According to The Carbon Trust*, electric motors use two-thirds of the £2B of electricity consumed by UK industry annually and they estimate that in many applications 40-80% of full load power is wasted. And with rising energy costs and the Climate Change Levy (CCL) increasing energy costs still further, how much could your business save by introducing energy saving measures?
Many direct-on-line (DOL) electric motors in service today are overrated, incurring unnecessary cost in energy and CCL. For instance, pumps and fans running flat out at mains frequency, continuously or on-demand, may be delivering more flow than necessary for the job they’re doing. And running at fixed speeds, they can’t adapt to changing loads.
A simple but effective way of reducing energy consumption to the minimum required for proper operation and adjusting motor performance to suit changing loads is to use a variable speed drive (VSD). This is where MCS comes in, because we can supply, install and commission VSDs for new and existing motors.
Imagine the savings that could be made by fitting a VSD to the motor shown left. But it’s not only big motors which show justifiable savings! Fitting VSDs to motors as small as 0.75kW can achieve energy savings which show a payback in a reasonable time, as demonstrated in a 3-year in-house investigation carried out by Suzuki Hamamatsu Automotive Parts Manufacturing Company Ltd, in Japan, which won a major award in 2001 for its energy saving initiative. This initiative has subsequently been implemented throughout the Suzuki Group.
◘ Click to download a .pdf file of the report about the Suzuki project
And UK companies can benefit doubly by implementing such energy saving initiatives, in the form of Enhanced Capital Allowances (ECAs) which allow the full cost of VSDs and high efficiency motors to be written off against taxable profits in the year in which the investment is made, instead of being written down at 20% per annum on a reducing balance basis. Companies paying 28% Corporation Tax would see a reduction in this year’s CT bill of £224 for every £1,000 spent on energy saving equipment. And as well as reduced energy consumption there are other benefits:-
- Reduced maintenance costs because equipment runs at lower (optimum) speed rather than running flat out
- For applications such as dust/fume extraction which exhaust outside the factory to atmosphere, reduced heat loss
- For pumps, fans, etc. a VSD avoids the need for equipment such as valves, baffles, etc. for adjusting flow which show a negligible reduction in energy consumption
- For conveyors, lifts, etc. a VSD avoids the need for mechanical equipment such as variable ratio gearboxes, which are expensive and prone to wear, for adjusting speed
- Instantaneous and infinitely variable response to changing loads
To be eligible for an ECA, the equipment must be on The Carbon Trust’s Energy Technology Product List (ETPL). ECAs also cover direct costs such as delivery of the equipment to site, and installation, up to a maximum claim value. For example, for a 55kW VSD for an existing motor, this is currently £7,178; for a package including a 55kW VSD and new, energy efficient motor this ranges from about £12-16k for a standard motor, dependent on its polarity, and £16-23k for a flameproof motor. MCS can also advise you about ECAs and can select suitable equipment from the ETPL.
MCS’s Energy Saving Service can:-
- Identify potential energy saving opportunities for new and existing motors
- Size and specify new energy saving motors
- Size and specify variable speed drives (VSDs) for new and existing motors
- Design, build, install and commission motor control panels
- Provide a full set of technical documentation, circuit drawings, manuals, etc.
- Train your Plant Engineers to use the VSD for optimising motor performance
- Provide on-going after-sales support and a breakdown call-out service
- Supply equipment on the ETPL eligible for an Enhanced Capital Allowance
◘ Click to download a .pdf file explaining in more detail how MCS can help you save energy
An example of an energy saving project undertaken by MCS
Variable speed drive reduces energy costs
Installation of a 55kW VSD for controlling fan speed on a dust extraction unit supporting three paper converting machines. With all three machines running, the optimum fan speed was found to be 37Hz, representing approx. 60% energy saving [i.e. (37/50)³ = 0.405] which achieved a payback in less than one year. By fitting a baffle in each leg of the ductwork, to isolate individual machines, and connecting a ‘Run’ signal from each machine into the VSD, fan speed is automatically reduced according to the number of machines running and energy consumption is reduced still further. Another benefit is that reduced airflow reduces heat loss from the factory.
◘ Click to download a .pdf file of the case study
* The Carbon Trust is an independent company set up by the Government in 2001 to accelerate the move towards a low carbon economy by working with organisations to reduce carbon emissions and develop low carbon technologies.
◘ To find out more about The Carbon Trust, click on the link: www.carbontrust.co.uk [^]
◘ To find out more about ECAs and the ETPL, click on the link: www.eca.gov.uk/etl [^]