What is the difference between playing the lottery and saving energy?

01 October 2007

It’s quite simple—when you save energy you can be assured of a profit, but when you play the lottery it’s down to luck. Tim Wills of SEW-Eurodrive explains.

Controlled drive technology saves costs in the long run
Controlled drive technology saves costs in the long run

By using energy-efficient electrical products and systems consistently, we could save 40 billion kWh of energy a year. This amount corresponds roughly with the total annual energy consumption of public facilities in a country like Germany. In recent years, the electrical industry has developed a range of innovative and energy-efficient solutions, now we need to make use of it.

Potential for saving energy
Manufacturers of electrical drive engineering technology therefore play a key role when it comes to saving energy. The first area where savings can be targeted is the development of energy-efficient motors. These are standard motors whose energy efficiency is improved by a few percentage points, using increased amounts of copper and iron and changing the design.

In 1998, European motor manufacturers concluded a voluntary agreement with the European Commission to market energy-efficient motors more effectively. Since then, the market share of energy-efficient motors has increased to more than 90% (Fig. 1). However, the major part of this share is made up of motors in efficiency class “EFF2.” Even though sales of motors in the high-efficiency class “EFF1”, which are approximately 20% more expensive than motors in class “EFF2”, has increased six-fold since 1998, the share is still a meagre 5%.

Lets assume energy-efficient motors gradually replace the approximately 30 million old motors in stock today. Given an average improvement in efficiency of four percent, this leads to annual savings potential, in industry, of 5.5 billion kWh.

However, the second potential for saving energy, with electronic speed controllers, is four times higher. It makes sense to use speed controllers in systems where the load of a motor driven application depends on the speed, for example, pumps, fans and compressors. In the past, mechanical controls such as chokes or throttle valves, which consume a lot of energy, were used—and all too often they are still used today.

Regenerative frequency inverters also offer the option of feeding braking energy back into the public power grid instead of dissipating it via braking resistors or mechanical brakes. The best examples in this case are elevators and electric tracks. Today, only a small percentage of drive solutions installed in industry are operated with energy-efficient electronic speed controllers. However, as far as saving energy is concerned, it would be a good idea to use electronic speed controllers in 50 percent of all drives. This would generate annual savings of around 22 billion kWh.

Since the first records of sales of frequency inverters, they increased eight-fold by 2005. In the same period, the number of frequency inverters produced rose to almost a million. The number of AC motors sold increased in the same year by 3.4 million. Therefore, virtually every third AC motor sold is equipped with electronic speed control. In addition to the “electrical” possibilities, there are also significant savings to be made by manufacturers of machine and system solutions themselves. According to studies carried out by the European Commission (e.g. the SAVE reports), up to 60% of the total electrical and mechanical energy saving potential lies in the selection of the optimum mechanical processes and operating points. (Fig. 3)Therefore, there is every indication that machine manufacturers ought to focus on optimising systems as a whole. A number of leading pump manufacturers showcased optimisation programs at this year’s ACHEMA in Frankfurt. Customers can use these programs to work out the TCO (Total Costs of Ownership) based on a range of load profiles, the required (energy-efficient) motor, control type (electronic or mechanical) and typical maintenance intervals. (Fig. 2)

The success achieved to date by energy-efficient technology, based purely on voluntary measures to increase the amount of information available and voluntary agreements, speaks for itself. At the same time, efforts to implement these technologies must be given priority, to save not only energy, but also the environment.

How is this possible? The products themselves are available and ready for operation. The necessary planning resources are also in place. So we have to ask ourselves whether the voluntary measures agreed so far are sufficient. Common sense dictates that the technological and economic advantages of these products ought to be leading to high demand for energy-efficient drive technology in industry. But this is not the case. What then is preventing successful market penetration? The key is in the supply and decision-making chain.

First, life cycle costs are not being given enough weight in investment decisions and second, it is difficult to convince manufacturers to replace familiar, tried-and-tested technology with new, energy-efficient products. However, the vast majority of motors or complete electric drives are not delivered to end customers but supplied to OEMs.

These “middlemen” then have to offer a better deal than their competitors, using the sales price as a selling point rather than the operating costs of the machine. Consequently, it is important to motivate decision-makers in purchasing departments to take more than the procurement costs into account.

Political policy must therefore support both efforts to accelerate this transformation. It must promote awareness of the importance of saving energy and resources. Economic incentives to encourage companies to purchase energy-efficient machinery and drive systems are a good idea. Government could also promote user training to analyse energy-saving potentials and offer advice on how to implement the new technology. Increasing cost pressure from international competition is a passive aid in this context. For example, one major automobile manufacturer recently decided only to use EFF1 class electric motors.

There are billions to be made by saving energy through simply using it more efficiently. We have to make ourselves aware that there is money to be made by saving energy—for each and every one of us. Furthermore, we are not only saving money for ourselves, we are also saving the environment.

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