The Drive to Replace Turbines
Electric drives offer an alternative to the use of steam and gas turbines in the oil and gas industries. The electrification of mechanical drives lowers emissions and reduces environmental taxes. In this sense, electrification helps with the achievement of ambitious climate protection goals. Electric drives are also low-maintenance machines that have a long service life, which reduces operating costs.
Companies that operate oil and gas facilities are facing major challenges. For example, they have to comply with increasingly stringent emission standards and guarantee the highest possible degree of facility availability, all while keeping their operating costs as low as possible. In view of this, more and more facility operators are now replacing their steam and gas turbines with electric drives. That’s because turbines generate high maintenance costs and emit greenhouse gases that force operators to pay what sometimes amounts to millions of euros in environmental taxes for each turbine every year. Electric drives, on the other hand, are low-maintenance machines that have a long service life – and they’re also emission-free.
Carbon dioxide emissions need to be dramatically reduced if the ambitious goal of the Paris Agreement to keep the rise in global average temperature under two degrees Celsius between now and 2100 is to be achieved. “This scenario involves the long-term substitution of electrical energy for fossil fuels,” says Gunther Schwarz, a project manager at Siemens Process Industries and Drives. “That means we will increasingly need to replace gas and steam turbines with electric drives. Although Siemens itself manufactures and sells turbines, electric drives nevertheless represent an innovative solution for the future.”
Our scenario involves the long-term substitution of electrical energy for fossil fuels.
The trend of using electric drives in place of gas and steam turbines is already under way. According to a study conducted by the U.S.-based Research and Markets institute in 2018, a clear trend can be discerned toward electrification – i.e. the replacement of mechanical components with electrical components. For example, the number of electric motors sold for vehicles, wind power plants, and machine tools is continuously increasing. Now, this electrification trend can also be seen in the area of industrial facilities. “We welcome this development, of course,” says Schwarz, “and we at Process Industries and Drives sell a lot more than just drives. We’re actually a solution partner that offers everything you need to convert to electric drives, from the initial idea to planning and operations – and all from a single source.”
Only Once Every 25 Years
Turbines at industrial facilities are currently used to perform tasks that require up to 90 megawatts of power output. They maintain pressure in pipelines in the oil and gas industries by pumping fluids into them, for example, and are also used to operate pumps and compressors at refineries. Still, each application situation is different. For example, if a turbine is used to power a generator that in turn produces electrical energy, then there’s really no reason to use an electric motor. It also makes little sense to use electric drives when “free” steam from another process is available. Finally, if there’s no power grid around, as is the case in the Australian Outback, you don’t even need to think about using an electric drive.
Electric drives should, however, always be considered wherever their use makes sense. For one thing, they operate completely free of emission, which makes their use exempt from taxes on greenhouse gases – something that can save a company millions of euros every year. It’s true that emissions are merely shifted if the electricity used to power electric drives is produced from a fossil energy source. However, power plants designed for a specific output under unchanging environmental conditions do in fact produce fewer emissions per megawatt than smaller and more flexible turbines in the field. In addition, the more electrical energy that’s produced from renewable sources, the lower will be the greenhouse gas emissions accounted for by electric drives. This is already the case in Norway, which covers nearly one hundred percent of its electricity requirement with energy from renewable sources.
In addition to contributing to reduced stress on the environment, electric motors are highly efficient, consume less energy than steam and gas turbines, and have a long service life, even when operated at variable speeds. They also remain largely unaffected by changes in humidity or ambient temperature, and their output can be adjusted as needed. Electric motors require less maintenance than turbines – they can operate for up to five years without having to be shut down. Depending on the environment they’re used in and the stresses they’re exposed to, electric motors usually don’t require a general overhaul until 25 years after they’ve been commissioned. They can be turned on and off quickly, which reduces downtime, and they also make less noise than turbines. Electric motors have efficiency ratings as high as 96 percent; the efficiency ratings for turbines range from 30 to 40 percent . Finally, the cost of operating an electric motor is as much as one-third lower than the cost of operating a turbine.
Quick Capital Recovery
Obviously, one might ask whether Siemens isn’t competing with its own turbine business by marketing electric drives. “That’s the wrong question,” says Schwarz. “Customers are interested in lowering their costs, and we offer them the best solution for their needs, whether it’s a turbine or an electric drive.”
Siemens’ business operations with electric drives for oil and gas industry applications began in 2013, when a refinery in the U.S. replaced a steam turbine with an electric drive. The refinery recouped its investment in just two years, which was quicker than expected. “We were positively surprised by that,” Schwarz explains, “so we took a closer look at such retrofitting projects and developed an overall concept. Among other things, we now offer high-speed motors built using a patented manufacturing process. These motors, which are used to directly drive fast-operating compressors, are part of our complete package, along with other motors. So customers have less to worry about. They save money and help contribute to the development of an electrified future, so to speak, while also meeting their obligation to reduce emissions.”
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