I particularly like the following article by Dan Horman on Business Spectator. I believe that helping households realise savings through more energy efficient environmentally friendly means and re-configuring their loads to make use of their solar generation, should be the starting point. Work out how best to make use of the solar energy being produced and then if there is some left over, and only if it is significant, consider battery storage. Why would you put your solar energy back on the grid when feed-in tariffs are at best 10c/kWh and at worst 5c/kWh…


Are batteries what energy consumers really need?

Tesla’s release of the Powerwall has set the world a-buzz. It is undoubtedly a brilliant product, but the question that remains to be answered is whether the market is ready for mass adoption of this product.

Already there are pages and pages of number-crunching analysis regarding the costs and savings of ‘PV plus storage’, and the numbers reveal an answer something along the lines of ‘it doesn’t make sense for every home to have a battery yet, but it’s close enough to have traditional utilities shaking in their boots’.

These cost analysis’ ignore the fact that our current energy infrastructure and available technology is not yet ready to competently and efficiently deal with a mass deployment of residential batteries.

Tesla boss Elon Musk referred to his innovation as “the missing piece of the puzzle”. There is some truth to this statement as affordable energy storage has been viewed by many as the golden chalice of renewable energy. However, many also recognise that at the same time as completing a puzzle, Musk has strewn a completely new puzzle across the floor and simply laid a single piece.

This new puzzle could be called “Energy Infrastructure Gen 2”. The corner pieces of this new puzzle are energy efficiency, energy management, the internet of things and automation. A central piece is also taken up by the electric vehicle and somewhere lying on the floor still upturned is a solar inverter that is capable of charging the Powerwall at 400V DC without first converting to AC (the vast majority of hybrid inverters, including ours, currently charge at 48-60V DC).

When you add a battery to a grid-connected home with solar PV you more than double the number of possible energy flows from three to seven:

The choice on how this energy is managed needs to be instantaneous and automated to get the best value out of the significant investment made. If you add the potential for demand management and load shifting, the complexity is significant. Is it optimal for me to use solar energy now to meet current demand or to charge my battery for use at peak times? Until these challenges can be met in a manner that is reliable, explained simply and can occur without intrusion into users’ daily lives, PV plus storage will remain a solution that generates a hell of a lot of excitement, many quotes, but very little successful implementation.

The world needs technologies to deal with the variable nature of renewable energies as they take a larger and larger share of our energy production. However, it is doubtful that an energy infrastructure that involves a battery on every garage wall is the optimal solution for anyone. If this battery is in our car, rather than sitting on the wall next to it, the solution starts to make more sense as we then start to deal with one of the other challenges of reducing CO2 emissions – transport. Stranded assets and a utility death spiral may give some a sense of righteous satisfaction to some, but they are not good outcomes for society. The grid – or at least micro-grids – will continue to fill a large hole in the puzzle; whether the names that fill them are the same as now will be largely determined by their actions in the next give years. The grid is not dirty, the power behind it currently is.

The internet of things is coming and innovative companies are investing in this world where energy decisions are based on data that was previously unavailable. We have seen early successes with smart thermostats and commercial demand management. Look for these innovations to continue and start to encompass energy storage.

Households considering purchasing a battery should first spend their money on LED lights and other energy efficient appliances, then they should take a look at their energy use and see how they can adjust their consumption patterns to match their solar output, potentially utilising smart automation to achieve this. If the desire for energy storage is still strong, let it drive you around in your brand new electric vehicle. You will not only use more of your excess solar, but also reduce your emissions further.

Residential solar installers looking for the next way to make a dollar or get a new sale across the line should focus on helping consumers with the above points. Look to package up solar PV, LED lights with an energy management system that enables them to match demand with solar PV output with minimal hassle. At the very least you know that the government or utilities are going to be powerless to stop you implementing energy efficiency and energy management solutions in your customers’ homes – not so with energy storage.

If both the consumer and solar installer have executed the above program to perfection and are still hungry for more then perhaps it is time to look at residential energy storage. But I expect by that stage your local micro-grid operator can offer you a better deal.

Dan Horan is an Australian living in Shanghai as the General Manager for Autarco’s China business.