PowerShaper Wiki

I have created this post as a Wiki which means that anyone on the forum can edit and add to it themselves. I will try to keep it tidy, but otherwise see how it develops. For more information about how to use the Wiki post have a look at this topic on the Discourse official forum.

The purpose of this post is to help organise the different threads and posts and links about the PowerShaper that already exist on the forum.

PowerShaper Community Wiki

Please add in links to useful threads and posts and links in the categories below. If the category you want doesn’t exist just create it!


The HEMS is a Raspberry Pi powered Home Energy Monitoring System. This system connects your smart home devices and allows you to create powerful automations as well as monitoring dashboards. This is also the device which connects to our system to support the flexibility of the electricity grid.

External resources

  • HEMS User Guide - a basic user guide about how to access your HEMS interface. Created by the PowerShaper team.
  • Home Assistant Documentation - the HEMS is built on top of the Home Assistant project. The largest open-source community project in the world.
  • Home Assistant Forum - There is a massive community of resources and information out there around Home Assistant, much of which will apply to the HEMS.

On the forum

EmonEVSE electric vehicle charger

PowerShaper participants with EV chargers will have had an EmonEVSE charger installed. This open-source hardware has a high-level of interoperability

External resources

  • PowerShaper EV charger user guide - a basic user guide designed for PowerShaper users with the EmonEVSE.

  • OpenEnergyMonitor - the EmonEVSE was developed by OpenEnergyMonitor with OpenEVSE and their website has a great collection of resources and information about the system.

  • OpenEnergyMonitor community - the open energy monitor community is a great place for the more advanced questions about the EmonEVSE system.

On the forum

  • EVSE Control Charge Rate - a topic created around how to control the charge rate on the EmonEVSE against solar output.

Shelly relay switch and immersion heaters

External resources

For PowerShaper users with connected immersion heaters they are controlled by a ShellyEM wifi connected relay switch.

Help make this Wiki better!

Please feel free to contribute directly to this wiki (just click the edit button at the bottom!) with things and links you have found useful. If you have ideas about how this could be better organised, or think something major is missing or just have an idea about making this better - share your ideas below!

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Just been looking at regional CO2 intensity on https://www.carbonintensity.org.uk/ and it’s showing 15gCO2/kWh.
But the HEMS Signal CO2 intensity is showing 185 gCO2eq/kWh. It’s a big difference. Are they measuring the same thing? What geographical area is Signal data?

This is a good question! The CO2 Signal on the HEMS is using a core Home Assistant integration that you can read about here. That relies on the CO2Signal API, which uses the same data source as Electricity Maps here. Why this differs from the Carbon Intensity API data available here, I am less certain. I will see if we can figure out any of the possible reasons for this and get back to you.

I am looking forward to the next stages of the PowerShaper flex project.
I like the “Combined Flexibility” feature. It is going to be interesting to watch.
Are you still recruiting participants? Is it geographically based / limited to NW England or Gtr Mcr?

Have gone back and looked into this more closely. I think it’s because CO2 Signal value is average for Great Britain (and only updated every 3+ hours), whereas I was looking at value for North West on carbonintensity.org.uk, which appears to be updated more frequently.