Maximizing the Energy of Solar Panels
National Semiconductor is entering the photovoltaic market with new technology designed to increase the effectiveness of solar panels under variable light conditions. National's SolarMagic™ technology recoups up to 50 percent of the lost energy, dramatically improving the economics in shaded and other real-world conditions. The SolarMagic technology maximizes the energy output of each solar panel, compensating for much of the energy lost due to shadows from tree branches or power lines, dust and debris, and panel-to-panel mismatch.
Today's solar installations are disproportionately impacted by shading conditions, which significantly limits the design, location, and energy output of typical residential solar installations. Shading conditions can even invalidate local and government incentives, making these installations cost-prohibitive. National's SolarMagic technology minimizes the system impact of shading and other outdoor conditions, maximizing the energy output of each solar panel.
For more information, contact solarmagic@nsc.com.
Frequently Asked Questions
Solar Technology Background
- How does solar power work?
Solar power directly converts the energy delivered by the sun into electricity. Solar cells are made up of special semiconductor materials that absorb the light given off by the sun. The light absorbed by the solar cell produces electrical energy in the semiconductor. Individual solar cells are then arranged into solar panels consisting of many connected cells as seen in the photograph on this page.
- How much light energy does the sun provide?
The sun provides an enormous amount of energy. If we were able to harness all of the energy provided by the sun, we would have 10,000 times more energy available than the current energy usage of the entire planet! Solar energy is a tremendous resource, and one that is not going away any time soon.
- What does a typical solar power installation look like?
Solar panels are installed in arrays of multiple panels. These arrays can range in size from as few as 10 panels on the roof of a house to as many as thousands of panels in a commercial building or utility solar power plant.
- How is the solar power harnessed and used?
The two options for a solar power system are grid-connected or stand-alone. Stand-alone systems consist of a solar array connected directly to a battery and inverter which converts the DC current generated by the solar panels into AC current that powers devices, such as lights or air conditioners. Batteries are usually required in stand-alone systems to provide energy during night hours. In the grid-connected option, the solar array is connected to an inverter that delivers AC current to the utility electrical grid. In this situation the solar power generated can offset a portion of the homeowner's utility bill, and in some cases, excess power can be sold back to the local power utility. Over 80% of the installations today are grid connected and that number will increase in the future.
- What is the efficiency of current photovoltaic cells?
The energy conversion efficiency (sunlight to DC energy) of current photovoltaic (PV) cells range from about six percent for a thin layer cell made of amorphous silicon to 23 percent for high-quality single-crystal silicon cells. Some very special manufacturing techniques have produced cells in the high 30 percent range. Today's typical single crystal silicon cells usually average around 14 percent, thereby giving module efficiencies of 11 to 12 percent.
- Does solar power make sense, from an economic standpoint?
The cost to install solar power has been decreasing every year. Some predictions have solar generated power reaching parity with grid power within the next few years. As costs decrease, the time required to pay back the initial investment shortens. Of course, with the increased energy production provided by the addition of SolarMagic technology, payback times get even shorter.
Impact of Varying Light Conditions
- What types of problems do non-uniform shading or shadows cause for solar power?
Shading just a few cells will drop the panel's output disproportionately, often to less than half. It can even take out an entire panel. The impact of shading on a PV array has a much greater influence on the electrical energy harvest than the footprint of the shadow. Shading just a few cells will drop the module's output to less than half. National's SolarMagic technology allows each panel in the array to operate at its peak performance regardless of the shading of the other panels in the array.
- What happens to a dirty photovoltaic cell?
The impact of soiling on PV output is a frequently mentioned and widely misunderstood issue. Designers commonly estimate that, in the absence of rigorous manual cleaning, soiling will reduce annual generation by one to four percent. Bird droppings, pollution, and dust from traffic or farming activities accumulate rapidly, however, and can reduce output by as much as 20 percent over the course of a dry summer. Other variables -- such as surface material and orientation -- are also believed to influence soiling.
- What factors, other than shading, cause problems for solar panels?
Other known problems include solar panel mismatch, panel aging, and panel failures. SolarMagic technology is able to help overcome these types of problems by optimizing the energy output of each individual panel in an array.
- Why not just improve the solar cells?
Solar cell and panel manufacturers are constantly improving solar cell technology. The industry depends on these improvements to continue its march to ever-improving price-performance points. But it is not enough. Even with a constant rate of improvement, overall panel efficiencies will still be relatively low for years to come. Delivering every bit of performance possible out of each panel remains an important goal. National's SolarMagic technology complements the solar cell manufacturers' improvements by ensuring that the full potential of improved solar cells is realized under real-world conditions across an entire array.
SolarMagic Technology
- How will National's new technology work? What are the benefits?
National's SolarMagic technology uses our expertise in power conversion and advanced algorithms to get the most energy possible out of each panel in a solar array. Today's systems are limited by the weakest link, and one or two compromised panels can take down the entire string or array. This is somewhat similar to a section of Christmas lights that go out when one light fails. However, with SolarMagic technology, if one panel in a solar installation is shaded, dirty, or otherwise compromised, that panel is allowed to produce what little energy it can while the other panels continue to operate at their full potential.
- Is this commercially available? Will it be sold to installers or home owners?
National's first SolarMagic product has entered field trials with a limited set of customers. We are currently gathering performance data in real-world conditions and optimizing system performance. We expect the first SolarMagic converter to be commercially available to installers in by the first quarter of 2009.
- How can I get more information about National's SolarMagic technology?
Please contact solarmagic@nsc.com.
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SolarMagic technology maximizes energy output of each
solar panel even when partially shaded
Technology Demonstration
See how SolarMagic technology increases energy output in adverse conditions.
CNBC Exclusive Interview
Brian Halla talks about SolarMagic technology on CNBC's "Closing Bell"
Brief Video Segment: "The Green Report"
SolarMagic technology enables a whole new world of solar energy
Resources
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