Residential case study: Rob R.

Amber Customer Story – Rob Rendell

When one of Bendigo’s top sustainability consultants installs solar at his home, don’t expect the usual. That’s certainly true for Kangaroo Flat resident Rob Rendell, co-founder of RMCG, one of Australia’s leading agricultural and environmental consultancies based in Bendigo.

Access wholesale electricity market

Rob is one of the early adopters of a new system for buying and selling solar electricity directly on the wholesale electricity market.

Rather than getting paid around 5 cents per kilowatt hour for his solar exports, Rob can earn up to $15 per kilowatt hour when wholesale prices spike.

Rob sees a lot of similarities with the “water market” which he is very familiar with and this sparked his interest in Amber.

Australian innovation

Rob gets paid for his solar exports using an innovative app developed by Melbourne energy tech company and electricity retailer, Amber.

To trade his electricity, Rob has invested in a 13kW solar panel system and a Tesla Powerwall 2 battery. He also switched his electricity retailer to Amber and signed up for Amber for Batteries, smart battery optimisation tech with an app that provides him with full control of his battery.

Using time-based electric heating, strategic use of a wood fire, solar hot water, purchase of an electric car combined with using ‘Charge HQ’ app, plus switching to time-of-use electricity tariff are all part of Rob’s “rewired system.”

Level playing field

Now, when wholesale electricity prices are high, Rob exports his stored solar energy to the grid and gets paid the same as big energy generators. And when wholesale prices are low, Rob can buy power from the grid at just a few cents per kilowatt hour – including keeping his battery topped up for later on.

Best of all, when prices go negative, Rob gets paid to use grid electricity. And if he times it right, he even gets paid to charge his electric car!

Whilst Amber for Batteries puts power into the hands of householders – literally – for some, making the most of it can mean making some changes to when they use most of their power.

This is particularly the case if you produce an excess of solar that you don’t use and your battery can’t store. Fortunately, Amber has now added settings that provide protection from negative wholesale prices for customers with SolarEdge, Sungrow and Alpha ESS systems and there’s a curtailment solution for Fronius, SMA Huawei that will be available soon. And they’re learning fast from expert users like Rob who are providing useful feedback.

Solar sized for winter

“Our objective with our solar power system is to generate as much electricity as we use”, said Rob.

“Because our winter electricity usage is much higher than summer, we needed a large enough system to cover our winter demand. Our system was designed with our winter usage first and foremost. But that means we’re generating a large surplus in summer.”

“Whilst we soak up some of our summer surplus electricity charging our electric cars, there’s still often lots left over during the daytime – typically in those peak sunshine hours between 11am and 3pm. Rob said. “More than the battery can store and more than we need in our home.”

“A key lesson I learnt is that one should put as many north facing panels on as steep a slope as possible (45 degrees) to maximise winter production – east and west facing panels whilst useful in summer don’t help much in winter which is the key time”, said Rob.

“This does mean a surplus in summer which the grid is slowly adapting and evolving to manage.  I think this summer excess will be a “watch this space” and Amber is best suited to provide options.”

Timing is everything

“We try to shift our electricity loads so we’re storing and using power when grid prices are low, and exporting stored electricity when prices are high”, Rob continued. “Combined with a time-of-use tariff for grid electricity we can completely avoid using the grid even in winter during the expensive peak period of 3pm to 9pm.”

“It’s a simple concept and works pretty well for us most of the time.”

Capitalising on the evening peak – and sometimes the morning peak

“Amber enables us to send our stored energy to the grid when the grid needs it most. That’s typically in the evening when everyone’s home from work. It’s also when wholesale electricity prices are highest.”

“Occasionally Amber purchases energy during the night when prices can be low, stores it in our battery, and then exports first thing in the morning during the morning peak.”

Air conditioning with a clear  conscience

“Around Australia, the use of air conditioners during hot evenings is the big energy killer”, Rob commented. “However with this system, our solar provides all of the energy and the battery stores sufficient energy to enable full air conditioning with no impact on the grid.”

Greening the grid

“It’s a win/win. We get paid a great rate for our stored energy when we export it during the evening peak. And we’re helping grid go greener as our solar exports are offsetting the amount of electricity required from coal and gas fired power stations.”

“Amber shows that there’s clean energy future where solar owners are fairly rewarded for making the grid greener, more reliable, and cheaper for everyone. We reckon that’s great. That’s why we’re happy to be with Amber.”

“Being part of developing a new approach is rewarding although it must be recognised that there are still many challenges including being able to optimise feeding into the grid during the morning before the feed-in-tariff goes negative and developing options that suit all of the different systems that people have. I think our system will become a common arrangement which focuses on meeting winter demand primarily, includes a battery, an EV and electric house heating”, said Rob.