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

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.”

 

Orchard Field Community School

Orchard Field School meets it high demand within strict grid restrictions

Orchard Field Community School is a large primary school in Banbury, Oxfordshire and a member of the Low Carbon Hub Solar Schools portfolio. The installation was installed in Summer 2015.

Challenge

Orchard Field Community School is a large primary school with a very high energy demand.  The school’s roof along with being large also curves around in a crescent moon shape. This presented a challenge in terms of how to secure the panels to the roof. The lengths of rail which we normally used on gable roofs couldn’t be used.  This also presented a challenge in terms of how best to wire the solar PV modules to the inverters, as panels facing in slightly different directions have different outputs depending on the location of the sun.  Orchard Field was therefore a tricky set up.

The final challenge was also to limit the potential export to the national grid. Despite the high demand on site solar PV export was limited to 50kWp, meaning that we needed to find a way to prevent the PV system from generating 50kWp more than the demand on site at any point in time – a very likely occurrence over the summer holidays.

Benefits

On a clear spring day the solar PV system meets the total energy demand on site. During the Summer this happens  more and more. Whatever the weather this system makes a significant reduction to the School’s electricity bills. And like all our installations in schools it has become a valuable educational tool for the pupils.

Why they chose Joju?

Joju have been one of the preferred suppliers of the Low Carbon Hub for several years and Orchard Croft is just another fantastic example of us working with them.

Headmistress Dawn Shilston said “As a school we feel incredibly proud to be doing our utmost to reduce our Carbon Footprint. It is incredible to consider we are the largest Solar Roof Project on a Primary School in Oxfordshire with our school roof hosting 384 solar panels. It has been an invaluable exercise in educating our pupils for the future on the importance for us all to explore the possibility of using renewable resources for our energy.”

Read More about the installation and all its savings here at Low Carbon Hub

 

 

Merton Council leads the way

Merton Council

London Council leads the way with green energy portfolio

Merton Borough Council have added over 200kWp solar PV to their impressive portfolio of solar in the last 3 months, creating 190,000kWh of free energy for local Schools every year.

Merton Council continue to demonstrate their green energy leadership by being the first council to install solar PV following the cuts to the FITs believing in the benefits that solar PV provide to the council despite the reductions in rates.

Challenges 

Merton had an impressive portfolio of solar PV before Joju started working for them. Sadly there previous installer had gone out of business and as a result left them with a number of sites which were not functioning correctly. They needed a new contractor to help them continue their program and fix any pre-existing system issues. This is where Joju were able to step in. Merton selected us to carry on the work because of our high ranking on the Fusion21 framework and based on personal recommendations.

The benefits

Each School has benefitted through reduced bills. At the same time the Schools’ have the capacity to access up-to-date data produced by the PV system, which is be used for educational purposes. The Council also see a long-term return on their investment through the new FIT.

What they said about us

“Joju Solar installed over 170 kWp of solar panels in under 2 months on challenging school sites across the London Borough of Merton. All stages of the process from planning to install were excellent and we have received high praise from the sites themselves about the way their teams worked on site.

Even in the current Feed in Tariff regime we can see the benefits of installing PV on sites and we are very pleased to have partnered with Joju for these installs and will be continuing to work with them in the future.”

Cabinet member for Environmental Sustainability and Regeneration, Councillor Andrew Judge said: “The installation of so many solar panels to our buildings around Merton is integral to the future of our community. I’m delighted as these solar panels will not only help save money and cut running costs by generating our own electricity, but will also allow the borough to become more environmentally friendly.”

You can read about the installations on Merton Council Website here

Watch a video on the installation here

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

 

 

Fox Primary School

Fox Primary School shows its cunning with solar installation.

Challenge
To install an 18kWp installation on the flat roof of this primary school in Notting Hill, Joju Solar worked with the school to secure some of the last capital grants available, totalling 50% of the total cost.

“I’d have no hesitation in recommending Joju Solar. This was an exciting project for our school and unlike other projects we’ve carried out. This meant we needed an installer we could trust and understood the issues involved in working in a live school environment. Joju Solar installed our school’s PV system on time and on budget and worked in accordance with all our requirements. I found them helpful, professional and expert at what they did. Many thanks.” Paul Cotter, Headteacher

Solution
After much planning and discussions we decided to install the system over the half-term break so as to cause minimal disruption to pupil and school life. The project consisted of 98 PV modules connected to the 3-phase supply of the building. This allowed the installation team to carry out the project with little problems.

Rewards
By generating green electricity on their available roof space the school can now expect to save over 8 tonnes of carbon dioxide emissions each year and reduce their electricity bills at the same time.