A flurry of press releases announced the imminent arrival of Tesla Energy in Australia. So what? No biggie? It’s just the most promising thing to happen to battery storage prices since people started hooking up battery packs to their rooftop solar arrays. For our green home design, it couldn’t have happened at a better time.
What’s the story with Tesla Energy?
First Tesla Energy announced they had launched their 7 kWh and 10 kWh Powerwall battery packs in the USA. This was quickly followed by news about plans to release the units in the Australian market. It’s worth looking at the press release just to see what good designers can do with something as boring as a battery pack. They look sleek and sexy – too good to hide away in a utilities room. Since they come in a range of colours, it’s tempting to make them a wall feature and conversation starter. Who could resist walking over to touch a device that looks this good? Anyway, I digress.
The local press then picked up the story and provided more details about possible prices. The probable change to how much Australian consumers will have to pay is eye-popping. It’s about a third of what batteries currently cost. A 10 kWh Powerwall is likely to cost around $4400. If the predictions are correct, we could get 30 kWh of electricity storage in 2016 for the same price people are paying for 10 kWh in 2015.
Apparently, the electricity retailers have started to realise the market is undergoing a fundamental change. AGL has announced they will soon be marketing a package that includes grid connection, solar cells and a 6 kWh battery pack. Perhaps the tide is beginning to turn. Retailers are starting to work with embedded generators to come up with a better electricity system that takes full advantage of household solar power generation. Up until now, they appeared to be fighting a rearguard action against a fundamental change in the market place.
So, what’s Tesla Energy got to do with us?
This announcement is likely to have a significant impact on the way we design our electricity system. Going off-grid is the stretch goal. However, there are limits to what we can afford. Assuming the cost of batteries is about to fall by so much, the stretch goal just became more achievable. If electricity suppliers are considering their options with regards to grid connections and solar/battery installations, there may be a desirable (and economical) middle ground.
David has looked at the available space on the roof. We could fit a 36 panel 9 kW solar farm up there. Given that a full charge on the Nissan LEAF takes 15 kW, we’d need a large system assuming we were running off-grid. I’d have my very own little power station to manage and maintain. There’d be a ladder somewhere bolted onto a wall so that I could occasionally climb up on the roof to check out the panels and, perhaps, do a bit of maintenance.
I feel the need for a spreadsheet coming on. With so many factors involved, we’ll be using a a range of calculations to work out what combination is both affordable and true to our goals. It may be off-grid with a small generator as emergency back-up. It could be a hybrid system with batteries and a back-up grid connection until the time (and prices) are right for severing the connection with the electricity retailer. Luckily, I have kept data on how our 2 kW system performed at our last house. This should help with predicting actual solar cell performance throughout the year.
We are feeling positive about this aspect of our design. With so many possibilities popping up, it gives us confidence we can demonstrate being ‘green’ can also mean being ‘economic’.