Hi Peter, an interesting article, giving the user perspective that is so valuable.

In a previous role, I worked as Technical Manager for one of the largest retailers of solar power at the time and designed and installed a large number of remote area (off-grid) power systems. The two major issues that had to be taken into account, as you point out, were batteries (the best tech of the day was the cylindrical electrode lead-acid batteries) and the trade-off between storage and backup generation. I put batteries into a separate category for two reasons; firstly, they are relatively fragile and a poorly maintained battery will be easily damaged. Second, they are relatively expensive and users nearly always want to underspecify capacity, which makes maintenance that much harder. In addition, training users to properly maintain unsealed liquid-electrolyte batteries is not trivial.

The Powerwall batteries that Musk is manufacturing remove most of those concerns. You're not quite correct to say they are the same as in Tesla cars, but they are similar in some ways. They are Lithium Polymer cells, which are maintenance-free and have high-levels of built-in "intelligence" to ensure that they operate optimally for durability. As a result, they are limited to relatively low rates of discharge (2kW) because household voltage is significantly lower than that of the Tesla car and it is high current that destroys batteries. Secondly, a LiPo battery can be charged to around 80% of capacity in a very short time, while getting the additional 20% takes much longer (this is the basis for the Tesla supercharge stations), and it also means that even small periods of sunshine will provide significant charge top-up to a LiPo installation, where a PbH+ battery requires high current for long periods to get much in at all.

Within a few years the price of battery storage will drop by around an order of magnitude. PV price per Watt will drop nearly as fast. As a result, backup generation will be increasingly seen as unnecessary.

And users won't require training.

Good article and an interesting post by Minns.. one minor point. The Kyoto protocol was signed in Howard's time but famously it was not ratified until the Rudd government got into power.

As for the economics, sure the new battery products interest a number of people but the costs are still substantial and the grids may well change how they charge for electricity - introducing a set fee for access to the grid with reduced usage charges.. then it may become a choice between going off the grid and setting up all this still expensive equipment, or staying on and not bothering at all..

Considering the emissions that would be generated in manufacturing these batteries does anyone have any insight into how much carbon, if any, is actually saved by using them?

Mark, the Tesla "gigafactory" is entirely powered by PV to the best of my knowledge.

Your Grazer friend may be winning for now, and at the expense of ordinary power users and those who can't afford to invest in their own independent power?

But that price gouging day may soon be over, with schemes available for fully independent off grid power, costing less than the price gouged power bill, thanks to innovators like the aforementioned Tesla/micro grids.

[I have the solar system; now I just need an effective and affordable battery!]

Sort of like killing the goose that laid all those "gold plated" eggs.

Were I your (owed a living?) Grazer friend, I'd be looking for opportunities to use his (gold plated) power to promote additional on farm production!

(Irrigation/tramlines tilling/rechargeable electric vehicles/on farm production or processing/cooking/freezing/pasteurizing/providing fast food/coffee breaks/hot water/electric B-B-Q's or a fast recharging service for (the phone just died and a dead phone is no use at all in an emergency, but particularly a medical emergency where literal seconds count) travelers)?

If only to maintain a useful return on his investment!?

I mean there is just one constant in the entire universe, and that one constant is constant change!

And we need to adapt to change or be crushed by it!
Rhrosty.

Bring on the power wall baby!

Sounds a bit like a cross between a lithium ion battery and a polymer based ceramic fuel cell?

Perhaps a better informed Craig Minns could further enlighten us on this very interesting and timely development!

What do you know to be the expected life; and maybe you got out too soon mate?
Rhrosty.

Nothing to do with fuel cells, Rhrosty, it's a similar technology to that used in your mobile phone. Projected life (which is conservatively defined to be the period during which the battery provides full rated storage) is 10 years, but I expect that will be extended fairly quickly due to current advances in charging control.

I haven't left the field mate, I'm back at uni working on my electronic engineering degree with a major in energy systems.