The key to an untapped resource

The worldwide electrical energy crisis may be less severe than is usually envisaged, says Megger’s
Mark Johnson.

According to recent press reports, Rodigo de Rato, former head of the International Monetary Fund, has expressed concern over the lack of capacity in power generation systems worldwide and the potential detrimental effects that this will have on the global economy.

Undoubtedly, this concern is well founded, but there is an important aspect of this situation that is almost always overlooked - the power utilities are, almost without exception, failing to make the best use of their currently installed generating capacity.

The root of the problem is downtime. At any given time, a small but significant proportion of the world’s power plants are shut down or operating at reduced capacity because of unforeseen equipment failures. This situation is getting steadily worse because lack of available capital for modernising power plant increasingly means that ageing equipment has to be kept in service long beyond its original design lifetime. 

Inoperable plant effectively represents an untapped reserve of generating capacity, but what can be done to make this reserve available?

The best answer is to prevent failures before they occur and therefore eliminate the need to take the plant off line. This may sound like an impossible goal and, of course, not all failures are preventable, but in electrical plant a very large proportion of potential faults can be detected before they progress to an actual breakdown.

The key is a well-implemented programme of predictive maintenance based on routine testing. For example, regular high-voltage insulation tests on a transformer can reveal that the insulation is starting to deteriorate, long before this deterioration forces the transformer to be taken out of service. Other items of plant are equally amenable to this kind of predictive maintenance.

Revealing a potential future fault does not prevent it from developing further, but the crucial issue is that it allows time for plans to be made to replace, repair or circumvent the defective item without major disruption to the operation of the generating plant as a whole.

The routine testing that underpins predictive maintenance costs money, of course, as does the test equipment necessary for its implementation. It is, however, important to consider these costs rationally. The best of modern test equipment is versatile, fast and easy to use. Often it can log and analyse results automatically, eliminating the need for the tedious, error-prone and timeconsuming transcription of results.

All of this means that the labour costs for regular routine testing, even is large installations, are much lower than might be expected, especially if those expectations are based on the use of traditional test equipment. In addition, modern instruments are very competitively priced, so the initial outlay on test equipment is also likely to be comparatively modest.

The really important consideration however, is neither of these points. It’s simply that even a single breakdown can have a direct and consequential cost that total to tens or even hundreds of times more than the cost of implementing an effective preventative maintenance programme.

What does all this mean in practice? The total installed generating capacity in the USA alone is of the order of 1,000 Gigawatts. If 1% of this capacity is out of commission due to equipment failures, the country has lost 10 Gigawatts of capacity, equivalent to the output of around eight power stations.

If routine testing and predictive maintenance can reduce this figure by half, it could provide a gain in capacity equal to the building of four additional power stations! And don’t forget that these figures are based on the USA alone. Worldwide, the gain would be even larger.

It’s also worth bearing in mind that making best use of available plant by reducing breakdowns not only lessens the need for capital expenditure to build new plant, it also eliminates the adverse environmental impact that building and operating this new plant would inevitably have.

For electrical utility companies worldwide, the message could not be clearer - for a relatively small investment in routine testing and preventative maintenance, it’s possible to get more out of existing generating plant.

That not only saves money and helps to protect the environment, it also goes at least some of the way toward addressing the lack of power plant capacity that could, very soon, be a significant damping factor on the growth of the global economy.