Hacking an energy tariff that changes price every half an hour


416 words / 2 minutes

energy tariffs
carbon intensity
electric vehicles
ev charging

In February, Octopus Energy launched the Agile Octopus tariff. Linked to wholesale energy prices, the tariff price changes every half an hour. In the future it may even pay you to use energy when prices drop below zero.

Pod Point was one of twenty-two companies invited to their first Hackday. We were given access to the Octopus Agile API and a simple problem to solve: How can we use existing smart home technologies to make energy bills cheaper?

Charging an electric vehicle (EV) at home increases electricity consumption and costs, this is something we have previously explored. A common solution is to switch to a differential tariff1 like Economy 72 or dynamic tariff like Agile Octopus. These tariffs are perfect for EV owners who can drive or during the day when energy prices are high and charge overnight, when prices are low. Importantly, differential tariffs help to balance the energy grid. Consumers defer their intensive energy consumption to off-peak hours, reducing demand on the grid during peak hours and reducing CO₂ emissions from fossil fuel energy generation.

Using the Octopus Agile API, we built a proof-of-concept app to demonstrate a feature we called 'smart charging'. When enabled the feature works out the cheapest timeframe for Pod Point customers on the Agile tariff to charge their vehicle. The customer can see when their car will start and finish charging with an accurate cost.

For customers without an Agile tariff we added a feature that would use the Carbon Intensity API to select a timeframe of low carbon intensity. This provides similar functionality to all Pod Point customers, assisting them to defer their EV charging to hours when grid demand and CO₂ emissions are lower.

The project was favourably mentioned in both award categories, placing 5th for 'Biggest Impact' and 6th for 'Most Technically Interesting'.

  1. Differential tariff is an example of demand side management where the price per unit of energy varies with the consumption. This helps balance the rate at which power is used and the rate at which power is created: https://en.wikipedia.org/wiki/Differential_tariff

  2. Economy 7 is the name of a differential tariff provided by United Kingdom electricity suppliers that uses base load generation to provide cheap off-peak electricity during the night. The night (off-peak) period lasts for a total of seven hours, hence the name; however it may or may not be a continuous period, as it may alternate between the two prices during the night: https://en.wikipedia.org/wiki/Economy_7