Amber for Batteries – one user’s experience

One solar citizen who switched their energy provider to Amber for Batteries has generously shared their experience from April to September in the blog below.

We live in a duplex townhouse in North Epping in Sydney’s north-western suburbs, and have been a solar-powered house for several years, starting in 2011 with a system consisting of 1.5kW/6 modules and a 4kW SMA inverter. These were the days of $0.66/kWh FiTs (Feed-in Tariffs) – thank you NSW government and AGL! This system was upgraded to a 6kW/20 modules and a 5kW SolarEdge system in April 2017, with a Tesla PW2 battery being added 4 months later, and an EV (Renault ZOE) 8 months after that. Having been an EnergyLocals/Evergen customer for several years, we changed our electricity retailer to Amber for Batteries last April, following a recommendation by Solar Citizens. We were quite happy with the EnergyLocals/Evergen combination, but the Amber offer looked interesting, particularly the management of the battery and access to wholesale prices.

Apart from having to deregister our system with Evergen, which took a couple of weeks, the change-over to Amber was trouble-free. Lots of useful information was provided, both by customer support staff and on their website. I had intended to compare the Amber charges with what EnergyLocals would have cost, but this proved to be difficult due to the different charging periods, different FiT regimes, and the change of charges for both retailers at the start of the financial year. We decided to stay with Amber for at least 6 months to give their system time to learn our power consumption habits, and us to learn about how it worked. Given what has happened with the arrival of spring in the last few days, it looks like Amber for batteries has got us worked out.

Amber for batteries has 2 modes – Earnings Optimiser and Battery Booster. The following analysis is based on observations over the last couple of weeks.

• The Earnings Optimiser mode attempts to maximise earnings, by discharging the battery to the grid if FiTs rise above about $0.25/kWh, and provided the forecast is for sunny weather. The discharge happens early in the evening and occasionally early in the morning. If it happens in the evening, the battery will be discharged to about 30%, which leaves sufficient charge in the battery to keep the house load supplied without needing power from the grid. Our system was switched to this mode at the start of official spring on the first day of September.
• The Battery Booster mode keeps the battery topped up, and only sends power to the grid if the FiT gets to about $1.00/kWh or more, and then only discharges a fraction of the available charge. Our system was in this mode all winter, except when we were going to be away for the night and not running the A/C to keep warm.

Both modes will occasionally charge the battery from the grid overnight, particularly if the forecast for the next day is doubtful.

The screen grabs below are a good illustration of Amber in action. They are from a free application called “Powerwall Companion”, which captures all sorts of useful historical information about the PW. These grabs show the power flows for a full day, and the level of battery storage for the same sunny day. The next day was also forecast to be sunny in the morning and partly cloudy in the afternoon. 

There was a very short feed from the battery to the grid at just after 07:00, followed by the battery being charged by sunshine from 07:15 to about 10:45, and the hot water system (a heat pump) being run from 09:00 to about the same time. The solar power was then fed to the grid attracting a FiT or cost of a couple of cents/kWh. Negative FiT – aaarrrggghhh! The sun went down at about 16:45, and at about 17:45 the battery began to feed the grid at around 4.5kW until around 19:15, until the battery had about 30% left. The FiT during this period was around $0.25/kWh.

The house load of around 0.3kW was then supplied by the battery until around 07:15 when the sunshine made its way through the fig tree foliage and onto the solar modules. 

In summary, the Amber for batteries system is very clever, and so far does the job of maximising the efficiency and benefits of our solar/battery system better than I could. I am yet to calculate the financial benefit compared to EnergyLocals/Evergen, but will tackle that when we have had a couple more months of data.