6 billion and annual capital charges plus operating costs of more than $300 million/year. ‘
It would cost less than $50 million/year to keep Huntly and its coal stockpile available.
By the time it is commissioned the world is likely to have cooled and born again climate scientists may well be encouraging us to burn fossil fuels to raise carbon dioxide levels to warm the climate and make up for the shortfall in agricultural growth caused by global cooling!
So, face up to it! Burn coal or promote gas or suffer major blackouts and very high prices in a dry year!
[1] https://www.stuff.co.nz/business/107389651/the-promise-of-nz-windfarms-dissipates-as-it-announces-a-major-review
[2] https://www.bbc.com/news/science-environment-45640706?utm_source=CCNet+Newsletter&utm_campaign=f9bbc5f1d8-EMAIL_CAMPAIGN_2018_09_26_12_20&utm_medium=email&utm_term=0_fe4b2f45ef-f9bbc5f1d8-20166425