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Steady advances in solar, wind markets prompt demand for modularity and durability in assembly designs.
BY MATT VINCENT
Current trends affecting the market for connectors and cable assemblies in the area of renewable energy, especially for solar power/photovoltaics (PV) and wind turbine technologies, are persuasive in their relevance for manufacturers and designers.
Recent reporting (July-August 2009) in Connector Specifier sister publication RenewableEnergyWorld.com revealed that in 2008, the U.S. used less energy, but more renewable energy. In addition, energy flow charts released by the Lawrence Livermore National Laboratory (www.llnl.gov) showed that Americans used more solar, wind, nuclear, and biomass energy in 2008 than they did in 2007; and that the nation used less coal and petroleum during the same time frame, and only slightly increased its natural gas consumption (Figure 1).
RenewableEnergyWorld.com also reported that the recent Monthly Energy Review issued by the U.S. Energy Information Administration found that production of renewable energy for the first third of 2009 (January 1 to April 30) was 6% higher compared to the same time period in 2008. According to analysis from the Sun Day Campaign (sun-day-campaign.org), in April 2009 alone, renewable energy sources accounted for 11.1% of domestic energy production and exceeded the amount contributed by nuclear power. Total U.S. energy consumption fell 5.7% during the first four months of 2009, compared to the same period in 2008?with fossil fuel use accounting for almost the entire decline.
“As Congress continues to debate energy and climate legislation, it would do well to take note of the clear trends in the nation’s energy mix,” says Ken Bossong, executive director of the Sun Day Campaign. “Fossil fuel use is dropping sharply and nuclear power is barely holding on to its market share, while month-after-month, the mix of renewable energy sources continues to set ever-higher records.”
Narrowing the focus to the wind and solar markets, for those in the interconnect industry, recent developments are equally encouraging.
Wind systems rev up
According to the American Wind Energy Association’s (AWEA) second quarter (Q2) market report, released in July, the U.S. wind energy industry installed 1,210 megawatts (MW) of new power-generating capacity in Q2 ?09, bringing the total added this year to just over 4,000 MW (compared to the 2,900 MW added in the first six months of 2008). Further, during the second quarter, the U.S. wind energy industry completed a total of 1,210 MW in 10 states, most notably in Missouri where wind power installations expanded by 90%, and in Pennsylvania and South Dakota, which ranked second and third in terms of growth rate in Q2, expanding by 28% and 21% respectively.
During the quarter, three wind turbine and turbine component manufacturing facilities were opened, four facilities were expanded, and eight new facilities were announced, bringing the total of opened, expanding and announced facilities up to 20 since the beginning of the year. All new installations nudge total U.S. wind power generating capacity to 29,440 MW, says AWEA.
“Even in an economic meltdown, the installation of over a gigawatt of wind shows that the technology is mature and destined for long-term growth, no matter what the economic conditions happen to be,” comments Scott Sklar, president of renewable energy consultancy The Stella Group, Ltd. (www.thestellagroupltd.com).
“I think if you look at the top five turbine manufacturers, their Q3 to Q4 has picked up dramatically over Q1 to Q2,” adds Eric Fried, global director for alternative energy, at Tyco Electronics (www.tycoelectronics. com). “The number of bookings for most OEMs slowed down in the first part of this year, but I would say, overall, the market is still on a steady increase, if you look at the number of manufacturers putting capacity into North America. You have Siemens mounting a facility in Colorado [at the AWEA annual conference in June, Siemens Energy announced the establishment of its U.S. wind research and development center in Boulder]; Vestas also has two facilities there, their blade and nozzle groups, and of course all the ones going into Iowa.”
Fried states unequivocally that, for wind energy systems, the two biggest factors are availability (or uptime) and?closely related?a necessity for modular components.
“Typically, in a wind turbine, a lot of the lug connectors and heavy-duty communication connectors and other components that have been used are legacy-type products from the heavy industrial market,” he explains. “I think what the wind industry is finding out is that, as the volumes are increasing, some of those legacy-type products that they pulled off the shelf 10 years ago aren’t really suitable for what they need in terms of reliability and availability; i.e., the amount of time a wind turbine has to be up to produce electricity.”
Fried continues, “For a wind tower, if it’s not up, it’s not making money. Plug-and-play, of course, is the key phrase, and that has to do with both how quickly a wind turbine can be brought on line and how quickly it can be maintained?switching out one subsystem or cable assembly for another?so that that downtime is minimized.”
He adds, “Every time you have a system that’s modular, you have to have interconnects, and in wind systems, those interconnects can be anywhere from low voltage and medium voltage to fiberoptics and Ethernet.” Interestingly, whereas the Industrial Ethernet protocol is usually seen as ubiquitous in wind turbine systems, Fried discerns an increasing shift to fiberoptics. “There are definitely two or three Ethernet switches in a wind turbine,” he says, “And, of course, you have all the interconnects and cables for that, but I would say fiberoptics is probably playing a larger role now for communications between the control systems and the data systems.”
Concerning modularity in wind systems, Fried says that the variety of plug-and-play solutions are meant to replace mechanical connectors that have to be installed in the field. By way of example, he explains, “The numerous power sections going down the tower have interconnects at each power break, or each section of the tower. When they install the power cables, there’s one of two ways to do it: run one cable length, which can get very expensive and heavy, or do multiple segments. In most cases, they do multiple segments, where the interconnect has typically been a mechanical connector, such as a screw lug.”
Fried continues, “After they affix the connector, they have to put a heat shrink on top of that in the tower. Draka just introduced a tower connector?actually, a Tyco Electronics product developed exclusively for Draka?that is an IP54 solution that is pre-terminated at the manufacturer; when the cable is dropped, it is automatically plugged into the mating connector. These connectors are what you call ?idiot proof,’ because they’re color-coded.”
 FIGURE 2. UV-resistant cabling rated for high levels of flexing and torsion, such as these Weidmuller solutions, are a must for solar deployments. |
Fried concludes that always comes down to cost when moving from a mechanical solution to plug-and-play. “But when I look at advantages, I look at safety first of all,” he notes. “You don’t have to have a person sitting in that tower when it’s 110 degrees outside, and he doesn’t have to be a licensed electrician to make that connection in most cases because it’s already terminated?it’s just taking two cables and plugging them together. There’s a cost advantage there.”
Solar energy: twists and turns
On the solar front, in its annual report, U.S. Solar Market Trends 2008, the Interstate Renewable Energy Council (IREC) revealed that both PV (photovoltaic) and solar thermal installations grew rapidly in 2008, with work funded by the U.S. DOE through the Solar Energy Technologies Program.
The report found that although PV installation growth had been steady for many years, the annual growth rate doubled when the federal Investment Tax Credit (ITC) increased in 2006. “By 2008, the capacity of PV installed each year was triple the annual amount installed in 2005,” comments Larry Sherwood, the IREC report’s author. “More than 33,500 sites installed PV in 2008, with 62% of these sites and 87% of the installed capacity connected to the grid. Most of these instal- lations are mounted on buildings, but some are ground-mounted installations.”
The report says early indicators point to solar market growth in 2009, though likely at a slower rate than during the past several years, with the market again shifting toward high growth rates in 2010. “For all solar technologies, the United States is only a small part of a robust world solar market,” notes Sherwood. “Product availability and pricing generally reflect this status. Germany and Spain are the top markets for PV, and China is the largest market for solar thermal collectors.”
“2009 has been kind of a Jekyll and Hyde year for solar,” offers Bruce Hofmann, director of marketing at Weidmuller North America (www.weidmuller.com). “There have been a lot of advancements as far as efficiencies go and making it scalable, especially for commercial and residential use, but also for industrial. At the same time, there’s been kind of a shake up of the technology providers because of the scarcity of new capital. Some of the medium-to-small providers hit hard times and had to go out of business.”
Hofmann attributes the softening in the market to a paucity of equity and venture funding, as well as tentative spending at the municipal, commercial, and business levels: “Solar was going very strongly up until the global recession of 2009. Then most of the implementation projects either got curtailed completely or just indefinitely postponed. Stuff that was supposed to happen in 2008 was approved, but can’t be funded until 2010 or 2011.”
In terms of applications for widely distributed solar networks, as with wind turbine systems, Industrial Ethernet protocols, such as ModBus and Ethernet/IP, are among the most pervasive. From an engineering perspective, there are IP67 and reliability concerns when it comes to designing solar networks?the physical layer often being the weak link in the chain, which heightens the need for reliability in connectors and cable assemblies.
“Because they don’t play in Ethernet full time, I think a lot of engineers in solar aren’t totally aware of the technology at their disposal,” adds Hofmann. “They go with standard Cat 5 cabling, then in two or three years they start having failures at the connector and in the cable, and they’ve got to go back and diagnose the issue. The problem is that we have no legacy of Ethernet-controlled solar energy systems of any major size in the U.S. that’s more than a few years old.”
As a must in solar deployments, Hoffmann stresses the use of UV-resistant cabling rated for high levels of flexing and torsion: “People don’t think about this in an office environment or even in a factory environment, but cables deployed outside are constantly blowing in the wind, so you need a cable designed so that it can basically move back and forth 24/7, and never harden, get brittle, or break.”
Hoffman adds, “If you have a solar array that moves?most of them are adjustable, based on the azimuth of the sun?you also want a cable that can twist, whereby you don’t lose the integrity of the twisted pair inside the jacketing, regardless of how many years its outside.”
Hoffman concludes, “Our Steadytec Ethernet connection technology was built for industrial automation, which is what solar deployment really is. Our engineers in Germany built a whole line of interchangeable RJ-45 bulkheads and connectors for cable assemblies to run Ethernet in automobile factories where sparks, smoke, water, and anything else could hit them. If you have Ethernet anywhere in your plant?whether it’s fiberoptic, or copper Cat5/5e/6/6A, IP20, IP67 (something that’s weatherproof, has pull-out strength)?you can connect within and outside of an enclosure or cabinet, into any kind of switch or sensor device.”
Lightning strikes?twice
Both Weidmuller’s Hofmann and Tyco Electronics’ Fried agree that the need for suitable overcurrent/undercurrent protection and safeguarding against damaging electrical surges brought on by lightning strikes is of critical import in both solar and wind energy deployments.
“Anywhere lightning strikes the ground will change the primary earth level around a solar system,” explains Hofmann. “Especially in solar array systems where there’s a large geographic footprint, if lightning hits one end of it, it can potentially destroy the circuitry for signals on the other end because you’ve got power and signal both going to and coming from every single solar panel.”
Fried concurs that “both from the insurance company’s standpoint as well as the owner-operator,” catastrophic lightning strikes are among the biggest concerns in wind turbine deployments. In fact, a large part of Tyco’s wind power initiative is providing protection against them.
“If a tower does get hit by lightning, what’s the damage incurred which they don’t see initially?,” observes Fried. “Our roadmap at Tyco Electronics looks at how to decrease the amount of energy that’s flowing down the blade, into the hub, and into the nozzle, and to dissipate that energy before it actually hits ground. The other thing is to understand not only if the power has been hit but what is the wavelength of that strike?and which blade has been hit. That information becomes very critical in terms of keeping wind turbines available and making them safe for the areas they’re operating in.”
In May, Underwriters Laboratories (UL; www.ul.com) announced it would offer testing and certification of wind turbines in accordance with new safety standard requirements. UL says the service, offered in partnership with Germanischer Lloyd (www. germanlloyd.org), a wind energy equipment certification organization based in Hamburg, Germany, provides wind turbine manufacturers with safety compliance certifications that meet both U.S. and IEC requirements.
“Specific for wind energy, the new program focuses on electric shock and fire safety,” comments Evelyn Butler, UL regional business manager. “There are also considerations for mechanical, structural, and blade performance; however, our programs today don’t cover them?mainly because the standards that are utilized for those other three areas are international, and they don’t specifically address concerns for the U.S. market, which do tend to revolve more around electric shock and fires. So, our programs were intended to fill that gap.”
Butler elaborates, “By electric shock and fire safety, we mean basically providing an environment where a service technician or anyone within the environment would not be in danger of any type of electric shock hazard or potential fire hazard from the equipment being in performance. A good example would be requirements that ensure that the insulation on a connector is suitable for any potential increased voltage that might come down to that point, that could either cause the connector to fail, or for it to be an exposed, live part that somebody could touch and get an electric shock from, or that might cause a fire to start.”
Regarding the establishment of standards for solar energy systems, Butler notes, “That particular certification program has been in place for more than 30 years. We cover the panels themselves; we also investigate the inverters, the meters, the connectors, the fuses, the wiring?a number of things that make up the entire system. That includes electric shock and fire safety, but there’s also a very integrated perspective on performance.”
She adds, “Particularly for the solar modules, because a lot of them are made up of so many plastic-based materials, there’s potential danger there. Depending upon the type of plastics that are used, if it’s something that’s going to be on a rooftop or an office building for 15 to 20 years, you’re concerned about its ability to withstand the elements and not present any electric shock hazards over time.”
Help is on the way
In July, U.S. Energy Secretary Steven Chu announced that the Department of Energy (DOE) will provide up to $30 billion in loan guarantees, depending on the applications and market conditions, for renewable energy projects. Another $750 million will support several billion dollars more in loan guarantees for projects that increase the reliability, efficiency, and security of the nation’s transmission system. The two new loan guarantee solicitations are being funded partly through the American Recovery and Reinvestment Act of 2009, and partly through 2009 appropriations. “I think the Recovery Act is definitely helping to inject a lot of positive optimism about the use of solar, and for wind as well,” says UL’s Butler. “We still see projects being funded, and developed and finished.”
She continues, “For solar, I would say that because the programs have been around longer, there’s much more of an acknowledgement of that from the regulatory community, both here in the U.S. and outside. For wind, it’s still growing. There’s still a lot of work to do to get people familiar with the programs, the services, and how it really helps them. Typically, for a wind farm project, we’re talking two to three years of development; so, for something that started two to three years ago, there’s a lot of encouragement. They want to get it finished because they want to reap the benefits. That’s also where we might see a bit more hesitation in terms of new projects.”
For wind and solar renewable energy technologies, Butler points out that UL’s ultimate goal is to help support the growth of both sectors, “not only here in the U.S., but also internationally.”
She concludes, “We recognize and acknowledge the need for supporting the world’s direction on the use of renewable energy as a much more prevalent part of our energy mix. In order to support that, we want to give manufacturers programs to help them with things like market access, helping them to provide some level of confidence or assurance to building or electrical inspectors who have to sign off on a project. When they see our mark, they understand the diligence and care we’ve put into evaluating the product, and have confidence in accepting that installation as not posing any potential hazard. For manufacturers, that’s also a good sense of security, in that they don’t have to worry about their product being questioned?and it gets installed.”
MATT VINCENT is senior editor of Connector Specifier.
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