Waikato River hydro operator says NZ must make some big calls on investing in renewable power for the future – with the conservation and financial costs that come with it
Geoff Anson has been working on the Arapuni and Karapiro hydro dams since he was 24 years old. Back then in 1980, each dam on the Waikato River had more than 100 workers; they were the centres of small villages.
That's all changed – now they're mostly automated. Motorists whizzing past on State Highway 1 can still see the empty houses left behind at places like Atiamuri. Anson and his team of 10 work across three dams, popping in as required to do checks and upgrades. "My friends all say I must own the bloody place by now."
Anson, now 66, has managed through big changes to technology and rural life; now he is managing through environmental changes that are posing new challenges for this country's ageing hydro power infrastructure.
Mercury is investing in modernising the nine-dam Waikato River hydro system. These dams (some nearly a century old) contribute about 10 percent of the country's generation.
This is renewable electricity, but it comes with other environmental impacts on the river and its surrounds.
Mercury's $75m project to modernise the wartime-era Karapiro Power Station will increase its peak capacity by 17 percent to 112.5MW – enough to charge 6000 electric vehicles.
The company says such efficiency gains aren't big bang projects like Turitea wind farm, but they show a respect for renewable generation and the Waikato awa. It runs an ecological monitoring programme to understand the impacts downstream, five-yearly riverbed degradation and riverside erosion surveys, and an annual Lake Taupo foreshore survey.
"The pressure on water is obviously real," Mercury chief executive Vince Hawksworth tells Newsroom. "But hydro is a great source for New Zealand. There is quite rightly an increasing focus on water quality, and that's really important .... I think where we are advocating for is government policy statements that send a strong signal that we can continue to invest in these hydro plants."
"Infrastructure such as dams blocks the flow of sediment, one of the causes of sinking and shrinking deltas. For example, over 100 billion tons of sediment is now stored behind upstream dams, greatly reducing sediment flows to coasts around the world." – Michele Thieme, World Wildlife Fund
Should Mercury, and should New Zealand, be doing more to regenerate the country's longest river and other waterways, forests and native biodiversity? As New Zealand prepares its ramped up National Determined Contribution for the COP26 climate summit in Glasgow, this country's emerging challenge is to strike a new balance between building and upgrading critical renewable energy, and restoring the natural environment.
To a great extent these objectives are in conflict but, done right, environmentalists argue nature-based solutions can contribute as much to slowing rising temperatures as does industrial-scale renewable energy generation.
World Wildlife Fund freshwater scientist Michele Thieme says rivers and their floodplains have the potential to act as shock absorbers to climate change. But maximising their ability to do so requires strategic interventions that keep their natural features intact or incorporate green and grey infrastructure that allow natural processes to occur.
"There's over 200 consents on what we can we can do with the river, and we abide by those rules ... and they get stricter every time we reconsent. The way I see it is if we carry on with strategic maintenance, I can't see why they won't still be producing electricity in a clean green environment in 50 to 100 years' time." – Geoff Anson, Mercury
Writing at Mongabay, she argues that governments and business leaders must prioritise climate adaptation actions that include rivers as part of the toolbox of nature-based solutions for solving the climate crisis.
"Infrastructure such as dams blocks the flow of sediment, one of the causes of sinking and shrinking deltas. For example, over 100 billion tons of sediment is now stored behind upstream dams, greatly reducing sediment flows to coasts around the world."
Citing a recent study, she says at least 25 million people live above sediment-starved deltas and so are vulnerable to increased coastal flooding and inundation. "Deltas that are starved of natural sediment flows are at risk of being inundated by rising seas," she says.
"The natural flows also provide sediments to reinforce riverbanks and deliver nutrients to fertile agricultural lands and mangrove forests along the floodplains and a river’s edge."
Thieme also argues that as climate change exacerbates floods, it is more important than ever that we protect and restore floodplains and wetlands.
And because river systems and wetlands are among the most biologically diverse and productive ecosystems on the planet, they provide a source of protein for hundreds of millions of people. "As communities become increasingly stressed by climate change, it is more important than ever to protect the basic needs that rivers provide."
Renewing the future
Anson is no fisherman. He thinks it's a waste of time.
But he does spend a lot of time down at the river, swimming or walking his fox terrier cross, Olive. He says Mercury and its workers take their responsibilities to the waterway seriously.
"There's over 200 consents on what we can we can do with the river, and we abide by those rules," he says. "They're hard and fast and they're there for the protection of the environment and the river and the resource. And cleverer people than I am put them all together – they're time-honoured and negotiated between all interested parties. And they get stricter every time we reconsent.
"The way I see it is if we carry on with strategic maintenance, I can't see why they won't still be producing electricity in a clean green environment in 50 to 100 years' time."
Hawksworth, his boss, says nearly every hydro plant in New Zealand will need reinvestment and upgraded technology. "Many of them are approaching 60, 70, 80, 100 years old. So as they go through that, they require a significant investment in refurbishment. And when you do that refurbishment, of course, one of the things that we're addressing is really only looking at returns that occur if that plant keeps operating for another 50 years."
Most of the ageing dams and intake structures need upgrading to meet modern standards – and this is costly.
"If we're taking a long-term view to 2050 for decarbonisation, then we should be looking to taking a long-term view on market structures and regulatory frameworks that have served us reasonably well to date. But actually, we want to go faster. The question now is, how do we go faster?"
