Electricity generation in NZ – Keeping the Lights On

Electricity generation in NZ – Keeping the Lights On

In 2020, New Zealand generated 42,858 gigawatt-hours (GWh) of electricity with hydroelectricity making up 56%. The installed generating capacity of New Zealand (all sources) as of December 2020 was 9,758 megawatts (MW), from hydroelectricity, natural gas, geothermal, wind, coal, oil, and other sources (mainly biogas, waste heat and wood).

While it would be very nice to have clean, quiet, cheap energy in bulk supply and pretty much everyone agrees that it would be ideal, there is only one problem---It doesn't exist.

Yes - there are wind and solar generators being built all over the world but they only add a small amount to the overall power demand.

These renewable sources of energy (solar and wind) have limitations and we need to remember that wind and solar only work when the wind blows and the sun shines, but we need energy all the time.

Any clean, cheap energy is obviously welcomed but they currently do not have the capability of replacing Thermal Power Generation.

We all care about our planet in some form or other, but most of us are also realistic and don’t believe in some idyllic utopia where everything can be made perfect by wishing it so.

In April 2025 the Resources Minister, Shane Jones spoke in the media about protesters camping at a West Coast mining site. He said that they should be condemned for their selfish and dangerous actions that put themselves and others at risk

He also stated; “I cannot fathom the mentality of these blow-ins from other parts of the country to think that they have a right to speak for the hundreds of people who derive their living from mining.

“They turn up, reportedly with an eight-month-old child in tow, to protest what is a legitimate industry going about its lawful business. In the process they are putting themselves in danger and sapping the resources of Police and other agencies.”

 “This lack of awareness and consideration for others is mind-boggling. New Zealand is relying on a stockpile of 1.2 million tonnes of coal to keep the lights on this winter”.

While the Labour government under Jacinda Ardern stopped the mining of coal in New Zealand for power generation, they didn’t actually stop the burning of coal for generation. They just exported the detrimental environmental effects of mining by sourcing coal imported from Indonesia.

We are importing millions of tonnes of dirty coal from Indonesia so that our thermal station at Huntly can continue to supply the power required to keep the lights on.

Most coal fired power stations do NOT send 60 to 70% of the energy they use up the chimney. The boilers of modern power station are normally around 96% efficient with the exhaust heat being captured and re-used to heat the air and water before they enter the boilers.

The very slight amount exiting the stack is moist as in condensation and CO2. There is virtually no fly ash because this is removed by precipitators or bagging plants that are 99.98% efficient. The 4% of energy that is lost is mainly due to heat transfer through boiler wall convection.

Coal-fired Power Stations are highly efficient with very little heat loss and can generate a massive amount of energy for our needs. They can generate power at efficiency of less than 10,000 b.t.u. per kilowatt and cost-wise that is very low.

Huntly Power Station on the Waikato River is the country's largest power station and produces approximately 1435 MW of electricity from burning either coal or natural gas.

With the benefit of hindsight and looking back a couple of years to the situation where New Zealand was almost totally reliant on fossil fuelled generation, caused by the lack of hydro generation capacity due to drought conditions, and taking into account current global warming effects we are going to need to develop a significant increase in sustainable generation if we are going to keep the lights on in the future.

Recently we came very close to having rolling power cuts as a regular thing due to the lack of supply from hydro generation or wind generation. There was one incident in August 2021 where power cuts were instigated due to a lack of availability of electricity supply.

While we have stopped mining coal in New Zealand for power generation we haven’t actually stopped burning coal for generation. We have just exported the detrimental environmental effects of mining by sourcing coal imported from Indonesia.

We are importing millions of tonnes of dirty coal from Indonesia so that our thermal station at Huntly can continue to supply the power required to keep the lights on.

Based on an average generating output of 1.5 megawatts (of unreliable power) to replace just the Huntly power station you would require over 1,400 wind generators.

The maximum size wind generator is 3 Megawatts, which can rarely be attained on a continuous basis because it requires substantial forces of wind. And for the same reason only generate when there is sufficient wind to drive them.

This of course depends where they are located but usually they only run for 45% -65% of the time, mostly well below maximum capacity. They cannot be relied on for a 'base load ‘because they are too variable. And they certainly could not be used for load control.

As for solar power generation much research has been done over the decades and there are two types.

Solar thermal generation and Solar Electric generation but in each case they cannot generate large amounts of electricity. The maximum rate at which the sun's photons can be converted to electrons is about 33%. Our best solar technology is at 26% efficiency.

According to the published reports the CO2 in air has risen from .034% to .038% in air over the last 50 years.

To put this percentage of Carbon Dioxide in air in a clearer perspective;

If you had a room 3.7 x 3.7 x 2.1 metres the area carbon dioxide would occupy in that room would be .25 x .25 x .17m or the size of a large packet of cereal.

NZ emits 0.17% of the world's total carbon Dioxide and the government wants to reduce this by 100% by 2050 or reduce emissions by 0.17 % of the world's total CO2 emissions.

What effect will this have on existing CO2 levels?

The figures state that the CO2 in air has risen from .034% to .038% in 50 years.

Assuming this is correct, the world CO2 has increased in 50 years by...004%.

Per year that is .004 divided by 50 = .00008%. (Getting confusing -but stay with me).

Of that because we only contribute 1% our emissions would cause CO2 to rise .00008 divided by 100 = 0.0000008 %.

Of that 1%, we supposedly emit, the governments wants to reduce it by 20% which is 1/5th of .0000008 =...00000016% effect per year they would have on the world CO2 emissions based on their own figures.

That would equate to an area in the same room, as the size of a small pin.

For that they have gone crazy with, emissions trading schemes.

The cost to the general public and industry will be enormous, crippling and even closing some smaller businesses.

So the next time someone tells you that wind, solar and batteries are the magical solution for all our energy needs ask them if they have an idea of the cost... to the environment or are they just living in a dream.

“With current plans, the International Renewable Energy Agency calculates that by 2050, the disposal of worn-out solar panels will constitute over double the tonnage of all of today's global plastic waste.”

“Worn-out wind turbines and batteries will add millions of tons more waste. It will be a whole new environmental challenge.”

Before we launch history's biggest increase in mining, digging up millions of acres in pristine areas, encourage childhood labor, and create epic waste problems to fuel the battery requirements associated with the sustainable energy dream, we might want to reconsider our policies on the fuels that make our modern world possible; and which technology is making easier and cleaner to use every day.

The fact of the matter is that we will still need to use thermal generation for some time to come or face rolling blackouts at times.

Here in New Zealand we have another option that will allow us to keep the lights on without the need to import dirty coal from Indonesia.

Instead of filling our landfills with waste we can use that waste to produce power by incineration. Given the latest technology available, there will be less harm done to the environment from using waste as a fuel than there is from importing and using coal. 

According to the Waste Hierarchy, the recovery of energy from waste is the next preferred method after recycling. Disposal to landfill is the least preferred method of waste management, yet it is the current best practice in New Zealand.

There is a place for these green technologies but we need to look beyond the myth of zero emissions and identify the true embedded environmental costs of making and replacing them to allow for an accurate analysis of the benefits in comparison to the current energy generation methods and other possible methods.

The Auckland region produces approximately one and a half million tonnes of waste per year that mostly goes into landfills.

The Labour government committed to stopping the use of fossil fuels and converting to electricity use instead and given this focus on the use of electricity to replace the use of fossil fuels the demand for electricity is going to increase exponentially.

New Zealand currently does not have the capacity in sustainable generation of electricity to stop the use of thermal generation outright.

If the hydro lake levels drop significantly due to weather effects and the wind doesn’t blow at that time then we will need to rely on thermal generation or see rolling blackouts as happened in August 2021.

There is another option that should be explored as soon as possible and that is to use incineration of waste to fuel power generation rather than using imported coal.

Instead of filling our landfills with waste we can use that waste to produce power by incineration. Given the latest technology available, the relatively simple engineering needed to transform the Huntly Station to use waste, the availability of area for the processing of the waste, the existing transmission network and the existing rail network into the site, there will be less harm done to the environment from using waste as a fuel than there is from importing and using coal. 

By using waste incineration at Huntly Power station we can achieve the following benefits;

1. 1. Reduce the amount of waste going into landfills
2. 2. Reduce the methane emissions from landfills accordingly
3. 3. With the new incineration technology available we can reduce the amount of greenhouse gas emissions of thermal generation from coal burning.
4. 4. Utilise the existing supply infrastructure into Auckland the largest market.   
5. 5. Gain time to develop the sustainable generation capacity from wind and solar without the need for rolling blackouts.

We have the capability on government owned land where the infrastructure could be sited to accommodate the sorting of the waste streams into separate recyclable and incineration resources.   

Yes it will require the construction of a new plant dedicated to the incineration of waste but the renewal of the Huntly power station will soon be required anyway due to its current life span.

There are no reasons not to use waste incineration when compared to the environmental effects from burning imported dirty coal.