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We need two kinds of data to participate in a market:
  • operational metering: readings from the asset to understand and optimize asset usage. We typically need these with as low latency as possible
  • settlement metering: readings from the asset or site boundary meter, which we send to the market operator as proof of delivery
Operational metering always comes from the asset we’re optimising. Settlement metering can also come from the asset (known as asset-metering), but in many markets we’re required to obtain readings from the site boundary meter (boundary-metering). Axle can obtain boundary meter data for consenting households if you don’t already have access to it. In cases where we use asset metering, we may have to pass additional qualification checks to confirm that the metering provided by the asset is sufficiently accurate.
CoP11 is a UK standard which is required to use an asset’s metering in the wholesale market. Axle has extensive experience qualifying assets for CoP11 - please get in touch to discuss how we can qualify your asset

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Communicating asset telemetry

The kind of telemetry we gather varies by asset.
  • Charge Power (kW)
  • Plugged in (boolean)
  • State of charge (SOC) (%)
  • Plugged in (boolean)
  • Charge Power (kW)
  • State of charge (SOC) (%)
  • Inverter Power (kW)
  • Grid Power (kW)
  • Solar Power (kW)
  • Power (kW)
  • Temperature (°C)
For sites with a CT clamp installed at the grid boundary, Axle can collect half-hourly CT clamp readings through supported asset integrations, or you can push them to the Asset Readings endpoint as boundary_import_energy_kwh and boundary_export_energy_kwh.CT clamp data measures site-level grid I/O similarly to a boundary meter, and is treated as such when verifying delivery.

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Reading direction and sign convention

When you send readings to the Asset Readings endpoint, the sign of each value tells us its direction. For readings that can flow either way, the convention is positive = import, negative = export:
  • Import means power/energy flowing in — from the grid into the site, or into the battery (charging).
  • Export means power/energy flowing out — out to the grid, or out of the battery (discharging).
All other reading types are unidirectional and must be non-negative. The table below summarises the label values accepted by the endpoint:
Reading timestampsThe start_timestamp and end_timestamp of each reading must match the shape of its label, or the reading is rejected:
  • Half-hourly interval energy (charger_consumption_energy_kwh, heat_pump_consumption_energy_kwh, hot_water_tank_consumption_energy_kwh, boundary_import_energy_kwh, boundary_export_energy_kwh): start_timestamp must fall on a half-hour boundary (minute :00 or :30, zero seconds), and end_timestamp must be exactly 30 minutes after it.
  • Instantaneous (boundary_import_kw, battery_inverter_import_kw, solar_power_kw, battery_state_of_charge_pct, battery_stored_energy_kwh): start_timestamp must equal end_timestamp.
  • Lifetime registers (charger_lifetime_consumption_energy_kwh, boundary_lifetime_import_energy_kwh, boundary_lifetime_export_energy_kwh): point-in-time meter reads, so start_timestamp must equal end_timestamp.
Timestamps must be timezone-aware. A rejected reading comes back with accepted: false and an error message; other readings in the same batch are still accepted.
You can push telemetry to our Asset Readings endpoint, where you’ll find a list of accepted reading types

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Obtaining boundary meter data

Axle can obtain boundary meter data on your behalf, with user’s consent and proof of address. Contact us to discuss the best way to incorporate this consent collection into your product.