In Australia more than 1.4 million households have rooftop solar panels, with double digit growth every year. In Perth one in five homes have solar power. Combined they equate to the biggest source of power generation in the state. The problem is solar power is only available when the sun is shining. Why install battery storage? An obvious drawback to using solar power on its own is that it is only available when the sun is shining. At night time households are still completely reliant on the grid – often from fossil fuel sourced power such as coal and gas. In addition to maximising the on-site benefits of solar generation, battery storage can also play a role in smoothing peak demand issues on the broader grid, reducing the need for costly network upgrades.
Josh’s House is a 10 Star housing development near Fremantle in WA that is demonstrating that high performance energy and water efficient housing can be delivered for a similar price and timeframe to conventional homes. The three bedroom, two bathroom family dwelling looks like a regular house but is acting as a ‘Living Laboratory’ as part of a research project undertaken by Curtin University, the CRC for Low Carbon Living and Josh Byrne & Associates (JBA)
The existing 3 kilowatt (kW) solar panel system produces nearly double the electricity used over the year, making the house comfortably ‘net zero energy’. Despite this, monitoring undertaken over the past 12 months has shown that over half of the power consumed (56%) is still being sourced from the grid.
By installing an 8 kilowatt hour (kWh) solar energy storage system along with the existing 3kW solar panel arrangement, Josh’s House will only be using the grid for around 3% of its electricity needs.
Now, you might ask why not go the last step and go entirely off grid? Well it is technically possible, but it’s expensive. The small amount of power required from the grid will be imported during winter, when there are consecutive days with little sunshine.
To take the last 3% off grid, it would require a much larger solar PV system (from 3 to 5kW) and a much larger battery (from 8 to 14kWh), and because this extra capacity would be used infrequently, it would take a very long time to pay off. Meanwhile the system sized for Josh’s House cost around $12,000 installed and will take approximately eight to ten years to pay off through reduced bills.
View Comments
I notice the ABC TV News report last night signed off with a message about maintaining the grid and energy poverty for those that might not otherwise afford this system. Why?
If we take the grid supply charges as representative of the cost of the 'grid', then it will be cheaper to provide everyone with these systems. Perhaps community ownership of local grids will be important, but THE grid is an expensive dinosaur.
Are the batteries in Josh's house available to the public to purchase and if so, where can I go to check them out?
Take note of the 3% figure. You will see it everywhere, including my own system in Canada at latitude 51. PV and batteries seem to hit the sweet spot at 97% and the remainder off grid will be provided by a generator. My own system is 12 kw PV array and 40 kwh of AGM sealed lead acid which have about 20 kwh available at 50% discharge. Soon lithium will arrive and yet the final 3% is just out of reach.
If the generator is needed 3% of the time...
That's 11 days a year. I've had power outages which lasted 2 or 3 days. As long as those 11 days aren't all consecutive, you can just ride it out.
If can cut your usage during that time period down to minimum necessities -- don't open the refrigerator unless you need to, etc. -- your only required electricity usage is keeping the house above freezing temperature and below heatstroke temperature, assuming you use electric heating.
Isn't the alternative to:
(a) set up a "low usage mode" to conserve energy that last 3% of the time;
(b) set up a portable (diesel/gas) generator to generate energy that last 3% of the time.