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System architecture

Local vs cloud is the wrong fight. The useful question is what still works when one layer fails.

Responsive control belongs close to the devices. Forecasts, remote access and fleet analysis often benefit from the cloud. A robust home energy system defines the boundary clearly.

Editorial owner GridPassport research team Last reviewed Evidence Sources, assumptions and limitations are shown on this page.

Short answer

The strongest pattern is usually hybrid.

Device safety stays inside the inverter, battery management system, heat pump or charger. Fast household control runs locally. Cloud data improves the plan, but the most recent valid plan and a conservative fallback remain available in the home.

A product should explain that behavior directly. "Local" and "cloud" are architecture labels, not proof of reliability.

Comparison

Each layer is good at a different part of the job.

DimensionLocal-firstCloud-firstSensible hybrid
Device controlLAN or fieldbus path.Vendor or cloud-to-cloud API.Local primary path where supported.
Internet outageCan continue if rules and authentication are local.New commands may stop.Cached plan plus local fallback.
Forecasts and tariffsMust be imported and cached.Easy to aggregate centrally.Cloud data validated and stored locally.
Remote accessNeeds a secure remote path.Usually built in.Cloud interface with local execution.
PrivacyMore telemetry can stay at home.More data may leave the property.Minimize and document cloud data.
Maintenance riskLocal hardware and software need upkeep.Depends on vendor accounts and service availability.Both failure domains are tested.

Three questions

Draw the system before judging it.

  1. 01
    Where is the decision made?

    Inside the device, on a local controller or in a remote service?

  2. 02
    How does the command reach the device?

    Through LAN, RS485, Modbus, a vendor gateway or cloud-to-cloud API?

  3. 03
    Which inputs need the internet?

    Tariffs, weather, solar forecasts, remote commands or demand-response events?

Failure behavior

"Offline mode" must describe a real policy.

Internet unavailable

Keep local device links, respect the last valid plan only while it is fresh, then move to a conservative schedule.

Cloud data stale

Mark forecasts and prices invalid after a defined age instead of treating yesterday's data as current.

Local controller stops

Devices return to manufacturer-safe behavior and remain manually controllable.

Device rejects a command

Read back actual state, stop repeating unsafe requests and expose the failure clearly.

GridPassport view

The Passport is local because the home needs a durable control point.

GridPassport uses cloud services where they add real value: forecasts, remote access, software delivery and analysis. The Passport keeps the household coordination layer close to the devices.

That architecture does not make every integration local. Some manufacturers expose only cloud APIs. Compatibility must therefore state the actual path and what happens when it fails.

The conclusion is the same as at the beginning: use local control for the responsive household loop, cloud services for wider context, and test the boundary between them.

FAQ

Local and cloud questions.

Is local home energy management always better than cloud control?

No. Local control is valuable for responsive device commands and useful operation during an internet outage. Cloud services are well suited to remote access, forecasts and large-scale processing. A robust design often combines both.

Will a local HEMS work without the internet?

Only if its rules, credentials, device connection and required data are actually available locally. The word local by itself is not proof of offline capability.

Which energy functions should prefer local control?

Time-sensitive functions such as export limiting, peak control and device setpoint changes usually benefit from a local path, while device safety must remain inside the certified device.

What still needs the cloud?

Weather, tariff feeds, remote access, software updates and fleet analysis commonly use internet services. A local controller can cache the latest valid plan and use a defined fallback when those inputs disappear.

Does local control guarantee privacy?

No. Privacy depends on what data is collected, stored and shared. Local processing can reduce the data that leaves the home, but the product must document its actual data flows.

Sources

Architecture and resilience references.