Powervault for the people

Powervault .jpg

We’re after Agile trial participants with to help us work out what cheaper, greener water heating will look like in a post-gas Britain.

In this BEIS-funded trial, we're teaming up with home battery experts Powervault to work towards the gradual electrification of water heating through a combination of home solar PV, off-peak Agile pricing, and an electric water heating system.

Join the trial now for £100 cash and £50 account credit!

We've now filled up all the trial slots for participants with a Powervault 3 battery. However, we still have a few more places for the monitoring group. To take part you'll need an electric hot water heater (also known as an immersion heater) capable of being monitored either by a Smartplug or other monitoring device. Powervault will arrange for an electrician to install this monitoring device at no cost and in exchange you’ll get £100 cash from them, and £50 credit on your Octopus Energy account!

Applications close 30 April. Participants chosen on a first-come-first-served basis.

Calling all early adopters! Octopus Energy is proud to reveal a pioneering new link-up with Powervault trialling the energy technology of tomorrow, today.

Powervault 3 helps you reduce your energy bills by storing free solar energy (if you have solar PV) or cheap energy from the grid.

Powervault is a battery that is about the size of a dishwasher, though it’s stuffed with lovely cheap energy rather than dirty pots and pans. It’s an attractive piece of kit and sits unobtrusively in your home. On a time-of-use tariff such as Octopus’s Agile tariff, it cleverly knows when electricity is cheap on the grid (because electricity changes in price at different times of the day).

When energy's cheap, Powervault fills itself up. When it's more expensive, it shares that cheap electricity with the house. Simples.


We're teaming up with Powervault to trial this beautiful little slice of smart energy.

This brand new collaboration seeks to find out whether we can use the battery’s brain to heat water more efficiently. If you want to get involved, you need to be on our groundbreaking Agile tariff, a time-of-use tariff that allows you to make the most use of the ability to buy energy when it is at its absolute cheapest.

Our trial is funded by the Department of Business, Energy and Industrial Strategy (BEIS), which is looking at a strategy for the gradual electrification of hot water to reduce our dependence on fossil fuels in the coming years. It’s essential work.

The Committee on Climate Change says: “Meeting future carbon budgets and the UK’s 2050 target to reduce emissions by at least 80% of 1990 levels will require reducing domestic emissions by at least 3% per year. This will require existing progress to be supplemented by more challenging measures.”

Get involved...

For a research project like this, we need two groups of homeowners:

  • those who already have the battery in their home
  • those without the technology who can therefore act as a control group to compare how much the technology provides a benefit compared to the standard

So we’re recruiting both groups – which means there are two ways you can get involved in the trial:

  1. Join the Powervault 3 battery trial by buying a heavily discounted Powervault 3 battery (a whopping 25% off the RRP of £5k)
  2. Join the monitoring trial as one of our control group members, allowing us to monitor your hot water energy costs and receive a cash reward for doing so (no Powervault 3 needed)

The Powervault battery trial

If you want to buy the Powervault 3, this is what’s in it for you:

  • Powervault has agreed a £1,250 discount for any Octopus Energy customer who takes up this trial
  • Free installation, a saving of up to £500
  • The opportunity to store solar energy (or cheap electricity bought off-peak from the grid)
  • £50 credit from Octopus Energy on your energy account
  • Free inclusion of an Energenie smart plug, linked to your electric water heater. The smart plug will turn your immersion heater in the tank on and off.And it will record all the energy you consume to do so
  • You’ll get results from the trial on your energy consumption of your hot water heater
  • Your Agile breakdown will give you half-hourly results on your usage so you can see exactly where your money is going and how much you are saving

April UPDATE: We've now filled all Powervault 3 group slots. You can still get involved in the monitoring trial...

The monitoring trial

If you want to be in the control group that doesn’t have the battery, this is what’s in it for you:

  • £100 as a thank you from Powervault for taking part in the trial
  • £50 credit from Octopus Energy on your account
  • Free installation of a monitoring device, linking to your electric water heater
  • You’ll get the results from the trial on your energy consumption from your hot water heater
  • And you’ll get information on Octopus Energy’s Agile tariff in order to improve energy consumption

This is a super limited trial. All 10 Powervault 3 group slots are now full. We can accept 40 for the monitoring group. First come, first serve (subject to some T&Cs that we've outlined for you below).

Applications close April 30th. Once this deadline passes we'll be in touch for more info, and will let you know if you've made it into the trial.

Shifting your consumption supports a low-carbon future

Signing up for our Powervault trial means doing your bit in a government-funded research project, investigating the impact of smart water heating in conjunction with home battery storage and time-of-use tariffs.

We call this sort of technology (both the battery and time-of-use tariffs) Demand Side Response (DSR). It’s where the energy you buy and use can be shifted to a different time of day (out of the peak period when energy's most expensive and carbon-heavy).

Collectively, we need to shift our usage out of peak times to reduce strain on the grid, and make more of the abundant green energy here in the UK that often goes to waste. But without any battery storage, no one would want to delay dinner or children’s baths.

The beauty of this system is that you CAN move the time you heat your hot water, or use large appliances like dishwashers, washing machines and dryers.

Water costs loads to heat, so this trial is a great way to measure the impact of shifting energy consumption out of peak times.

Make sure you're okay with these conditions:

Trial participants will be decided on a first come, first serve basis, as long as you've agreed to the following conditions. Applications close April 30th. The trial runs for six months. You can leave the trial at any time, but it's worth making sure you can do the following for the next six months...

  1. You must have an internet connection within your home and be willing to keep the monitoring devices connected for the duration of the trial.
  2. You must keep the monitoring equipment attached to your electric hot water heater for the duration of the trial.
  3. You have to stay on our Agile Octopus tariff for the duration
  4. You have to stay living in your house for the next six months
  5. You must agree to these terms and conditions.

Read on for FAQs...

How do I get on the trial?


Register your interest in the monitoring trial here.

This will be first-come first-served basis so sign-up quickly to get on the list. We’ll get in touch with everyone who registers their interest by 14 April for further information.

Powervault 3 install slots have all been snapped up. We're still accepting trial participants for the control group – once the April 30th deadline passes, we’ll be in touch to let you know if you’ve been successful.

Do I need to change my tariff?


Trial participants will need to have a smart meter we can link to, and be on our Octopus Agile tariff.

Can the battery charge up on electricity from the grid?


The battery can be charged either from home solar PV or from grid supply.

Do I need to have solar panels?


The Powervault system is designed to store your excess solar energy and make that available for you at night.

But with the Octopus Agile tariff integration it’s now possible to benefit from the system without solar panels. The payback won’t be as good since the battery is charged from low Agile prices instead of free solar power, but the system will still work and be useful!

How long will the trial last?


This is a six-month trial.

What happens when the trial is complete?


Summary data on the trial will be provided to everyone that takes part.

If you're part of the Powervault 3 trial – at the end of the trial, the P3 is yours to keep.

If you're part of the monitoring trial – you'll receive £100 thank-you. The monitoring equipment can either remain in your home, or we'll remove it. Up to you!

What if I move house during the trial?


If you're part of the Powervault 3 trial – the P3 can't be moved from the house during the trial, so you can only take part if you're not moving house in the next six months.

If you're part of the monitoring trial – if you move house, or the monitoring equipment is disconnected, you may still receive the £100 incentive. Whether you do or not will be determined by Powervault, based on the length of time you took part before you moved or your equipment was disconnected.

Do I have to stay on the Octopus Agile tariff?


For both trial groups (monitoring and P3) you will need to remain on the Octopus Agile tariff for the duration of the trial. But you can swap off this tariff at the end of the trial, which is six months from its start.

Published on 4th April 2019 by:

image of Phil Steele

Phil Steele

Future Technologies Evangelist

Hey I'm Constantine, welcome to Octopus Energy!