RenewEconomy
In November 2016, our analysis shows that a Tesla Powerwall and a 5kW rooftop solar system could deliver electricity around the same price as grid power. Our latest estimate shows solar and storage is now significantly cheaper.
In late 2016 Tesla launched the Powerwall 2, halving the price of storage relative to Powerwall 1.
In a note in November 2016 we analysed the economics of one of these batteries plus 5kW of rooftop solar plus grid for back-up and exports, relative to grid-only supply for a household with north facing roof in Adelaide that consumes 4800 kWh per year.
The comparison worked out the annual bill with and without PV and battery.
The Climate Council estimates that there were 20,000 home battery installations in 2017, more than triple the 6,750 new installations in 2016.
And a couple of weeks ago the South Australian Government announced a policy to install 50,000 Tesla Powerwall 2’s plus 5 kW PV in a deal that would involve the government owning the assets but the households involved paying 27 cents per kWh for the electricity.
This notes looks again at the economics using the latest information on prices.
Bruce Mountain is director of CME
This post was published on February 21, 2018 10:09 am
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It would be more complete to include a solar+grid option in the comparison. With the reduced cost of solar and increases in feed in tariffs then this may in fact still be the cheapest option for customers.
The PV is giving all the savings, adding a Powerwall just makes the payback worse. The grid makes the best "virtual battery", I get 15c FIT during the day, and charge my 2 EV at 13c overnight. The cost of my "virtual battery" is -2c, ie I make money using the grid to store my solar PV. It makes no financial sense to install a Powerwall except for power during power outages.