Pump element is overlooked

Mitch Holmes of Grundfos' Water Group argues the environmental impact of the enhanced capital allowance initiative is compromised by a failure to look into hydraulic efficiency

There is still a large amount of confusion over the whole area of enhanced

capital allowance (ECA) and the consequences of having just motors, without

pumps or pumping systems on the energy technology product list. Although plenty

has been written on the subject, very little forms a cohesive picture which

can be readily understood.

International rescue

At the Earth Summit in Rio, 1992, in excess of 150 countries agreed to limit

man-made emissions of green house gasses (GHG). This decision formed part of

the global ambition to stop the atmosphere from overheating. By the 1997 Kyoto

Summit, it was agreed that developed countries would aim to reduce GHG emissions

by a further 5.2% between 2008-2012. The EU committed itself to an 8% reduction

in emissions, with the UK contribution being agreed at 12%.

Following this, a government initiative was introduced to drive down GHG emissions

generated from electricity production. The Climate Change Levy (CCL) has been

levied on business users to encourage the reduction of energy consumption. The

CCL is applied at different rates, depending on the energy content of the different

sources. For instance:

  • Liquid petroleum gas (LPG) – 0.07 p/kW/h,
  • gas, coal, lignite and coke – 0.15 p/kW/h,
  • electricity – 0.43 p/kW/h.

Electricity attracts a higher tax rate as a considerable proportion of fossil

fuel energy is lost in combustion, transmission and distribution. Petrol, diesel,

road fuel gases, mineral oils, waste and other renewable energy sources are

not taxable commodities under this scheme.

To encourage companies to switch to more efficient and environmentally friendly

options, an incentive was introduced in the 2001 budget. This took the form

of a claimable allowance for businesses that invest in energy efficient technologies

including boilers, refrigeration, combined heat and power, lighting, pipework

insulation, thermal screens and motors and drives.

The ECA helps to lessen the impact of the CCL’s affect on fuel bills by allowing

companies to set 100% of the cost of approved energy saving equipment against

corporation tax in the year of acquisition. Instead of writing down capital

equipment over a period of years, the ECA provides a cash-flow advantage which

helps to offset the capital investment cost.

How to qualify

The energy technologies list includes both variable speed and fixed speed high

efficiency motors with efficiencies typically between 83%-95%. When these motors

are fitted onto pumps it is possible to claim the ECA on the percentage of the


price of the motor.

Additionally companies can also claim ECA on costs directly associated with

the provision of the product, i.e. transportation, installation, modifications

to existing plant and machinery and commissioning. Professional fees also qualify

if they are directly attributable to the acquisition and installation. Finally,

the allowance can be claimed where costs have been incurred as a result of altering

an existing building, incidental to the installation of qualifying plant and


Defeating the object

With motor efficiency rising as high as 95% there is little scope for improvement

in this area, however, considering 20% of the world’s electricity bill is spent

on powering pumps, it is vital the bigger picture is taken into account. It

is possible to claim ECA on a high efficiency motor, irrespective of the efficiency

of the pump it is attached to. It is not unusual to have pumps with an efficiency

point as low as 40%. Therefore, consider the possible impact on electricity

consumption if the same benefits were applied to hydraulic efficiency.

Grundfos has identified a number of ways that hydraulic efficiency could be

improved. Enhanced impeller design, for example, can result in a more streamlined

flow in the impeller and reduced eddy flow and friction loss. Since such small

margins of error are involved, Grundfos has developed highly specialised laser-welding

technology, which operates at, so far, incomparable levels of accuracy. With

this technology, the impeller design and construction are fine-tuned to the

point of theoretical perfection. This alone can contribute to increasing efficiency

by up to 4%.

Another method is to minimise internal leakages caused by the pressure differentials

within the pump. Tests and calculations have shown that an impeller seal clearance

gap of 0.1mm, between the impeller and the chamber in a pump, results in a 5%

drop in efficiency. To reduce internal leakage to a minimum, it is now possible

to use a floating seal ring between chambers, providing a virtually perfect

seal. If a 10% increase in pump efficiency is achieved smaller motors can often

be used to power the pump at any given duty point. A smaller motor represents

a reduction in both capital investment and running costs.

With these technological advances now available, it is possible to achieve

hydraulic efficiencies in excess of 80%. When this factor is combined with the

accessibility of high efficiency motors, the result could be a major contributor

in reducing GHG emissions and help the UK move towards achieving its environmental


Every year 900,000 multistage pumps are installed around the world, if they

were all as efficient as the Grundfos CR range, the electricity saving in the

first year would be 1.45tWh. Put into context, this equates to 590,000 tonnes

of coal. If this was then used to generate electricity, emissions would be in

the region of 1.43M tonnes of carbon.

The way forward

When purchasing white appliances, there are energy rating labels giving an easily

identifiable guide to the efficiency of the overall unit. In the case of a washing

machine this would include the motor and washing mechanics as one. Could this

be the way forward within the pump industry? Perhaps classifying pumps as one

complete unit with a combined efficiency, grading and labelling would help to

alleviate some of the confusion that currently exists.

Building on this, the combined pump unit should be included on the energy technologies

product list, ensuring the pump industries continued contribution to the environment

and Kyoto Protocol.

There are many financial, ethical, environmental and practical reasons to look

closely at this topic. The environmental abuse of the last century was mainly

a result of ignorance. However, the advances being made by manufacturers like

Grundfos Pumps will prove valuable when specifiers design products that can

make a real difference.

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