Industrial Energy Costs: take control

In recent months, the cost of energy for manufacturing and process companies has risen significantly. As recently as April, the cost of gas per therm, which had been stable for some time, was under £0.50; by October, however, the cost had jumped to over £2.50 per therm. That’s a staggering 400% plus increase in gas prices in just six months. A similar, although not quite so dramatic, situation is now taking place with oil prices, which have topped $80 dollars a barrel for the first time in three years.

As a result, industrial companies that are dependent on gas or electricity for powering their manufacturing operations find themselves in a situation where their operating margins are being increasingly squeezed. We’ve already seen factories being forced temporarily to close or reduce their output. These include the fertiliser manufacturer, CF Industries, which halted production at its two plants in the UK for several weeks, while steelmakers have had to pause production during hours of peak electricity demand.

Predictions from industry analysts are that costs will rise still further in the coming months, as seasonal demand from consumers and industry starts to take effect.

Although it’s the big energy users – chemicals, steel and glass – that are making the headlines, the rapidly rising cost of energy is hitting all manufacturing companies. In the short term, there’s little that many can do to mitigate the effects. Indeed, many industrial companies have already done a lot in recent years to reduce their energy costs; for example, by installing energy efficient production equipment, such as variable speed drives, heat recovery systems and process optimisation controls, or by minimising heat losses from buildings.

Energy costs and industrial boilers
One area for energy saving that is often overlooked is the operation of industrial boilers, especially in sectors where large volumes of live steam are used.

Industrial boilers use considerable amounts of energy. The larger the boiler, the more energy is consumed and potentially lost. Although modern, high efficiency boilers can offer a possible solution, these can be expensive to source and install, often causing considerable disruption. Perhaps more to the point, many companies have perfectly serviceable boilers that are far from reaching the end of their operating lives.

For these companies, one option is to consider how they treat the boiler feedwater, as this can have a direct impact on the number of blowdowns that are required. In simple terms, reducing the number of blowdowns will reduce both energy and water consumption.

Most industrial boilers will have a water softener to reduce the minerals in feedwater that cause scaling. Chemical treatment may also be used. However, neither can reduce the level of total dissolved solids (TDS) such as inorganic salts and carbonates. It is these dissolved solids that contribute to the need for blowdowns. And it’s an established fact that each blowdown uses around 10% of heated boiler water. So, every blowdown is effectively flushing water, energy and money down the drain.

Improve the quality of boiler feedwater and start saving
The solution is to improve the quality of boiler feedwater by minimising the levels of TDS. This may require investment in additional water purification equipment – normally a standard reverse osmosis system – but the cost savings can be significant. For example, the blowdown costs for a standard 8 tonne/hour boiler in a live steam application with just a softening system in place, could be reduced by more than £50,000 p.a.

In most applications, installing a reverse osmosis system is a straightforward procedure, with minimal disruption. Purchase, installation and subsequent maintenance costs can be relatively low and with a typical operating life of around 10 years the return on investment through energy and water savings can be considerable.4