The number of large-scale solar farms is set to increase around the country over the next 10 years. As each one is planned, there is always a debate about use of land for renewables vs use of land for farming. While we also advocate for solar arrays on buildings and warehouses, this article explores the potential for a win-win situation where farming takes place underneath, or between the photovoltaic panels. This system is called agrivoltaics, and is more developed in other Western European countries and in the U.S. and East Asia than it is in the U.K.
Sustainable Hockerton commissioned Hockerton Housing Project Trading Limited (HHP) to explore the potential for a localised agrivoltaic pilot project. The research was funded by the Community Energy Fund (Midlands Hub) and HHP worked with agricultural consultant Stephen Briggs of Abacus Organic. We are seeking a lease from local farmer Simon Christy to run a pilot project next to the community wind turbine in Hockerton and use this sample site in our research.
Throughout our research, we have been in communication with Elements Green, who are leading on the public engagement around the 1-gigawatt Great North Road (GNR) Solar Project which is nearly on our doorstep. Our aim was to make them aware of the potential for food growing between the panels in case this can be factored into the GNR solar project.
Agrivoltaics systems can reduce the effect of over-drying and overexposure to sunlight in hot dry climates further south by providing much needed shade. However at our latitude we run the risk of insufficient light levels if crops are over-shielded by photovoltaic panels. Therefore we needed to explore which crops might work under such a system, and what would be the optimal spacing of the panels to allow for efficient solar capture as well as sufficient light for crops and ease of farming between them.
We are grateful to Stephen for his comprehensive and extensive review of different models for agrivoltaics and illustrative examples of how these models have been tested out with different crops in different climatic contexts. We discovered that PV panels are being developed for agricultural use on greenhouses, in open fields, and some are designed to rotate or tilt to allow tractors to pass; capture sunlight from both faces; or be translucent to enable light to pass through them.
Stephen also helped us to conclude what kind of agrivoltaics system and which crops might be best suited to our sample plot of land in Hockerton. Leafy greens or berries showed most potential.
These findings are available for download in Stephen Briggs’ report.
We have also produced a reference list of academic research on agrivoltaics, and an overview of pilot projects happening overseas and in the UK.
While there is a growing body of research on Big-Ag agrivoltaics projects, involving heavy inputs and large machinery, what we would be doing on the land in Hockerton would be much smaller scale and more suited to a market garden scale of agriculture. Small-scale food growers are often limited by the challenge of accessing land.
We noticed that while some of the bigger land owners are agreeing to lease their land to the Great North Road Solar Project (and therefore giving up on farming this land), there might be an opportunity for smaller-scale food growers to work the land between the panels without big machinery and using less environmentally impactful farming methods. Given that the margins are narrow, especially for tenant farmers, we modelled at what scale this could be feasible and which crops would suit such a system. Our findings are available here.
In the next phase of our work, we will be working with local farmer and landowner Simon Christy to seek planning permission to install a solar array on the fields next to our community wind turbine, and to design a community allotment or locally-owned soft fruit enterprise to run between the panels. Like the turbine, the plan would be for the community to buy shares in the array and for its benefits to feed into our village sustainability grant which is available year on year to each household to make their homes and gardens greener. We might also find we are eating more berries in our village!
For more information about our research, please get in touch.
Last week we had two work experience students with us. They have written up their experience in two journals which are available here and here. It was great having the two students who worked hard and achieved a lot outside in our organic growing area.
It is great to see young people being so enthusiastic about one of the most important aspects of our lives – food growing. We wish them every success in their future endeavours. Regenerative agriculture involving people within nature based solutions is key to our sustainable future.
Describing Howgate Close as eco-homes is to understate its performance. Most notable are these five 2-bed homes and four 1-bed homes, all operate beyond zero carbon. They are on the outskirts of Eakring a rural village near Southwell/Ollerton in Nottinghamshire.
Design Origin Of Howgate’s Eco Homes
Hockerton Housing Project (HHP) design for the Eakring Eco Homes project, uses the design principles applied at HHP. The HHP’s Architects, are Professors Brenda and Robert Vale, The Vale’s. Check out HHP building standards and FAQ
These design principles were first published in The Vale’s 1975 book, ‘The Autonomous House’, and implemented at their former Southwell home, ‘The New Autonomous House’. It’s worth noting, that over 40 years later, The Vale’s design principles have been applied less than 7 miles from The Vale’s former home. To their credit, on July 27th, 1994, their Southwell home became the UK’s first dwelling to export photovoltaic-generated renewable energy to the National Grid.
“What makes the Eakring (Eco Homes) project truly exceptional is the unique combined experience of the HHP design team. A team that has twenty-four years of designing, constructing, maintaining, and servicing the UK’s largest collection of autonomous earth-sheltered buildings.”
Final Assessment Report
Compliance with Condition 12
Newark & Sherwood District Council
July 2019
Prior to construction, Dr Parsons undertook technical adjustments to the approved design raising the EPC Rating from a SAP Rating of 84 to 143.
Design Principles
Introduced in detail below, are Howgate’s design principles. Also provided is third-party verification of their performance via the Standard Assessment Procedure (SAP).
Passive Solar Design Techniques
Intrinsic to the buildings performance, is the utilisation of the passive solar design principles pioneered by The Vale’s. HHP’s application of these techniques include;
- Southerly orientation
- High thermal mass superstructure
- Super-insulated envelope
- Renewable energy
- Solid external walls (no cavities)
- Floating slab (no foundations)
- Contiguous external insulated envelope (no cold bridging)
- Triple glazing
- Reduced reliance on mechanical ventilation
- Externally located window and door jambs (improved Psi values)Hot water demand at source (no stored hot water)
- Back-up electric underfloor heating
For the record, Dr. Parsons first conceived the idea of his replicable development solution in 2015. His intention was to resolve several local issues that have both national and global significance. He observed, a shortage of local affordable rural homes and a progressively diminishing bio-diversity in the surrounding Nottinghamshire countryside.
Eradication of the risk of fuel poverty was a priority for Dr Parsons while nurturing a conducive neighbourhood that mitigates greenhouse gas emissions. He succeeded in his aims. Additional aspects of the model comprise, taking 10 acres out of intensive arable farming, constructs nine homes for rent and installs 60KW’s of solar panels (142 panels) He’s also planting 10,000 trees and hedgerow, creating wildflower meadows, scrubland, and a wetland.
“..an opportunity to address some of society’s most pressing issues: rural housing shortages, climate change, soil restoration, carbon sequestration, biodiversity, water management, and community cohesiveness.”
Dr. Parsons
(as reported in CLA Magazine)
Furthermore, this Case Study demonstrates these eco homes are a viable alternative to conventional social housing and affordable homes. Equally important, they also deliver a new level of energy efficiency and carbon mitigation associated with Eco Homes or Zero Carbon Homes.
“Howgate Close epitomises the aims of the Councils De-Carbonisation Plan and would encourage more of the same.”
John Robinson
(CEO Newark & Sherwood District Council)
2023
Eco Homes Provide An Acceptable Return On Investment (ROI)
In evaluating the viability of Dr. Parsons model, it’s useful to refer to Howgate’s Return On Investment (ROI). Usefully, the model’s efficiency of investment is assessed on several levels; economic, carbon emissions, social and community integration.
First, at an economic level, Howgate achieves a 5% ROI with a 20-year payback period (Amortisation) using conventional financial performance measures.
Second, carbon emissions provide another performance metric with national and global implications. According to the nine Energy Performance Certificates (EPC’s), the homes collectively mitigate 16 tonnes of carbon emissions each year from their renewable energy generation. Adding a further 9 tonnes annually of carbon sequestration annually is the re-wilding of 9 acres. Consequently, the site’s Biodiversity Net Gain (BNG) will likely exceed Natural England’s soon-to-be mandatory minimum 10% benchmark.
Furthermore, full financial benefits of the 60KW’s of roof-mounted photovoltaics are given to Howgate’s residents. Consequently, first 10 months’ energy bills, average less than £1 per day across all nine homes. 54pence/day as of 12th July 2023.
It should be noted that Dr Parsons investment returns at Howgate Close compare favourably to their financial cost.
Luke Jackson Eagle Building Specialists– Builder of Howgate Close
It was interesting to catch up with Luke to see how he found the challenge of the build we will be doing a more in-depth blog with Luke next, so this is just a taster.
“The general technology wasn’t a challenge as I was familiar with Hockerton Housing Project, it excited me. The lads working for me were far more sceptical it wasn’t until a winters day when the buildings were airtight that they started to appreciate how warm they were. In the end the proof was in the pudding as they say. In all honesty even I didn’t quite realise how efficient they would be!”
An opportunity has arisen to rent or buy a 2 bedroom super energy efficient apartment at the top of the Hockerton Housing Project. This apartment is part of a wider development of similar properties. It has very good mobility access both externally and internally with wide internal doorways. It has parking for 2 vehicles. Rent is £925 pcm.
The property consists of entrance/utility room, internal hallway, main bedroom, bed/work room, kitchen/diner/lounge/ garden room/sunspace. It is connected to mains and broadband. Access to private woodland 1- mile circular walk from the property and to secure cycle shed shared with other residents.
For more information please email contact@hockertonhousingproject.org.uk or telephone 01636 816902.
I am pleased to announce that in conjunction with Sustainable Hockerton we are now working with students who are solving the climate crisis on a regular basis.
We often get requests for help with dissertation projects in the form of requests to answer questionnaires or taking part in interviews. Sustainable Hockerton has agreed to fund some time to enable this support to occur. This is a limited resource so there will be a queuing system. In exchange for our input students will be requested to supply their finished work for publication on our website so that others can share their insights.
The climate crisis needs all hands-on deck to create a new way of living that does not destroy our atmosphere and decimate the wonderful species around us. Academic learning on how we do this is a critical step. Action based on good knowledge and understanding is now urgent for all of us.
As an example, Ellen Potter a student from the University of Sheffield ask us to be interviewed on the a topic she was assigned to written on. The title was How Do Cooperatives Put into Practice New Ecological Relations? HHP is a cooperative acting as a catalyst for change towards sustainable development and Sustainable Hockerton is a cooperative society developing community owned renewables and promoting sustainable living, so we were able to help her with this. Her report can be found here and is a good example of the in depth thinking necessary to start solving the problems we face. She has produced a thoughtful and well-argued case for cooperation and its ability to value what is not on a typical business balance sheet. working with students is very rewarding. This fits well with Dr Geeta Lakshmi and my work on community, value and power. This latter work may help facilitate financiers to understand arithmetically the wider value of capital within organisations. Link to paper and here.
How can better ecological relations be put into practice? We have been working on this. Here is a practical live project. Located at the western gateway to the Nottinghamshire village of Eakring, the site’s 10 acres have been taken out of agriculture production to provide nine homes within a managed wildlife area.
Eakring farmer and retired GP, Dr Chris Parsons, describes his project, Howgate Close as an opportunity to address some of society’s most pressing issues: rural housing shortage, climate change, soil restoration, carbon sequestration, biodiversity, water management and purification and community cohesiveness.
Howgate Close’s main objective is to provide local people who’ve been priced out of home-ownership, with high quality rented homes, offering low running costs, low maintenance and access to the open countryside. Also underway are plans to benefit the wider community with permissive access rights to part of the wood pasture.
Dr Parsons engaged the local ‘Hockerton Housing Project’ (HHP) to design ‘Howgate Close’ formally Eakring Eco Houses, using the design principles applied at HHP by its Architects, Professor’s Brenda and Robert Vale. Jerry Harrall is now also closely involved and writes more about the project here. It has an impressive SAP score you can see above, 142A.
To conclude. As Ellen says “humans and nature are not separate entities”.
This is something we need to heed and act upon.
