Howgate Close – The Full Story

Many factors currently impact the building industry, but seldom is sustainability and self sufficiency at the top of the pyramid. The Howgate Close project flips this precedent on its head by providing a new style of communal living. In this case study, we will examine what the project means for our future, and how EWI Pro products contributed to the delivery of a fossil fuel free community.

The concept

When examining the ideal staging ground for the project, the small parish of Eakring in the Newark and Sherwood district of Nottinghamshire stood out. Eakring has a storied past when it comes to oil extraction. Eakring operated one of Britain’s largest inland oil fields throughout its 27 year operative history. The memory of the past is immortalised with 6 restored ‘donkeys’ littering the Eakring area.

The civil parish is firmly on its way to decarbonisation; three wind turbines have been erected, a 12mW solar farm has been built, and over 250mW of roof mounted photovoltaics are installed. A crucial issue with becoming self-sufficient when considering energy supply is the current extortionate costs of energy storage.

The architects behind the project are the renowned autonomous living experts, Professors Brenda and Robert Vale. Their Hockerton Housing Project has now been in operation for 24 years, and adheres to the mission statement:

“The Hockerton Housing Project is the UK’s first earth-sheltered self-sufficient ecological housing development.  The residents of the five houses generate their own clean energy, harvest their own water and recycle waste materials, causing no pollution or CO2 emissions.  The houses are still amongst the most energy efficient purpose-built dwellings in Europe.”

The brains trust behind the project also include Dr Jerry Harrall who specialises exclusively in architectural design for fossil-fuel-free designs fit for a post-hydrocarbon era. Despite the experience that was behind this project, gaining planning permission was taxing. Eco project designs must display something particularly innovative to sway the determining council to supply planning and building permission.

The four principles of passive solar design

At its core, the Howgate Close project puts sound scientific ideals into practice. Passive solar design relies on utilising the climate, the building’s location, and materials to minimise energy usage, summarised in the following four principles:

• Southerly building orientation – optimising solar gains for heating, lighting and ventilation
• Selective glazing locations – maximising glazing on the south elevation for solar gains, reducing glazing to the north, east and west to reduce heat loss
• High thermal mass structure – using dense building materials to act as a large storage radiator, stabilising internal air temperatures
• Super-insulation envelope – which reduces the rate of heat loss from the buildings while increasing their capacity for retaining stored heat.

The principles themselves are millennia old, and well practised throughout history. Our ancestors often occupied southern facing caves to ensure the maximum thermal comfort. With these principles in mind, Howgate Close delivers spectacularly. Based on the fossil fuel free operation, and renewable energy provisions, the 9 house settlement currently has the theoretical capabilities to supply another settlement of the same size with the required energy. The energy provisions include 60KW of roof mounted photovoltaic cells. A truly remarkable renewable energy achievement.

EWI Pro contribution

The major contribution to this project on our side was the supply of materials to form the super-insulation envelope. Achieving passive house status is crucial to an effective energy efficiency strategy, and insulation forms the most important element. Ultimately, you are trying to eliminate thermal bridges throughout the whole construction. The following products were utilised to effectively deliver this envelope that ensures that the ambient temperature of the structure remains at 23 degrees Centigrade:

• 230mm of EPS
• EWI – 225 Premium Basecoat
• Fibreglass orange mesh
• EWI – 076 in 20001 Premium Bio Silicone Render

You can find all these products here. The installation of the insulation followed our simple build up system guides.

What else does this project achieve?

Freedom from fossil fuel use is undoubtedly a desirable standard for all projects, but one may question how a large-scale project on farmland affects biodiversity. A process often championed in conservation is rewilding. In essence, rewilding is a form of ecological restoration which aims to recreate areas that correspond to their natural uncultivated state. This process usually requires human interference. The Howgate Close project under Dr Chris Parsons promotes the process of rewilding a 10 acre area, including:

• 10,000 trees, hedgerow, and wild flowers
• A wildlife pond treating effluent discharge

Based on the material composition of the whole build, it is expected to achieve a SAP score of 142A which places it into the highest of brackets for energy efficiency. Only 0.01% of properties registered in the UK are reaching that standard. The newly formed community at Howgate Close also gains access to woodland pasture meadows, as part of the rewilding project. The architects also project that the rewilding part of the project, in conjunction with the housing being built-in to the environment, will result in a net biodiversity gain.

The projects have certainly had a marked influence on building practices. Hayfield Avenue, and the recently approved Hayfield Lodge in Cambridgeshire, are both zero carbon-ready home schemes. The fossil fuel free status will be achieved by a combination of air source heat pumps, solar PV panels, energy-efficient underfloor heating, and EV charging points.

Furthermore, the UK Government has recently confirmed a £1.14 billion devolution deal for the East Midlands. Derbyshire, Nottinghamshire, Derby, and Nottingham will have a new regional mayor to effectively deliver local solutions to the energy crisis. The newly combined authority can focus on working towards Net Zero with cleaner air and new low carbon homes, backed by the installation of external wall insulation.

Final thoughts

All portents in relation to energy costs and our energy efficiency are bleak. The 19 million homes with an EPC rating of C are due to pay £748 more annually than houses in higher brackets. Affordability is certainly the primary barrier to any improvements with fossil fuel free and zero carbon aims. Around 34% of those surveyed are not able to afford the upfront costs. The outlook is bleak as close to 85% of registered homes are rated C or worse. However, ONS analysis projects that improving energy efficiency from band E to C can yield average savings of £1,719. Perhaps the solutions lie overseas. The UK Government grants are mostly unknown and under-utilised, but the French initiative MaPrimeRénov’ aims to provide funding for 700,000 renovations.

A constant issue when discussing renewables is the space they will take up. During the Conservative leadership race, both Liz Truss and Rishi Sunak denounced the need for more photovoltaics, as farmland should be reserved for food production. The Energy Monitor discusses how this process can solve both the issues of energy and food shortages. However, there is also a solution to this. Photovoltaic farming has the potential to combine grazing ground or farmland with energy production. You can read more about this process here.

– Details of project from http://drharrall.com/blog/