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S Georges' SPorts Centre, Scott Brown Rigg, Architects
April 7, 2021 In

St George’s College Iconic Solar Sports Hall

St George’s is an independent mixed Roman Catholic co-educational day school in Weybridge Surrey. The school have recently constructed a new Sports Hall for the school as their existing sports hall was only sized for 500 students (all boys).  The new sport hall now caters for over 1000 pupils (both boys and girls) over a wide range of sporting activities.

The new hall is a flagship architectural building, designed by Scott Brown Rigg Architects, with many unique design features that required careful integration of the solar PV.

The structure of the building is made from curved glulam columns and roof beams, which support a plywood deck.  Above the roof sites 150mm insulation, finished with a Sika Sarnafil single-ply roof membrane.  The roof is curved in two directions much like the Olympic Park velodrome, and also features diamond-shaped roof ventilation towers.

Careful Integration of Solar

As such, the design needed to account for the following sensitivities:

  1. As a high-end architectural project, aesthetics were paramount to the client.
  2. The installation mounting system needed to work with the curved surface of the roof.
  3. We needed to avoid shade from the ventilation towers.
  4. The chosen system needed to be lightweight so as not to compress the insulation, or led to puddling of water
  5. The system needed to be non-penetrative
  6. We needed to install sufficient solar PV to meet overall building CO2 targets.

The building carbon targets implied the building had a target of 32kWp of solar PV to generate 29,688kWh of electricity per year.  To meet this brief, we installed a system of 119 JA Solar 270W modules, connected to a single Solis 30kW inverter.

 

Sika SSM1 mounting system

Joju Solar are the solar energy partners of Sika Sarnafil who manufactured the roof membrane system.  Working closely with them and the main roofing contractors, Malone Roofing, we designed and delivered what we to believe to be a prime example of sensitive architectural integration of a commercial solar PV roof.

The chosen mounting system was the Sika Solar Mount SSM1, which offers several unique features, ideal for this project.  The mounting system consists of plastic triangular frames pitched at 15 degrees.  These frames use rubber fixing flaps, that sit over the frames which are then rubber-welded directly to the roof membrane.  Because the frames are bonded to the roof surface, the system is ballast-free, and therefore very lightweight.  This not only simplifies construction but helps from a structural engineering point of view, especially in case such as this where the span of the roof is large.  It also prevents compression of the insulation layer and puddling of water on the roof.

Uniquely, the mounting system and the roof membrane itself are covered under a single point warranty.  As Sam Rogan, Sika Sarnafil Technical Advisor explains: “The SikaSolar system offers a low profile panel with high output,  that is fully compatible with Sarnafil single ply roofing membranes”.  This avoids any potential conflict between the multiple contractors on-site, as there is a single holder of risk and responsibility.

Primarily designed for flat roofs, the SSM1 is limited to being installed on roofs of less than a 10-degree pitch.  We therefore restricted our array to those unshaded areas of the roof that met this design requirement.  The area chosen was such that optimisers were not required and the system could be strung on a single 30kW inverter.

As a further step to enhance the aesthetics of the installation, the DC cable routes were laid in channels cut into the insulation membrane, which were then covered with the main roofing membrane.  This removed the need for an unsightly cable tray running across the roof and preserved the clean aesthetics of the building.

 

(Images 1&3 courtesy of Scott Brown Rigg Architects)

Find Out More

  • Our PV design team is on hand to help you realise the solar part of any new build project, large or small
  • We have even integrated a bespoke solar PV array into the roof of Salisbury Cathedral
  • Solar schools like St George’s are a speciality of ours – find out more about the hundreds of solar schools we’ve already built
solar roof tiles, integrated solar, BIPV, ThamesWey
December 10, 2019 In

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 in both the commerical solar panels and public sector renewables spheres.  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

 

Electric police car, charging, chargepoint, New Motion, Central Southern REgional Framework
February 20, 2019 In

The Thin Blue Line Goes Green

“The trouble is that the bad guys don’t have environmental targets”, declared Dennis Ord,
Head of Transport for Surrey & Sussex Police.  “That means our priority is a vehicle that can deliver the performance we need, but also at low environmental impact”.

Electric Police Cars

With this in mind Surrey and Sussex Police purchased 60 BMW i3 full electric cars.   The vehicles will be used by officers to carry out day-to-day policing activities such as visiting victims or witnesses to take statements, or as part of door-to-door inquiries.   Environmental targets were not the only benefit here – the much lower running costs of electric vehicles compared to diesel or petrol, means that each force is expected to save £120,000 over the next five years.  That’s valuable funds that can be used elsewhere in the police budget.

Procuring electric car chargepoints

Of course, the 60 new electric vehicles needed their own dedicated chargepoints, and with the vehicles on order, installed at short notice.  Surrey and Sussex Police decided to procure through the Central Southern Regional Framework, run by Hampshire County Council, which offers a streamlined procurement process, whilst simultaneously ensuring high quality products and service.  The Central Southern Regional Framework is available to all councils and public bodies (health service, police, fire etc) within the south of England.

Smooth Project Management

30 fast chargers were installed for Surrey Police for across 8 sites in November 2018, followed by a further 40 chargepoints for Sussex Police in December 2018.  “Our main challenges were the rapid turnaround times required – if the vehicles arrived and they couldn’t charge, it would have been a disaster”, said Joju’s Operations Director Joe Gabriel.  “These were also live police sites, requiring careful project management to ensure disruption to police activities was minimised.”

Police Leading the way

The Police are modernising their policing with the procurement of a fleet of electric vehicles and associated infrastructure – benefitting the environment and their balance sheet at the same time. As such it is a perfect example of both the benefits of institutions switching to electric fleets and of how public institutions can procure the necessary infrastructure.

The bad guys don’t stand a chance!

Further reading

commercial battery storage, sonnen, repower balcombe, sussex, Eco8
May 3, 2017 In

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
January 25, 2017 In

On the grounds of Chilworth Manor

In Autumn 2011 Joju installed a 196 panel ground mounted solar system in the grounds of grade II listed Chilworth Manor, Surrey.

Background

Chilworth Manor is a historic country house located in Surrey. The manor, itself, is grade II listed by English Heritage. In 2011 Joju were commissioned to install a ground mounted solar array.

READ MORE

December 15, 2016 In

Green Oak leads the Way with LEDs

Green Oak school leads the way with LED installation

Background

All schools and teachers know that the environment in which children learn and work in is crucial to both their education and how they behave. Negative work spaces can create negative behaviour and limit a child’s opportunity to excel. Lighting plays a crucial role in creating a positive working environment and too many classrooms around the country still have inefficient lighting, issues with broken lights, flicker, and mismatched colours, which can all hamper the learning environment . Many schools are beginning to realise the potential for improving their classrooms through LED lighting, which is both aesthetically more pleasing but also creates light more conducive to learning. Green Oak Primary school is one such school who saw the potential in installing LED lighting to improve their school’s learning environments.

The Project

In Autumn 2016 Joju replaced 68 existing luminaires (light fittings). Dated and flickering batten fittings were replaced with sleek slimline LED panels that sit in the recessed ceiling. Rooms that originally had lights of different colour, which is unsightly to say the least, were all replaced with cool white LED lights. Flickering lights have been replaced with modern, instant-on lamps that have transformed the classrooms.

The Benefits

The LED installation at Green Oak will reduce energy bills by 5,600 kWh per year. We estimate that to be a saving of £611 per year (that’s about £10 for each fitting). Over the lifetime of the LEDS they will deliver over £12k of cost savings and when all benefitsare taken into account we expect a payback of four years. LEDs need replacing less often than fluorescent tubes, which offers significant maintenance saving. This will be especially true in the two-storey sports hall, where specialist access equipment is required every time a fluorescent tube fails.

What They Said

The Headteacher of Green Oak school, Miriam Morris said “Joju provided a fantastic service to Green Oak working at all times in a professional manner at the school. They installed the lights during half term, so it didn’t have any adverse impact on us in school. The job was completed efficiently and on time and the results are fantastic. The LED lighting has made a real positive difference already to the aesthetic and working environment of the classrooms where they have been installed. It has changed things so much that many of the staff thought that the school had been completely repainted when they came back after the week of holiday!”

The project at Green Oak was funded by grants raised by Wey Valley Solar Schools Energy Co-operative, a member of Joju’s long term community energy partner, Energy4All.” Project co-ordinator Rachael Hunter said “We know from past experience that working with Joju will always be a pleasure. The service and knowledge of the project manager was second to none and we always feel confident in Joju’s ability to complete a job to the highest spec.”

 

December 7, 2016 In

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.’

 

 

April 26, 2016 In

Wey Valley Schools

Community funded installations for secondary schools in Southern England

The Wey Valley Solar Schools (WVSSC) Co-operative is a community-owned energy co-operative set up by local people from the towns of Guildford and Godalming in Surrey. A 2011 share offer raised £625,000 from individual investors to put solar panels on the roofs of six state secondary schools in Surrey. The addition of a subsequent site gave an initial total generation capacity of 267kW over seven schools. Investor members have so far received annual returns of over 7%.

The Co-operative provides schools with:

  •       renewable energy free of charge or at a heavily discounted rate
  •       the ability for each school to cut their carbon emissions by up to about 20 tonnes per year
  •       an educational package to explain and monitor the renewable energy being generated by each school

In 2015 WVSSC made a second share offer to raise between £200,000- 250,000 to fund substantial extensions to solar installations at Godalming College and Beacon School of up to 285 kW, more than doubling the generating capacity of the Co-operative.

Joju Solar were delighted to be chosen by Wey Valley Solar Schools as the preferred contractor for this ongoing project and have worked closely with them to deliver their installations. We also provide monitoring and maintenance for the solar systems helping ensure that they continue to get the most energy and best financial returns across their whole portfolio.

Testimonial

“Wey Valley Solar Schools have used Joju Solar on numerous installations. They have been excellent and I recommend them. They have compared very favourably indeed with the other contractors of which I have experience. They have plenty of experience in dealing with sensitive sites (e.g. schools) and working around operating sites. They are completely aligned to the community energy movement and to find this together with technical expertise has been a real joy. Their quotes are firm and contain no hidden extras. They are easy to work with and very supportive because we are all trying to deliver the same mission.” Mike Smyth, Director, Wey Valley Solar Schools