Home December 2016

December 2016

Advanced Blade Pitch Systems: Insights and Trends

Five Key Tech Trends to Watch

Preparing for the next energy storage revolution: Energy storage is one of the important elements of the pitch system. In the past, all electrical pitch systems used batteries. However, over the last few years, the cost of ultra-capacitors has come down, in large part, due to their broad adoption by the automotive industry. Ultra-capacitors, which have the major advantage of much longer maintenance intervals, have progressively taken on traditional batteries. They are likely to entirely replace batteries within the next few years as they continue to be increasingly cost-competitive.

But even as ultra-capacitors are seemingly here to stay, energy-storage technology is in such high-speed development that there is no telling what the next innovation will bring. Since energy storage systems are components that wear out relatively quickly, they might need to be replaced during the lifetime of the turbine by newer, more competitive products. For that reason, choosing a pitch system that has the flexibility to open up to different technologies for energy storage will offer a long-term advantage.

Why electrical pitch systems will finally take over hydraulic solutions: Over the last few years, electrical pitch systems have become affordable, reliable, and safe. For these three reasons they are gradually replacing the traditional hydraulic systems at an increasing rate.

Although hydraulic systems are extremely reliable and have fast pitching performances, their tendency to leak remains a significant downside, if not a deal breaker. Indeed, oil leaks are bound to occur during the lifetime of the turbine and cause significant disorder in the hub. Anybody who is familiar with operating wind farms knows that nothing is more common than the sight of black patches of oil and grease leaking down through the space between the tower and the nacelle. The fear of leaks also explains why hybrid electric-hydraulic concepts have been almost entirely abandoned.

A vast majority of the newer turbine designs rely on electrical pitch systems. Specifically, all machines designed for extreme weather conditions or for offshore — two major areas of future wind power deployment — are better suited to electrical systems that can handle hot or cold temperatures and have lower maintenance requirements.

Individual pitch control: A genuine technology breakthrough: In the wind industry, the pressure to lower the cost of energy is high. Investors who focus exclusively on lowering CAPEX and increasing the payback rate too often choose to ignore the fact that turbines deliver their energy over 25 years. However, taking into consideration the total lifecycle of the assets in order to reduce the cost of energy is paramount if the overall loads are to be lowered on the turbine as well as securing the optimal output. During the last couple of years, a number of improvements have been introduced that help run the pitch systems more effectively, the most important being Individual Pitch Control (IPC). By reducing loads, this ground-breaking technology brings the full breadth of its benefits over the entire lifetime of the wind project.

Let’s keep in mind that the pitch and turbine-control systems together represent only 4 to 6 percent of the total turbine cost depending on the turbine size. This cost can be largely offset thanks to the benefits of IPC. Not only does IPC lead to more annual production, but this innovation can also, through the reduction of structural loads, extend the lifetime of the assets by up to five years. In addition, the reduction of loads allows for a lighter overall turbine design with a cheaper bed frame, or smaller tower. IPC can enable OEMs to increase blade length while keeping structural loads low. That is a key driver to help bring turbines to lower wind areas, which is another key trend in wind-farm development.

The leading international OEMs understand the advantages of IPC well, especially those that are experienced in delivering long-term O&M contracts. Unfortunately, this approach to long-term asset management is not widespread in the industry yet. Although everybody agrees on the benefits of IPC on a theoretical level, only a limited number of OEMs already have implemented it in their designs. One of the reasons for the relatively slow adoption of IPC is the initial installation cost of the additional hardware and software needed as well as its higher control complexity. The second reason is the lack of empirical proof of the long-term indirect financial gains. The last reason is that most pitch systems in the market today are not fast enough to use IPC. Pitch speed is key to taking full advantage of the load reduction capabilities offered by individual pitch control.

Despite all this, IPC is bound to continue to be steadily integrated into modern turbine designs, especially for offshore turbine.

Pitch system redundancy will boost offshore availability: The continuous growth in turbine size, especially offshore, poses new challenges and opportunities for pitch control. As blades are getting longer, they are exposed to increasingly asymmetric wind forces across the sweep area, creating fierce demands on the pitch system. Downtime, which causes heavy financial loses, must be avoided at all cost. Due to the reduced accessibility of assets at sea, minimizing maintenance requirements as well as increasing availability have become decisive criteria for the project owner. For the same reason, the demand for remote troubleshooting is much higher than for onshore projects. And the key to achieving all this is redundancy.

Redundancy has been the vision for a while, but excessive cost was the main impeding issue. Fortunately, offshore turbines offer significant economies of scale that should allow for the use of costlier, high-performance pitch systems, whilst still achieving the best overall cost of energy. These systems are set to deliver outstanding reliability through redundancy.

Essentially, the traditional single pitch motor design will give way to designs incorporating multiple smaller pitch motors. These motors will distribute the loads around the pitch bearing while reducing slack. Full redundancy will ensure continued availability even if one part of the system fails.

Image 1

Pitch motors are heavy components, and repairs due to breakdowns are costly. However, if two pitch motors are in working condition, the turbine can still deliver energy, albeit at a reduced load, until the weather permits the maintenance crew to reach the site.

As the offshore wind industry develops, pitch control redundancy will play a key role in keeping large turbines safe and running.

Making sense of pitch systems retrofitting: Although only one-third of installed turbines globally are equipped with active pitch control systems, retrofitting them is less straight-forward than it seems. Turbines are often too small to justify the investment. In addition, old models often cannot be fitted with new pitch systems without upgrading the entire turbine control.

This situation is going to change progressively in the next five to 10 years as bigger turbine models become eligible for retrofitting. However, only 1.5- to 2-MW turbines associated with a good Power Purchase Agreement can justify the replacement with a bigger rotor, along with an upgraded pitch system. The other exception concerns poorly performing wind farms, where defective pitch systems need to be upgraded even if the rest of the turbine operates as planned.

Making the Right Blade-Pitch System Call

Reliability always comes first: Any company looking to integrate a pitch system into its turbine design must, first and foremost, recognize the pitch system is a central part of the turbine safety system. It has to work seven days a week, day in, day out. That’s why OEMs always should select partners backed by a strong track record in system reliability.

Of course, cost is an important factor, as well as reducing structural loads and extending the turbine lifetime. Nonetheless, unwavering reliability is the first consideration to take into account, because a failing pitch system can destroy the asset it was meant to protect.

One important element is the speed at which the system can pitch blades according to variations in weather conditions. This is vital when coping with extreme weather events that will eventually hit a fleet during its 25-year lifetime. When exposed to such events, lower quality blade pitch systems may not be able to cut out of the wind fast enough or as calculated, and damage the entire turbine.

The guarantee for reliability comes from the extensive field experience brought by thousands of pitch systems designed for different turbines, operating in different climates, and different countries. Only a handful of companies in the global wind industry have acquired such track records.

360-degree understanding of wind-turbine control: Secondly, pitch systems are an integrated part of the overall turbine control system, which means that the continued cohesion of its various components must be ensured. Experience has shown pitch failures often come from a lack of understanding of how intimately all the turbine control elements interact with one another.

To get the right pitch system for a turbine prototype, a complete set of simulations is required. This can be achieved by using “Bladed Models” with a full WTG model simulation. Combined with practice, know-how, and a lot of field experience, thorough simulations can determine the optimal solution.

Image 2

It will also help to ensure the turbine is suited to its operating conditions. In this instance, an extensive and diversified track record and the breadth of feedback data it generates are important.

And yet, to build their turbine, some OEMs quaintly still imagine they can save costs by shopping around for the cheapest off-the-shelf components. Lowering the turbine, CAPEX becomes the only objective worth pursuing for them. Nonetheless, they are likely to learn that, for all the money it might save upfront, they will remain at the mercy of potential downtime. When failure does occur, the odds are the unfortunate OEMs will be looking for a recognized control expert within days.

Off-the-shelf products can do what they can do. At the very least, the entire control system must be thoroughly tested and assembly must be optimal. Even then, they are never going to be as well-integrated as when both pitch and turbine-control systems come from the same supplier.

The final advantage resulting from having a single technology partner for the combined control and pitch system is effective troubleshooting. All lines of inquiries are addressed in a single point of contact. It is especially useful since, in most cases, OEMs do not know which element of the system is actually causing the failure. Finally, it will help resolve issues quickly, as well as maintain a well-optimized complete system.

The benefits of system flexibility: Successful pitch-control suppliers are, above all, technology companies that have demonstrated their ability to stay at the peak of innovation over time. The level of flexibility of the selected technology is a key parameter to take into account.

With regard to turbine development, OEMs must take a long-term view of pitch control and look for a technology partner that can supply the system they need today, but also the system that will be needed in the future. Indeed, all the lessons learned from the first design can be drawn upon to create the next, more advanced system, instead of starting from scratch with every turbine prototype.

A flexible system can adapt more easily as the turbine design gets upgraded. Being flexible means staying clear of systems that have a low degree of versatility and adaptability, such as compact low voltage pitch systems. Going with mainstream technology offers high sub-components availability over time, and will ensure the best long-term benefits out of the pitch-control system.

Successful Project, Successful Partnership

Achieving optimal pitch control and minimizing structural loads requires a unique set of design and technology skills. It requires expertise in load simulation, control algorithms and wind-turbine optimization. It demands a partner that can deliver a complete design process and run all simulations of the turbine to truly deliver the optimum pitch system needed for prospective field conditions. And above all, it demands a partner that can deliver the twin goals of optimal annual production and asset safety. 

Strong Winds Ahead

0

Without gazing into an actual crystal ball, it can be tough to see exactly which way the breeze may be blowing for the wind industry for the coming year.

But by using 2016 as a barometer, it is possible to make an educated guess on where the industry is headed in 2017.

The biggest catalyst for wind was the renewal of the Production Tax Credit (PTC) in January.

“The PTC extension that we received provided a really great multi-year plan with some visibility out to 2019,” said Duncan McIntyre, president of Altenex, an Edison Energy Company. Altenex helps commercial, industrial, and institutional energy users purchase renewable energy. “It allows developers in the whole industry to plan around the incentives and make sure the projects are completed appropriately.”

And that was important, because at the end of 2015, the industry was caught in a whirlwind, according to McIntyre.

“There was a scramble to complete projects before the PTC expired,” he said. “There were developers raising capital for physical construction, but as a result of that PTC cycle, the quantity of high quality projects that were available for immediate transaction actually dwindled by the end of (2015). Any project that was in a too-early stage of development was abandoned because people didn’t want to spend money to develop it if they couldn’t get it built in that cycle.”

Because of that rush, when the PTC was extended in January, wind projects were scarce. The current PTC expires Dec. 31, 2019.

Rebuilding Year

“I think 2016 was a rebuilding year for the industry in terms of quality development assets,” McIntyre said.

The industry has been playing a bit of catch-up in 2016, but the business case for investing in wind has never been stronger, he said.

“There’s a business case associated with every corporate buyer,” McIntyre said. “Sometimes that business case is they want to put a major stake in the ground around sustainability or climate-change leadership, so this is a way to do that. In some other instances, it’s more purely financial. Companies want to save money, and they want to manage their risk. Renewable energy is a tool to accomplish financial, risk, and sustainability objectives.”

McIntyre predicts the areas that will see the most activity in the coming year will be deregulated markets at the retail level.

“Texas is a great example of a market that’s very open,” he said. “The business case is strong. And it’s strong because businesses can demonstrate that they’re able to save money. The sustainability leadership is strong.”

McIntyre also expects to see more activity with PJM Interconnection, a regional transmission organization that coordinates the movement of wholesale electricity in Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and the District of Columbia.

“PJM is another example of a market where there’s been less corporate activity historically,” he said. “We believe there will be more. When we look at 2017, I think it will be a big year for corporate PPAs in the PJM market, and there’s a fairly open wholesale market. There are plenty of pockets of deregulated retail supply — Ohio, parts of Illinois — so the market systems are there, and the business case is strong in certain places. Those are the areas where we will see the most activity.”

And the perception that the U.S. lags behind wind production in other countries couldn’t be further from the truth, according to McIntyre.

Maybe that was true 10 years ago, but a lot has changed since then.

“I would say we’re a pretty serious player, if you look at the last five years,” McIntyre said. “If you look at the number of gigawatts we’re bringing online per year or per quarter, I would say we’re a pretty meaningful market.”

Corridor Saturation

Something on everyone’s radar is the risk of saturating traditional wind corridors in the U.S.

“I don’t think anyone knows the answer to that question as to what the appropriate level of wind penetration is that can still allow the system to balance appropriately,” McIntyre said.

But he said an increase in natural gas facilities has helped support an increase in areas ripe for wind penetration.

“Gas plants have a degree of flexibility that didn’t exist with nuclear plants or certain coal plants, so I think we’re improving the potential for renewables penetration,” McIntyre said.

As far as traditional windy markets becoming unavailable, he said he doesn’t see that happening anytime soon.

Technology Advances

And part of that reason is the industry is constantly improving wind-turbine technology.

“You don’t need the strongest wind resource available anymore to make a compelling argument for renewable energy,” McIntyre said.

A continuing trend for larger turbines, taller towers, and bigger blades is driving that technology need.

“And manufacturers are very much meeting that need,” he said. “They’re developing the products and what’s interesting to me is that some of that technology is developed for reasons you would not expect, or it’s benefiting the industry in ways you would not expect.”

McIntyre gave Ohio as an example. The state recently changed its setback rules. Those rules dictate how far away a turbine can be placed near a property line.

As a result, fewer turbines are allowed in a certain area. With taller, bigger turbines, more power can be produced with fewer assets.

One area many in the industry are watching is whether President Barack Obama’s environmental policies will be allowed to take stronger actions against carbon emissions.

“There are some open questions,” McIntyre said. “The Clean Power Plan is making its way through the system.  And there are more and more discussions around using market mechanisms like a price on carbon. And while some of the policy questions get sorted out, the commercial and industrial market continues to adopt and benefit from renewables offtake.”

Deregulation

But beyond technology, beyond EPA restrictions, McIntyre said the biggest positive move for the industry going into 2017 would be more deregulation.

“We think that the industry could grow faster and be more meaningful as a contributor if users had more control,” he said. “Look at a market like Texas — deregulated wholesale and deregulated retail. That’s a great structure because the end user, let’s say it’s a corporation, chooses to buy power from a local retailer, from a local utility in some cases, and they can also choose to buy directly from a big wind farm.”

The biggest inhibitor to growth occurs when regulations make it difficult to do anything other than buy from their retailer, according to McIntyre.

“Creating the open-market structure and then creating the commercial structures is an ongoing trend that I expect to see more of next year,” he said. “They allow for competition, and they allow for buyers and sellers to meet up, and that ultimately drives down costs. And so that’s the start.”

ABB Launches Flexible ‘Plug And Play’€™ Microgrid Solution

0

ABB announced a modular and scalable “plug and play” microgrid solution to address the globally growing demand for flexible technology in the developing market for distributed power generation. The cost-efficient, containerized solution is relevant for mature and emerging countries and will help maximize the use of renewable energy sources while reducing dependence on fossil fuels used by generator sets.

 ABB’s innovative technology with the PowerStore Battery and the dedicated Microgrid Plus control system as well as cloud-based remote service provides power access to remote areas and secures a cost-efficient uninterrupted power supply to communities and industries during both planned and unplanned power outages from the main grid supply.

Image 1

All the equipment required to run the microgrid — ABB’s power converter and dedicated control system, Microgrid Plus, as well as battery storage — has been integrated into a container for faster, easier, and safer deployment. The customer can choose to configure the microgrid to integrate energy from solar, wind, main grid, or diesel generator supply, based on the application and local conditions.

ABB’s modular microgrid is compact and has four pre-designed variants in the range of 50 kW to 4,600 kW, to meet varying customer needs. The standard integrated functionalities include grid-connected and off-grid operation with seamless transition. It is a containerized solution designed for easy transportation, fast installation, and commissioning onsite. Operations and maintenance is enabled via a cloud-based remote service system, another example of ABB’s clear positioning as a pioneering technology leader driving the energy and fourth industrial revolutions.

“Our modular, standardized, and scalable microgrid solution will provide cost efficient access to reliable power for rural and urban applications, as a plug-and-play solution,” said Claudio Facchin, president of ABB’s Power Grids division. “It exemplifies ABB’s continued commitment to innovation and reducing environmental impact by enhancing the integration of renewable energy sources and reducing dependence on fossil-fuels, all key elements of ABB’s Next Level strategy.”

ABB is a pioneer and world leader in microgrid technology with more than 30 completed installations across a diverse range of applications serving remote communities, islands, utilities, and industrial campuses. ABB’s comprehensive microgrid offering includes consulting, design and engineering, supply, installation commissioning, and lifecycle services. 

Source: ABB

For more information, go to www.abb.com