Wind Power Steadily Advances -- Look for efficiency in wind power construction and maintenance
Energy from the daily power of the wind is no longer something we smile about and refer to as something such as a story from Jules Verne or H.G. Wells. Wind power is here to stay.
By Paul Hull
Energy from the daily power of the wind is no longer something we smile about and refer to as something such as a story from Jules Verne or H.G. Wells. Wind power is here to stay. It has proved itself. It works. Like most new technologies--such as television, computers and phones--it started with many people laughing at the idea. Like new technologies, it has had its share of fly-by-night experts--makers, installers and contractors. Once large, reputable companies have become involved in wind energy--companies such as Duke Energy and Siemens--there has been an improvement in everything. Construction and maintenance have become important, as they are with every other new technology and industrial innovation.
Getting power from the wind is not a new, American idea. Think of all the ships that have sailed the world to find new countries, foods and other resources that we now consider natural and normal. Those ships were powered by wind. The windmills that powered grinding wheat, a staple food in many countries, have been around for centuries. The turbines in the tall wind power towers are driven by wind just as the windmills in places such as Holland worked for the benefit of everybody living there. My own concept of turbines is of machines that can drive almost anything; they are powerful, like those that can send aircraft with hundreds of passengers at several hundred miles per hour across the sky from one city to another, from one continent to another. Wind is powerful. Most of us have seen storms where the wind uproots trees and flattens buildings, so it is surprising just how little wind is required (just a few miles an hour) to run the turbines in wind power towers.
Supporting all this power requires strong foundations. You can't just dig a hole and push a pole down. That will not support the energy maker many feet above you. The nacelle at the top of a wind energy tower can weigh as much as 75 tons, and the towers themselves--some 200 feet tall--are made of steel.
Supporting the Machinery
The nacelle is the box at the top of the tower. It contains the turbine, a gear box, transformers, a generator, and other mechanical devices and controls. The three blades that drive the system are 100 feet long or more. The owner of the wind power tower will contract with a company to install the system. Contracts vary and contractors can be involved with installation as well as operation and maintenance without being the owner. There are good contractors for this work and responsibility, and it is essential that the one who does your work is qualified and reliable. It's like any carpentry or plumbing project you have at home; you make sure the people you hire to do the work are qualified and responsible.
Towers do not grow like wheat, though many are on farms. The towers must be transported by reliable carriers, and there must be an access route for the tower parts to their final location. That usually means building access roads. Much of the preparation for new wind towers relies on basic construction and can be done by competent construction contractors. The access roads, for example, must be built to accept the equipment needed for installing the towers. That equipment can include excavators and dozers, but it will mostly involve cranes, large, powerful cranes that require safe travel on the access roads and, almost certainly, a stable crane pad near the tower.
Although many wind power systems are for individual buildings or residences, I am thinking of bigger sites in this article. One of the most encouraging moves for wind power is that an increasing number of larger wind farms are being ordered and built, so this solution for our energy problems is not directed too much to individuals, but more on communities and businesses with many employees and much equipment. The American Wind Energy Association--a helpful source of information and advice--believes that 100,000 new wind turbines will be needed in the next 20 years to supply 20 percent of the nation's electricity, which is probably why electric utilities have become so committed to the concept and installation of wind power. All these machines, like every other machine, will require proper maintenance to keep performing at their best efficiency.
It's probably not a question of somebody climbing the towers every few days. A typical wind turbine will require routine service once or twice per year, because oil and filters need to be changed, components need to be inspected, and you'll need to give the bolts the best torque. The expected lifetime of a wind tower is 20 years to 30 years. At some time in that span, say in five or 10 years, parts will wear down and need to be repaired or replaced, and the owner should be prepared for damage caused by weather or other external sources--just as you would for any outside equipment.
A task that accompanies all equipment maintenance is having a reliable way to know if anything is likely to go wrong. When you purchase a wind power system, the manufacturer will provide a supervisory control and data acquisition (SCADA) control system for it--but that's not the real problem. Most electric utilities have a 24/7 staff to monitor their operation and equipment; many wind power systems do not. Before you question how difficult it is to monitor a wind tower, remember that some utility-scale systems'--called that for obvious reasons--may comprise hundreds of towers spread over thousands of acres. The answer, as it has been for electric utilities, is technology, a technology that can monitor hundreds of towers at the same time. Is that kind of technology too expensive? Consider the cost of having many employees climbing up hundreds of feet on hundreds of towers to do the same thing.
A SCADA system monitors a system in real time, but the system may be more complicated than that. Some systems--such as WindAccess from Alstorm Wind North America--gives historical data that would allow the person monitoring the system to see the current temperature of a component but also see what the temperature of that component had been for the last several weeks. Such information can tell the operator when the best time would be to perform maintenance on the component and alert users when a turbine may have a problem that requires immediate rather than scheduled attention. While some of the technologies seem expensive when you first read about them, the cost of alternative solutions can quickly dispel doubts. Consider that a lift truck can cost $2,500 a day and a crane much more than that, whereas technologies can allow you to achieve the results you need with no complex moving of vehicles and equipment. As in most other industries, there will be a constant development of new technologies to make the operations and maintenance of wind power more efficient and more profitable. Wind power is still in its infancy in the US, but this may be the best time to see what is available to improve the operations at your site.
Let me end this article by restating the support of wind towers is your first concern. There have been experiments and trials about the best way to support the tall towers at ground level, and there is no short cut to save money during that initial stage of the wind energy project. Drilling down into rock could be a good start to a good foundation. Compressive strength of 5,000 psi may be advisable for the concrete floor supporting the tower. Strength and safety are your first considerations and no short cut is recommended. We are going to see more towers across our countryside, and, like everything else in utilities and construction, they must be safe and efficient--at the time of installation and throughout their working life.