The future of home energy

19 January, 2021   By: Ruth Callaghan

Every year, extreme storms leave hundreds of thousands of homes without power for days.

And as unlikely as it seems, one of the solutions to Japan’s devastating blackouts can now be found on WA roads — it’s the Nissan Leaf electric car, which is not only free of tailpipe emissions, but can act as a mobile battery that can plug in and power buildings when the energy grid fails.

Now, when the electricity goes out, Nissan has agreements with dozens of local governments and companies in Japan to make its electric vehicles (EV) available to keep the lights and other vital services on.

The Leaf is just one example of how battery and renewable technologies are changing the way we power our lives.

Across the world, the push to decarbonise economies, reduce reliance on fossil fuels, and drive the uptake of renewables is leading to governments reimagining the traditional generation, transmission and distribution of power.

And WA, with abundant wind and sun, as well as vast distances between towns, is a perfect location to test new ideas.

RELATED: How to make your home more sustainable (on a budget) »

How WA's power grid is different

Kate Ryan is executive director with Energy Policy WA, a government agency charged with planning the State’s future energy mix and network.

“Western Australian power systems are unique,” she says.

“With one large, isolated electricity grid servicing most people in the state, and many smaller grids in our regions, we can’t rely on power from other states to balance our grid.

“Matching supply to meet demand is an everyday challenge, one which has become more dynamic as solar and wind power have provided a greater share of our electricity supply.”

To understand the scale of potential change, it helps to think about the way our current networks operate.

The southern part of WA between Kalbarri, Kalgoorlie and Albany is covered by Western Power’s South West Interconnected System (SWIS) representing about 1.1 million homes and businesses.

Beyond the SWIS, Horizon Power supplies electricity to 100,000 homes and 10,000 businesses over a massive 2.3 million square kilometre area.

The SWIS has traditionally relied on fossil fuels as the main source of energy, but in recent years, wind, solar and other renewable energy sources have begun to challenge the dominance of coal and gas.

In October 2020, the combination of wind and solar for the first time generated more power in WA than coal.

If renewable biomass is also counted, renewable sources beat gas generation for the first time as well.

And while some of that renewable energy is generated by large-scale wind or solar panel farms, one of the fastest growing contributions is made by small-scale distributed energy resources (DER) that are exporting power to the grid. DERs include home energy storage batteries, community batteries and of course the 2000 rooftop solar PV systems installed each month in WA.

Bringing power generation to household level

Solar PV now generates as much as three Collie power stations, the largest single dispatchable generator in the network.

“So many Western Australian households have already installed solar panels to provide cleaner and cheaper power, and we’re building the power system around them,” Kate Ryan says.

“Frameworks are being created that will allow renewables and batteries to provide the energy and services needed to keep the lights on.”

But while the widespread uptake of solar is great news for carbon emissions, the electricity network wasn’t originally designed with renewables in mind.

In the middle of the day, when more than a quarter of homes are generating power, there is excess power output and limited demand. But when householders arrive home and the sun sets, demand rises just as solar power generation falls away.

The existing network was also not set up to receive as much energy back in the other direction, as is now being generated by rooftop solar.

A further issue lies in the way we charge for electricity.

Changing when and how we use energy

Customers who sharply reduce their network demand through rooftop solar save money, but also contribute less to the fixed costs of maintaining and upgrading the network serving their homes, leaving those without solar PV panels to shoulder a greater burden.

One initiative to address these challenges has already been implemented, with a change in the way people are rewarded for installing solar energy.

For new solar customers and those upgrading their systems, instead of a flat rate for every unit they contribute to the grid, the day rate is lower while the evening rate, when demand is greater, is higher. Running powerheavy appliances during the day is still a cheaper option than paying 28.8c/ kWh for Synergy power.

“Using power when the sun is shining makes the most of the renewable energy being produced and helps to balance supply and demand,” Ryan says.

But there’s another benefit of the new scheme – it now becomes more lucrative to collect and store unused solar power during the day, and sell it back to the network once the sun has gone down.

To do this requires batteries.

A household battery, which can cost between $7,000 and $13,000, according to Western Power, can store excess solar power not used by the home.

Western Power is now trialling both community batteries, which save up solar power from a group of homes to smooth the export of energy to the grid, and PowerBanks, which are similar but work in both directions, allowing homes to withdraw power from the community battery when the sun goes down.

Bigger batteries are also being added to improve the stability of the system.

For households, though, the big battery development is likely to drive in on four wheels.

Using your car to power your home

With the advent of cars like the Nissan Leaf, and the release of bidirectional charging systems in Australia, we are on the cusp of vehicle-to-grid charging, which will be a game changer for powering both your car and home.

Already being trialled in the ACT, customers with solar panels charge the Leaf’s 40kWh battery with solar energy during the day and then use energy to supply a home’s power needs at night.

RELATED: Common myths and misconceptions about electric cars »

With a car battery about four times the size of many current home batteries, it brings the future of zero-emissions living much closer.

Alex Forrest, RAC manager vehicles and fuels, believes the introduction of vehicle-to-grid charging could spur more people to invest in an electric vehicle.

“The cost of batteries has continued to keep prices of EVs high, which is the hurdle many consumers continue to struggle to leap over,” Forrest says.

“If EV owners are able to utilise extra features in their vehicles such as bidirectional charging, then that would be another reason to make the move into an EV.”

A parked car would have new value, as it could sell back unused solar power at peak times of the day, and just as in Japan, having a vehicle that could power a home in a natural disaster or during widespread outages could also be an incentive for WA residents, particularly in areas prone to energy interruptions.

“It would be possible to use the electricity stored in an electric vehicle’s battery for about three days in the event a household’s regular power source is cut, making it a potentially viable source of back-up energy,” Forrest says.

While the car battery would eventually need to be topped up, it could offer an option for people in areas prone to blackouts, or those with solar panels wanting to use their own solar-generated power when the sun is down.

With most household vehicles sitting used for around 95 per cent of the time, the idea of a car doing double duty as a generator is an exciting prospect.