Reuse on The Rooftop Farm Wimbledon
Turning waste into mushrooms and more at our local rooftop farm!
As the owners and managers of Centre Court Shopping Centre, here at Romulus we were looking at ways during lockdown to improve the business. One of the challenges we faced is dealing with food waste, which if not separated properly, can end up in normal refuse bins leading to methane production (a greenhouse gas more potent than carbon dioxide).
We discovered that delicious oyster mushrooms (and more!) can be grown off of used coffee grounds. The mycelium from the fungi break down the food waste into compost and fruit into mushrooms that can then be harvested and sold. This both reduces food waste and produces locally grown produce without the need for complex and energy intensive supply chains.
This case study highlights activities that some businesses can do to support the borough’s net zero by 2050 target, by tying into Workstream 1 of Merton Council’s Climate Delivery Plan focussed on sustainable consumption and the low carbon economy.
Centre Court are keen to play their part in a more sustainable and community-oriented Merton. We have challenges in dealing with food waste which could be reused but is often just mixed with general waste, ending up on landfill or the local energy recovery facility.
We saw an opportunity to create a locally grown, supply chain free, and biodiversity enhancing business to achieve this waste reduction. We use fungi to create a circular economy, turning waste into edible delicacies.
We are currently growing a gourmet mushroom variety called ‘grey oyster’. They grow on a mix of straw and spent coffee grounds sourced from cafés and restaurants local to Centre Court.
Coffee grounds would usually go to landfill or the local energy recovery facility from these businesses after use, so by growing mushrooms, we’re able to repurpose this waste product to grow something new. We add this mix to reusable buckets instead of single use plastic grow bags, meaning there is little to no waste produced during the growth cycle. Once our mushrooms are harvested, we use the spent mushroom compost as mulch on our pots and planters in the rooftop garden. The mushroom compost provides both major nutrients and trace elements for the soil, as well as mushroom mycelium which is essential for a flourishing ecosystem. This allows us to eliminate our waste completely from production and prevents us from needing to source nutrient additives, closing the loop on our farm.
All of our suppliers and customers are hyper-local so our produce has virtually zero food miles and is delivered without single-use plastic packaging.
Reducing local coffee ground waste in the borough. From October to December 2022, we rescued over 200kg of coffee grounds from the bin.
A farm providing locally grown gourmet mushrooms with little to zero food miles.
Eliminating the use of single use plastic in production and distribution.
Focusing on hyper-local suppliers, adding to the green economy of the borough.
Using mushroom farm by-products to increase biodiversity and improve the health of our rooftop garden.
Next steps and call to action
From early 2023, we are expanding our mushroom growing skills to try out other varieties. This includes shiitake mushrooms which also grow on coffee grounds. This will mean we can recover even more coffee waste locally and collect more regularly.
We have re-cycled the Christmas trees that were part of the decorations at Centre Court and inoculated the trunks with a mushroom variety called nameko. This variety takes several months to colonise the tree before producing mushrooms, so the results of this experiment are yet to come.
As we head into spring and summer, we will have more opportunity to expand our food garden and develop the local green infrastructure of the borough. We plan to grow seasonal staples like tomatoes, kale, cucumbers, and strawberries, as well as wildflowers, beer hops and some unusual tubers and squashes. The aim is to grow these off the mushroom compost and compost from other food waste generated as part of the operations of the centre.
- May-August 2022. Set up of farm in progress
- September 2022. Started growing and set up relationship with Costa to collect coffee grounds
- October 2021. First flushes grown of grey oyster mushrooms
- November 2022. First sale of mushrooms to a local food box provider
- January 2023. Test of growing nameko mushrooms on Christmas trees
There is no shortage of used coffee grounds, but it is important this waste is separated from other coffee waste so it is not contaminated.
Working with partners who have done this before is invaluable. There are great causes and other mushroom farmers who have made all the mistakes already!
Mushrooms don’t like it when it is minus 5 degrees for a week either!
Contact for enquiries
Improving the economic wellbeing of young residents through green skills
Merton’s Towards Employment team develop and deliver projects that increase the economic wellbeing of young people. We engage Merton’s young people from marginalised, economically vulnerable cohorts in debate and activity that increases their aware of green agenda.
The canons project was a space that had been redeveloped and a new café had been built. We were contacted by colleagues in the council to help source residents to build the furniture needed for the café.
Colleagues at Vestry hall sourced Solo Wood Recycling to support the project. All furniture was being built from recycled wood.
We advertised this as a work experience opportunity for our Merton Care leavers.
We used a budget of £1800 for time and resources
Work experience opportunity for Merton’s Care Experienced Young People.
The work experience programme was organised to take place during the first two weeks of the summer holidays. All work took place on site and in the outdoor area, Residents were provided with water, rest breaks and lunch. They were also given engagement vouchers for attending.
The young people were able to develop and learn new skills doing carpentry, using tools and built several pieces of furniture from recycled wood.
A grand open day was arranged, with members of the public, the Mayor and several Merton staff members attending.
The young people’s effort and work was very well received, and they received certificates for taking part.
Next steps and call to action
Some of the young people that attended the work experience programme were successful in obtaining a job in the pop up café.
Articles were in the local press about the success of the event.
We intend to build on opportunities such as these. This includes looking at additional funding that we can work in partnership with Solo Wood to create more projects.
Timescales for the session were tight, if we had more notice we could of advertised the session to more residents.
Useful links and other information
Contact for enquiries
Merton Council Towards Employment Team
Reuse through pre-loved circular ski wear
WhoSki.com set up by Merton residents Sally Warren and Nicola Davenport, is an online peer-to-peer marketplace dedicated to pre-owned ski/snowboard clothing. We exist to keep hard-to-recycle snow wear in active usage for as long as possible, helping reduce its carbon footprint, making skiing more affordable and promoting sustainability in the winter sports sector.
WhoSki.com won the Merton Business Innovation award at the 2022 Merton Best Business Awards.
Ski clothing is almost impossible to recycle due to its composition from numerous layers of technical fabrics and fixings. It is costly, designed to last, struggles to decompose and is likely to be hanging around for 200+ years. Currently, unwanted ski clothes are among those which end up in landfill, are incinerated and are now even found being exported and dumped in the Global South.
We wanted to keep this clothing in active usage, raise awareness of the issue of textiles waste and support environmental campaigns in the winter sports sector.
That is why we created WhoSki.com as an easy-to-use platform where anyone can quickly and simply sell and buy secondhand ski wear. It’s an easy way to pass on ski clothing which is still in good condition but is no longer needed, as well as recoup some of your investment in those piste pieces.
We also host a #SkiGreen Directory which lists businesses, organisations and resorts which provide sustainable services in the winter sports sector.
Our blog provides advice and information on skiing matters including how to travel, what to pack or wear, sustainability and resort information. Look out too for our tips on how best to buy and sell in the WhoSki.com marketplace.
We are active members of organisations including the international Re-Action Collective and the Ellen Macarthur Foundation community.
A leading outdoor apparel specialist estimated the carbon footprint of a ski jacket to be 72.7kg of CO2. Most of this occurs during the production and distribution phase. This means the more that we share and reuse, the more carbon we save through a secondhand marketplace.
In addition to reuse, we donate 25% of our commission on sales to Merton’s award-winning teenage mental health charity, stem4. Supporting a local organisation that does vital work with youngsters is a key part of our philosophy and we are proud to be a corporate partner of stem4.
Next steps and call to action
WhoSki.com will continue to build an engaged community of buyers and sellers across the UK who are actively extending the life of winter sports every time they use our platform. Anyone can sign up for free to list their ski clothes and receive alerts when new items drop on the site. Spread the word if you have friends, colleagues or neighbours who may be interested.
We have plans to extend the range offered via WhoSki.com beyond snow wear, helping keep even more secondhand active gear in circulation and out of landfill 365 days / year, this might include kit for a hiking trip, or for taking part in an expedition
- Keeping clothing in active usage is the best way to reduce it's impact on the environment.
- Make sure re-sale items are clean and in good condition. Use a professional local repair shop if your mending skills are not up to scratch
- Be transparent about wear and tear when selling on your clothes - no one wants a nasty surprise
- Price your items realistically
- Provide plenty of information and good photos when listing items for sale
- You're not just doing good for the environment, it's great to be able to say when someone asks where you got your gear ' It's pre-loved and it was only x£!
Useful links and other information
@WeWhoSki / facebook.com/whoskiLLP
Contact for enquiries
Buildings and energy
A tale of three new builds
An insight into the vastly different energy efficiency levels for homes completed in 2022.
In 2022, two large dwellings were completed on Marryat Road in Wimbledon and the EPCs issued in September. Both achieved a rating of B with a score only 3 points apart. However, in terms of the ambition to build a future-proof decarbonised residential building, the two approaches could not be more different. One maximised solar and installed an expensive ground source heat pump, considered one of the most ecological heating systems. The other installed gas heating and zero solar. The latter consumes nearly double the amount of primary energy per square metre than the other.
The weaknesses of the current EPC system – which attaches a greater importance to energy costs - in assessing environmental performance are readily apparent.
Compared to what is achievable, both houses represent a missed opportunity in the able-to-pay market to build a state-of-the-art ecologically optimised home in the Borough. Is this due to a lack of information on the part of the owners, architects and contractors? It is hard to imagine that at this level of the high-end market, additional costs to improve thermal transmittance and air permeability would have represented a significant challenge to overcome.
Completed in 2022, a 35-unit residential development, the ’Zero SW20’ in Raynes Park – designed at a much lower cost per unit - achieved a superior average thermal wall transmittance result compared to both houses (0.12 W/m2K versus 0.17 and 0.16 respectively).
However, what can be achieved today is highlighted at least on paper. Completed in 2022, 28 Lauriston Road is the current best in class home in Merton, achieving the highest EPC ever recorded in the borough. This house is estimated to achieve negative primary energy consumption on an annual basis.
Three new Wimbledon homes compared
|Annual primary energy consumption in kWh per m2
50 Marryat Road
54 Marryat Road
28 Lauriston Road
Source: EPC certificates
The ‘not quite’ Passivhaus
Number 54, represents the complete reconstruction of an Arts & Crafts house, doubling the size to 738 m², but with the original ambition to reach close to Passivhaus standards.
The building has a ground-source heat pump and a large solar array consisting of 32 panels with an output of 12.8kWp. The structure is timber frame with concrete block outer walls.
- Walls Average thermal transmittance 0.17 W/m²K * Very good
- Roof Average thermal transmittance 0.15 W/m²K ** Good
- Floor Average thermal transmittance 0.12 W/m²K *** Very good
- Windows High performance glazing Very good
- Air permeability measured at 4.5 m³/h.m²**** Good
- Heating Ground source heat pump Poor
- Secondary heating Gas fire N/A
The primary energy use for this property per year is 38 kWh per square metre (kWh/m2).
Primary energy use is a measure of the energy required for lighting, heating and hot water in a property. The calculation includes:
- the efficiency of the property’s heating system
- power station efficiency for electricity
- the energy used to produce the fuel and deliver it to the property
- Walls 0.11
- Roof 0.11
- Floor 0.09
- Air Permeability 0.6 m³
According to the Sustainability report, the dwelling has achieved a 71.9% reduction in CO2 emissions against Part L1A 2010 of the Building Regulations. This meets and exceeds the minimum target of 25% set in Condition 11.
The Energy Rating is B (86 points) with a potential of B (86 points). The date of assessment was 13 September 2022.
The conventional newbuild
Number 50 represents a more conventional newbuild (649 m²) with high quality fabric, but with gas boilers, air conditioning units and no solar PV.
The estimated primary energy consumption per square metre is nearly double the level of number 54.
- Walls Average thermal transmittance 0.16 W/m²K Very good
- Roof Average thermal transmittance 0.11 W/m²K Very good
- Floor Average thermal transmittance 0.12 W/m²K Very good
- Windows High performance glazing Very good
- Air permeability measured at 3.6 m³/h.m² Good
- Heating Gas boiler Good
The primary energy use for this property per year is 73 kWh per square metre (kWh/m2).
The Energy Rating is B (83 points) with a potential of B (85 points with a recommended installation of 2.5 kWp of solar PV). The date of assessment was 4 September 2022.
The real Passsivhaus – negative primary energy consumption
Also completed late last year, this 348 m² Wimbledon dwelling achieved an EPC rating of A with 123 points (date of assessment: 2 November 2022). This appears to the be the highest level ever recorded in Merton. The estimated primary energy use per year is negative.
- Walls Average thermal transmittance 0.17 W/m²K Very good
- Roof Average thermal transmittance 0.06 W/m²K Very good
- Floor Average thermal transmittance 0.11 W/m²K Very good
- Windows High performance glazing Very good
- Air permeability measured at 0.5 m³/h.m² Very good
- Heating ASHP with underfloor heating Very good
Including the roof-top solar system, this house’s energy use per year is -112 kWh per square metre (kWh/m2).
According to the surveyor survey the EPC assessment was conducted based on information provided by the builder and using the SAP standards in force when building regulation approval was received. Under the newer standards, the rating would be lower. However, the same can probably be said for the Marryat Road houses.
NOTE: This brief analysis is based on published EPC data. We are unable to verify whether these surveys have been correctly and consistently carried out.
Contact for enquiries
James Stettler – Volunteer Community Lead for Merton’s Climate Action Group.
Installing a heat pump in an Edwardian semi
Having insulated our 5-bedroom 1907 semi-detached home, upgraded to energy efficient appliances and lighting as well as mounted solar thermal and photovoltaic systems, we took the plunge in 2021 to go all electric, installing an air-source heat pump.
There are many misconceptions, which worried us e.g., heat pumps do not work in old homes, they are complex, expensive to run and noisy.
Following a somewhat challenging one-week installation process, upgrading most of our radiators to larger units and swapping our gas to an electric induction hob, we were able to officially disconnect from the gas network (for which Southern Gas Networks wanted to charge over £1,000) and now only have to pay for electricity.
Has it worked? Using a heat pump requires a change in behaviour as the unit is more efficient when constantly running. Radiators are lukewarm as opposed to hot, but our home stayed warm over the past two winters. No-one has complained about the noise from the outside compressor and our total energy costs are down around 9%*. Our gross annual electricity consumption of around 6,800 kWh comprises a very high demand in December and January. This balances out with how efficient the heat pump is during summer months in providing us with hot water.
Our total electricity bill – before taking into account the benefits from our solar panels – was roughly in line with the price cap for the average UK household of £2,500 last year. This is despite the fact that our home has uninsulated solid brick walls.
* Based on September 2022 energy costs and actual consumption figures for 2022 (the first year of all-electric data) and for 2020, the last full year of combined gas and electric data. 2022 was a relatively cold winter. This is important, as weather plays a significant role in the efficiency and costs.
- Our overall energy bill is down
- Only one energy bill to pay. Annual gas standing charge of around £100 avoided
- Our home emits no carbon and toxic NOx emissions.
- Our indoor air quality has improved with the switch away from gas to electric cooking
- There are still too few installers which understand heat pumps
- Upgrade of most radiators required
- Heat pumps do not provide instant heat as do gas boilers
- The upfront costs remain high and it may only make sense for those needing to replace their gas boiler and while the £5,000 government grant is available (https://www.gov.uk/apply-boiler-upgrade-scheme/what-you-can-get).
Annual electricity demand data (kWh) for 2022 – The first year of all electric data.
- January: 1328 (peak energy consumption)
- February: 820
- March: 611
- April: 309
- May: 143
- June: 96
- July: 65 (lowest energy consumption)
- August: 73
- September: 122
- October: 255
- November: 651
- December: 1313
Contact for enquiries
James Stettler – Volunteer Community Lead for Merton’s Climate Action Group.email@example.com
Building the next generation of energy champions
Energy Matters empowers schools to take climate action and save energy. Supported by Merton Council and Merton’s Climate Action Group the program equips school children to become 'energy champions.’
Through interactive workshops and comprehensive education resources, primary schools in Merton are fostering a sense of responsibility in young students to protect the planet, make a positive impact and take those lessons home to their families.
Children in the UK (United Kingdom) are rightfully worried about climate change. A survey by environmental charity Global Action Plan revealed 3/4 of students say that thinking about climate change makes them anxious. However, 1/2 of teachers feel ill-equipped to deal with student anxiety around climate change.
Schools are entrusted with the task of preparing students for the future they will inherit, ensuring they understand the consequences of climate change and are empowered to take meaningful action. But schools are also grappling with the practical challenge of managing running costs, particularly during a period when energy prices are volatile and fuel poverty is a growing concern. This delicate balance between sustainability, education, and affordability requires innovative solutions.
This is where the Energy Matters programme comes in! Energy Matters is being delivered by the Centre for Sustainable Energy (CSE), a national energy charity, with support from Merton Council and Merton’s Climate Action Group. The goal of Energy Matters is to support schools so that staff and pupils can become ‘energy champions’ - someone who can support their family, friends and the wider community with energy saving tips and help them to reduce their energy bills and cut carbon emissions.
By delivering a series of interactive workshops and providing comprehensive educational resources, CSE has been working closely with teachers and students to build climate awareness, energy-saving habits, and sustainable practices.
The workshops and resources have been specifically designed with teachers to engage students at an age-appropriate level, making complex climate issues accessible and inspiring them to act. Pupils are encouraged to explore the importance of energy conservation, renewable energy sources, and ways to reduce their carbon footprint. Through hands-on activities and thought-provoking discussions, the program helps students connect with environmental issues on a personal level.
Furthermore, Energy Matters has collaborated closely with school staff, offering tailored training on topics like fuel poverty, climate anxiety, and strategies to integrate climate education into the curriculum. By supporting teachers, the program ensures that climate-related discussions are constructive, empowering, and well-equipped to address students' concerns.
Energy Matters has made significant strides in engaging with schools and students across Merton. To date, over 1000 pupils aged 5-11, and more than 100 school staff have benefited from the program.
BeDifferent ‘Eco-Warriors Conference’
25 eco-warriors from multiple primary schools actively participated in creating climate action slogans and posters, the project has ignited a sense of enthusiasm and commitment to effect change within their schools and communities.
Climate adaptation workshop at Perseid Upper School:
The workshop helped pupils to understand more about climate change and the many ways in which we can adapt our areas through changing our energy and transport systems as well as how we can look after wildlife and create more access to green spaces.
“What a wonderful learning experience for them all! And they are excited to share their new knowledge with their peers soon.” Louise Tidley, Careers Leader at Perseid school
Energy workshops and assemblies with Malmesbury and Hillcross Primary Schools:
CSE reached over 600 pupils through a series of workshops specifically on energy to the Year 4 classes at Malmesbury Primary and to Nursery and Year 1 classes at Hillcross Primary.
Workshops and training for school staff:
“We are SO grateful for your support and inset day session a couple of weeks ago, it has really helped us to plan out how we want to start implementing more sustainability teaching across the curriculum. We would highly recommend your support to any schools looking to have a whole school approach in sustainability. Again, thank you for all of your ongoing support, it is really making a difference to our school.”- Almaz Ennis Morris, Nursery Teams Teacher and Eco-Schools Lead, Hillcross Primary
Next Steps and Calls to Action
Building on its successes, the Council, Merton’s Climate Action Group and CSE want to extend the reach of Energy Matters to benefit even more schools in Merton. Schools are encouraged to embrace this opportunity. Not only will it be easier to embed sustainability into their curriculum, but it will inspire a sense of environmental responsibility in their students. It will also aid schools in achieving a Green Flag Award for the school’s positive environmental commitments.
After a successful pilot phase in 2022, Energy Matters is looking to engage with more schools across the borough. In preparation for the next academic year starting in September 2023, CSE have been onboarding schools, delivering workshops, activities and assemblies for pupils and staff, readying them to develop an implementation plan for the new and improved energy education modules.
The Energy Matters project has taught valuable lessons about the significance of empowering students to address climate change and providing comprehensive support to teachers when discussing climate-related topics. It has also highlighted the importance of building sustainability within schools and fostering partnerships with families and communities.
CSE are continuing to support primary schools in Merton into the academic year 2023/24, if you work in a school and would like support from this project, or you would like your child’s school to participate, please get in touch firstname.lastname@example.org
A solar panel story
Are solar panels worthwhile? With the upfront cost, temporary disruption from scaffolding and changing electricity prices, it might be hard to determine. But the savings really can speak for themselves. This anonymised, but real-life example from a local resident shows just how much money solar panels can save you on your energy bills.
Before Mrs Smith’s 12 solar panels (a 3.6kw system) were installed, her semi-detached home was using approximately 5000kWh* of electricity in a typical year. This cost around £750 at the time.
Mrs Smith’s solar panel system was installed in 2018, at a cost of £4000 from the Greater London Authority’s Solar Together Scheme. A group buying scheme that helped participants reduce the cost of solar installations**. The equivalent cost as of January 2024 would be approximately £5,300.
The whole installation included the solar panels, the inverter, cabling connection to the consumer unit or fuseboard, scaffolding, admin costs, and the installer’s profit.
The installation was complete within a couple of weeks. A day for the scaffolding to go up, then after a few days the panels were fitted and connect, then the scaffolding was taken down.
Since being installed, the 12 panels have generated approximately 3,500 kWh of electricity each year, which meant that she only had to pay her electricity supplier for 1,500 kWh of her yearly usage. In the first year alone, this cut her bills from £750 to £250, saving her £500. This meant the payback period (the time it would take to recoup the costs of the original installation) was about 8 years.
She is also likely to make a significant profit. Solar panels have a claimed life of at least 20 years. If electricity prices remained static, she would be making a profit of around £500 a year from year 9 to year 20. That’s more than £5000, which she might consider putting towards the cost of battery storage, a heat pump, or other fabric measures to increase the energy efficiency of her home.
However, since the solar panels were installed, electricity prices have almost doubled. In 2018 she was paying around 15p*** for each kWh. At the end of 2023 the cost was around 27p per kWh. This means that over the course of 2023 alone, she saved almost £1000 on her energy bills, significantly reducing the payback period.
Next steps and call to action
Speaking with her neighbour, Mrs Jones, the savings became clear. Mrs Jones lives in an identical property with a very similar energy use of about 5000 kWh****. Her electricity bill for 2023 was approximately £1350. In contrast, Mrs Smith’s electricity bill was just over £400 (at 27p per kWh).
Although different size properties and lifestyles will alter the energy used and costs, it’s clear that solar can do a good job at reducing your demand on the national grid and your energy bills.
Solar panels need to face towards the sun to get the maximum amount of energy; ideally this means facing as close as possible to southeast, south, or southwest with no shading from trees or buildings.
Some roofs will not be able to accommodate solar panels. This could be for several reasons such as: building orientation, complex roof shapes, shading by trees or other buildings, structural strength, or the historical/architectural sensitivity associated with the building.
The design and manufacture of solar panels has evolved since 2018, with new and improved slimline and low-profile products on the market offering more discreet options.
The installation of solar panels and equipment on residential buildings and land may be 'permitted development' with no need to apply to us for planning permission. There are, however, important limits and conditions, detailed on the Planning Portal, which must be met to benefit from these permitted development rights.
* A kWh is a measure of one unit of energy usage.
**The solar together scheme is no longer being offered by the Greater London Authority, but such group-buying schemes may be worth investigating if they become available.
*** The price per kWh mentioned in this case study does not include the standing charge, which is set by your supplier and added to your energy bill. You are charged this cost every day, regardless of the amount of electricity you use. Currently this is around £120 per year.
****Although Mrs Smith and Mrs Jones’ homes use approximately 5,000kWh of electricity each year, the average for the 86,000 dwellings in Merton is lower, at around 3,500 kWh. For London as a whole, the figure is around 3,350kWh.