ExxonMobil lubes keep wind turbines turning

Krish Krishnan (left) and Ian Davidson are among the specialized group of ExxonMobil professionals working with the wind-turbine builders and component suppliers to formulate the Mobil SHC-brand of lubricants to fit customer needs.

The Mobil SHC brand of wind-turbine lubricants is enabling the wind-energy industry to develop and operate in more efficient, cost-effective ways in a highly competitive marketplace.

Some might be surprised to know that the products that keep wind turbines running at peak performance represent the fastest growing segment of ExxonMobil’s Mobil SHC synthetic industrial lubes business. In fact, across the globe, Mobil SHC gear oils help prevent wear in an estimated 25,000 wind turbines. Roughly 60 percent of gear-driven wind turbines manufactured in recent years are lubricated with Mobil industrial lubes.

Although it starts from a small base relative to conventional sources, capacity for wind-generated electricity worldwide grew last year alone by nearly 30 percent to 122 gigawatts, comprising roughly 128,000 wind turbines.

New capacity additions for 2008 were more than 40 percent higher than in 2007, and wind-based electrical generation is expected to grow an estimated 12 percent a year, on average, from 2005 through 2030. Even with this high growth rate, wind-power generation is forecast to supply 1 percent of global energy demand and approximately 5 to 6 percent of electricity demand in 2030.

Wind-power generation began with the earliest wooden windmills, used to pump water long before electricity was even a notion. Early incarnations of today’s towering, steel-and-fiberglass structures sprang up in earnest in the 1980s, and sites began proliferating in the mid-1990s. Europe has been at the forefront of the modern wind-power movement from the start, with countries such as Denmark and Spain well on the way to generating 20 percent of their electrical needs using wind power.

Many power providers and policymakers elsewhere in the world have also begun to view wind power as a potential renewable supplement to traditional energy sources. By the end of last year, the United States surpassed Germany as the world leader in wind-power capacity with 25 gigawatts — enough to generate 1 percent of total electricity nationwide. Other key growth markets include China, India and Portugal, with China alone earmarking more than $10 billion a year toward wind-energy initiatives through 2020.

“China’s minister of energy refers to the country’s wind patterns as a great strategic resource,” says Ian Davidson, global industrial marketing manager for ExxonMobil Lubricants & Petroleum Specialties (L&PS).

Tough duty
ExxonMobil’s pioneering synthetic-lubricant technologies have a long-standing reputation for serving the most demanding applications, and today’s wind turbines are extremely demanding. The largest models, designed to feed energy to extensive power grids, have rotors up to 400 feet in diameter churning up to six megawatts of electricity — enough to power roughly 1,800 U.S. households. “In terms of weight, they’re like jumbo jet planes sitting on stanchions in the sky,” says Davidson.

Wind turbines of the 1980s used gear oils formulated with traditional hydrocarbon basestocks. But by the mid-1990s, as the metallurgy of wind-turbine gearboxes evolved, traditional oils began to cause microscopic pits (micro-pitting), ultimately shortening the life of the equipment. ExxonMobil entered into a research and development collaboration with a major gearbox manufacturer to explore a synthetic solution to the problem.

The effort led to the 1998 introduction of Mobilgear SHC XMP, the company’s first synthetic gear oil for wind turbines. Today, Mobilgear SHC XMP is the initial-fill gear oil of choice for seven of the world’s top 12 wind-turbine builders. The Mobil wind-sector product line also includes greases to lubricate bearings and hydraulic oils that help pitch the huge rotor blades.

“By working closely with wind-turbine builders and their component suppliers through our engineering group, our research and development people gain an in-depth understanding of wind-turbine applications,” says Krish Krishnan, industrial marketing advisor. “We use that understanding to develop optimum product formulations for each application. We don’t design products first, and then try to fit them to these severe applications.”

Exceptional performance
Besides protecting against micro-pitting and other forms of equipment wear, Mobilgear SHC XMP exceeds the performance of traditional oils by extending the interval between oil changes from 18 months to three years or more. Mobilgear SHC XMP doesn’t clog filters and disable temperature and pressure gauges, as some other oils do. It also enables turbines to perform optimally in extreme ambient temperature conditions and maintains stability even in the presence of moisture condensation — common in humid climates.

A wind farm — or wind plant, as it’s more often called today — may have dozens of turbines in remote areas. “It’s not like a factory where individual pieces of equipment are readily accessible,” says Krishnan. “Windturbine lubes therefore have more requirements than most other types of lubricants, and customers need to be very sure about the lubricants they’re using.”

For operators of wind plants, the reduction in routine maintenance, along with lower rates of equipment failure, can add up to significant cost savings per turbine per year. And maintenance is a major consideration, since there’s no such thing as a “simple” oil change when a large turbine stands more than 300 to 400 feet high, perhaps in a remote environment or — as increasingly expected in coming years — offshore. Overall, Mobil SHC products enable the wind-energy sector to be more efficient, allowing it to better compete with other forms of energy.

Expertise and experience
ExxonMobil has centers of expertise dedicated to wind-sector lubes in North America, Europe and Asia Pacific. Together, they make up one of the lube industry’s largest technical support organizations for wind-turbine builders, operators and service companies. ExxonMobil’s wind specialists go beyond their technical call of duty, helping to enlighten customers on the outlook for wind-energy demand across the globe.

“We already operate in markets where turbine companies want to operate,” Davidson says, citing a manufacturer in India exploring opportunities for entry into the U.S. market. “They can count on our expertise and experience.”

ExxonMobil continues to invest in the development of next-generation wind-sector lubricants. “We’re working with equipment builders to understand their new frontiers in order to extend our technology to an even higher level of leadership,” says Davidson.

“It’s vital that we develop all economic sources of energy to fuel the future growth of the world economy and the growing global population,” says Alan Kelly, president of L&PS. “Those sources are going to include oil and gas, coal and nuclear, solar and wind. We’re going to need them all.”