COMMENT:

The growing sprawl of the Auckland's south-eastern suburbia would not be possible without burning colossal amounts of fossil fuels yet that's where SolarCity and Panasonic launched its latest initiative to entice people to use more sun-generated power.

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As SolarCity chief executive Andy Booth said, we simply can't continue to burn fossil fuels.

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Well, we can, if we want to wipe out humanity and most life on the planet through accelerating climate change.

This doesn't make business sense according to Westpac which is financially propping up SolarCity's revamped solarZero offering.

Photovoltaic panels and other parts of solar power systems have sharply dropped in price over the last decade, but that's been offset by the pricey batteries they now come with.

Tesla for instance quotes $14,800 for the Powerwall, plus installation costs of $1600 to $4700.

Big upfront costs puts makes solar an option for the wealthy few and that's what Stephen Tindall-backed SolarCity is trying to get around: for $85 plus GST a month, you get a single-battery solarZero system with six 295 Watt (peak) panels and the supporting gear like inverters and management computers plus an Amazon Alexa app.

The battery is a new design that Panasonic cobbled together and manufactured in Beijing, China. The nominal capacity is 6.4 kWh and the 1650 tall and 600mm wide and 280mm deep cabinet contains all the gear needed to run the solarZero system like a 3.6kW inverter.

It's recyclable in China (maybe in NZ too at some stage), silent and has a fully charged/discharged rating of 6000 times.

Multiple battery cabinets can be joined together for greater capacity (although SolarCity was coy about the cost, saying only "pricing will be bespoke").

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If you need more power generation and have the space for it, panels can be had as 9, 12 and 15 unit packages, costing $105, $125 and $145 (excluding gst) respectively.

The new solarZero. Photo / Supplied
The new solarZero. Photo / Supplied

One interesting add-on to the upgraded solarZero offering is the $8 a month community plan for sharing electricity between multiple homes and yes, existing customers will be upgraded to the new offering with new hardware.

The catch? You'll have to sign up for twenty ears. This gives you one battery replacement, a 25-year warranty for the panels, and locked-in wholesale electricity spot pricing to and from the grid.

Over twenty years, the single-battery, six-panel system will cost $23,460 including GST.

SolarCity's web site estimates that in Northland the saving will be $400 the first year, and $19,100 in total for the twenty-year period you sign up for.

A number of conditions needs to be met to hit those savings, including a five per cent a year reduction in energy usage through management and monitoring, and power prices increasing by 3.5 per cent annually.

It's difficult to say how well the economics of solarZero stack up without trying it and I'm weighing up whether or not to sign up for 20 years to do that.

The solarZero system looks like a tidy set up, and battery backed power in remote areas is a big drawcard if the Panasonic battery kicks in fast during outages.

Anything that reduces greenhouse gas emissions - and maybe even makes it affordable to charge electric vehicles in remote areas - is of course great.

That said, it's still early days for solar power and the long commitment and still not straightforward economics of systems like solarZero will make people hesitate before installing them, despite the removal of upfront installation costs.

If the government thinks local power generation through solar makes sense environmentally and will reduce our dependence on imported and increasingly expensive fossil fuels, maybe it should lean on power companies to create a subsidy for customers willing to make the long commitment to re-engineering our power grid?