Project Overview

Llancarfan Primary School is considered the first school in Wales designed to be net zero carbon for operational energy when in-use. Some key elements of the project include:

  • Positive contribution to the Welsh built environment, meeting the needs of today without compromising future generations
  • Demonstrating the use of PV with Battery Storage ‘on site’
  • A detailed performance in use model has been established and a live ‘digital twin’ monitoring system, Performing Places, will be used to monitor operational and maintenance factors during the first two years of occupation
  • Behavioural change as a key element of post occupancy to ensure the site is operated as intended, to achieve a zero carbon (on-site) school

Operational energy assessment modelled under CIBSE TM54, demonstrating NZC for operational energy, and a breakdown of annual energy consumption compared to a standardised model demonstrated an 11% heating reduction and 17% hot water reduction. With air source heat pumps (ASHP’s) and improved building fabric, annual consumption due to heating and hot water has reduced significantly, meaning energy consumption is more influenced by other uses e.g. equipment and catering. The team reduced energy demand and maximised renewables (PV 82kWp) with battery storage without the need for any off-site offsetting, thereby minimising the school’s environmental impact.

Key Sustainability Objectives/outcomes

  • Embedded a tailored Social Value Plan, integrating principles of The Wellbeing of Future Generations Act 2015 to create long-lasting, positive change within the local community. The plan identified local challenges/priorities and integrated social value activities within the delivery to maximise value including 4 new employment opportunities, 51 STEM engagements, a 100% Welsh labour force and 83% Welsh sub-contractors.
  • Project Bank Account, enabling all supply-chain partners to be paid from a single pot without payments having to cascade through different tiers.
  • Biodiversity across the site will be significantly enhanced with wildflower meadows, raised planters, native species of flora/fauna and a Sustainable Drainage System (SuDS).
  • Optimised standardised model to achieve NZC, maximising renewables and energy efficient technology e.g. ASHP’s meet hot water/heating requirements.
  • Third party verification by K2N (client lead) and by ClearLead Consulting (ISG lead) to ensure that operational targets are predicted, which will be reported to the Welsh Government for 5 years.

Notable Approaches/solutions

The approach to achieving a net zero carbon building for operational energy was based on UKGBC’s Net Zero Carbon Buildings Framework Definition:

  1. Reduce operational energy use: Building fabric at Llancarfan was improved, as well as catering equipment, plugged in equipment and low carbon heating. The Performing Places System will also monitor operational parameters and maintenance effectiveness.
  2. Increase renewable energy sources: PV installation on roofs was maximised (82kWp).
  3. Zero carbon balance: VoG’s aspiration is to achieve net zero carbon – operational on-site without the use of offsite renewables such as power purchase agreements (PPA’s) or carbon offsets.

Measurement and verification: annual energy use and renewable energy generation onsite must be reported and independently verified in-use each year for the first five years to the Welsh Government as a pilot scheme. At Llancarfan, operational energy performance is evaluated to verify net zero carbon and determine energy breakdown for future evaluation

Lessons Learnt

By openly sharing data, the Net-Zero Carbon Journey report has been presented to the Welsh Government Cross Department Group and shared with Constructing Excellence Wales to establish best practice.

Post completion, in-use data will continue to be shared in an open and transparent manner through annual reports and post occupancy surveys.

  • Organisational culture: Developed and shared tailored teaching resource, curriculum aligned, enhancing education.
  • High design quality: Published/shared detailed specification advocating NZC in future projects, transferring lessons learnt, driving continuous improvement within construction and cross-sector and supporting the Low Carbon Plan.
  • Used OneClick LCA: Modelling design and determining embodied carbon for development, providing real-time data, making efficient whole life decisions on material use.
  • Tackling the climate emergency: A pathfinder scheme developed through industry collaboration, with transferability of lessons learnt to educate and influence the infrastructure of the future, protecting the environment and achieving Welsh Government initiative targets.
  • NZC achievement commences from design throughout building lifecycle; it is important to engage and educate building users throughout the project lifecycle to optimise operational building performance. This is achieved through a tailored Soft Landings Strategy, including site tours to support familiarisation and video training, to ensure knowledge is retained to optimise building performance throughout its operational lifecycle.