The Council asked the Carbon Trust to carry out a bespoke series of energy audits and feasibility studies to identify and help build the business case for the most suitable measures and technology options for capital investment.
Tunbridge Wells Borough Council is the local government body for a population of around 115,000, covering the town of Royal Tunbridge Wells and extending out to Southborough, Paddock Wood, Cranbrook and Hawkhurst in Kent.
The Council worked with the Carbon Trust back in 2010 to develop a five-year Carbon Management Plan, setting a target to reduce greenhouse gas emissions by 25% by March 2015. This had potential financial savings and cost avoidance of more than £1.2 million.
One of the key ways it intended to achieve these cost and carbon savings was through introducing cost-effective energy efficiency measures and renewable energy generation where appropriate on sites.
To help achieve cost and carbon savings the Council asked the Carbon Trust to carry out a bespoke series of energy audits and feasibility studies to identify and help build the business case for the most suitable measures and technology options for capital investment.
The outcomes from these studies allowed the Council to have more confidence that the investments they were planning would deliver the expected cost and energy savings, and that the overall capital and revenue budgets associated with those projects were accurate.
The Carbon Trust carried out investment-grade audits of five sites in Tunbridge Wells, including the TN2 community centre, three large sports and leisure centres and the council depot for contract services, such as waste and parks contractors, and its associated offices. The Carbon Trust’s Investment grade audits provided:
Pre-audit energy consumption analysis identified the baseline energy consumption for each of the buildings, looking at usage trends and comparing them with industry benchmarks.
A major focus of the studies was assessing feasibility for renewable energy projects but the audits also addressed a number of other key areas such as energy policy, staff management and energy awareness, building fabric, lighting, heating, cooling, ventilation and motor management. This pinpointed where the most effective improvements to energy efficiency could be made. It also meant that the potential for implementing renewable energy technologies could be assessed in detail, with a view to reducing the carbon impact and operational cost of the estate.
Many of sites audited were found to already use less energy per square meter than benchmarks typical for buildings of their type. However there were still numerous opportunities to reduce energy consumption.
In order to lower the demand of energy at the sites the Carbon Trust advised the Council to make physical improvements to building infrastructure, such as improved roof insulation and energy efficient lighting.
In addition to this, changes could be made to system management to lower energy usage, such as to the backwash and mechanical ventilation regimes in the swimming pools at the leisure centre sites surveyed. Implementation of those measures across the sites could lead to cost savings of £180,000 and a reduction in carbon emissions of 900 tonnes.
The team also investigated the installation of renewable energy generation on the sites. Many of the sites were found to be suitable for solar PV installation and the optimal location and size for each array was determined. The payback period in all cases was less than ten years (determined using lifecycle analysis), with average annual cost savings varying between £4,000 and £27,000 and can deliver dependable long-term returns without having an impact of any future energy projects.
As well as looking into renewable energy generation, the potential for introducing or replacing combined heat and power plants (CHP) was also considered at a number of sites. Where that potential existed the Carbon Trust provided recommendations on the appropriate size, access requirements and locations for plants. The installation of a CHP plant was deemed to be particularly suitable at the Tunbridge Wells Sports Centre and the Weald Leisure Centre (pictured above), because there would be comparatively short payback periods thanks to their high levels of heat demand. Further investigations will be necessary, although this could enable a return on investment of just over two and three years respectively, with high carbon savings of 250 and 100 tonnes per year.
The work done by the Carbon Trust has allowed Tunbridge Wells Borough Council to move forward in their plans to increase usage of renewable energy and meet their carbon emission targets.