UK-GBC ON SITE LEARNING CASE STUDY - ONE BRIGHTON

Transcription

1 UK-GBC ON SITE LEARNING CASE STUDY - ONE BRIGHTON INTRODUCTION In November 2015 UK-GBC (with Bioregional and Feilden Clegg Bradley Studios) took a group of our members around BioRegional s exemplar sustainable development, One Brighton. This 172 apartment eco complex with café, community space and offices in the heart of Brighton, was created by applying the principles of One Planet Living to a large residential development but also using the sustainability learnings from the BedZed eco-village, one of the first sustainable residential developments in the UK. With five years worth of post occupancy evaluation (POE) data and a community-led energy services company in operation, this project provided an interesting and interactive tour. This case study summarises the project from the perspectives of the teams involved in delivering the development and highlights the lessons learned that can help inform future projects in progressing sustainable building and behaviours. PROJECT HIGHLIGHTS A 67% reduction in operational carbon emissions over the UK s existing housing stock (calculated at operation stage) with good potential to achieve a reduction of 89% or more by 2020, approaching the (near) Zero Carbon target for One Planet Communities Establishment of a community owned Energy Services Company (ESCO) to bulk purchase guaranteed green electricity (Renewable Energy Guarantee of Origin) On a whole carbon lifecycle assessment basis (operational and embodied impacts), One Brighton is achieving a 60% carbon reduction over existing housing stock Pouring of greenest concrete frame in UK post- tensioned concrete comprising 50% ground granulated blast furnace slag (GGBS) and use of 100% secondary aggregates First major use of low temperature fired clay block in the UK Two-thirds of residents changing to more pro- environmental behaviour based on design and information Inspired Brighton and Hove City council and its residents and businesses to become a One Planet City 1

2 PROJECT DETAILS Location: New England Quarter, Brighton, East Sussex Ratings: BRE Eco Homes 79.9% post construction, BREEAM Excellent for all commercial areas Completed: 2010 Developer/client: Bioregional Quintain Ltd and Crest Nicholson PLC Architect: Feilden Clegg Bradley Studios Principal Contractor: Denne Construction (Now owned by Bouygues Development UK) Community Energy Services Company: One Brighton Energy Services ONE PLANET LIVING From the very beginning the vision for developing One Brighton was to create a place which would enable residents to lead sustainable lifestyles. One Planet Living principles (developed by Bioregional) were used throughout the project to guide design and delivery and formed the sustainable framework to develop the strategy for the whole project. Fig 1, the 10 guiding principles of One Planet Living SUSTAINABILITY ACTION PLAN In order to deliver against the One Planet Living principles, a sustainability action plan was created (which was later renamed the One Planet Action Plan). To ensure the best sustainable outcomes possible from using One Planet Living principles, profiles of imaginary residents were used to drive design for sustainable lifestyles. To view the full One Planet Action Plan including targets set and profiles of the imaginary residents click here.

3 DESIGN AND CONSTRUCTION Using a comprehensive brief and the One Planet Living Action Plan, the design team focused on maximising the impact that the OPL principles could create focusing on: ZERO CARBON Green power for construction (with Green generators on-site) Generating zero carbon energy (biomass fuelled boiler, photovoltaic panels) ZERO WASTE Facilities and services to make recycling easy Construction waste to be less than 0.2% of construction cost SUSTAINABLE AND LOCAL FOOD Design in opportunities for on-site food growing Space for locally sourced food box delivery in lobby NATURAL HABITATS AND WILDLIFE Bird and bat boxes Brown roofs Habitats protected and enhanced EQUITY AND LOCAL ECONOMY 32% social housing with no compromise on space allocation compared to privately owned apartments All homes designed in accordance with the Lifetime Homes standard HEALTH AND HAPPINESS Minimise noise pollution Access to daylight Indoor air quality A sustainability integrator was appointed to oversee the integration of sustainability throughout the construction of the project. They ensured that contractors and subcontractors all understood the reasons behind the ethos of the project and their role in achieving the sustainability goals through inductions and workshops and monitoring progress on site. This approach was based on changing the culture of all those working on the project rather than just managing sustainability outcomes. SUSTAINABLE MATERIALS The criteria for material selection was based on a number of factors including embodied energy and water, recycled content, recyclability at end of life and affordability. One of the key elements of the buildings, the concrete frame, which represents a significant part of the whole in terms of volume, weight, cost, embodied energy and CO2 emissions received special attention during material selection. The concrete frame of the buildings was one of the greenest concrete mixes produced with a minimum of 50% GGBS (ground granulated blast-furnace slag) and 100% recycled aggregate 3

4 integrated into the mix. Finding a supplier that could deliver on this ambitious target did prove difficult as many would not supply the mix or would charge a very high premium. After negotiating a cost premium of less than 2%, CEMEX were selected and the finished product was shipped by barge to the nearby harbour. For the external walls the project used a low temperature fired clay blocks with highly insulating honeycomb structure. This system has low embodied energy and carbon emissions compared to concrete block alternatives and improves indoor air quality through the breathability of the walls. In order to use this system subcontractors required training. Once the correct skills were in place to install the brickwork the construction of the external walls was much quicker than traditional methods. One of the main challenges faced in material selection was finding locally sourced material. Some elements of the build, such as glazing and external timber had to be imported from Europe as UK manufacturers could not meet the level of quality or environmental performance required. SUSTAINABLE ENERGY The energy strategy for this project had ambitious targets with an aim to be Zero Carbon by Various strategies were employed to achieve this, focusing on design elements such as triple glazing, mechanical ventilation with heat recovery, 100% energy efficient fittings and the creation of an energy services company to provide and manage the energy. The One Brighton Energy Services Ltd. (OBES) company was set up to centrally manage the heating energy via a biomass boiler and to manage the incoming renewable energy source for the remaining supplies required. The company is a not-for-profit company that is communally owned by the leaseholders in the building and their involvement is written into the lease for each apartment to ensure they remain the sole provider of energy to the building. Through using this method of energy supply the current average annual bill per apartment is 900pa, consumption is well below that of a typical new build of the same size (approximately 30% less than the average 2 bed apartment). One of the challenges faced by OBES was that the original biomass boiler has not functioned

5 consistently as required and they have often had to rely on the back up boiler to provide heat. As the company is not-for-profit it has proved difficult to access the finance required for refurbishment of the system. However, using the sink-fund and the Government s Renewable Heat Incentive scheme, the company was able to secure enough funding to replace the boiler and improve the system for which they hope to see even further efficiencies and improve operational carbon from 67% above UK housing stock to 89% above. POST OCCUPANCY ANALYSIS An in depth post occupancy evaluation of the project has been carried out to determine how well the buildings are functioning involving various parties including Innovate UK, the Good Homes Alliance, UCL Energy Institute and Feilden Clegg Bradley Studios. The POE concluded that the project had excellent heat loss performance reaching almost Passivhaus standard. A building use survey provided mixed results with reference to heating and cooling of the building. Overall occupants are comfortable however the heating and ventilation (MVHR) system is being monitored to provide solutions to some issues. The POE highlighted the need to address cooling in buildings as this may become an issue for future designs, good ventilation strategies are key to this and further research needs to be conducted to ensure improved design. HEALTH AND HAPPINESS This project aimed, through design and ethos, to create a sustainable community that had minimal impact on the environment and maximum impact on occupant s health. The roof top allotments have been a great success and following this Brighton and Hove Council planning department have written a Planning Advisory Note on food and development. Residents have commented on the impact on their change in lifestyle, with one couple losing 35kg in weight between them over 18 months just through adopting a healthier lifestyle. Nearly 70% of the residents have modified their behaviour since moving into One Brighton. 5

6 LESSONS LEARNED The One Planet Living framework is a powerful way to align design, construction, sales and estates management The role of Sustainability Integrator is key to delivery, which ultimately supports cost effective delivery Good progress is being made on carbon emissions but more work can be done on the district heating system and biomass boiler to increase its efficiency. In particular, careful design of the distribution network and pipe insulation is important to prevent potential overheating in a highly insulated envelope. Overall financial performance for developer, purchaser/investor and resident (in terms of energy bills) is good More can be done to foster a sense of community, although this faces the challenge of having to deal with a transient community due to the large proportion of students among the residents. Ventilation strategies are key to occupant satisfaction and to avoid future overheating. However, MVHR (mechanical ventilation with heat recovery) systems require very careful design and coordination to work effectively and there is ongoing work to improve some issues with these at One Brighton. CONCLUSION During construction, the targets set were achieved in the vast majority of cases, and in some cases, such as on BRE EcoHomes, exceeded. In operational terms, the development is achieving many of its aims, but aspects such as overall carbon emissions still need work to achieve the 2020 target. A major step forward has been to deliver such an ambitious project cost-effectively and provide better returns for both the developer and purchasers, as well as reducing energy costs for residents.