solar roof tiles, integrated solar, BIPV, ThamesWey

ThamesWey’s Innovative Battery Microgrid

ThamesWey has recently installed an innovative solar/battery microgrid at a housing estate in Woking.  ThamesWey are a private company, owned by Woking Borough Council, set up to drive carbon reductions and the wider sustainability agenda in the Borough.  They own and manage over 600 properties in support of the Council’s Housing Strategy. ThamesWey offer a range of private rental properties including homes at more affordable rents and key worker accommodation.   ThamesWey have a long history in the solar energy sector; back in the 2000’s, and long before feed-in tariffs were established, they were the leading institution installing solar panels in the UK.  They installed their first solar panels back in 2001, and had installed over 5000 solar panels by 2012.

“It’s in our business plan to trial new technologies, so we wanted to run a demonstrator of centralised battery storage”, explains Rachel Lambert, ThamesWey’s Environmental Projects Manager.  “We wanted to find a solution that saved carbon, whilst simultaneously offering a strong economic case.  At the current state of technology, that required a highly innovative project”.

A Microgrid Serving 14 homes

The site chosen was a group of 14 homes, which already had solar PV installed as integrated solar roof tiles on 12 of the properties since 2010.  ThamesWey built the properties to code 5 of the former Code for Sustainable Homes , and designed them to run off their own private wire network.  ThamesWey import electricity into a substation, and then distribute  this electricity on to the connected homes.

“We came up with a concept of installing batteries at the substation as part of our own microgrid”, said Sam Pepper, Environmental Projects Officer.  “The idea was to capture the excess solar electricity that was being produced during the day, and to use this to benefit all the homes on the network, including those without  solar”.

Developing a microgrid with batteries

ThamesWey asked Joju Solar to help design and implement the scheme.  We undertook extensive modelling of the site, looking at ½ hourly usage and generation across the homes, and predicting what would happen if batteries were incorporated.

This was also a full financial model. ThamesWey buy in electricity that is priced every ½ hour on a real time tariff.  As a ‘commercial’ user, ThamesWey also incur high additional charges of 8p/kWh (called DUoS charges) at peak times between 4pm and 7pm every weekday.  We looked at the savings possible for a variety of battery models and operational regimes.

We settled on the installation of 3 x Tesla Powerwalls for a number of reasons:

  • Tesla offer the cheapest storage per kWh of battery capacity
  • Using 3 Powerwalls allows 40.2 kWh of electricity to be stored.
  • The 3 Powerwalls can supply 15kW of instantaneous power, allowing the aggregated load of the homes to be fully covered for most of the year
  • The Tesla Powerwall can be set up to import cheap, cleaner, night time electricity in winter months, adding additional savings when there isn’t excess solar available
  • The Tesla Powerwall can be set up to preferentially discharge when electricity prices are high to maximise savings – in this case during the peak DUoS periods of weekday evenings. By eliminating consumption across the 14 homes in the peak period, DUoS charges become zero.
  • An additional benefit of load shifting out of the peak period is that this is also when the grid is the dirtiest in terms of utilising fossil fuels.

Overall the scheme offers the best economics we have seen for behind the meter batteries, with a full return on investment within the 10 year warrantied lifetime of the Tesla Powerwall.

This centralised approach is approximately 5 times cheaper than the alternative of installing a battery in each home, showing the advantage of deploying batteries into a microgrid.

Installing a battery Microgrid

Joju installed the batteries at the substation over a 3-day period.  The only issue faced with the installation was making the final connection between the batteries and the supply in the substation, which needed to be switched off to manage the works safely.  Homeowners were informed in advance by letter that their supply would be briefly interrupted on the final day, and the necessary connection was made within 15 minutes.

Batteries for Sites with Landlord’s Supply

The ThamesWey project is a clear demonstrator of the strong economic case for batteries within a microgrid context.  At first glance it might seem that this kind of site is fairly unique, but the same approach can be adopted wherever there is a landlord’s electricity supply in place – most commonly in blocks of flats.  Any situation where the landlord buys electricity into a building (or site), and then sells on electricity to tenants, can benefit from battery storage behind the landlords meter (but in front of the tenants).  It’s a model Joju Solar are now rolling out at numerous sites across the country.

Mark Rolt, ThamesWey’s Chief Executive Officer concludes “We were delighted to work with Joju Solar to install these batteries at our substation as part of an innovative trial of a centralised battery. The associated carbon savings from maximising the use of energy generated from a renewable energy technology supports our founding commitment to reduce carbon emissions in the Borough.”

Find Out More

 

Rotherham, Metropolitan, Borough, Council, Wellgate, car park, solar PV

Rotherham Metropolitan Borough Council’s Full Set

Whilst we have seen residential customers installing the complete set of solar PV, battery storage, and electric vehicle chargepoints, it’s something of a rarity at a larger scale.  Rotherham Metropolitan Borough Council, however, have just completed a £600k scheme installing electric vehicle charge points across the borough, combining this with solar PV and battery storage at some of the sites.  Steve Brown, Transportation Officer, explains: “We’ve been very interested in the potential to replace our diesel/petrol fleet with electric vehicles to reduce carbon emissions and address air quality in the borough.  But we were very aware that doing so would increase our electricity consumption, and nationally there’d be a problem generating the electricity.  So we have looked to manage these knock-on effects ourselves by installing an equivalent amount of solar PV at the same time to offset this.”  And it’s not just the amount of new electricity that was a concern: “We wanted to use batteries to store this sustainable energy for us to use when we needed it, rather than when it was available

Developing the Scheme

The flagship site in the programme is the Wellgate multi-storey car park, which features 5 dual Alfen Eve charge points, 87kW of solar PV and 3 Tesla Powerwall’s for storage.  The solar PV was hosted in a unique way, on the top deck of the multi-storey.  “It’s an odd feature of almost every multi-storey car park in the country that no-one parks on the top-deck”, says Steve.  “They’re massively underutilised assets, so we took the decision to close the top deck and use this space for generating solar electricity.

An additional five sites incorporated both solar PV and electric vehicle charge points.  Hellaby Depot, Rawmarsh Library, Riverside House, Rother Valley Country Park, and Thrybergh Country Park host 17 dual charge points and 141 kW of solar PV.

Aston Health Centre, Drummond Street car park, Walker Street car park and Wath Library are also home to dual chargepoints, increasing the coverage of the public EV charging network in the Rotherham Metropolitan area.

If we build it, they will come

The main difficulty we had was whether the scheme would work at all”, said Steve.  “There’s a certain amount of ‘If we build it, they will come’ when developing a chargepoint scheme.  But Rotherham does not have the same level of per capita income as parts of southeastern England, and we didn’t know how quickly the community here will take up EVs, as they are still more expensive than petrol or diesel vehicles.

Funding from the Government’s Clean Air Fund early measures programme provided the initiative to get the scheme off the ground, and Rotherham Metropolitan Borough Council instructed Joju Solar to install the project, following a mini-tender through the ESPO Framework.  Joju Solar are uniquely well placed to deliver schemes like this as we are one of the largest installers of Public Sector EV charge point programmes, as well as having decades of experience installing solar PV and battery storage.

Our fears have been unfounded – the chargepoints are being widely used, and people are prepared to use charge points at outlying council offices and country parks.  From our point of view, it’s worked extremely well”.  The Council are seeing the solar PV generation being used on their own sites, reducing bills, and the battery storage is covering lighting requirements overnight.

A Holistic Public Sector Approach to EV Charge Points

Rotherham’s approach appears to be paying dividends, and there’s an appetite for more.  “The whole system has been really well thought out – there’s chargers in the basement for staff and outside for public use.  We’d like to do more of the same – perhaps in innovative locations like schools and colleges as well”.

Rotherham Metropolitan Borough Council’s pioneering scheme is a strong example to other councils, particularly in the way that they have looked at the larger energy picture.   Electrifying transport will inherently increase demand for electricity, and it shows a truly holistic approach to sustainability to consider how this will be provided as part of one installation programme.

Find Out More

  • We’ve developed the Joju Charging Portal – an information hub for public sector bodies looking to install electric vehicle charge point programmes
  • The Rotherham Metropolitan Council scheme was procured through the ESPO framework
  • See how the complete set of solar PV, battery storage and electric car charge points can help in the home
Tesla, powerwall, ev charging, electric vehicle

Chris’s Complete Set

Chris Savage has jumped straight into the smart electric future; he purchased the complete set of technologies offered by Joju Solar in one go.  His home now features a solar PV roof, Tesla Powerwall 2 battery storage, an electric vehicle charging point, and an Immersun device to divert any excess solar electricity into hot water heating.

Driven by his electric car

Chris’s reasons for getting solar and battery storage shows how complementary these technologies are.  Whilst we have seen people with PV roofs going on to get and electric car, for Chris it was the other way round.  “I’m fundamentally green, but it was getting an electric car that pushed me into finally doing this.  I’d been thinking about solar for some years, but it was the idea that it could help charge my car that was most appealing.”  Seeing an episode of Fully Charged about the Tesla Powerwall also prompted Chris to incorporate storage into his home energy upgrade.

The design challenge

Integrating so many components can be complex, so ensuring all aspects work well together is critical.  The system is designed so that the solar produces electricity in the day, which is used or stored in the battery.  The battery discharges in the evening and night-time into lights and appliances in the house, and trickle charges the car.  Chris has a plug-in hybrid Mercedes, which has a comparatively small battery capacity of 6.5kWh, so it’s not a drain on the battery.  Chris has got involved too: “I fiddled with the charging profile on the electric car, so it doesn’t exceed the output capacity of Powerwall”.  On the best days in summer, Chris’s PV system will generate more electricity than even the Powerwall 2 can take, so here any excess electricity is diverted into the hot water tank, using the Immersun, rather than being fed back to the grid.

Turning carbon into a game

It does give you a fuzzy glow to know you are producing your own electricity. It’s very interesting and I’ve been rather obsessive about it! We’ve managed self-powered up in the high 90%’s.  It’s almost a game trying to minimise grid electricity – a bit like driving the car, when we sort of consider it a failure to use fossil fuels

Further Reading

 

commercial battery storage, sonnen, repower balcombe, sussex, Eco8

Commercial Battery Storage at Turners Hill School

Good things come in threes for this commercial battery storage system

Background

Repower Balcombe is a community energy group founded as a positive response to threats of fracking in the area.  The group have funded solar PV on 4 schools in the area, including this one at Turners Hill Primary which was installed by Joju in 2015.  With their community benefit fund from existing sites bearing fruit, they decided to set up a battery storage project to understand this new technology better.

Commercial Battery Storage

The challenge for Joju Solar was to design and specify a battery storage system that maximises the benefits to the host school.

The school is typical of a small commercial battery storage system, which has very different characterisitcs to domestic battery systems.  The electricity supply to the school is 3-phase, so we needed to install storage across all three phases.  With 3-phase batteries of this scale not available in the UK as present, we installed 3 separate battery systems, each dealing with the load and generation on that phase.  You can see the three individual storage units, manufactured by Sonnen, in the photos.  Technically the greatest challenge related to the battery’s monitoring – it needs to monitor the extent of import and export from the school and the generation from the solar PV.  The PV system was some 20 meters from the battery installation so we needed to run long monitoring cables as part of the works.

The system operates under a regime where excess solar generation is captured during the day, and used to run the school in the evenings and through the night.  We gathered half-hourly electricity demand data from the school, and undertook a comprehensive modelling exercise to determine the optimal battery size.  In order to meet the evening and night-time demand, we settled on a storage capacity of 4kWh per phase.

The graph (left) shows that we have sized the system almost perfectly. The purple line shows the energy stored in the battery.  The solar charges it up to full capacity in the morning, where it remains until early evening.  Once demand is no longer met by solar, the battery discharges to meet demand on site.  It’s empty again just a matter of minutes before the sun comes up and starts charging it again!  Electricity imported from the grid, shown in pale blue is virtually non-existent; the school is running on its own solar generated electricity.

The installation and the stats

The installation took place at Turners Hill School in Turners Hill village in Sussex.  Joju Solar installed 3 x Sonnen Eco 8 4kWh batteries in just 2 days at the site.

The system is meeting the school’s needs for electricity in the spring/summer/autumn months.  However, it should be noted that in winter there will not be sufficient surplus electricity to charge up the batteries and the system will remain dormant at this time.

For this reason, paybacks for this battery system are long, and in excess of the battery lifetime.  Repower Balcombe were able to fund this project as they already had surplus funds generated for good causes such as this (i.e. saving the school money)

However, do not despair!  Our modelling shows that there are other ways of operating commercial battery storage systems in commercial premises that does give paybacks shorter than the battery lifetime, especially with the good economics of the Tesla Powerwall2 battery.  If you’d like to see how this could work for you, then do get in touch with our batteries and smart grids team.

Further Reading

  • Read how we pioneered storage in the community by installing batteries for social housing tenants in Oxford
  • For larger sites than Turners Hill, the Powerwall 2 looks to be an excellent option, and installs very easily
  • Find our more about our work with community energy groups across the country

Julian and Lorena join the All Blacks

Julian and Lorena join the All Blacks with installation of 16 Solarworld’s 285w mono black solar panels

Background

When Julian and Lorena contacted Joju about a solar installation with home battery storage they wanted something that was going to complement their new home and fit in with its aesthetic. This is a pre-requisite of many of our residential consumers who voice concerns about how solar panels will look on their roofs and whether or not they will ‘fit in’. With existing solar tiles already out there on the market and Tesla recently annoucing their plans for solar tiles (see our installer’s guide to Tesla’s solar tiles) plenty of options are available. It is possible, however, to get the right look with panels. And that’s exactly what we did with the Solarworld mono black solar panels.

The Installation

16 Solarworld 285w  mono black panels were installed on Julian and Lorena’s new build property in Virginia Water, near Wentworth. There new build property is  supported by 4.56 kWp of All Black solar panels. The panels were mounted “in-roof” which means that they are flush with the roof line so blending in beautifully to the dark slate tiles and creating a brilliant aesthetic.  As well as the solar array Julian and Lorena also had a DC coupled 6.4kWh Tesla Powerwall installed, which stores excess solar energy for use in the evening.

The all black panels from Solarworld are German engineered. They come with the TUV Rheinland Power inspection mark and a linear performance warranty covering a period of 25 years, SolarWorld guarantees a maximum performance degression of 0.7% p.a only,

What Julian thinks

Julian says: ‘The solar PV and Powerwall system is the perfect addition to our new house. We are very pleased with the installation by Joju Solar and excited to have the sun help power our home day and night.’

 

 

fully charged, robert llewellyn

Glenn gets Fully Charged

Glenn Tweedie’s decision to get a Tesla Powerwall and solar PV has led to both energy savings and TV fame!

Background

When Glenn Tweedie decided to have a solar PV array and a Tesla Powerwall installed on his family home in St Albans he probably hoped and expected that it would lead to energy savings for him and his family. What Glenn didn’t plan for was that the installation would lead to internet stardom and a starring role in Robert Llewelyn’s internet show Fully Charged. 

The episode of the show which featured Glenn and his family was filmed a few weeks after Joju installed the system, which included our first ever Tesla Powerwall installation in May 2016.

The Solution

In the Fully Charged episode Glenn talks to Robert Llewellyn about the benefits the Tesla Powerwall has brought to his family and just how much it has lowered their energy consumption from the grid. Indeed, on the day of filming 97% of Glenn’s Family’s energy had come from energy stored in the battery and produced by the solar PV. With only 3% being drawn from the grid thanks to both the 4.5kWp solar array and the Tesla Powerwall working in perfect harmony. Thanks to the SolarEdge PV monitoring platform Glenn and his family can monitor their energy usage via a smart app on their phones and laptops, which has enabled him to show his two sons just how much energy they are wasting when they forget to turn off lights and Playstations.

Getting Fully Charged

The video demonstrates perfectly the benefits of when a solar PV array is installed in sync with a home battery storage solution. The energy savings, the improved family education on energy usage, and even the status that come with having such a complete home energy solution are all highlighted and discussed in depth in the episode.

Watch the film Fully Charged Episode here

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Further Reading

  • Inspired by Glenn’s story, Robert Llewellyn went and got himself the new model Tesla Powerwall2 and an upgraded solar PV system for his Home of the Future
  • We blogged the installation of the Powerwall2 unit live
  • Find out more about our battery offering, and how we work with households