Solar innovation brings free power within reach

SAFE Engineering in Drury is home to NZ's largest photovoltaic solar array
Auckland Airport's solar panels power the arrivals corridor lights

Getting free power may seem like a pipe dream, but with solar power technologies getting cheaper the prospect of operating a self-sustaining building is now a reality.

"Solar electric power systems pay for themselves within about 10 years, and they'll last as long as 40 years," architecture firm Jasmax's sustainability manager Jerome Partington told NBR ONLINE.

"You're getting 30 years of free electricity."

The concept of installing solar panels and a small generator in residential homes is getting more common, but what about commercial buildings?

Many "sustainable" commercial buildings will employ some form of solar power, often dedicated for water heating.

The roof of Auckland Airport's international arrivals area, for example, is covered with 300sq m of solar panels which power the arrivals corridor lights.

Similarly, south Auckland's Drury heavy engineering company SAFE uses 360 solar panels to generate 70% of its electricity needs.

There are countless examples of Kiwi businesses using green technologies to become more energy efficient, but can a building be completely self-sufficient, generating all its own power?

It has not been done in New Zealand yet, but Mr Partington says one of Jasmax's new projects aims to achieve just that.

Tuhoe project

The building is a central administration, governance and meeting centre being built for Tuhoe in Taneatua, Whakatane, expected to be completed near the end of 2014.

With an area of about 1700sq m and 400sq m of solar panels, Mr Partington says the building will meet "net zero energy performance".

That means it will use only the energy it produces itself over the course of the year.

Because it will be connected to the grid, it will buy power during winter when solar generation will be lower and sell it back to the grid in summer, when it will be producing more than it needs.

The net result is a zero energy cost to the building.

Overseas examples

The concept has been used in the six-storey, 4800sq m Bullit Centre building in Seattle, USA.

It has solar photovoltaic cells with the capacity to produce 230,000kWh per year.

Twenty-six geothermal wells were bored to make the heating and cooling needs more efficient, and window blinds are controlled by an on-site weather station.

Similar concepts are being used in Denmark, where the government will soon require new buildings to use just 20kWh per sq m a year for basic energy needs such as heating, lighting and ventilation.

In comparison, one of New Zealand's most efficient "green" buildings, the NZI Centre, uses about more than 80kWh per sq m.

While that is a long way off Denmark's goal, Mr Partington says, if it can be done in a climate as harsh as in Denmark, or as cloudy as Seattle's, New Zealand can definitely achieve it. 

"We've got a climate that's three or four times more energy-rich than Denmark.

"We've got longer days, more sunshine, better rain – you name it – and yet we're not exploiting that. We're still relying on old technologies."

Not so simple

But achieving self-sustainability is not as simple as slapping solar panels on the roof. Everything about the building needs to be designed in the name of efficiency.

"It has to be well insulated, be getting as much daylight as possible, have very efficient equipment and lighting, and the users have to be aware of how to use the building," Mr Partington says.

He reckons buildings can achieve between 75% and 85% energy efficiency just by being smarter about the way they use power.

The rest of it can be generated through solar power.

Make a profit

In theory, businesses that continually generate more energy than they need could sell the excess back to the grid and make a profit.

However, electricity companies will not necessarily buy back the electricity at the same price they sell it at.

But he says there could be some regulation which rewards people for selling power back to the grid.

"The industry would like to see some regulations where you pay a nominal amount for using the grid for storage, maybe that's 25% of the cost, then you get a guaranteed 75% back."

With the cost of the equipment getting cheaper, Mr Partington thinks more businesses will consider self-sustaining solar power generation.

"There is a small investment at the start to get the right equipment, but you've done a huge amount of work and you've cut your power bill down dramatically.

"I do think more and more businesses will do it. They balk a bit at the capital cost but solar panels are actually very cheap and the system lasts for 40 years.

"That's the key for it to take off – it's a good business proposition. You buy 10 years worth and you get 30 free."

Mr Partington says New Zealand could use efficient buildings and solar power technology as an "innovation corridor" to sell developments to the world.

"If we actually start investing in practical solar energy and the electric cars, which become storage devices, you can start to have technology to sell abroad because we've got such a good climate to test it on."

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8 Comments & Questions

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The problem is peak demand (night time) is not matched by peak supply ( middle of the day). Likewise winter and summer respectively.

Works great if a few people get it but issues if the whole country moves in that direction.

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That is why the best PV system has to incorporate storage as well as feed-in to the national grid. The batteries should be in use during peak load, so the power you generated during off peak is being utilised when power costs and usage are at their highest.

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Adding batteries makes the installation much more expensive and complex. The grid should be able to be used, and it is criminal that the current price for power put back into the grid is only half of the power taken out of it. Other countries have encouraged development of these solutions by requiring power companies to buy at a higher price.

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I love the inventiveness of this technology but I am not convinced as to the eco green eyewash that invariably gets put out by those who fudge the true cost benefits. The true cost of these panels together with the cost of the batteries that are required to provide the instant switch on power households demand do not equate in this country to what should be an abundant and very cheap relative hydro and geothermal supply able to cope with peak loads. Wind power farms also are proving in Europe to be a far cry from the reliability of supply the theorists had everyone believe. Photovoltaic I would go for in a nano if my core electricity supply became unreliable or too expensive but as NZ main grid power is a politically contrived over-expensive price already then consumer price needs to drop first.

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Imagine if enough people in cities had solar and wind turbines. The suburbs (which during weekdays) are mostly deserted. Scale this up and you could have cities becoming energy generators. Perhaps there should be incentives regulated so that the utilites companies pay/credit for energy being put back onto the grid.

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Have you run any numbers to back such a wild claim? Are you a scientist, engineer or technologist of any kind? Or just an enthusiast?

NB: Promoting regulations to force uneconomic technologies into a country is tantamount to economic sabotage (a treasonous offence under the SIS ACT), your only saving grace is that you are ignorant of the real numbers.

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Where in the NZ SIS Act does it say this?? The word "treason" or "treasonous" does not appear anywhere. I'd like to see the case law that backs up your interpretation of the Act in this way.

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Steady on anonymous, I think he was just expressing an idea.

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