Mike Smyth, Energy4Al, Wey VAlley Solar, Schools Energy Coop, 100 solar installations

A special solar centenary

Here at Joju Solar, one of the things we believe in is the power of community energy, and we’ve worked closely with Mike Smyth for many years to install some pioneering community energy projects for schools (and other similar buildings) across the country.

 

Mike is the former Chair of Friends of the Earth Trust and the current Chair at Energy 4 All, The Schools Energy Co-operative and Wey Valley Solar Schools Energy Co-operative, and he’s always been passionate about environmental matters.

 

Last year, we completed our 100th project with Mike, and it was a special one… installing solar panels on the cloisters of Salisbury Cathedral. We couldn’t let this pass without catching up with him to talk about the landmark, Mike’s background and his hopes for community energy in the future.

 

So, grab yourself a cuppa, take ten minutes and listen to Mike’s story and his feelings about reaching 100… installs, of course!

 

 

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Solar And Storage LIVE, Contractor of the Year, 2020, Winner, Award

Joju Solar does the Double

Joju Solar has won ‘Contractor of the Year’ at the prestigious Solar & Storage LIVE awards, to add to the ‘EV Charge point Contractor of the Year’ title secured at the EVIEs last month.

The winners were announced on Friday, at the close of a three-day online conference and the awards now put Joju at the top of the pile across all their product offerings – solar PV, battery storage and EV charging infrastructure.

“Winning the Solar & Storage LIVE Contractor of the Year has been a long-held ambition and it feels amazing”, said Joju Solar Co-founder and Technical Director, Dr Chris Jardine.

“We’ve been working in the low carbon technology space for 14 years and this recognition is testament to the hard work put in by our team over that entire period – continually improving both technically and in terms of the service we offer.”

Joju Solar were recognised for their work on helping hundreds of homes reduce their carbon footprint, through solar, storage and EV charging.  Additionally, it has been an intensive year delivering community energy projects.  We installed 2MW of solar PV for Egni Coop in Wales, including the largest solar roof in Wales, at Newport’s Geraint Thomas Velodrome.  This project won the Community Energy Award at the Solar and Storage LIVE awards in its own right.  Other highlights in 2020 include a 39kW community-owned solar PV array on the roof of Salisbury Cathedral.

Joju is also working with more than 80 councils nationwide to install EV charge point infrastructure, simplifying the process and allowing councils to deploy charging infrastructure across their region without spending a penny.

“It’s very pleasing to be recognised across all our product offerings as offering excellent service in what we do.” said Chris.  “But this is still very much the beginning – the climate crisis hasn’t gone away; we still need lots more renewable capacity; and a complete electric transport revolution needs to happen in the next decade.  That’s always been our mission”

Octopus Energy Launch the Tesla Energy Plan

Electricity utility Octopus Energy have teamed up with Tesla to offer the Tesla Energy Plan – a unique electricity specifically for Tesla Powerwall owners.  By allowing Tesla to control the operation of the battery, householders can access both the best import prices available on the market as well as the highest prices for exported electricity.

What are the Tesla Energy Plan Tariffs?

There are two versions of the Tesla Energy Plan, depending on whether you also own a Tesla vehicle.

For households with a Tesla Powerwall, electricity costs 11p/kWh to import, and Octopus will pay you 11p/kWh for your exported electricity.

For households with a Tesla Powerwall and a Tesla vehicle, electricity costs just 8p/kWh.  Octopus pay for exported electricity at 8p/kWh.

There is no daily standing charge on the Tesla Energy tariff.

For comparison, a typical conventional electricity tariff would cost 15p/kWh for imported electricity, plus standing charges.  The amount paid for exported electricity depends on the amount offered by your supplier under the terms of the Smart Export Guarantee (SEG).  The highest rate on the market is 5.5p/kWh, with many suppliers offering much less than this.

 

 Who is eligible for the Tesla Energy Plan?

Several criteria need to be met to sign up for the Tesla Energy Plan.

  • You must be a residential customer – this is not a tariff for commercial sites.
  • You must have solar panels and a Tesla Powerwall2.
  • That’s all you need to qualify for the 11p/kWh tariff.
  • To qualify for the 8p/kWh tariff, you must have solar panels and a Tesla Powerwall2, a Tesla vehicle, and a home EV charger.

 

How do they do this?

Home battery owners typically store electricity generated by their solar panels and use this energy through the evening and night-time.  There is a strong incentive for householders to do this – they are better off not importing electricity at 15p/kWh than exporting it for just 5p/kWh.

This incentivises households to be self-sufficient in their operation.  However, there are wider electricity system benefits from battery storage.  Operating a home battery for the service of the broader system can offer further financial benefits to the householder – and this is what the Tesla Energy Plan does.

The scheme creates value in three different ways:

  • Electricity prices vary on the wholesale market vary, so Octopus can buy the cheapest renewable electricity available and use it to charge up batteries.
  • They can also control when electricity might be discharged from batteries back to the grid, and do this at peak times when providing electricity is most valuable.
  • By aggregating many batteries together nationwide, charging and discharging batteries can also be paid for providing grid services. These services help keep the national and local electricity grids running optimally.  Sevices include helping maintain a precise frequency on the grid or providing a short burst of power in the event of a failure elsewhere on the system.

Tesla control the operation of their fleet of batteries nationwide to behave as if t were one large generator – this is called a Virtual Power Plant (VPP).  Tesla controls the operation of the batteries – when they charge and discharge.  Octopus manages the financial side of this – customer liaison and billing.

By optimising in this way, Octopus can bundle everything together into a very attractive flat-rate tariff.

The real cleverness in the tariff is paying equal amounts for imported and exported electricity.  This ‘net-metering’ approach means there is no financial penalty to the householder no matter what the battery is doing.  Export electricity back to the grid? You get 11p/kWh.  Hold on to your electricity for use later?  You save 11p/kWh from not importing.  This gives Tesla complete flexibility in how they choose to operate the battery, whilst simultaneously providing the householder with a great deal on their bills.  Genius.

 

Is the Tesla Energy Plan a good deal?

Our residential project manager, Neil Russel, has been crunching the numbers on this!  Neil has modelled the expected annual electricity bills from a range of different electricity tariffs to see which ones offer the greatest benefits.

For more background, do check out our guide to electricity tariffs for the renewable home where we take a broad survey of tariffs for green electricity supply, and for integrating with battery storage and electric vehicles.

 

Tesla Energy Plan Modelled Annual Bill

When comparing the annual cost of electricity between the Tesla Energy tariff, Octopus Go and some other tariffs offered by competing companies we get the interesting table below. This simulation assumes an average electricity usage of 3,400 kWh a year in a home with a Powerwall and no Solar PV array.

ctopus Go, Tesla Energy Tariff, EdF, eon,

The Octopus Go tariff is a day/night tariff, offering electricity at 5p/kWh between 00:30 and 4:30 and  14p/kWh at other times.  Export payments would be under the terms of the Smart Export Guarantee.  The cheap night rate that Octopus Go offers allows a significant reduction in bills.  The Powerwall can charge from the lower night rate, to be used later in the day when electricity prices are higher.

The Tesla Energy Plan, even in the instances when the client has no solar, still comes out cheaper than most of the competition.  This is due to the lack of standing charge and a cheap 11p/kWh import tariff.

Octopus Go Tariff vs the Tesla Energy Plan

Octopus is offering two generous tariffs for battery and EV owners in the form of Octopus Go and the Tesla Energy Plan.  But which one provides households with the greatest savings?

The table below compares both tariffs, depending on the amount of electricity consumed and produced in the home. Positives values (blue) represent the financial benefits where the Octopus Go tariff is beneficial.  Negative values (orange) represent the bill savings where the Tesla Energy tariff is a better option.

From this table, we can draw four different scenarios for customers with a Powerwall and solar PV.

  • Zone A – If you produce more than you use – that is to say your house is a net exporter – then you will benefit most from the Tesla Energy Plan due to the 11p/kWh export tariff.
  • Zone B – If you are consuming somewhat more than you produce, then Octopus Go is your best bet. Here the electricity stored in the Tesla Powerwall covers the costlier evening electricity, with remaining import being dominated by the 5p night time tariff on Octopus Go.  This is likely to be the case for most EV drivers.
  • Zone C – If you have both high generation and high load, the Tesla Powerwall does not fully cover the evening load. This means the 11p evening import price on Tesla Energy Tariff is a better deal than the 14p/kWh on Octopus Go.  In this case, a second Powerall would be beneficial, and this would favour Octopus Go again.
  • Zone D – If you consume much more than you generate. Once again, the Tesla Powerwall does not cover the evening load, so the 11p import price on Tesla Energy Tariff is a better deal than the 14p/kWh on Octopus Go.  It has to be said though, such extremes of high use and low generation are pretty unlikely in the real world.

Concluding Thoughts

Choosing the right tariff to optimise the financial benefits you receive from your battery storage or electric vehicle is tricky.  But Octopus appear to have two market-leading tariffs from which to choose.

The Tesla Energy Plan is a significant development for battery storage for the next decade.  It extends the benefit of storage by interacting with the broader electricity system.  When it’s windy, your battery will be soaking up all that renewable power, not just what’s coming from your own roof.  And that will help us get even more renewables onto the electricity grid.  And it’s all possible because of the equal prices paid for imported and exported electricity – which seems a little thing, but it is going to have a huge impact.

Further Reading

Egni Coop, Awel Amen Tawe, Newport, solar, schools

How to install solar in schools

We’re currently building a 2MW community energy scheme with a Welsh community energy group called Awel Amen Tawe.  Their Egni Coop is working with Newport Council to install solar on their schools and other public buildings such as the velodrome.  Dan McCallum from Egni Coop, has written this rather excellent blog piece, looking at the finer details of the project panning and installation process.

READ MORE

Autum, acer leaves, japan

Solar Energy and the Seasons

As a solar engineer, it’s my job to understand the movement of the sun across the sky throughout the year.  However, a technical understanding of solar movement often feels at odds with my appreciation of the world around me.  That confusion comes from our cultural perceptions of the seasons, and their definitions.  So, when exactly do spring, summer, autumn and winter start and end?

Solar Seasons

From a solar perspective, we can look at the movement of the sun across the sky.  We know that at the summer solstice, June 21st , that the sun reaches it’s highest point in the sky, and that our days are longest.  Similarly, at the winter solstice (December 21st), the midday sun is at its lowest point in the sky, and the days are at their shortest.

Midway between the two solstices lie the spring (20th March) and autumn (22nd September) equinoxes.  These dates don’t get as much attention as the solstices, but consider this – on the date of the equinoxes, everywhere on the planet receives exactly 12 hours of daylight.  It doesn’t matter if you’re in Aberdeen or Abu Dhabi, on these days, everyone is equal.

soalr energy, seasonal variation

Solar energy varies from solstice to solstice

These definitions imply that the solstices and equinoxes are the midpoints of the seasons.  It’s always annoyed me when people talk about the summer solstice as the first day of summer – from a solar energy perspective it’s the middle of summer!  Crazy fools!

It’s something our pagan ancestors understood very well.  We know that they understood the passage of the sun across the sky in intricate detail – look how Stonehenge aligns with the summer solstice, and the entrance passageway to Newgrange in Ireland aligns with the winter solstice. The four points between the equinoxes and solstices were marked with festivals, each denoting the beginning of a season.  Beltane (May 1st) marked the start of summer, and Samhain (31st October) the start of winter.  These two, in particular live on in modern times.  May 1st is still celebrated as the start of summer.  In Oxford, for example, 1000’s of revellers gather at dawn to mark the start of summer, with choir singing, morris dancers, bands, and (lets be frank here) the chance to go to the pub at 6am.  Simialrly, Samhain marked the start of winter, and now lives on as Halloween.

Similarly, the start of spring was celebrated on 1st Februray (Imbolc) and the start of autumn (Lughnasadh, or Lammas) on the 1st of August.

And this is where the whole thing falls apart for me.  Really?  Autumn starts on the 1st August?   A week ago we had the hottest day the UK has ever seen, and today it’s meant to be the start of autumn?  Are you kidding me?

Thermal Seasons

The above description of the seasons doesn’t even tally with what we were taught at school.  Back then, I was told:

  • Winter – December, January, February
  • Spring – March, April, May
  • Summer – June, July, August
  • Autumn – September, October, November

So what’s the difference?  It comes about because our perception of the seasons is more about heat than light.  There is a lag between the times of maximum sunlight and the times of maximum heat, as it takes time for the land and oceans to warm up.  This means what we feel (temperature) is out of phase with what we see (sunlight).  If we consider the lag between sunlight and heat to be 1 month, that shifts the solar definition of the seasons in line with what we were taught at school.  If we consider the time lag to be longer at 6.5 weeks, then the crazy fools who say the summer solstice is the start of summer, would actually be correct.

temperature, Seasonal, London

Temperature in London, UK peaks after the summer solstice (from www.yr.no)

What if there aren’t 4 seasons?

Now here’s a thought.  What if there aren’t 4 seasons throughout the year?  In north European climates, the year can actually be divided into 6 seasons of 2 months each.  These are based on ecology – the observed plant and animal behaviours that are seen exclusively in these seasons.  They are defined as:

  • Hibernal (winter) – December and January. Bare trees, freezing cold, and snow.  Stay inside, hot chocolate, .mulled wine and Christmas
  • Prevernal (pre-spring) – February and March. Trees begin to bud, that first bright, clear, cold morning of the year, daffodils.
  • Vernal (spring) – April and May.  Trees come into leaf, cherry blossoms, and planting crops in the veggie patch.
  • Estival (summer): June and July. Hot, hot, hot.  Vegetation in abundance, t-shirts, shorts and flip-flops, and Glastonbury.
  • Serotinal (harvest) – August and September. Leaves begin to turn, crops mature (serotinal literally means ripening). The weather is still warm, barbeques in the back garden, but you might need some candlelight at the end of the evening.
  • Autumnal (autumn) – October and November. Leaves turn colour fully and fall to the ground.  Winter coat comes out, hats and scarves, kicking piles of leaves, and catching your breath on the morning air.

seasons, solar, thermal, prevernal, vernal, Estival, Serotinal, autumnal, hibernal

For me, this seems a much better description of the passing of the year.  The ‘extra’ seasons of pre-spring and harvest capture those time of year perfectly, autumn is reserved for just the period of falling leaves, and brilliantly, winter is only 2 months long.

So, as I write this on 1st August, welcome to the start of Serotinal!   That sounds a bit of a clunky phrase – and it might take a while to catch on!  But it doesn’t sound as weird as autumn starting, when its 25 degrees outside.

So, take a look around, observe your surroundings, and find which one of these three seasonal definitions suits you best.

Further reading

Fully Charged, 2019, LIVE, Robert LLewellyn, Helen Czerski, Jonny Smith, Maddie Moate, Silverstone

Visit Joju Solar at Fully Charged LIVE 2019

Joju Solar will be exhibiting at Fully Charged LIVE again this year.  The 3-day event will be held at Silverstone Race Track from Friday 7th – Sunday 9th June.  The event is put on by Robert Llewellyn and the team behind the Fully Charged Youtube Channel, and will feature all the latest from the world of electric vehicles, and renewable technologies for the home.

We can safely say that last year’s event was by far the best trade event we’ve ever attended.  The expected audience was well exceeded and 65% of those turned up within the first hour of the first day.  When the doors opened at 10am, the surging crowds were more like a Black Friday sale than any renewable energy show we’d ever been to.

Fully Charged, Joju Solar, talking

That’s our stall with the orange posters on the right hand side.  We didn’t stop talking solar, battery storage and EVs all weekend!

What to expect this year

This year’s event promises to be even better; the venue is now double the size and there will be a wider range of activities.  The highlights include:

  • The ability to test drive the latest electric vehicles on the Stowe track. There are an anticipated 1000 daily test drives, but with 10,000+ visitors expected, you are advised to keep an eye on the Fully Charged website for details
  • Over 100 exhibitors. We’ll be there of course, but expect to see EV manufacturers, EV chargepoint industry, energy utilities, and other green transport solutions among the stalls.
  • Our stall wll feature the latest Tesla Powerwall with back-up gateway, Sunpower’s new super-high-efficiency 400W modules, our latest EV chargepoint products, including lamppost mounted ones.
  • There will be 30 live sessions across the course of the weekend, hosted by Fully Charged Presenters Robert Llewellyn, Jonny Smith, Helen Czerski, and Maddie Moate.
  • Our Technical Director, Dr Chris Jardine, will be talking about “Streetwise solar, storage and charging for suburban EV drivers” at 12pm on Saturday

So grab your tickets and come and say hello!  We’d love to talk to you about any new projects you might have, or simply catch up with our old friends and customers.  Hope to see you there!

Oxford, Power Station, Project LEO, local grid, local energy

A Smart Local Energy System for Oxfordshire

Back in the 1890’s a power station in central Oxford powered a local grid that ran the city.  As demand for electrical power grew, many small local networks like this across the country were developed.  However, by 1925, such an approach was seen as inefficient and fragmented, and major review was conducted by Lord Weir.  The British Government created the Electricity (Supply) Act of 1926, which recommended that a “national gridiron” supply system be created. This was the formation of the National Grid as we know it, a back bone of high-voltage transmission lines feeding lower voltage local distribution networks.  One outcome of this, however, was that it supported a model of large centralised electricity generation; many GW of coal, gas and nuclear plants supplying the bulk of our power.

Now, in 2019, the challenges are very different.  With the need for rapid decarbonisation of electricity to mitigate climate change, not to mention the fact that renewables are now cost-competitive with traditional generation, we now have many smaller generators connected at the bottom of the electricity grid.

Which poses the question: is the old localised energy grid model a more appropriate way of managing our electricity system in the 21st Century?  Has the wheel turned full circle?

This is what a major new project, Project LEO (Local Energy Oxfordshire), is looking to find out.

Project LEO, logo

Project LEO

Project LEO is a £13.8m project over 3 years, run by a consortium of Scottish & Southern Electricity Networks, Open Utility (Piclo), EDF Energy R&D, Nuvvé, Low Carbon Hub, University of Oxford, Oxford City Council, and Oxfordshire County Council.  The aim of the project, as the name would suggest, is to develop a local electricity market for Oxfordshire, that supplies its own needs, ensures reliable grid operation, and rewards generators a storage for the energy and flexibility they provide.

Why is this project being developed in Oxfordshire?  Currently the grid in Oxfordshire is constrained, meaning it’s hard to connect more renewable energy projects to the grid; the grid is essentially full.  There are two potential ways to solve this:

  • upgrade all the wires and substations so they can take more power. However, the expense of this could be vast.
  • Develop a smart local grid, where storage and flexible demand soak up excess renewably generated power, to allow more renewable generation to be connected without massive upgrades of infrastructure

Put another way, lets imagine a new massive solar farm was connected to the grid.  In summer the excess power would blow up the existing substations – no-one wants that!  So the first option would be to build a new substation at considerable cost.  The second option would be to find nearby users to take that excess power, which is likely to be considerably cheaper.

Local Energy Marketplace

To facilitate this, Project LEO is developing a local energy marketplace, to control and manage the operation of the ‘assets’ in a smart local energy system.  These assets might include hydro generation on the Thames which could be ramped up and down, or large heating systems such as the Bodleian book depository, which could be used flexibly according to available renewable power. It could also include smaller solar PV systems, batteries and smart EV charging.

Joju Solar to play a part

And this is where Joju Solar comes in!  We’re going to be working with our long-term community energy partner the Low Carbon Hub to deliver solar and storage projects that integrate with the Project LEO local energy marketplace.  Lots of innovation will be required.  For example, currently batteries charge from solar, and discharge to meet demand within the home.  In future, batteries will still charge from solar, but might discharge when Oxfordshire needs it, rather than when your home needs it. This should reduce costs for everyone, and allow more renewables to be connected to the grid.  However, it won’t be easy; devices will need the ability to ‘talk’ to the grid for them to be able to respond to the signals from the local market.

It’s a very exciting step for us – to go beyond simply installing generation and storage in people’s homes and businesses, and actually help create a local smart electricity grid.  We can’t wait to get started.

Further Reading