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Flux tariff for solar and battery storage

Octopus Flux Tariff.

If you simply love your solar PV and have been searching for a dedicated tariff for both solar and battery storage then look no further than Octopus Flux. Plus Octopus has now gone a step further and on the 19th of July 2023 launched Intelligent Octopus Flux! (I will do a review on this soon. It is an automated version of the Flux tariff, similar to the Intelligent Octopus tariff which lots of Electric Vehicle owners love.)

With the increasing cost of energy, more and more people are looking for ways to reduce their electricity bills. One way to do this is by installing solar panels and a battery storage system in your home. By making your home into a virtual power station, you can save money by not having to buy electricity from the grid at peak times.  Octopus Flux takes this a step further by offering an import and export tariff all rolled into one.

Start harnessing the power of renewable energy now.  Invest in solar panels for your home and switch to a provider that offers innovative green energy tariffs. Octopus Energy can help you with both! ☀️

Do you have both solar PV and battery storage at home?

Solar PV and battery storage at home can provide a number of benefits such as increased energy efficiency, reduced electricity bills, improved grid stability and increased reliability of power supply. With the right technology in place, homeowners can save money while also contributing to a greener future and Octopus agrees!

If you have both solar PV and battery storage at home your heart may skip a beat at the sight of a dedicated tariff just for you. Octopus did have an exclusive tariff for owners of Tesla battery storage and solar PV called the Tesla Energy Plan but this has now ended and Octopus Flux has been launched.  The new tariff isn’t subject to a particular make or brand of solar panels or battery storage. You will need just an MCS certificate and solar PV.

The Octopus Flux tariff is for residential customers with a Smart meter and solar PV system at home. There is no requirement to have battery storage but it’s obviously one of the reasons why you would consider this tariff as you can time import and export.

Octopus flux tariff for battery storage and solar PV.

Octopus Flux customers will receive the best rates for both the power they use and the power they sell back, benefiting from three hours of cheap rates overnight and generous peak export rates. 

You asked, we deliver – Octopus Energy.☀️🪫 

How much will I pay for importing and exporting electricity on the Octopus Flux tariff?

Octopus Flux covers both imports and export. You’ll need to buy energy low, sell it high and get as much as you can as cheaply as possible or even better for free. It is a bit of a Del Boy tariff for those who are lucky enough to have Solar PV.

The Octopus Flux rates will change on the 1st of July 2023. Octopus Flux isn’t a fixed tariff so it can go up as well as down and will usually happen after the Energy Price Cap is reviewed.

Since 2019 Octopus Energy customers have generated and exported over 23295958 kWh (23 GW) of electricity. This is enough solar energy to power 8,033 homes for a year.  Not a bad day down the market and it is a win, win for everyone if you can turn your home into your very own power station. 🌍☀️

Octopus Flux

This diagram should help you better understand the concept. This is my interpretation of the Octopus Flux Tariff and not an official image from the Octopus Energy website.

In the summer, the yellow solar line will extend further, providing you with a greater chance to export energy at the peak rate while keeping your battery charged with green electrons. (Thanks to @eddiewawa for your sketch on Twitter 💚⚡️)

Octopus Flux has 3 time of use rates for import and export.

Octopus Flux has 3 rate periods and one standing charge.

  1. Super cheap rates between 02:00 – 05:00 every day, when you can top up your battery with any extra energy you may need.
  2. A peak rate between 16:00 – 19:00, is the optimum time to discharge your battery and export surplus energy back to the grid.
  3. A flat day rate that covers all other times.

Rates will vary slightly throughout the country. You can get a quote by inputting your postcode.

Au contraire (that’s the last of my Del Boy references) you could also consider Octopus Agile, Cosy tariff and Octopus Economy 7. If you have an EV also look at Octopus Intelligent and Go.

Is Octopus Flux a fixed tariff?

No, Octopus Flux is subject to change the same as the Octopus Flexible tariff. When the rates of our Flexible tariff change the Flux tariff will change too. Octopus will always give reasonable notice of any changes to your rates but unfortunately, the prices aren’t locked in.

These are the rates on Octopus Flux for South Wales, they may vary slightly geographically. 

During darker months it’s also worth looking at other Octopus tariffs.

octopus flux rates january 2024

The Octopus FLUX is a flexible tariff. It has an off-peak night rate which is limited to 3 hours 2:00 am to 5:00 am. During the off-peak period, you can import electricity for 17.22p per kWh. However, it also has a more expensive rate between 4p and 7 p.m. during peak demand hours from 16:00 to 19:00 each day when you will currently pay 40.19p per kWh. The rest of the time the cost is 28.71p per kWh. These are the Octopus Flux import rates in South Wales on 3rd January 2024, they may vary depending on your geographical location.

Octopus Flux is a flexible tariff meaning it can change over 12 months rather than being a fixed price.

Am I eligible to switch to the Octopus Flux tariff?

To switch to Octopus Flux you will need to be an Octopus customer and have solar PV.  The solar panels don’t need to be installed by Octopus although they can do that too!

You’ll need to have:

  • A smart meter providing Octopus with half-hourly readings.
  • A copy of the MCS document for your solar system.
  • Confirmation your local energy network was notified of your installation. *

* This will be a letter or email you got from your energy network after they were notified by your solar installer.

There is no longer a limit on the invertor. At launch, the AC was limited to 9kW. This limit has now been removed.

If you receive Feed-in-Tariff payments from Octopus or another supplier, they’ll also need a copy of your (Microgeneration Certificate Scheme) MCS certificate.

@sarah_go_green Get paid for excess solar with the @Octopus Energy flux tariff. #octopusflux #octopusfluxtariff #fluxtariff #solarpanels #smarttariffs ♬ Here Comes the Sun – Relaxing Instrumental Music

You can export as much excess solar as you want there is no restriction and you can own an electric vehicle and charge that on the Octopus Flux tariff too.

Why do I need an MCS certificate to switch to Octopus Flux?

The Microgeneration Certification Scheme (MCS) is a standards organisation. They certify low-carbon energy technologies and contractors – including heat pumps, solar, biomass, wind and battery storage. MCS is considered a mark of quality in the industry.

An MCS certificate is not a mandatory or legal requirement for system installation BUT Octopus have have decided to make it a part of its terms in all of their Octopus export tariffs.

If you want a copy of your MCS certificate or you want to check if one has been registered for your property you can contact MCS at 0333 103 8130, or email: hello@mcscertified.com. You can also check if an installer is listed as MCS certified.

You will need to show Octopus your MCS certificate if you want to be paid for exporting your excess electricity.

When Octopus receives your MCS certificate they will apply to the Distribution Network Operator (DNO) for an export Meter Point Administration Number (MPAN ) for your smart meter. Once the MPAN is registered by the DNO Octopus can then start paying you for your exported electricity. If you export without this you won’t get paid and Octopus will not backdate any payments.

Can I get paid for my solar export without an MCS Certificate?

Octopus Energy is launching a trial where no MCS Certificate is required for solar export but this is separate from this tariff where an MCS Certificate is still required.

I doubled checked with Octopus on Twitter and here is their response from 5th August 2023.

Am I limited to a 9 kW solar array on the Octopus Flux tariff?

No, this limit has now been removed. At launch, Octopus limited the total output (G99 limit) to 9 kW.

Here is some background information on the Octopus flux tariff and how the terms have changed.

At launch, you were limited to a 9kW invertor on the Octopus Flux tariff.

PV inverters are a central part of the domestic solar PV system.  They are typically about the size of a microwave and can help you keep track of your power output. Here’s a quick overview of what an inverter does.

  • Convert energy created by solar panels (DC) to electricity that can be used in the home and exported to the grid (AC).
  • Maximises power output.
  • Communicates with the National Grid.
  • Provides information on power production.
  • Ensures that your solar PV is operating safely.

The amount of energy your solar array produces (DC) can be different to the amount of power your inverter can output (AC).  This is what Octopus were previously limiting. On the Octopus Flux tariff, you were limited to 9 kW of output (AC) that can be sent to the grid at any one time. This limit has now been removed.

How do I switch to the Octopus Flux tariff?

The Octopus Flux tariff is now live. ☀️🪫

If you are an existing customer switch to Octopus by completing the online form and Octopus will take care of the rest.

New customers wishing to switch to Octopus Energy on the standard Octopus Flexible tariff first but as soon as your account is live and the switch has been completed you can ask to move to the Octopus Flux tariff.

As a new customer if you try to complete the Flux online form it will just direct you to the standard sign-up page. By using the linked page below to sign up you’ll get £50 credit after your first direct debit payment.  (I’ll also get £50 so a big thank you if you use my link)

Contacting Octopus Energy

If you are super keen once you have signed up as a new customer email hello@octopus.energy or DM Octopus on Twitter quoting your account number and ask to be moved to the Octopus Flux tariff as soon as possible as the switch is complete.  You can also phone them on 0808 164 1088.

My preferred method is to contact Octopus via Twitter they are really quick to reply but if you choose to call Octopus after signing up you can even select your on-hold music from your Octopus dashboard. They think of everything! Just ask if once your switch is complete they can automatically transfer you onto the tracker tariff. I’ve switched tariffs lots of times via Twitter.

Can I still receive Feed in Tariff (FiT) payments if I switch to Octopus Flux?

Feed In Tariff (FiT) closed to new applications in March 2019. If you are on the FiT you either signed up for 20 or 25 years depending on when you signed up.

On FiT you will be receiving a payment for;

  1. Energy generated
  2. Energy exported.

If you switch to Octopus Flux you can still receive FiT payments for energy generated but not energy exported. Octopus can cancel your FiT export payment if it’s registered with them. Alternatively, they will tell you when to contact the supplier your FiT is registered with to cancel it. Octopus Flux will then take over as your export tariff.

Once you cancel FiT export there is no going back. If you decide Octopus Flux isn’t for you you’ll need to claim the Smart Energy Guarantee (SEG) or another export tariff of your choice in order to be paid for your excess solar.

Just remember that deemed export is 50% of your generated energy. It doesn’t matter if you use all your solar and have nothing to export you still get the 50% payment on FiT. This is a good deal so you need to get your calculator out to see if you can beat it on Octopus Flux.  Deemed export is currently paid at the rate of 7.5p per kWh on FiT.

Is the Octopus Flux tariff a good all-year-round option?

For 21 hours hour of the day, the lowest price you will get for exporting your excess electricity is  17.26p per kWh.  This is higher than the Smart Energy Guarantee or the Octopus Outgoing fixed rate of 15p per kWh. So for those without battery storage (it is not a necessity on Octopus Flux) as the days get longer this is quite attractive especially if you don’t have an electric vehicle to fill up. Yes, the peak rate is higher for import but you should be able to avoid this in the spring and summer.

This EU sunshine database is a quick way of reviewing how output might change throughout the year. It is quite handy if you have a new solar PV system and are not sure.  I have attached an example below, it is shows data based on solar PV in Cardiff.

Octopus Flux tariff

As you can see from this tweet and the chart above solar PV starts producing more energy around February and it keeps going up until the height of summer.

If you don’t generate that much excess electricity in winter and have a small battery you can choose to switch away from the Flux tariff from November or December through to February then like Nickie switch back as the days get longer. If you have battery storage the Octopus Flexible tariff with the Economy 7 option is worth considering if you are not eligible for an EV tariff. You’ll get 7 hours off-peak to charge your battery and you will be eligible for Octopus Fixed Outgoing which is 15p per kWh all day long.

A quick snapshot of Fay’s home in February 2023.

This is an example of a home with battery storage and solar PV. Fay has 14 panels on her roof and two batteries which can store 3.6kWh (so 7.2kWh is our total capacity).  The snapshot should highlight why in the winter months you may have less to export to the grid. (@Fay_Purcell, Twitter, thanks for the data!)

Octous flux

Fay has an electric vehicle and is currently on the Octopus Go tariff. She gets paid 4.1p per kWh to export any excess electricity. In this example, she is NOT charging her EV.

If you scroll down the page you can also see from Ben’s spreadsheet below that his export really drops between December and March. Many people switch tariffs throughout the year. Octopus agile export, as an example, is defiantly more popular when there’s more daylight in the summer it may well be the same for Octopus Flux.

As you are not committed to a contract with Octopus Flux like all Octopus tariffs you can switch away at any time. So, without a doubt, this is a great tariff if you have a simple solar PV array and want to export at the best prices as the days get longer.

We try not to export as we only get around 4p/kWh for it, but it’s definitely a balancing act as you have to try to guess how much to charge the battery the night before, how much PV you are going to get during the day & how much electric you are going to use! – Fay

As you add in more hardware, such as battery storage, the maths gets a little trickier.  It really does depend and your home set-up and your energy needs.

Octopus flux tariff review

Everyone with solar PV seems to have a spreadsheet but don’t panic if this is all new to you. You are actively trying to make your home greener taking control of where the electricity you use comes from. I like Fay’s illustration which is a graph form. A lot of the systems provide this data so don’t worry about having to be a maths bod!

Home battery state of charge in the summer with Solar PV. 

@Eddiewawa’s Twitter data shows his typical battery state of charge for July.  He has overlayed it onto the Octopus Flux tariff timeline. As you can see, his battery stays charged until later in the evening due to the extended daylight hours. If Eddie didn’t need the excess energy he could easily export it to the grid during the Octopus Flux peak rate window. He would mostly likely have lots to export and some to store for later. (Eddie has an EV so we discuss how he decides to use that energy further down the page)

Octopus flux tariff


Octopus Flux tariff v Cosy Octopus tariff.

If you are one of the green pioneers who has lots of green solutions for your home, such as a heat pump, solar PV and battery storage Octopus Energy will have a tariff to meet your needs. There have been two new smart tariffs launched so far in late December 2022 and February 2023, Octopus Cosy and Octopus Flux. Finding which one suits your needs will take a little consideration as everyone’s home needs are different.

There are two main differences between the Octopus Flux and Octopus Cosy tariff.

On the Flux tariff, you’ll get 3 hours of off-peak compared to 6 hours off-peak on the Cosy tariff. The rate is the same but you will get 50% fewer off-peak electrons.  That’s because the Cosy tariff is designed for heat pumps that need to be consistently on in the winter. Its aim is to help stay customers stay warmer for less. This is ideal in the winter especially when there is a limited amount of sunshine but maybe not such a necessity in the winter.

The peak rates and times are the same on both the Octopus Cosy tariff and Octopus Flux.  The day rate and the standing charge are also the same on both tariffs BUT for export, the most you will be able to get is 15p per kWh on Octopus Flux. So it depends on two things, the time of year and how much electricity you usually have spare to export to the grid. This is important as you could get double the export rate on the Flux tariff. The Flux tariff offers an attractive 29.19p per kWh export between 4 pm and 7 pm. (This is based on a quote for South Wales)

Both Octopus Cosy and Octopus Flux offer export rates way above the 4.1p per kWh on the Smart Energy Guarantee. In my opinion, Octopus Energy puts other energy suppliers to shame with their groundbreaking tariffs.  This is a quick summary but there are so many variables I thought this would just highlight the two obvious differences and benefits between tariffs.

Octopus Intelligent Tariff v Octopus Flux – Let’s add in an electric vehicle just to mix things up. 

Octopus Flux is not designed for EV owners. If you have an electric vehicle Octopus has two dedicated tariffs just for you, they are Octopus Go and Intelligent Octopus tariffs. That being said if you have excess solar you could benefit from much higher export rates on the Octopus Flux tariff. Whilst on either of the Octopus EV tariffs you are restricted to the basic 8p per kWh export rate on Octopus Go and 15p per kWh on the Intelligent Octopus tariff.

The export rates for both Octopus Go and Intelligent Octopus changed in September 2023. They are no longer limited to the 4.1p per kWh export rates applied when the comparisons were written below. Please take this into account when reviewing these tariffs.

Meet Eddie 

Eddie is an EV driver. He has a Tesla Model Y Long Range, with an assumed real-world range of 250 miles. Eddie has solar PV and battery storage.  He can generally get away with importing most of his home electricity on the off-peak import rates.

Eddie has kindly sent me these figures where he has compared the Octopus Intelligent v Octopus  Flux tariff based on his electricity needs at home. (@eddiewawa on Twitter)

Octopus flux v intelligent tariff

The Octopus intelligent tariff is the clear winner when you compare Eddie’s own figures for Octopus Intelligent versus Octopus Flux. The issue Eddie has is he wants to be on an EV tariff BUT it limits his export options. The Octopus EV tariffs offer a cheaper import rate for a longer period each night.

In this illustration, Eddie exports his excess solar at 4.1p per kWh. He could get more if he was on a non-smart tariff for importing his electricity. Eddie could also consider a tariff, such as the Octopus Agile export tariff but then he wouldn’t be able to be on one of the dedicated EV tariffs which are Octopus Go and Intelligent Octopus.

Eddie will be sticking with the intelligent tariff BUT every home is unique and everyone’s needs are different so it is important to sit down and do some maths in order to work out what is right for you. You can read my review on all the Octopus Outgoing/Export tariffs in another post.

Comparing Octopus Go to the Octopus Flux tariff.

Meet Ben

Ben has an electric vehicle with a 73 kWh battery. He drives 8,000 miles a year and averages 3.6 miles per kWh.  Ben charges his EV off-peak and drives 2000 miles a year less than Eddie.  He has solar PV on a west-facing roof with a maximum 3.28 kW peak. His home battery can store 5 kWh of electricity. (@SimsBSims on Twitter)

Here are Ben’s forecasted costs based on last year’s electricity figures. He is on the current Octopus Go tariff which is 12p per kWh off-peak.

Octopus flux export rates

Unlike Eddie Ben exports less electricity to the grid and also imports less too.

spreadsheet octopus flux


Comparing real-world examples on the Octopus Flux Tariff.

Ben exports 490 kW less than Eddie and imports 513.5 less too. He also doesn’t need to charge his EV as much as Eddie as he drives his EV less. His home usage is different as his needs are different.  Ben, would be better off on the Octopus Flux tariff. He would save £139.12 on the Octopus Flux tariff compared to Octopus Go.

Ben has registered his interest to switch to the Octopus Flux tariff. He will switch from Octopus Go as he will make quite a savings over the year.

These two examples hopefully highlight that everyone is different. Please don’t listen to anyone who claims to know what is best for you. Throw away comments that one or the other tariffs are best may not be correct. With smart tariff as everyone’s home set-up and energy needs are different you really need to sit down and do the maths.

Thanks to Ben, Eddie and Fay for crunching the numbers and allowing me to share them! 💚

Thankfully Octopus allows you to switch between tariffs. If you think you have your sums wrong you can very easily switch tariffs. All it takes is a DM, phone call or email.

If you own an EV, solar PV and battery storage here are some quick questions you could ask yourself if you want to stick your figure in the air to see if Octopus Flux is right for you.

  1. How many miles do you drive a week? A low mileage could be a good indication that Flux may well be worth a shot, especially from March to October.
  2. Could you charge your EV from solar during the day if you have a slightly higher mileage?
  3. What does your export/import balance look like? Do you regularly need to top up large amounts from the grid? You may find in the summer you have vastly different answers. Don’t be scared to have a spring/summer tariff and a winter tariff. It’s easy to switch between the two!
  4. How much control do you have over your battery? The daytime export rates on Flux are already good, but that peak rate is extra juicy! Being able to schedule a forced discharge and export in the peak means being paid even more for your solar by time-shifting it. Just remember the days are longer in spring/summer so you may be automatically exporting in any event as your batteries are full.
  5.  Are you happy to just have a go? – You are not locked into tariffs with Octopus, so if it doesn’t add up for you switch to another tariff.  If you switch away from say, Intelligent Octopus to Octopus Flux you’ll have to wait 30 days to switch back to that tariff but you can always choose another smart tariff or even a regular standard tariff. (Although there are so many smart tariffs you’d find a better solution)

Finger in the air v spreadsheets.

The finger-in-the-air approach may appeal to you if you want a quick general idea of if Octopus Flux would be best for you. I get lots of questions about the viability of Octopus Flux if you own an EV but the answer depends on your circumstances. There are serval spreadsheet enthusiasts out there who share their figures and even let you input yours. You’d get a definite answer one way or another that way but spreadsheets make me come out in a cold sweat. 😀 If you want figures you could also look at the Octopus Compare app which I understand also includes a Flux comparison.

Bye, Bye Tesla Energy Plan.

In February 2023 the Tesla Energy Plan was removed and was replaced with Octopus Flux.

Here is a Facebook group that has been set up (not by me).  There are lots of discussions about what people plan to do next. I have messaged Octopus to see if I can get any clarification and will keep this page updated with any developments.

You can read my full review of all Octopus export tariffs here.

Tomorrow is another day and the sun will always come up!

Don’t worry if you’re unsure which Octopus tariff is right for you. There are plenty of options to choose from and you can easily switch between them at any point in your journey – there’s no need to make a permanent decision as none of the tariffs are fixed so you won’t be missing out on a deal if you decide to switch to another tariff later.  All Octopus Energy tariffs are currently subject to change. There are no fixed-period tariffs to choose from at the moment.

Octopus flux battery storage

I am a bit of a geek and I like looking at the National Grid to see where their energy comes from. It changes with the weather and the seasons.  If you have home solar PV you have far more choices. You can decide when and if to use energy from the National Grid. In doing so you can help reduce your carbon footprint and make the grid greener.

If you want a great insight into how you can be a part of changing how we all use and consume energy this is a great video of Greg Jackson explaining the Octopus vision in March 2023. You’ll need half an hour but you can dip in and out. As someone who’s buying into this technology early, you’ll love it.


Octopus Energy is pushing the boundaries of what customers can expect from their energy provider.  As an Octopus customer, you benefit from the company’s investment in technology and smart energy solutions, giving you more options than ever before!  The sun will always rise, and with it, new possibilities thanks to Octopus!

Octopus Business Tariffs if you have solar panels.

If you have a business with solar panels added to your premises take a look at Octopus Panel Power Tariff. 

There is also a new time-of-use tariff for businesses called Octopus Shape Shifters which is a smart time-of-use tariff. (No solar PV required)