Situation

Hammerson’s sustainability vision is to create retail destinations that deliver net positive impacts socially, economically and environmentally.  As part of this, they have set a target to be Net Positive in carbon, resource use, water and socio-economic impacts by 2030.

Hammerson completed the first phase of Elliott’s Field shopping park in Rugby in 2015, achieving BREEAM Excellent. The second phase offered Hammerson the opportunity to push the boundaries further, contributing to the company’s commitment to become Net Positive and marking a significant milestone in its carbon objectives.

Hammerson set two key sustainability targets for the scheme at the outset:

• BREEAM Outstanding, the highest accreditation, achieved by less than 1% of new, non-domestic buildings, the highest retail score in the UK in 2017 and a world first for a shopping park.
• Zero carbon for all regulated energy usage, with energy efficiency measures reducing carbon emissions and on-site renewable sources offsetting the remaining emissions.

The team included Piper Whitlock as architect, Silcock Dawson as building services engineer and Hoare Lea as technical advisor and sustainability consultant.

Actions

Initiatives that contributed to zero carbon include:

• Passive design features to minimise energy demands, including high performance fabric and glazing, with optimised U-values: roof (0.16 W/m²K), walls (0.18 W/m²K), exposed floor (0.22 W/m²K), glazing (1.6 W/m²K).
• Efficient building services to further reduce energy use, including high efficiency LED lighting in all external areas, operated through both a time switch and daylight sensors.
• Agreements with retailers to fit out units with energy efficient systems. Limiting parameters in heads of terms included variable refrigerant flow (VRF) heating and cooling systems with a 4.5 minimum seasonal coefficient of performance (SCOP) and a 6.5 minimum cooling seasonal energy efficiency ratio (SEER), along with high efficiency mechanical ventilation heat recovery (MVHR) systems and limiting values for lighting loads.
• 775kW PV array on the rooftop to offset all remaining regulated emissions.

Materials and waste examples:

• 100% of aggregates from recycled sources, including foundations, pipe bedding and capping.
• 91% of materials for the shell achieved a BRE Green Guide to Specification rating of A or above.
• Changes made so a substantial majority of materials came from manufacturers with ISO 14001, BES 6001 or FSC certification (80% of entries in materials register), including high volume elements such as the structural steel frame, significant portions of the external walls, rainscreen cladding and louvres from FSC sources.
• Design variations to reduce embodied carbon, including replacing steel and aluminium with timber, acting as a carbon sink.
• Limited construction waste generated (1.5m³ per 100m² of floor area, versus 1.6m³ BREEAM benchmark) and 98% of all waste diverted from landfill, achieving all BREEAM waste credits including innovation.

Additional sustainability initiatives implemented included:

• Rainwater harvesting for flushing toilets in the amenity block and Starbucks.
• 36 cycle spaces, along with cycle paths linking to local cycle routes.
• Amenity block with 12 lockers and two showers to encourage staff to cycle and run to work.
• Creation of a canal bankside nature area for wildlife, protecting wild orchids and providing priority habitats for wild butterfly species.
• Features to enhance ecological value, including over 22,000 new plants, bird boxes, bat boxes and log pile habitats for invertebrates.
• Educational programme with Warwickshire Wildlife Trust, to promote wildlife awareness on the River Swift running through Elliott’s Field, including interpretation boards and signed walking trails to the Oxford Canal.

Financials

• The project, inclusive of all sustainability initiatives outlined above, exceeded Hammerson’s internal hurdle return rates, meaning the scheme was both profitable and sustainable.
• The PV alone will save retailers an estimated £55,000 annually, with further savings expected from the enhanced energy efficient fit-outs.
• Savings will be verified by comparing design predictions with operational performance data, in conjunction with occupiers.

Benefits

• High quality environment for shoppers inside and outdoors.
• Energy and CO₂ savings for retailers through efficient design.
• Secure, cost effective access to electricity from the PV array for retailers.
• 300 tonnes of CO₂ saved annually through the PV array.
• Contributing to Hammerson’s commitment to become Net Positive by 2030.
• Building relationships with occupiers from the outset and supporting their sustainability goals.