The Welsh Government’s Department for Economy Science & Transport is on a drive to create better business facilities in more rural parts of Wales. As part of this, it is working with Carmarthenshire County Council on the gateway Cross Hands East Strategic Employment Site, located on land to the east of the existing Cross Hands Business Park. Building on previous Passivhaus schools and BREEAM Excellent sustainability standards, this team saw the potential for Cross Hands to be an exemplar for other future low carbon workspaces. The project aims to achieve net carbon zero in use standard and alignment to the RIBA 2030 Climate Challenge for operational energy using active building systems.

Many contractors are not used to being asked for this approach; so they tend to focus on compliance rather than excellence in use performance when it comes to sustainability. As a result, knowledge about active building technologies, where assets generate and store renewable electricity to meet their own needs and intelligently redistribute the surplus to other buildings, electric vehicles, and back into the grid, was low amongst the partners being given the challenge of setting a precedent with this project.

As Cross Hands progresses beyond phase 1, it will be a model for low carbon business developments across Wales. The active building and low carbon specifications being developed for this project can be used elsewhere, creating a blueprint for future workplaces and encouraging the uptake of active buildings. To demonstrate the demand for low carbon workspaces, Carmarthenshire Council is also working with developers to ensure affordable rates for business residents. The buildings being constructed are also hybrid – offering both office and industrial spaces – allowing them to meet the different or blended needs of many fast-growing businesses today.  The programme is due for completion of RIBA stage 4, having worked hard to ensure smart power and heating systems, and comprehensive metering and monitoring systems, are properly assessed and incorporated into the detailed designs.

Carmarthenshire County Council and the Welsh Government brought in the Active Building Centre (ABC), a centre of excellence working to accelerate the UK’s drive towards net-zero carbon by transforming the way buildings are powered and heated.

Working more innovatively required a sharing of the risk involved. The Welsh government, Carmarthenshire County Council and the ABC established a contract that agreed shared liability and a commitment to collaboration. With this in place, the Active Building Centre Research and Technology Organisation (ABC RTO) began running a series of workshops with contractors to help move the sustainability of the design beyond compliance and towards excellence in both construction and operation.

When there are knowledge gaps between partners in a project, innovative collaboration is difficult, as there is little appetite for risk within the programme for the works (development) to be completed. 

To de-risk this new active building approach, the ABC is advocating the digital replication of the scheme in operation to test alignment of client expectations and design requirements. This allows the design to be amended before construction. In addition, a comprehensive monitoring system will be installed, measuring ground-truth actual performance against that predicted for the project, with a view to further reducing any performance gaps.

The ABC worked on the creative design solutions to make Cross Hands an exemplar of low carbon development, offering strategic direction on how the assets could deliver whole life value, as well as operational and practical advice on carbon specifications, such as appointing an active building clerk of works.  A RIBA 2030 Climate Challenge target for operational energy usage has been set for the design and build phase of development. Active building overlay to RIBA stages is part of the pathfinder status of this project and aligns with the ABC’s philosophy that you need to understand the desired behaviour of a building and processes involved from the outset. By following ABC Design technical and design principles, the team have taken a 'fabric-first' approach, achieving very good insulation values for the building envelope; whilst remaining within the target budget identified in the cost plan. This has enabled a complete re-think of the heating strategy, moving to a low carbon system that will ensure comfort for occupants and reduce operating costs for tenants. Once marketable unit sizes were defined, working with estates representatives of Carmarthenshire County Council, the building and systems designs were created to allow multiple sizes to be accommodated on the plot. This enables fledgling businesses to grow on-site, without the considerable expense of relocation. The proposed design also provides capabilities for electric vehicle charging onsite to support the decarbonisation of transport.

The Cross Hands project involves a multi-disciplinary design team including commercial architectural practice Stride Treglown, specialists Clarke Architects, and the SPECIFIC Innovation and Knowledge Centre. ABC are working closely with Western Power Distribution to deploy a novel high capacity transformer on the site, which will allow intelligent grid energy demand flexibility further reducing the carbon footprint of the scheme in operation. 

• Active Building Centre
• Carmarthenshire County Council
• Clarke Architects
• SPECIFIC-IKC
• Stride Treglown
• Welsh Government

The Active Building Centre (ABC) advised on fabrics and thermal envelopes, as well as assisting the building services engineer with regard to the solar PV strategy - whether the generating capacity on a tenant's roof feeds directly to them, or centrally to the landlord for distribution to reduce utility bills across the site's occupants. In addition, ABC Design Principles dictate that economies of scale and energy flexibility are improved with the installation of energy and heat microgrids linking the energy users on the site. Again, the ABC is providing advice to the engineering team on how best to optimise these systems. The proposed design also provides capabilities for electric vehicle charging onsite to support the decarbonisation of transport. The ABC is funded by the Transforming Construction Challenge.

As Cross Hands progresses beyond phase 1, it will be a model for low carbon developments across Wales. The active building and low carbon specifications being developed can be used elsewhere, helping to standardise future approaches and encourage the uptake of active buildings.

Working more innovatively required a sharing of the risk involved in trying new things. The Welsh government, Carmarthenshire County Council and ABC established a contract that agreed shared liability and a commitment to collaboration.

To de-risk this novel systems approach, ABC is digitally replicating the proposals to test them for latent weakness. This allows the design to be amended before construction. In addition, a comprehensive monitoring system will be installed, measuring the ground-truth actual performance against that predicted for the project, with a view to further reducing any performance gaps.

The starting point for designing an Active Building is to follow the 6 core Active Building Centre principles:

1. Building fabric and passive design – An integrated engineering and architecture design approach that considers orientation and massing, fabric efficiency, natural daylighting and natural ventilation to deliver occupant comfort with low energy.
2. Energy efficient systems – Intelligently controlled and energy efficient systems used to minimise loads such as heating, ventilation and air conditioning (HVAC), lighting, and vertical transportation. Also, predictive control strategies are optimised and refined using data capture via inbuilt monitoring and standard naming schemas.
3. On-site renewable energy generation – Renewable energy generation to be incorporated where appropriate. Renewable technologies should be selected holistically, given site conditions and building load profiles.
4. Energy storage – Thermal and electrical storage should be considered to mitigate peak demand, reduce the requirement to oversize systems, and enable greater control.
5. Electric vehicle integration – Where appropriate active buildings integrate electric vehicle charging. As technology develops, bi-directional charging will allow electric vehicles to store energy and deliver it to buildings when required.
6. Intelligently manage integration with micro-grids and national energy networks – In addition to intelligent controls, active buildings manage their interaction with wider energy networks. For example, demand side response, load shifting & predictive control methods.

Active Energy
The active building and low carbon specifications being developed for Cross Hands can be used elsewhere, creating a blueprint for future workplaces and encouraging the uptake of active buildings.