A new way to measure solar panel degradation

Despite many benefits and relative popularity as a renewable energy source, eventually, the sun does set on even the best solar panels. Over time, solar cells face damage from weather, temperature changes, soiling, and UV exposure. Solar cells also require inspections to maintain cell performance levels and reduce economic losses.

So, how does one inspect panels in real time, in a way that is both cost-effective and time-efficient? Parveen Bhola, a research scholar at India’s Thapar Institute of Engineering and Technology, and Saurabh Bhardwaj, an associate professor at the same institution, spent the last few years developing and improving statistical and machine learning-based alternatives to enable real-time inspection of solar panels. Their research found a new application for clustering-based computation, which uses past meteorological data to compute performance ratios and degradation rates. This method also allows for off-site inspection.

Clustering-based computation is advantageous for this problem because of its ability to speed up the inspection process, preventing further damage and hastening repairs, by using a performance ratio based on meteorological parameters that include temperature, pressure, wind speed, humidity, sunshine hours, solar power, and even the day of the year. The parameters are easily acquired and assessed, and can be measured from remote locations.

Improving PV cell inspection systems could help inspectors troubleshoot more efficiently and potentially forecast and control for future difficulties. Clustering-based computation is likely to shed light on new ways to manage solar energy systems, optimizing PV yields, and inspiring future technological advancements in the field.

“The majority of the techniques available calculate the degradation of PV (photovoltaic) systems by physical inspection on site. This process is time-consuming, costly, and cannot be used for the real-time analysis of degradation,” Bhola said. “The proposed model estimates the degradation in terms of performance ratio in real time.”

Bhola and Bhardwaj worked together before and developed the model to estimate solar radiation using a combination of the Hidden Markov Model and the Generalized Fuzzy Model.

The Hidden Markov Model is used to model randomly changing systems with unobserved, or hidden states; the Generalized Fuzzy Model attempts to use imprecise information in its modeling process. These models involve recognition, classification, clustering, and information retrieval, and are useful for adapting PV system inspection methods.

The benefits of real-time PV inspection go beyond time-sensitive and cost-efficient measures. This new, proposed method can also improve current solar power forecasting models. Bhola noted that the output power of a solar panel, or set of solar panels, could be forecasted with even greater accuracy. Real-time estimation and inspection also allows for real-time rapid response.

“As a result of real-time estimation, the preventative action can be taken instantly if the output is not per the expected value,” Bhola said. “This information is helpful to fine-tune the solar power forecasting models. So, the output power can be forecasted with increased accuracy.”


Link: https://www.sciencedaily.com/releases/2019/01/190110141735.htm

How do solar panels work?

Fifty years ago, solar panels were so expensive that they were used mainly for powering billion-dollar space probes, and that’s about it. But as the panels became cheaper — and as environmental worries about coal and other fossil fuels made renewable energy sources like solar more attractive — solar panels began sprouting up all over the place.

There are now enough solar panels installed in the U.S. to power about 11 million homes. Collectively, the panels produce about 1 percent of the country’s total electricity. Experts expect that share to rise sharply over the next 20 years, as solar panels get cheaper and more efficient at converting sunlight into electricity.


Solar panels generate electrical current by exploiting a phenomenon first described more than a century ago by a French physicist. In 1839, Henri Becquerel noted that silver and platinum electrodes in an acidic solution produced small amounts of electricity when exposed to light. This reaction became known as the photovoltaic effect, meaning “light into electricity.”

It wasn’t until 1954 that the first practical “solar cell” was created by scientists at Bell Laboratories in Murray Hill, New Jersey. Their silicon-based device arrived less than a decade after researchers at Bell invented the transistor, which is now a key component of electronic devices.

“This was a golden era of solid-state devices pioneered at Bell Labs, and solar cells were one of them,” says Hugh Hillhouse, a professor of chemical engineering at the University of Washington in Seattle and a solar power expert. “The architecture of [some transistors] is very close to a solar cell… they are actually very similar to each other.”


Modern solar cells are made of semiconductor materials like silicon or cadmium telluride. Light falling on this material energizes its electrons, giving them enough energy to create a flow of electrical current.

A typical solar panel combines dozens of solar cells in an electrical circuit to produce a usable voltage, which can provide power right away or be stored in batteries for later use. Some solar power installations can feed power directly into the electricity grid.

Since the amount of electric power produced by solar panels depends on the intensity of light, they don’t work well on cloudy days and not at all at night. A common solution is to back up solar power installations with batteries that store extra power until it is needed at a later time.


For a long time, the high-quality silicon used in solar panels was hard to manufacture, which made solar panels prohibitively expensive for most applications. Their use was limited to specialized applications, like powering spacecraft.

NASA’s grapefruit-sized Vanguard 1 satellite was the first to use solar cells when it was launched in 1958, and solar panels are still used extensively in space. The International Space Station, for example, is powered by arrays of solar panels that can generate up to 120 kW of electricity — enough to power about 40 homes.


The cost of silicon used in many solar panels has dropped sharply over the last 20 years, with the result that, in the sunniest parts of the U.S., commercial solar power is now as cheap or cheaper than generating power from fossil fuels.

6 kW installation of solar panels, enough to power a typical American home, now costs about $14,000 — a fraction of what it would have cost a generation ago.

Hillhouse says that as the costs of manufacturing solar panels continue to fall, and the technologies used to make them continue to advance, solar power could eventually produce enough electricity to meet 20 to 60 percent of America’s energy needs.

“Even if all research stopped tomorrow, the economics are already such that photovoltaics are going to grow tremendously,” he says. “There is absolutely nothing that I can see that can stop the very rapid growth of solar in the next 10 to 20 years.”



Link: https://www.nbcnews.com/mach/science/how-do-solar-panels-work-ncna957231

TNB aims to increase customers via SARE, NEM schemes

KUANTAN (Dec 20): Tenaga Nasional Bhd is targetting to increase the number of customers next year through the implementation of the Net Energy Metering (NEM) and the Supply Agreement for Renewable Energy (SARE) schemes via its wholly-owned subsidiaries TNBX Sdn Bhd and G-Sparx Sdn Bhd.

TNBX Sdn Bhd Senior Manager (New Product Development) Dr Aznan Ezraie Ariffin said the increase was expected, following the various opportunities and incentives offered to customers under these schemes.

“As at August 2018, there are 230 residences, 83 commercial buildings and 39 industry players benefiting from the NEM implementation, which began in early 2017.

“We expect many more parties, especially industrial customers, will take advantage of the opportunities offered as the schemes will benefit both TNB and customers,” he said.

Aznan Ezraie was speaking to reporters after the launch of the Renewable Energy Seminar organised by TNB Pahang and the state government, which was officiated by State Science, Technology, Green Technology, Communications and Multimedia Committee Chairman Datuk Mohammad Fakhruddin Mohd Ariff, here today.

Aznan said the schemes would also expand the use of green technology in TNBX’s operations because solar power was environmentally friendly, and has lower operational and maintenance costs in the long term.

“Apart from this, the use of green technology can generate side income by reselling excess solar-generated power back to us,” he said.

Meanwhile, Aznan Ezraie said TNB was in the midst of planning to expand the SARE scheme to individual users and and was optimistic of achieving the 20 per cent target for renewable energy by 2025. — Bernama

Link: http://www.theedgemarkets.com/article/tnb-aims-increase-customers-sare-nem-schemes