Positioning the Sun's Energy

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It is predicted that by 2030, global consumption of energy will have increased 40%; thus, many world leader's and energy executives are concerned about how to meet these accelerating energy demands.

While most energy debates focuses on the cleanliness and eco-friendliness of energy sources, the simple concern about how to produce enough energy to meet demand seems to trump all arguments. Yes, we are all in favor of affordable, cleaner energy. However, the importance of cost and cleanliness diminishes somewhat in comparison with the problem of shortage. Thus, it is prudent to employ a comprehensive, multi-source energy strategy going forward.

Lets briefly examine some of the current energy facts and trends, 2012 vs 2011:  
• Global coal consumption increased by 5.4%, making it the fastestgrowing form of energy outside of renewables. Coal accounts for 30.3% of global energy consumption, the highest share since 1969.
• Natural gas consumption grew by 2.2%.
• Shale gas and shale oil are expanding rapidly, mostly in the United States.  
• China overtook the US as the largest generator of power in 2011.
• In 2012, the United States had the largest oil production growth outside OPEC countries for the 3rd year in row.
• North America is likely to become energy independent by 2030.
• In 2012, the largest increase in renewable energies was seen in solar energy.

There are powerful forces that will help the world meet its energy needs. For example, there is a tremendous increase in energy efficiency, allowing for more GDP to be produced with less energy. This has been a result of the competitive pressure of energy costs among providers.

Another economic force spawned by competition exists on the supply side. There is a never-ending pursuit to develop new technologies that can facilitate the emergence of alternative energy sources but also access to traditional energy sources not previously available. Shale gas and tight oil are a result of such progress.

Geopolitical Energy Shift
North America will continue to see increases in energy production not because the resources are concentrated there but rather its above-ground conditions are suitable for further development of new technology. Open markets and a stabile political environment breeds competition for the development of new efficient technologies. Companies feel secure to invest.

North America is predicted to become energy independent by 2030. If this happens, other countries will become more energy dependent due to their increase in demands and inability to meet them with their own resources. This will affect global energy economics. Today, half of the US trade deficit is from energy imported to fill voids in demands. To the extent that the United States becomes almost self-sufficient, that portion of the US deficit will shrink which will cause energy deficits in other countries to rise. This is again due to increased demands and less exports from the United States.

Renewable Energy
Over the past several years, renewable energy sources-such as solar energy­ have become increasingly important contributors to the world's store of available energy. Solar power generation was up 86% in 2012 over 2011 gaining market share; however, it still comprises only 2.1% of global energy use. Its use will continue to increase, as that of most technologies in the alternative energy sector.

Rapid renewable growth remains contingent on government support. Renewables as a subsidized sector are not subject to market competition, being costly and not yet competitive. The hope is that renewables will become competitive as prices fall, which seems likely.

Positioning Technology and Energy Production
Positioning technologies have played a role in energy production, primarily in surface mining. Benefits in the form of coal production increases along with reduced machine costs are well documented. The recent boom in solar farm installations has affected the design and manufacturing of new application-centric machines as well as application-centric positioning systems. For example, to answer the need for quick-working, accurate equipment, Vermeer has developed the PD10 pile driver. The PD10 was specifically designed to meet the tight accuracy tolerances demanded by commercial solar contractors and the expansive solar fields they install.

The Challenge—Positioning Piles
The construction of solar farms begins with a series of piles or posts driven into the ground per design. The design is a grid with a typical tolerance of 1cm x and y horizontally and .5 cm vertically. Once the piles are in place, the solar panels are installed on top of the piles in accordance with the accuracy requirements.

These grids are usually established using traditional survey methods. Some sites will establish a baseline with a total station or GPS receiver. A tape is pulled between the two points and stakes, and "whiskers" are used to mark the grid points along the baseline.

There are a couple of issues with this method. First, the construction company often must rely on an outside firm to establish the base points and mark the intermediary grid points. Of course this incurs an expense in money and time before construction can begin. Most contractors want the ability to manage this portion of the work internally, if possible.

Another issue is the removal or location "disturbance" of the stakes. This can happen because of adverse weather conditions or machines and vehicles roving across the site unintentionally disturbing the markers. This can be very frustrating because the discovery of slight positional disturbances occurs while assembling the solar panels, after-the-fact. Vandalism is also a common problem.

The cost associated with traditional survey methods is between $2.00 and $4.00 per stake, racking up a substantial expense over the life of the project. For example, many solar farms have between 100,000 and 800,000 stakes. Sites may have 5 to 10+ pile-driving machines working on a single site. A positioning system investment that increases efficiency while reducing survey costs is easily justifiable.

Summary of Requirements
• Accuracy
• Efficiency
• Reliability of the stake/marker position
• Cost
• Contractor's ability to control schedule without relying on a surveyor

The Solution
The challenges discussed above are common in repetitive measurement and staking processes. Pile driving, especially for solar farms is easily enhanced by applying 3D machine control and positioning technology. It is actually a simpler application when compared to the articulation monitoring complexities, software calculations challenges and so forth, that can occur in dredging, landfill compaction, fine grading, 3D drilling, etc.

Nate Harmon, an application sales specialist at RDO Integrated Controls in Phoenix, Arizona, was approached last August by a contractor looking for solutions that might improve their solar pile-driving efficiency.

"Our customer was looking for methods that would reduce or eliminate the cost of a survey firm," Nate said. "We started by selling and training them on a GPS base and rover system. This equipment allowed the customer to stakeout design points similarly to the the survey company. This solution did provide the independence our customer was looking for." Nate added, "It didn't take long for the customer to ask if they could somehow put a similar system on their pile-driving machine."

Additional sensors enhance the positioning performance of the machine.

Positioning System Anatomy
Positioning systems are fairly new in solar-farm pile driving; they are a work in progress. This diagram depicts the anatomy of a basic system.

Summary of Positioning System Components
1. GNSS Receivers and Antennas two RTK GNSS receiver positions provide precision location and heading.
2. Pitch and Roll Sensor-indicates mast/feeder plumb.
3. Laser Receiver-augments GNSS elevation with higher accuracy. The laser sensor indicates to the machine when the desired elevation is reached and automatically slows and then stops the hammer. This is independent from the GNSS positioning.
4. Computer Display with application software-A rugged, environmental computer and display is required because most of these machines are open cab and therefore exposed to the elements. Each positioning company providing solutions in this space approaches the software differently. Take a look at each company's software before making a final decision, and see what works best for your operators, data workflow, and overall company goals. The user interface and data workflow are key considerations for purchase.

Several enhancements are under development by the various positioning companies. These enhancements may involve a laser-range finder for monitoring hammer elevation. This would augment GNSS elevation providing better accuracy (3mm over GNSS's 1cm) and would offer no laser transmitter setup (note the current laser augmentation as shown in the Anatomy image). Hydraulic controls to autonomously position the machine including plumbing the feeder, could all increase efficiency and accuracy while reducing the required skill level of the operator.

Companies such as Vermeer are enhancing these machines' capability and working closely and openly with positioning system providers, all of which benefits the customer with ever-evolving features.

Energy drives our economies and our lives. Global demand will continue to accelerate at an alarming rate, and we must maintain an "all hands on deck" approach to energy production nurturing technologies that bring efficient alternative energy sources. Positioning technology will continue to play a role as our energy landscape continues to change. MC

Randy Noland is the Managing Editor and Cofounder of Machine Control Magazine.

See PDF for the list of references.

A 1.784Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

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