Case Study

MoD invests in Invertek for energy efficiency drive

MoD invests in Invertek for energy efficiency drive


The MoD's Defence Estate was spending around £1 million a day on heat, light and power and wanted to find ways of creating savings.


The Optidrive Eco was introduced to ventilation and boiler pump systems. The annual savings achieved at one site along were £16,000 as a result.


Variable speed drives from Invertek Drives, supplied and commissioned by sales partner Motor Control Warehouse, are helping CarillionEnterprise (C-E) to achieve savings at Beachley Barracks as part of the Ministry of Defences (MoD) energy Spend to Save programme.

The programme involved investing in projects throughout the Defence Estate to achieve significant reductions in its £1 million a day spend on heat, light and power. Motor Control Warehouse worked with C-E on a number of MoD sites, the largest single site installation was completed at RAF Cosford where 48 drives from Invertek have been installed as part of DIOs Spend to Save programme. 

The savings at Beachley Barracks, Chepstow, are expected to be achieved by the introduction of 12 Optidrive Eco HVAC variable speed drives on ventilation systems and boilers across the site to regulate the speed and flow of water and air.

Kevin Muttitt, Energy Implementation Manager at C-E said: “The variable speed drives have been introduced as one of seven key energy reduction technologies forming part of our 2012/13 Spend to Save programme of works. We estimate that the savings of over £16,000 per annum will see the scheme pay for itself in just under 15 months.”

C-E manages the site for the Defence Infrastructure Organisation (DIO), the MOD's property and services provider. It appointed Motor Control Warehouse to survey the site and produce a detailed analysis of all the drives that could be controlled. The equipment chosen included Invertek Optidrive Eco HVAC fan-pump inverters. A total of 12 inverters were installed on various fan and pump applications with motor frequencies/speeds typically reduced from 50 hz to between 35 and 40hz, easily meeting the project objectives of a minimum 20% reduction.

Using Optidrive Eco HVAC to reduce fan/pump speed during periods when maximum flow is not required provides the maximum possible energy savings. A 20% reduction in speed can reduce the energy consumption by up to 50%.

Kevin said: “Installing the inverters provided less mechanical stress on belts and couplings as the inverters offer an inherent soft start and soft stop for the load under control. As an example a 15kw hot water circulation pump running at a load of 14.7kw, 50hz operation, had its frequency reduced to 40hz and the load dropped to 7.4kw, achieving a 50% reduction.”

Steve Setterfield, C-E Assistant Site Estate Delivery Manager, said: “The variable speed drives were installed in Beachley as part of several sustainability initiatives. The work was carried out through the summer months when disruption to heating would be at a minimum. To date there has been no noticeable drop in performance and we are already seeing a reduction in energy use.”

Motor Control Warehouse worked closely with C-E on all aspects of the drives installation from undertaking initial site surveys and identifying the most energy efficient solutions, to installing and commissioning the Optidrive HVAC drives.

Bleddyn Powell, Managing Director, Motor Control Warehouse, said: “CarillionEnterprise chose the combination of Invertek Drives and Motor Control Warehouse to fulfil this contract because the partnership ticked all the boxes. Probably the best IP rated HVAC inverter on the market today, along with Motor Control Warehouse who boast some of the most experienced inverter engineers in the business. 121 Optidrive inverters were installed in total across the MOD sites, ranging from 2.2kW to 30kW. Needless to say the entire project ran without a hitch and exceeded the clients expectations with respect to the mechanics of the install, the product and energy saving.”

C-E is managing an extensive variable speed drives programme roll out across 25 of the Establishments it manages for DIO find out more by visiting More details about Invertek's energy efficient fan and pump control can be found here.