Energywise iconEnergywise

Lasers Can Remotely Monitor Oscillations of Wind Turbines

Wind turbines, like any machine with moving parts, can fail. They have a useful life span, after which the loading on the various pieces including turbine blades and tower could cause decreases in efficiency or, in very rare cases, outright collapse. That loading comes during normal operation, but the oscillations the turbine undergoes play an important role in just how long a turbine will survive. Heretofore, sensors placed physically on the turbine have been the method of choice for measuring the oscillations. But lasers might work better.

A new system, to be demonstrated at an IT conference called CeBIT in Hanover, Germany, in March, combines a low-power laser with a camera to comprehensively assess oscillations of a wind turbine. Unlike the sensors-on-the-turbine technique, with which the oscillations are really only recorded at the specific points where the sensors sit, the laser-based method captures the entire oscillatory pattern—on the blades, tower, all of it—and paints a more complete picture.

Researchers at the Fraunhofer Institute in Germany created the new system. From a press release:

"The centerpiece of the system responsible for this is an IT-based tracking system combining a camera and a laser. These are mounted on a head that can pan and tilt to follow the rotor blades. The camera records images of the installation and forwards these along to software that processes the images and builds a model of the rotary motion from the data. With the help of this information, the pan and tilt head is positioned so that the laser automatically follows the rotor blades. The camera simultaneously collects data about the exact position of the roughly two-to-three centimeter laser spot on the rotor blade in order to stabilize it on the revolving surface."

The researchers, led by Ilja Kaufmann, say that the system is easily transportable, and can work from hundreds of meters away from the turbine itself. Assuming it's possible to correct for the laser's motion, even monitoring offshore turbines from a boat should be feasible. As many wind farms near the ends of their prescribed operating lives, systems like this can help operators make choices regarding when to decommission a turbine. "Operators can use our technology to [evaluate] their installations," Kauffman said. "We can provide decision-making assistance for questions like 'Is it in good enough shape that I can continue to operate it, or should I sell it and build a new one at the same site?'"

This idea seems to solve a few issues with turbine monitoring: keeping track of the full turbine rather than just individual points, and making the process easier. The new tool and technique make it simple to monitor one turbine, move the system to the next one, and so on. And it seems that idea is gaining steam: below is a video of another method for remotely monitoring a wind turbine using interferometric radar from up to a kilometer away. The days of sensors on turbine blades may be on the way out.

Attack on California Substation Fuels Grid Security Debate

When at least one sniper attacked a substation in California last April, the power did not go out. But the incident did bring the issue of power grid security to a new level.

New reports about an attack on Pacific Gas & Electric’s (PG&E) substation in California last April raise questions about the vulnerabilities of the U.S. power grid. The Metcalf transmission substation was not a critical facility, but the Wall St. Journal speculated that the attack could have been a test ground for a larger attack.

The former Federal Regulatory Commissioner, Jon Wellinghoff, told the Wall St. Journal it was "the most significant incident of domestic terrorism involving the grid that has ever occurred" in the U.S.

The assault took place in the middle of the night when at least one person entered an underground vault at PG&E’s Metcalf substation and cut fiber cables. Soon after, one or more gunmen opened fire on the substation for nearly 20 minutes. They took out 17 transformers and then slipped away into the night before police showed up.

Despite the coordination, tossing around the word terrorism might be premature. The attack appeared planned, but for now, the Federal Bureau of Investigation doesn’t think a terrorist organization is involved.

No matter who carried out the attack, there are questions about how to balance investment against attacks both physical and cyber. Foreign Policy magazine reported that Wellinghoff has noted that the recent focus on cybersecurity has overshadowed the need to rethink physical security.

Read More

India Aims High With 4-Gigawatt Solar Plant

The fourth-largest energy consumer in the world is starting to make some noise on the renewables front. India, with its growing population and GDP, has announced plans to build a massive 4-gigawatt solar photovoltaic plant near Sambhar Lake, west of Jaipur in the state of Rajasthan. This would dwarf all existing PV plants around the world, and would nearly triple India's existing solar generating capacity in one fell swoop.

Nature reports that the mega-project will cost $US 4.4 billion, and will take seven years to complete. The plant would go a long ways toward India's plan to have 20 GW of installed solar capacity by 2022 [PDF], up from essentially zero only a few years ago. Of course, building anything this big often means delays and cost overruns, especially in a country not known for strong electricity infrastructure. Still, it's an encouraging sign that India is trying to move beyond its historical predilection for building coal plants.

Read More

Hybrid Generator Would Cut Military Base Fuel Costs in Half

The phrase "An army marches on its stomach," often attributed to Napoleon Bonaparte, underscores the importance of logistics in the military. And in the 21st century, keeping up the supply of diesel fuel is one of the most challenging logistical tasks for military forces in the field.

Last month, the U.S. Department of Defense (DoD) awarded a contract to a company that says its “hybrid generator” can reduce the amount of fuel used by generators at outposts by more than 50 percent. The company, Earl Energy, uses a rack of batteries coupled to diesel generators—and, if available, solar panels—to optimize fuel consumption. It’s one of a number of projects funded by the Department of Defense to reduce fuel consumption through efficiency and renewable energy.

Today, the U.S. military powers its operating bases with diesel generators that run continuously. The problem is that it’s difficult to match the generating capacity with the actual power load from air conditioners, electronics, and other gear, which fluctuates during the day and in different seasons. And when the demand for power is lower than the generator’s full capacity, the fuel efficiency drops off dramatically and the maintenance increases.

At the same time, the electricity requirements for bases in places such as Afghanistan have gone up substantially. Compared to a Marine battalion a decade ago, bases now have more than twice the number of radios and vehicles and three times the number of computers, according to the Department of Defense.

Earl Energy’s FlexGen “hybrid generator” is wired to a diesel generator running at full capacity, which is how it's most efficient. When there is excess power, the diesel generator charges the batteries. If the batteries have enough stored energy to meet the demand for electricity, then the generator shuts off. In tests in Afghanistan, the Earl Energy system allowed the generators to run three to six hours a day, compared with around the clock before it was installed, says Doug Moorehead, the CEO of Earl Energy.

A former Navy Seal, Moorehead saw first hand the perils of transporting fuel while stationed in Iraq. Fuel and water convoys are frequent targets. For example, in one three-month period in 2010, six marines were wounded during convoys (a rate of one injury for every 50 convoys). The financial cost is great as well; fuel can cost $2.64 to $3.96 per liter ($10-$15 per gallon) by the time fuel is delivered to outposts, says Moorehead. "If you reduce the fuel consumption, you can now cut [the number of fuel convoys] in half,” he says.

After Moorehead’s time in the Navy, the MIT graduate attended Harvard Business School and then went to work at lithium-ion battery company A123 Systems, where he worked in the grid energy storage group.

With funding from a previous Department of Defense program, Earl Energy was able to build prototypes for its energy storage device. It now has about a dozen units in the field, which are partially charged with energy generated by solar panels. The system’s control software can be used to manage multiple generators in order to create a base-wide microgrid.

The contract Earl got last month under the Mobile Electric Hybrid Power Systems (MEHPS) program is for delivery of products that conform to the Department of Defense's specifications and could lead to purchase of about 50 units, says Moorehead. "It shows that the DoD is very serious about hybrid generators," he says. (Another company, UEC Electronics, was also awarded a contract to build a generator that fits on a trailer and combines energy storage and solar power.)

Last fall, Earl Energy won another contract from the Army Communications-Electronics Research, Development and Engineering Center (CERDEC) to design power converters based on silicon carbide. "All existing power electronics are silicon-based but the next generation uses silicon carbide, which allows for much higher voltages and conversion efficiencies,” Moorehead says. The company expects its power converters, which will be used with its generators by the middle of next year, to be 80 percent lighter and 70 percent smaller than existing models.

Outside of the military, there is growing interest in distributed power generation, both in grid-connected and off-grid scenarios. Concerned that severe storms will knock out power for long periods, businesses and institutions such hospitals and universities are looking at on-site power generation with natural gas and solar. Meanwhile, microgrids can bring power to places in the world where there is not a reliable centralized grid, whether it’s remote parts of Alaska or rural villages in developing countries.  

Indeed, Earl Energy has ambitions beyond the military. This spring, it will begin testing a hybrid generator at a drill rig in Texas. This installation will use a design similar to the FlexGen hybrid generator, but it will include fast-acting ultracapacitors instead of lithium-ion batteries connected to a 1.2 megawatt generator. Oil and gas drillers typically use very large diesel generators, but drillers are looking for ways to use natural gas that is available from wells to save money and reduce emissions from their operations, Moorehead says.

Image credit: Earl Energy

EC Sees Heavy Pricetag to UK Nukes Plan

Government incentives for a pair of proposed nuclear reactors could cost U.K. taxpayers as much as £17.62 billion, thus exceeding the reactors' projected cost. The EC figure is a preliminary estimate included in an initial report to London published on Friday by European Commission competition czars. The letter notifies the British government that—as we predicted in December—Brussels is launching a formal investigation to assess whether the subsidies violate European state aid rules. 

The preliminary findings suggest that the U.K. and E.C. are on a collision source. As the Financial Times summed it up this weekend: "The severity of [the EC's] initial concerns will cast a shadow over government hopes to win approval for the deal."

Read More

European Union Fanning Offshore Wind Energy in India

As India tries to power its emerging economy, it will look beyond coal  to offshore wind energy. And, it will be getting some help from the European Union, which will be coming up with a roadmap and help with financing.

The plan, which falls under the umbrella of the Global Wind Energy Council, focuses on the states of Gujarat in the northwest and Tamil Nadu in the southeast. It will be a four-year process, although the results will include projections up to 2032. The wind council says that the specific objectives are to lay the groundwork for offshore development through resource mapping, policy guidance, and capacity building measures. The stakeholders will also evaluate the infrastructure needs and make suggestions as to how to move the energy from offshore to the urban areas where it's needed.


The India-EU effort is called the Offshore Wind Power Development project, which is supported by a € 4 million contribution from the European Union’s Indo-European Cooperation on Renewable Energy program. India’s Ministry of New and Renewable Energy will be overseeing the work. Like Europe, India, would like to become less dependent of fossil fuels and to use more renewable energy, says the European Union’s Ambassador Joao Cravinho.  

Onshore wind energy is firmly planted in global markets. But offshore wind projects are mainly the domain of Europe, which is the host of roughly 6000 megawatts of capacity that have been installed in the North Sea, Baltic Sea, and Irish Sea. China, though, has made inroads in the offshore wind area, with Japan, Korea and Taiwan in the early stages of development. India has become the latest such nation to make forays.

The main obstacle is the high associated costs. In some cases, the price of offshore wind power is two-three times as high as onshore wind power, says Navigant Consulting. Industry, though, is working on deploying larger wind turbines to achieve better value.

The European Union has been a role model: Its offshore wind deals account for 10 percent of its annual wind energy installations, says the European Wind Energy Association. The goal, it adds, is to increase those levels from 6000 megawatts today to 40 000 by 2020 and 150 000 megawatts by 2030, or 14 percent of the EU’s electricity demand — considered by some experts to be impractical given the today’s cost.

The Smart Grid Needs an App Store, says Silver Springs Networks

With all the buzz around the Internet of Things, it’s easy to lose sight of the fact that the electricity grid already operates with millions of connected meters and sensors. Yet writing applications for these programmable machines is too hard, which blocks the full potential of the smart grid, says Silver Spring Networks.

The Silicon Valley-based company this week will introduce software designed simplify the process of programming meters and sensors on the grid and capturing the huge amounts of data they produce. It will launch the software, called the SilverLink Sensor Network, on Monday to coincide with the DistribuTech utility industry conference.

In the United States alone, there are more than 46 million smart meters installed, according to the Institute for Electric Innovation, and worldwide shipments of smart meters are expected to top 100 million per year in a few years. Often utilities ping smart meters every fifteen minutes to monitor customers’ power usage, generating mountains of data every day. There are a number of other connected devices that produce energy-related information, such as smart thermostats that work over home WiFi networks. Utilities, meanwhile, increasingly have sensors in grid equipment, such as transformers and power lines.

The problem is that collecting and analyzing streams of data from smart meters and other digital devices is expensive and slow, says Anil Gadre, the executive vice president of products at Silver Spring Networks. The result with smart meters is a situation where these two-way meters perform useful, but a fairly limited set of applications, such as automated bill reading or locating faults after a power outage. But the growing utility digital network could be used for a number of other applications that benefit both consumers and utilities, he says.

“Everybody expected that when they installed these giant networks in the smart grid that they’d get a whole lot more out of it than they already are,” says Scott Young, senior director for software applications and analytics at Silver Spring Networks. “If we unleash the data, it will look a lot more like the Internet is today.”

The SilverLink Sensor Network is cloud-based software that provides a set of APIs to access meters and other devices. The APIs create a gateway to these machines without forcing programmers to learn proprietary network protocols and data formats. That software effectively creates a platform on which Silver Spring Networks, utilities, and third-party application developers can write custom applications that uses smart grid data. Silver Spring Networks manages the APIs and hosts applications, much the way Apple or Google host app stores for smart phones and tablets.

Startup PlotWatt intends to use the software to collect and analyze meter data to tell people how much energy different appliances use and what the projected annual costs are. Similarly, another company called Bidgely itemizes electricity bills, compares your usage to other people's, and provides personalized recommendations on how to save energy.

Silver Spring Networks also signed on a few partner companies that intend to use the platform to create applications for utilities. For instance, startup AutoGrid uses data from different sources to generate more accurate power forecasts, alert utilities of line voltage problems, and run demand response programs to lower peak-time power use. 

For more applications like these to flourish, the programming model for the smart grid needs to change, says Gadre. Today, meter data is typically collected and placed in a database for analysis. But being able to query meters in near real time opens up new possibilities. For instance, a smart meter could communicate that power rates are very high and tell that home's electric vehicle charger to charge when rates are lower. Or the inverters that convert solar panels’ direct current to alternating current could make adjustments to make sure the voltage is stable on a power line. Utilities could also provide up-to-the-minute forecasts of monthly bills to consumers based on near real-time information.

It’s more likely that specialized software companies, rather than utilities, will develop these new types of applications, says Young. Utilities often lack the technical skills that a software company brings and many are struggling to effectively use the large amounts of data they now produce.

Silver Spring Networks makes the IP-based wireless networking built into smart meters, but it says its software can work with other networks. As a company, it’s trying to earn money by providing services, such as big data analytics, that make use of the existing infrastructure. “This giant network exists and it’s largely under-utilized," Young says.

Who Pays for Grid Expansions When Homeowners Generate Their Own Electricity?

Grid operators have met their match and it's a growing number of distributed generators—erstwhile electricity consumers who've ended their reliance on the grid because their needs are met by rooftop solar panels. But this exodus from the grid is occurring just as transmission systems are being expanded to prevent congestion and to handle more centrally-generated renewable energy. The utilities say the cost of these upgrades is the financial responsibility of everyone, including those who've become energy independent. Now state regulators are trying to find solutions.

On Wednesday, the system operator in Texas announced plans to spend billions to expand and upgrade the transmission lines crisscrossing the state. That decision has profound implications, considering that Texas is expected to see its power use rise by 2.1 percent a year compared with 1.5 percent for the rest of the nation.

The Electric Reliability Council of Texas (ERCOT), says it will, by 2018, plow $3.6 billion into fixing up or expanding a total of 16 different deals, amounting to 5300 kilometers of transmission lines. Some of those upgrades are needed to transport wind energy from remote locations to the urban areas where it is consumed.

Similarly, Northeast Utilities, which serves 3.6 million electric and natural gas customers in Connecticut, Massachusetts and New Hampshire, wants to add transmission infrastructure throughout its area and plans to spend $4 billion doing just that. It needs to make up for capacity shortfalls and to replace 2700 megawatts that will be lost by 2017 as several coal and nuclear power plants are retired. Meanwhile, new wind power generated in Maine is expected to come online and be transported into the utility's load centers in Boston.

Read More

Carbon Capture Success in Alabama, $1 Billion Pledge in Illinois

Last week carbon capture proponents in the United States got two bits of good news. First, Mitsubishi Heavy Industries and Southern Company Services said they have successfully tested a technology that captures and sequesters carbon dioxide from coal plants. Later in the week, the U.S. Energy Department pledged to come up with about $US 1 billion for the $1.65-billion FutureGen 2.0 carbon capture and storage project in Illinois.

Based on the results released Tuesday, Mitsubishi Heavy says that it will accelerate its program to commercialize the technology. Southern Company owns the 2657 megawatt power plant in Alabama that the technology was tested on. The U.S. Department of Energy and the power industry’s  R&D  arm, the Electric Power Research Institute, also pitched in.

Read More

Thermophotovoltaic Device Has Potential to Reach Huge Solar Efficiencies

Traditional photovoltaic solar cells have an inherent limit on the efficiency at which they can convert sunlight into energy. This limit—based on the bandgap of the material used and known as the Shockley-Queisser limit—is about 33.7 percent for standard solar cells. It is essentially due to any material's inability to respond to all wavelengths of sunlight; so what if there was a way to change the wavelengths that actually reach the cell to those it converts best? MIT researchers have unveiled the best-yet version of that idea, known as solar thermophotovoltaics. 

These modified solar cells place an absorber/emitter device above the cell itself. Sunlight is absorbed by this layer, it heats up—a lot—and emits light tuned directly to the bandgap of the PV cell beneath it. That means that much more of the energy in the sunlight can turn into electricity. According research in Nature Nanotechnology by graduate student Andrej Lenert and colleagues, this idea offers the benefits associated with both solar thermal power and traditional photovoltaics, and the ability to harness much of sunlight's spectrum and thus achieve extremely high efficiencies.

In theory, these devices could climb all the way toward 80 percent efficiency and beyond, though for now we'll have to settle for a mere 3.2 percent. Still, that is more than triple the efficiency of previous efforts, which have peaked at around 1 percent.

Among the reasons for the huge gap between potential and reality is heat. The new device's absorber-emitter reached a temperature of 962°C; at those temperatures, the devices are difficult to optimize and operate. The 3.2 percent achieved is a result, the investigators say, of the specific materials and design of the absorber-emitter: the outer layer uses an array of multiwalled carbon nanotubes, and the emitter portion is a photonic crystal layer made of silicon and silicon dioxide .

"Our device is planar and compact and could become a viable option for high-performance solar thermophotovoltaic energy conversion," they wrote in the Nature Nanotechnology. And it also has the potential to aid in energy storage, since heat is an easier stored form of energy than electricity. The prototype has reached 3.2 percent, but the group thinks 20 percent, which would put it in range with standard PV modules, is well within reach. In an e-mail, Lenert told me that "efficiencies beyond this level will require improvements in low-bandgap cells, as well as even better control of the thermally-driven spectral conversion process using wavelength and angular selective surfaces." The research center at MIT is pursuing those and other angles to bring this idea into popular use.

Advertisement

Newsletter Sign Up

Sign up for the EnergyWise newsletter and get biweekly news on the power & energy industry, green technology, and conservation delivered directly to your inbox.

Advertisement
Load More