Thursday 21 November 2013

GE wants to power up older wind turbines
18 Oct 2013

Earlier this year, General Electric Co (GE) launched a package of technologies and services to improve output from its newer wind turbines like the 2.5 120, calling them "brilliant" at predicting and producing wind power. Now it's bringing those same capabilities to its existing turbine fleet by packaging them into a new suite called "PowerUp" to improve older wind turbines' output and profitability.

Andy Holt, general manager of GE Energy's projects and services group, explained to us how it works: GE analyzes a customer's wind turbine capacity, turbulence, weight, its current condition and age, how hard it's been run, explore the on-site wind regime, and generates a list of possible improvements. "We'll put on as much as we can to optimize and maximize their output and revenue", he said.

One of these capabilities is the company's venerable WindBoost, which essentially nudges a turbine to run a little bit harder if conditions allow for it. Vortex generators, meanwhile, can be applied on the blade to decrease separation and increase lift. Other features that can be bundled with PowerUp run the gamut from trailing-edge serrations to reduce noise, to a winter operations mode that ramps down as ice forms.

Another aspect to PowerUp borrowed from the "brilliant" turbine setup is enabling predictability and condition-based maintenance, "having machines telling us when we have issues" to eliminate unplanned downtime, Holt said.

PulsePoint software monitors set points in the turbine to gauge factors including vibration, bearing temperature, and filter pressure. Other software awakens turbines to recognize when they're falling behind other turbines nearby and alert the dispatch center to find out why, or conversely notice if a turbine in the group (or groups) could be revved up to take advantage of current conditions

These types of tweaks take a page from what GE has done for its gas turbine customers, Holt pointed out.

The company especially sees a sweetspot for PowerUp in its flagship fleet of 9,000 1.5 77 turbines running nationwide, since "the technology has moved so far since we built the earlier machine", Holt said.

For just those turbines, GE claims that PowerUp could increase a wind farm's output by up to 5% and a 20% increase in profit per turbine--even a 1% energy output increase would add another 420,000 MWh annually, according to the company. Holt walked us through how GE came up with those numbers:

  • 2.3% more output per machine: Using WindBoost to run a little harder off the gearbox
  • 0.5%: Seasonal tuning, such as changing pitch parameters from summer to winter
  • 1.2%: Winter ice operations, sensing ice formation and derating/shutting itself down
  • 1.5-2%: Vortex generators on the blades
  • 0.5-1%: Blade cord extensions with slightly larger aerodynamic areas, increasing the velocity at the top of the blade
  • 0.5-1%: Trailing-edge serrations

Of course not every customer site will apply all of those improvements, but taking an average across GE's entire fleet the company calculates a 5% improvement in output.

That's "big enough to matter", Holt said, "and it's also just the beginning". Given the relative youth of GE's fleet of turbines in the US (averaging 5 6 years) repowering of entire hubs and nacelles isn't yet a big services business, but PowerUp could fill a big need for customers who are keen to know more about their turbines' performance in wind speed regimes of between 5-7 meters per second, shy of the rated output.

"We're taking advantage of the design life in the machine that's being underutilized because of lower winds, and that's given birth to a whole upgrade business", he said.

Customers will pay for PowerUp based on "validated performance improvements" i.e, the additional power that gets produced. "We just commit to selling MWs [to customers]", Holt said. "This is a simpler way to do business with us". PowerUp also can be incorporated into existing VICOSC&M contracts.