Although it's the land of the long white cloud, Gareth Williams says New Zealand does well by world standards when it comes to solar energy.

Although it's the land of the long white cloud, Gareth Williams says New Zealand does well by world standards when it comes to solar energy.

Williams is the chief technology officer at solarcity. He says; "On the whole, it's good for sunlight here. While it can be cloudy, you have to look at the total amount of solar radiation across a 12-month period.

"On that basis we get about 30% more solar radiation as Germany or the UK. Those two countries are both committed to solar energy. In fact, we're not far behind the sunnier states of the US."

solarcity is a full-service energy business. It accounts for a third of all new solar installations in New Zealand.

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In this case, full-service means solarcity handles everything. Customers pay a fixed monthly fee for the solar panels and battery. This includes the installation and maintenance.

There is no big upfront cost to buy the hardware. solarcity controls the hardware with its own software. This monitors electricity use and supply, optimising everything in the background.

A full-service approach is important. Although the economics of solar power and battery storage have improved over the years, people can still take years to recover costs when they buy and install their own systems.

Williams says a combination of strategies means solarcity can make its service affordable and customers are guaranteed savings from Year One.

That long white cloud is still an issue. There are days when the sun doesn't shine. Moreover, New Zealand's energy demands peaks on winter evenings when there isn't any sunlight. To get around this, solarcity combines roof panels with a smart storage battery. The battery has a specific design for local conditions.

Williams says the battery means customer can store excess power for when they need it. The solar panels charge the battery when the sun shines.

If there isn't enough sunlight, solarcity provides an electricity plan. Customers pay spot price for the electricity needed to keep the battery topped up. Spot-price energy plans have been controversial; electricity prices can spike when demand peaks. That's not the case when there's a battery to carry customers through peaks.

Williams says his customers get about about 25 to 30 percent of their electricity from the grid. "Our customers don't use much grid electricity. The battery means they don't need to buy their power at peak times when prices are high."

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A side benefit of this approach is that solarcity customers have power when the lines are down. Williams says it's possible to manage the system so that only essential services use the back-up power supply.

Another side benefit is that the constant power monitoring means solarcity's system is aware of unusual use patterns. It notices if a hot water cylinder is faulty or leaking. Customer can get an alert telling them about the problem.


Watch more about solarcity here.