Navigant Research Blog

Intellectual Property Battles Roil the Wind Power Industry

— February 11, 2015

Wind turbine vendors vigorously pursue intellectual property (IP) advantages in technology and ruthlessly defend them to maintain an edge over their competitors. The 2010 clash between GE and Mitsubishi over low-voltage ride-through and variable speed operation reportedly caused Mitsubishi to start sweeping its cavernous exhibit booth at trade shows, on the lookout for electronic surveillance devices planted by rivals. In another example, IP battles between Kenetech and German supplier ENERCON—the world’s third-largest wind turbine vendor by market share in 2013—resulted in ENERCON abandoning the U.S. market entirely.

One of the latest patent fights to spill into the headlines is between ENERCON and Siemens, over so-called de-rated operation. Who will win this round is anyone’s guess, but it’s another example of the rapidly advancing technology that continues to improve the performance, efficiency, and grid-friendly capabilities of wind turbines.

Slowdown, Not Shutdown

De-rated operation is the ability of a wind turbine or an entire wind plant to operate below its maximum capacity during times of high wind speed. Traditionally, when wind turbines reach their thresholds for maximum wind speed (around the 25 meter per second range), they will enter a cut-out and shutdown mode to protect the rotor, tower, and drivetrain from damaging stress. However, this process takes the electricity production offline, which can destabilize the broader power grid. As the commercial-scale deployment of wind turbines increases, this becomes a larger concern.  De-rating uses a range of control methods, from pitch control of blades to generator torque control to operate a wind turbine at below its maximum capacity.

For example, instead of a 2 MW wind turbine shutting off once it encounters its threshold cut-off wind speed parameters, it can reduce its output to (for example) 50% capacity, or 1 MW. This ensures that the wind plant remains operational, balancing the grid, and that kilowatt-hours continue to be produced instead of lost due to a full shutdown. There are also economic inefficiencies associated with stopping and restarting wind turbines that can be avoided by running at reduced load. This approach can be used to continue the operation and revenue generation of a wind turbine that is experiencing high operating temperatures within the turbine drivetrain, which can trip a control system that shuts everything down to prevent damage to the turbine. De-rating can allow power production to continue while temperatures are reduced to acceptable levels without entirely shutting the turbine down.

Storm Warning

ENERCON named its system Storm control; Siemens calls its system High Wind Ride Through (HWRT). GE Energy—likely as a way to avoid a similar IP battle with ENERCON—uses a de-rating approach that collectively de-rates all of the wind turbines at a wind plant. Spain’s Gamesa fought a 3-year battle to invalidate ENERCON’s patent, but lost in February 2014. Other vendors currently have or are bringing to market similar strategies—and all are certainly watching this patent fight closely from the sidelines.


A New Dawn for Lead Batteries

— October 2, 2014

Donald Sadoway, a materials scientist at the Massachusetts Institute of Technology, is considered one of the smartest and most creative battery scientists in the world.  So admired is Sadoway that, when former Microsoft CEO Bill Gates wanted to learn about batteries, he took Sadoway’s course.  Afterwards, he approached Sadoway and the two discussed the topic of how to rethink battery design from a blank page of paper.  That discussion led to the founding of Ambri, a startup company that is based on Sadoway’s ideas for how to build a better battery.  And at the heart of Ambri is Sadoway’s concept of a high-temperature liquid metal battery whose cathode and anode literally float one on top of each other.

Ambri’s first attempt at a prototype involved the metals antimony and magnesium.  The concept worked, but the high melting point of magnesium (650 degrees Celsius) and the relatively high cost of that material made the prototype battery too expensive to compete against lower-cost batteries like lithium ion and lead-acid.  So Sadoway and his research team kept working.  In a paper just published in the journal Nature, the team released the results of their second prototype, which uses an old standby material of the battery industry: lead.

Melting Point

The battery consists of three basic inputs: lithium salts, lead, and antimony.  The lithium serves as the anode, or negative electrode, which holds the energy in storage while the battery is being charged.  Alloyed together, the lead and the antimony form the cathode, or positive electrode, which releases electrons during the discharge of the battery.  Once the battery is heated so that the alloy mixture and the metallic lithium melt into liquids (which requires a temperature of 253 degrees Celsius), the battery can start cycling through charges and discharges.  The lower temperature means that there are fewer parasitic losses during cycling, which makes the battery more efficient (the paper claims a 73% round trip efficiency, which is similar to the efficiency of many flow battery technologies).

More interestingly, Sadoway’s team calculates that the cost of input materials for the battery would be a mere $68 per kWh, which compares favorably to almost every other battery chemistry.  Finally, the Nature paper shows that accelerated testing of the battery predicts that, after 10 years of daily 100% cycling, the battery will still have a usable capacity above 85% of the capacity the battery had when it went through its first charge/discharge cycle.  In that regard, it compares to accelerated testing of other high quality batteries.

Lead Leader

Will Ambri’s new battery take over the market share of the other incumbent battery technologies?  It’s not likely.  Because the battery needs to be kept at a high temperature, it won’t function well in situations that require maximum flexibility and uncertainty.  However, it will be an excellent choice for any application that requires a long-duration and highly consistent charge/discharge cycle.  Although that’s a niche of the overall stationary energy storage industry, it could eventually be a large one.  Decades from now, when people talk about lead batteries, they might just be referring to Ambri’s molten battery, not their car starter batteries.


On the Grid, Time Is of the Essence

— October 2, 2014

The precise calculation of time is at the bedrock of nearly all modern technology, including mobile telecommunications.

In technology, we’re talking really granular time – time measured in milliseconds or less.  Early telecommunications were based upon time-division multiplexing (TDM), and telecoms today still depend upon successors to TDM.  Newer smartphones have onboard accelerometers and gyroscopes to measure velocity in three dimensions – all time-based.

Electric grids are no exception.  An instructive example is the time-synchronized phasor measurement unit (PMU).  Synchrophasors are networks of PMUs that measure the phase angles of the alternating current (AC) at various points along a high-voltage network.  Power flows from higher angles to lower angles, so some difference in phase angles (the phase shift) is expected, but not too much.  As wide area situational awareness tools, synchrophasors can supply an early indication that something is amiss in a high-voltage transmission network.  After-the-fact analysis shows that during the Great Northeast Blackout of 2003, phase angles that were normally shifted by 25 degrees had increased to a 135-degree shift.  Had synchrophasors been widely available and deployed at the time, it is likely that much of the outage could have been foreseen and prevented.

Obey the Time

But time is critical to synchrophasors’ performance.  To ensure coordination, all the PMUs in a network take their time stamp from a single GPS satellite.  The time stamp is added to the reading and sent to a phasor data concentrator (PDC).  This typically happens 30 times per second.  Comparisons at the PDC or other central sites indicate whether or not phase shifts are within expected tolerances at each PMU.  Out-of-tolerance measurements indicate that immediate action is required.

Here’s the problem: if the time stamp is unreliable, then a valid comparison of phase angles is impossible.  Synchrophasors are but one example, and for sure there are worse things that could result from the loss of reliable time service – loss of geospatial information systems, for example.  But the point remains: time is key.

All of this leads to time as an attack surface for smart grids.  PMUs are one of many devices in a grid that rely upon synchronized time to give utilities control of their networks.  Newer clip-on line sensors promise to make distribution management more granular as well, by taking thousands of readings per second.  Again, those readings must be accurately time-stamped to be of any use.

Point of Vulnerability

Disrupt time and you disrupt the grid.  How many ways are there to disrupt the time signal across a synchrophasor network?  Taking out a satellite is an extreme possibility, but there are simpler earthbound approaches.  My paranoid security mind just won’t let me list them in this blog however.

We depend upon time for much of what we do.  We need time readings to be there for us reliably, down to the millisecond or less.  And yet, time is not defined as a U.S. critical infrastructure sector.  Where is the defense for this irreplaceable asset?

I must credit Frank Prautzsch of Velocity Technology Partners for raising time as an issue at a recent cyber security conference.  Frank’s point, which I hope I have amplified here: while we consider complicated attack scenarios against smart grids, there are some really basic things that must also be defended.  Time is among the most basic of them all.


With 3D Technology, You Can Print Your Ride

— September 29, 2014

At the recent International Manufacturing Technology Show in Chicago, a car was printed in just 44 hours.  A sporty-looking black coupe, the Strati was built using a large-scale printer known as a Big Area Additive Manufacturing (BAAM) system.  A BAAM can build products that reach up to 8 feet in length, as opposed to the 1-foot dimension now available from desktop commercial 3D printers or at your nearby UPS Store.  Printing the body of the car in carbon-reinforced ABS plastic live at the conference, the demonstrators showed the utility of 3D printing for industrial and commercial products.  Not that cars can or will be mass printed anytime soon, but the cost and time in the engineering design process, from concept to design to prototype, can be reduced for high-end industrial products.  The likelihood of seeing a Strati roll down your street anytime soon is very, very small.  Perhaps if the Strati was printed with carbon fiber or other strong materials from new arrival MarkForged, coming across one in public would be more likely.

The use of 3D printing in the automotive industry is increasing, even though automakers have been using advanced manufacturing for decades.   Ford has used 3D printing for testing axles, brake rotors, and cylinder heads.   General Motors (GM) recently highlighted the use of 3D printing to prototype parts for the 2014 Chevy Malibu, both inside and out.  At GM’s Rapid Prototyping lab, the front end was redesigned, printed, and tested for aerodynamics in the wind tunnel, cutting costs and saving time.  Inside the car, designers are using 3D printing to test the visual look and accessibility of parts like internal trim and seat-back panels.  Yet, it took an act of nature for GM to make waves in the 3D printing world.  In early September, a rainstorm caused flooding in GM’s Rapid Prototyping facility in Detroit, Michigan, ruining equipment.  As a result, GM purchased over $6 million worth of 3D Systems products, including the iPro 8000 Stereolithography printer.  In the small 3D printing world, this is large, as it validates the value of the small form factor 3D printer.

Auto API

Other manufacturers are showcasing the use of 3D printing.  A scaled-down version of Toyota’s FT-1 concept car, presented in April at the New York International Auto Show, now seems like old news.  At first glance, the same appears true for Honda printing 3D versions of its concept cars.  Yet, Honda is going one step further by making the printing plans (the computer-aided design [CAD] files) available for free download, in the hopes that fans will print their own designs, creating a new kind of conversation between designers and consumers.

The most interesting deployments of 3D printing in cars are still in the concept stage.   As part of his master’s thesis at the Umea Institute of Design in Sweden, Erik Melldahl worked with BMW to design the Maasaica, an off-road coupe designed for rural Africans.  Printed from a biodegradable material composed of mycelium mushrooms and grass, the material can be grown in a number of days.  The car would collect ambient water for cooling and local uses, and it would be connected to the Internet.  Melldahl’s bushmobile highlights how 3D printing is changing industry – by enabling the redefinition of what a car is, how it’s made, and how it interacts with its environment and its users.


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