SUSTAINABLE BUILDING DESIGN FORESTERHILL
In its present form, the construction industry is not sustainable. Neither are the products we deliver. Traditional methods are carbon-intensive – and the built environment is the single biggest source of global CO2 emissions. Collectively, our sector consumes around one-third of the world’s natural resources, generating vast amounts of waste and pollution in the process. All of this is compelling us to rethink the way we design, engineer, construction and operate our buildings and infrastructure – putting our innovation activities firmly on the agenda.
It is our goal to minimise the negative impacts of our operations and maximise the quality of the built environment for future generations.
FORESTERHILL ENERGY CENTRE, ABERDEEN
2012 winner of BREEAM Industry Award
Aim: With the boiler plant nearing the end of its economic life, NHS Grampian decided to replace it with a new, more environmentally efficient energy centre; one that would reduce CO2 emissions by 15% and be able to provide increased energy requirements associated with recent and future developments at the Foresterhill Health Campus.
Approach: The full project team worked in a co-ordinated manner from the outset, at the early design stage; working towards common goals.
Results: Early collaboration and innovative thinking led to the facility achieving an ‘Excellent’ BREEAM rating with a score of 83.32% - representing the highest within the category.
The ever increasing importance of designing energy efficient solutions in the built environment is visible through government stipulations.
Scottish Capital Investment Manual (SCIM ) guidance states that: All new build above £2m are required to obtain a BREEAM Healthcare or equivalent 'Excellent' rating; all refurbishments above £2m to obtain a 'Very Good' rating. If the capital costs are less than £2m, projects should undertake a BREEAM pre-assessment to establish whether BREEAM is a viable option.
NHS Grampian’s new Energy Centre was commissioned to serve the current and future energy and heating requirements of the Foresterhill Health Campus, responding to issues such as:
- Failing and insecure current energy production facilities, with boiler plant nearing the end of its economic life and high associated labour costs
- Increased energy requirements associated with recent and future developments at the Foresterhill Health Campus
- Steep increases in energy costs, driven by volatility in the world energy market
- NHS Grampian, NHS, Scottish Government and Central Government initiatives to implement more sustainable energy production methods to reduce carbon emissions.
By assessing potential options, considering lifecycle costs and value for money, the project team decided to replace the existing boiler house with a new, more efficient energy centre. The new plant includes a gas turbine combined heat and power plant, a biomass boiler and three dual fuel boilers.
These will provide heat, and around 90% at peak loads of the electricity requirement of the Foresterhill Health Campus. The key drivers were to:
- Replace the current plant that was no longer capable of delivering against key performance indicators in target cost, sustainability and reliability
- Meet increasing site energy demands from new and redeveloped facilities supporting new clinical services designed to improve patient treatment and care, together with additional medical teaching and research facilities for the University of Aberdeen
- Respond to NHS and government initiatives to implement more sustainable energy production methods to reduce CO2 emissions by 15%
- Reduce site energy costs.
The steam plant includes:
- One gas turbine CHP unit providing base load steam demand and 5.3MW of on-site power generation
- One 1.5MW biomass steam boiler fuelled on locally sourced wood chip to meet the higher winter steam demand
- Two 8.5MW and 1 x 6.5MW dual fuel (gas/oil) steam boilers to meet peak demand.
The steam plant configuration was designed with N+1 redundancy to provide security of supply with a 1MVA standby generator providing ‘black start’ capability and a gas booster set providing 2000m3/hr at 18 bar pressure.
The entire plant is housed in a single building with integral woodchip delivery and storage using fully automated flatbed ‘walking-floor’ trailers. The plant is designed to provide a 16% reduction in CO2 emissions (9830 tonnes/annum) and a 39% reduction in energy costs (£2.95m at 2010 prices).
Air dispersion modelling using ADMS was undertaken to determine the minimum height of flue stack required to ensure there was no increase in levels of air pollutant concentrations (NOx, CO, PM10 and PM2.5 particulates) at local sensitive receptors.
The BREEAM Excellent rating secured by the new Foresterhill Health Campus Energy Centre reflects the overall project team commitment made to sustainability. The centre will provide reliable and efficient energy supplies capable of meeting patient care, staff and visitor requirements for years to come. It will reduce energy costs and carbon emissions through improved generation efficiency, and incorporates flexibility to meet future expansion requirements.