Tracking The Sun Makes Solar Panels More Efficient On Land & On Water
All life on Earth is dependent on energy from the sun. Today, we have solar panels that are incredibly efficient compared to their predecessors from 50 years ago, but that efficiency is compromised if the panels are not oriented properly toward the sun. The problem is complicated by the fact that the axis of the Earth is tilted, which alters the angle at which sunlight hits our planet at different times of the year.
Fixed solar panels, like the ones in a typical rooftop solar system, operate at less than their maximum efficiency most of the time. That means their output is less than it would be if they were pointed directly at the sun during most of the day. Tracking systems can help increase efficiency, but add cost and complexity to any solar system. Are the advantages they offer worth the extra money?
Bill Bender is the head of Solaflect in Vermont. He and his team have devised a solar array composed of 16 panels — about the size of a typical rooftop solar system — that has a nominal output of 6.25 kW. The Solaflect system is mounted on a multi-axis device that keeps those panels pointed directly at the sun all day long. The result, he says, is a 40% increase in efficiency. Watch the video to see the Solaflect system in action.
In a storm, the tracker tilts the array to a horizontal position to minimize the force of strong winds. The company has installed about 1200 systems so far, mostly in New England. His customers really appreciate that the snow slides right off when the tracker stands the panels up vertically.
The company has a number of sales and leasing programs that allow customers to pay for their Solaflect systems with the savings they realize on their utility bills. While knowing they are using zero emissions electricity to power their homes is a plus, they also have the benefit of knowing they are protecting themselves from regular increases in utility rates that typically average about 3% a year.
Solaflect Energy designed the first Solaflect Solar Tracking system in 2007. The US Department of Energy awarded the company $2 million in grants to further develop the technology. Today, because of continuous investment and engineering improvements, the patented Solaflect Tracker is the most advanced and reliable residential and small business solar power system on the market, the company says.
Floating Solar With Multi-Axis Tracking
Earlier this year, we reported on research by scientists in Australia who suggested that installing floating solar in the world’s oceans could produce enough electricity to meet the needs of every person and corporation on Earth. That report found that equatorial areas are best suited to floating solar because they seldom are subject to hurricanes and other major storm events. (That may change as the Earth continues to heat up.)
Solaris Float, a company based in Portugal, says it has developed an innovative floating solar solution that is unlike the conventional floating solar systems. With single or dual axis tracking, the floating island is powered by electric motors to keep the array aligned with the sun. Those motors consume less than 0.5% of the total energy produced. According to the BBC, the system, which the company calls PROTEVS, is the first to merge floating solar panels with sun tracking technology.
Its first floating solar installation is currently located in Oostvoorne Meer, a lake in the southwest Netherlands. It consists of 180 mobile solar panels with a capacity of 73 kilowatts of peak power. Like the Solaflect system, the company says its tracking system provides an increase in energy production of up to 40%, thanks to its sophisticated technology that permits its double sided panels to follow the movement of the sun as it traverses the sky every day.
The company is offering two types of floating solar systems, according to Interesting Engineering. The first is the PROTEVS+, which features 180 modules with dual-axis tracking. It has a diameter of 38 meters and occupies an area of 1,444 square meters. The second is the PROTEVS Single 360, which uses a single axis tracker. It has 410 solar panels mounted on a fixed slope of 10 degrees and a capacity of 147 kW.
According to Solaris Float, the PROTEVS solutions are modular, detachable, and scalable, with an easy installation process. Because the modules can be detached, the islands can be merged to form a larger floating solar farm.
Additional Benefits
In addition to providing renewable electricity, Solaris Float says its floating islands have beneficial effects on the bodies of water where they are located. The shadows formed by the floating structure and solar panels reduce the temperature of the water beneath the array. The company claims a 60% reduction of evaporation in the body of water below.
The company says water quality is also increased due to a reduction of algae and other micro-organisms because of that shadowing. This reduction can be further enhanced by the installation of oxygenating equipment on board the floating islands.
Solar Farms Take A Lot Of Space
According to Popular Science, solar farms that track the sun come with limitations. It says the Solaris Float systems won’t be as efficient near the Equator because the panels will stay horizontal the entire day. They will also need to be installed in places with weak tidal currents to prevent the systems from being pushed out of position.
The magazine also made reference to a study from Leiden University in The Netherlands which estimated solar farms need 40 to 50 times the area of coal-fired generating stations and 90 to 100 times the land required by methane fired facilities. Of course, those estimates do not include the enormous amount of land required for coal mines and methane gas fields and the infrastructure needed to get those fuels to where they are consumed.
The Takeaway
Efficiency is key to addressing the challenge of a warming planet. More than half of the energy created when fossil fuels are burned is wasted, much of it as heat. In the past 50 years, that wasted energy is equivalent to the heat from 25 billion atomic bombs. We simply can’t afford to do that anymore if we want to keep the Earth habitable for human beings.
Efficiency often makes the difference between new technologies being profitable and losing money. Tracking systems for solar installations do add cost and complexity, but can be crucial when it comes to a customer’s return on investment, especially at higher latitudes where the sun is lower on the horizon most of the year.
Solaflect and Solaris Float are both making important progress toward more efficient solar arrays. That increased efficiency makes the business case for solar energy more appealing by shortening the time needed to achieve a positive return on investment for residential and commercial solar customers alike.
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