I'm SG Ready. I did not know this. Perhaps it does not matter.

Now that our house is bedded in and everything is operating well, I've been reading some of the specification details and small print.

It turns out that both the Tesla Powerwall 3 and our Mitsubishi Ecodan ASHP are "SG Ready".

A "Smart Grid" is one that can signal to devices via a "Home Energy Management System" (HEMS) the stats of the grid and if it would be good to reduce load where possible or to increase it.

I wonder if this is one of the sources of the "smart meters will let them turn your fridge" stories we seen and causing some people to oppose smart meters.

As far as I can tell, smart meters and the Smart Grid signalling are two quite different things.

Here is the UK, the Smart Grid does not seem to have much traction. One DNO, UK Power Networks does mention Smart Grid on their website and says "Learn more at our dedicated Smart Grid web-pages." but the "Find out more" button goes to their DSO home page which has no mention of Smart Grids.

With the rise of cloud control (e.g. for Tesla and Octopus Energy) and integration I suspect that Smart Grid technology is going to languish and wither.

Some info sources:

Tesla PW3 

  • https://energylibrary.tesla.com/docs/Public/EnergyStorage/Powerwall/3/InstallManual/BackupGateway/2/en-mt/GUID-D106719D-D672-4169-B493-20EE5536DB7D.html

Mitsubishi Ecodan

  • https://support.reduxi.eu/hc/en-us/articles/29791853282961-Connect-Mitsubishi-Ecodan-with-Reduxi
AI search notes:

Mitsubishi Ecodan heat pumps feature built-in Smart Grid (SG) Ready contacts that allow them to integrate seamlessly with photovoltaic (PV) solar systems and smart home energy controllers. [1, 2, 3]

How SG Ready Works on Ecodan
  • Smart Contacts: The Flow Temperature Controller (FTC) inside the Ecodan system includes dedicated digital inputs (such as terminal connections for relay signals) labelled for smart grid or solar integration. [1, 2]
  • Relay Logic: By using normally open (NO) relay switches from external energy managers (like a myenergi eddi or PV inverter controller), the system can cycle through different operational states based on live grid signals or surplus solar generation. [1, 2, 3]
Operating States
  • State 1 (Normal Operation / Off): Standard running mode governed by internal schedules and user thermostat settings.
  • State 2 (Locked / Off): Optional forced shut-down state if commanded by the utility/grid operator during peak demand (where permitted).
  • State 3 (Increased Operation / ECO-PV Mode): Triggered when there is surplus solar energy; the heat pump marginally raises target temperatures (such as boosting domestic hot water to 60°C) to store free thermal energy in the cylinder. [1]
  • State 4 (Forced ON / BOOST): Maximum output state where compressor and immersion elements are forced on to maximize heat storage when power is cheap or abundantly available. [1]




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