Navigant Research Blog

Evaluating New Frontiers in Wind Energy: Saying Goodbye to Blades, Part 2

— January 13, 2017

Tablet Device with StatisticsThis blog is the second part in a continuing series examining new and innovative technologies in the wind energy industry.

The first blog in this series discussed the Vortex Bladeless wind turbine. The Spanish company behind the Vortex has been successful in securing funding, but it has yet to move out of the R&D phase and still has a long road ahead before actual orders are placed. In addition to the oscillating tower design, wind turbine engineers have explored other concepts that can generate electricity from wind. One particular company, Saphon Energy out of Tunisia, has come up with a design inspired from ancient sailboats and movements of fish and birds. The turbine is unique, and the small startup has big aspirations for how its machine could revolutionize the industry.

The Saphonian does not work in the same manner as a typical wind turbine—in fact, the company does not define it as a wind turbine at all. The system works with a disk that moves around in a figure eight motion driven by the wind. While specific details of the exact process for how exactly the unit uses this mechanical motion to generate electrical energy have not been disclosed by the company, it is believed that the machine uses a system of hydraulic cylinders and fluids to essentially run a hydraulic pump backwards in order to extract energy from wind.

Saphon Energy’s Saphonian

Saphon Energy

(Source: Saphon Energy)

Excitement and Skepticism

Saphon Energy has made several claims with its machine which, if true, would make it a very desirable option for developers interested in distributed wind. So the question is, if these claims are true, why hasn’t the Saphonian made bigger noise in the wind energy industry? Saphon says its wind system can generate twice as much energy as a conventional wind turbine with the same swept area while also boasting an efficiency of 70%. Because the Saphonian is not classified as a turbine, it is not subject to the Betz Limit, which says that a turbine can convert no more than 59% of the kinetic wind energy into electrical energy. These claims need to be shown in real-world applications before they can be taken seriously. Additionally, the figure eight motion would likely cause significant stress on the rotor system and quickly lead to material fatigue. The only explanation currently offered by the company is a vague state-of-the-art design statement that does not disclose how the machine counters mechanical stress. As of now, the system is only designed for power outputs of 20 kW to 50 kW. Developing a machine that is scalable up to commercial-scale size of 3 MW or more while maintaining a competitive cost will prove to be a significant challenge.

While skepticism for the Saphonian should be expected, there’s still reason for optimism for the young company to eventually break into the market. Microsoft signed an alliance with the Saphon Energy in 2014 as part of its 4Afrika initiative. The company has also been the recipient of several awards, including the 2015 Gulfstream Navigator Award. The company also has reportedly signed an agreement to make a 1 MW test site in India, where it will install 50 of its 20 kW machines by 2018. An agreement to actually install the machines is a major first step for a small wind startup like Saphon, and while news has been relatively quiet for the company in recent months, there’s reason to believe the company has the opportunity to make a dent in the global wind market. Though a substantial uphill climb remains, this innovative startup is worth committing to memory for the time being.


Evaluating New Frontiers in Wind Energy: Saying Goodbye to Blades, Part 1

— August 19, 2016

TurbineThis blog is part one in a series evaluating new techniques in extracting power from wind.

Wind power is no different from any other energy technology in that it is constantly evolving and the quest to find the most efficient and cost-effective method is seemingly never-ending. As a result, there is no technology or design that is off-limits as long as it effectively creates power from wind. For over 3 decades, the bladed turbine has been the default technology in the market. To put it a better way, it has been the only technology in the market, and for good reason. It is effective and it has been researched and tested by hundreds of companies for years.

The bladed turbine has established a firm foothold in the wind power industry, and it isn’t going anywhere. That being said, it has been brought up that the advancement in efficiency of bladed turbines has begun to plateau. Whether or not this is truly the case, the notion has inspired engineers around the globe to break the mold of traditional wind power. One idea has been to get rid of blades altogether.

Vortex Bladeless

One startup that is looking to capitalize on this concept is Spain-based Vortex Bladeless. Still in the R&D phase, the company developed a narrow, cone-shaped structure to siphon power from the wind. The concept is completely different from the traditional bladed turbines which, simply put, use wind to turn the blades, which rotates a shaft and runs a generator. The Vortex design creates turbulent eddies in the wake of the tower. These spinning vortices create an oscillation, typically a no-no in the architecture and engineering world as it induces unwanted stress on the surrounding structures. Vortex, however, is using these oscillations to generate electricity using an alternator that multiplies the oscillation frequency.

Vortex Bladeless Tower Design

Vortex 6m Prototype

 (Source: Vortex Bladeless)

Market Skepticism

The company advertises two different systems: the Vortex Mini and the Vortex Gran. The former is a 4 kW system and the latter is (supposedly) capable of producing 1 MW+ of power. The benefits of these machines, according to Vortex, are that they cheaper to build and maintain due to fewer moving parts and less wear and tear. Furthermore, the company says they are quieter and more environmentally friendly. These claims have yet to be fully vetted and some are already showing skepticism. It is too early to really confirm or deny the company’s claims of a 53% reduction in manufacturing costs and 51% reduction in operating costs. Initial concerns stem from the fact that the oscillation frequency would continuously change as the wind speed fluctuates and thus the frequency of the electricity generated would be nearly impossible to control or predict. It would require a complex and likely very expensive electronic control system in order successfully export this power to this grid. History doesn’t appear to be on Vortex’s side, as a similar concept was introduced several years ago and never made a dent in the market.

The Spanish startup claims to have raised $1 million from private donations and government funding and is hoping to complete a round of donations in the United States. Additionally, Altair has stepped in to provide support in the form of free software licenses and training. Altair’s finite-element analysis and computational fluid dynamics packages are expected to help Vortex move toward a more simulation drive approach in their design. There are some favorable signs for Vortex to become a legitimate market presence in the wind industry, but the company has a long road ahead. A 100 W prototype is in development and the 41-foot Vortex Mini is expected to be ready by 2018. The company must overcome countless obstacles before inking a contract is even conceivable, and winning over the skeptics might be the biggest challenge of all.


The Growing Role of Energy Storage in Microgrids

— May 23, 2016

GeneratorEnergy storage systems (ESSs) have an important and diverse role in microgrids. Solar PV and other renewable distributed generation (DG) technologies require a voltage source in order to synchronize. This has typically been done with a backup generator; an ESS provides a similar voltage source but without the emissions of a diesel generator. Recent advances in microgrid automation systems, however, have made ESSs less of a necessity in partially renewable-based microgrids. According to industry leader ABB, microgrids with as much as 50% of load coming from renewable sources do not need an ESS. This is 10% higher than previously believed. Despite this, microgrids without some form of storage are not likely to become the norm, as ESSs provide a number of other advantages aside from being a voltage source. Peak shaving, smoothing power flow, and volt ampere reactive (VAR) support are just a few of the supplemental functions an ESS frequently serves. Islanding and black-start assistance further support the case for storage use in renewable DG microgrid systems.

The most recent update of Navigant Research’s Microgrid Deployment Tracker investigated the use of ESSs in microgrids across the globe. According to the report, of the greater than 15 GW of microgrid capacity accounted for in the Tracker worldwide, almost 25% utilized ESS in some form, up from a reported 17.5% of projects in the previous Tracker update in 4Q 2015. This is a result of ESSs being present in over 40% of new project capacity from the most recent update.

The chart below shows the percentage of ESS utilization by microgrid segment for both the 4Q 2015 and the 2Q 2016 Tracker. While ESS utilization grew across all categories, the commercial and industrial (C&I) and utility distribution segments saw the most significant increase, growing 40% and 23%, respectively. C&I microgrids have traditionally been led by diesel combined heat and power (CHP) systems in the past. The jump in energy storage use among microgrids in this segment likely signals a shift to solar PV and other renewable energy use that has a higher need for ESSs.

ESS Utilization by Microgrid Segment, World Markets: 4Q 2015 and 2Q 2016

Adam Wilson Blog

 (Source: Navigant Research)

This is further supported by the fact that solar PV capacity in microgrids grew by almost 840 MW since the last update of the Tracker, an increase more than 5 times greater than CHP capacity growth. The combination of solar PV and ESS is expected to grow in popularity across most segments and regions of the microgrid market. The declining price points of energy storage and solar PV technologies and an increasing focus on renewable sources are largely responsible for this shift. It has also been suggested that the combination of CHP, solar PV, and lithium ion energy storage represents the ideal mix of technologies for microgrids, particularly in the United States.

The high functionality of storage systems along with the growing presence of renewable generation in the microgrid market bode well for the future of ESS. These systems are expected to remain a core technology in the microgrid industry for the foreseeable future.


Building a Better (and Bigger) Wind Turbine

— February 11, 2016

Der Rotor wird angesetztIn early 2014, MHI Vestas, a joint venture between Vestas and Mitsubishi Heavy Industries, announced its new V164-8.0 wind turbine. Designed for offshore use, the massive wind turbine is currently the largest in production and already has secured orders at multiple offshore wind farm projects including the Burbo Bank Extension, the Walney Extension, and the 448 MW Borkum Riffgrund II project in Germany. At 80 meters long, the blade is the largest in the industry, not counting the 83.5 meter blades used in the Samsung S7.01-171 turbine currently in limbo. A team of researchers has been given a grant by the Department of Energy’s Advanced Research Projects Agency-Energy program to develop a 50 MW wind turbine that would require a blade at least 200 meters long. The idea is that a single machine capable of producing the same amount power normally generated by 10 to 20 machines will reduce overall construction and maintenance costs.

Researchers from several different institutions will collaborate to design this massive turbine. Led by the University of Virginia, the project will also include engineers from Sandia National Laboratories, the University of Illinois, the University of Colorado, the Colorado School of Mines, and the National Renewable Energy Laboratory. Corporate advisors will include Dominion Resources, General Electric (GE), Siemens, and Vestas. The project will be a continuation of the work Sandia has completed on a 100-meter blade (328 meters in diameter) that would go into a 13 MW wind turbine. Doubling the length of a turbine blade is no small task. Segmenting the blades can help solve the construction and transportation issues; however, the massive weight and associated blade fatigue, peak stresses, and cost are major limiting factors.

Cutting the Weight

Sandia has experimented with several different technologies in an attempt to reduce the weight of the blades. The addition of a carbon spar cap, new core materials such as balsa, and flatback airfoils have all been examined. The company accomplished a weight reduction of over 50% from its original 100-meter blade design, which weighed in at 114 tons. Studies and testing have continued in order to quantify potential issues such as tip deflection, panel buckling, flutter speed, and aerodynamic design load.

Palm Trees for Turbine Inspiration

Adam Wilson Blog

(Source: Popular Science)

These blades will utilize a design called the segmented ultralight morphing rotor. They will be built and assembled in segments to avoid the difficult logistics of transporting blades built as a single unit. Because of the blades’ adaptability to windflow, they will have less structural mass (i.e., ultralight). Unlike conventional turbines that are configured upwind of the rotor, these turbines would be placed downwind. This feature, combined with the segmented nature of the blade, allows them to bend forward in order to reduce stress in strong windstorms such as hurricanes. This feature was inspired by the way palm trees move in wind storms. When speeds are within the optimal power-producing range, the blades will spread out in order to maximize energy generation.

Chances are slim to none that this technology makes it into the marketplace anytime soon, if at all. However, people today are surrounded by once seemingly impossible technology deployments from the nano to macro scale. At the very least, research projects like this are showing that when it comes to advancements in wind turbine technology, turbine vendors and researchers alike are not afraid to think big.


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