9 minute read
EMERGING TECHNOLOGIES TO ENHANCE LARGE SCALE PV PROJECT PERFORMANCE
Prelude
In order to improve the plant performance there could be multiple focus areas, right at the plant design stage to integration stage to achieve optimized plant performance. It is important for developers, EPC Contractors, O&M service providers to consider various options/ strategies to increase their plant yield at a minimal cost. Knowledge about the performance of solar power plants results in correct investment decisions and better regulatory framework, THE EVERtechnical enhancement of solar shadow losses, inverter losses,EVOLVING ROLE OF DATA & AI IN photovoltaic technology. Emerging Technologies are being used to reduce different losses like DC cable layout losses, AC wiring losses and module miss-match losses. Use of AI and ML is being done in performance monitoring and GREEN enhancement. Let's read in details ENEon EmerginRGYg Technolo Agies MIDSTo Enhance L Targe CScalOVIDe PV Project Per19formance
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JAYMIN GAJJAR
SENIOR RESEARCH ENGINEER ENERGY & POWER SECTOR, CSTEP
Emerging Technologies Can Boost Solar ‘Power’
On the 75th Independence Day, the Prime Minister spoke about India crossing the milestone of 100 GW of installed renewable energy (RE) capacity. Of this, solar power accounts for 44 GW.
Solar power is a key resource for RE installations, but low efficiency of solar power systems can pose considerable challenges in harnessing its true potential. Employing the emerging innovative technologies in solar panels and solar tracking systems can increase energy production and yield better economic benefits, enhancing the overall efficiency of solar plants. In doing so, the focus should be on large scale solar plants, as they comprise over 80%
photovoltaic (PV) installations across the country.
Several solar technologies being explored at the global level are in different stages of development. While India has adopted some of the emerging technologies, it has not done so on a scale large enough to make a difference. To fully actualise India’s solar potential, their large-scale adoption is essential. The enabling features of some of these technologies are presented here.
of the solar-
Solar Panels
Presently, polycrystalline Si solar panels—which have an efficiency of 15 17%—- are most commonly used in India. However, other current and upcoming solar panel materials, like crystalline Si, thin films, and perovskite solar cells, can offer higher efficiency. Their benefits and development stages are illustrated in Figure 1. The demand for solar trackers is increasing globally
Figure 1: Emerging solar panel materials / technologies Figure 2: Assumptions considered for PVSyst simulation
Figure 3: Generation and cost of energy profiles for 1 MW solar - PV system with and without single - axis tracking system
Solar Tracking Systems
(due to rising solar
energy demand). According to "Solar Tracker Market, 2021-2028" ,
Fortune Business Insights’ latest report, the market size is expected to
reach $ 54.23 billion by 2028, with a CAGR of 16.3% between 2021
and 2028.
Tracking systems not only boost sunlight harnessing, but also maximise the overall efficiency of the solar power system. Currently, two types of trackers are available, single-axis and dual axis. Of these, single-axis trackers are expected to dominate the market due to lower cost and longer lifetime.
Global research shows that a solar plant with bifacial panels and single-axis trackers can cost approximately 15% more than the conventional solar plant with mono-facial modules at a fixed tilt. However, the former can generate >20% energy and sometimes even up to 35-39% energy, under optimal conditions.
Comparative Performance Analysis
In order to understand the performance of a large-scale solar plant with and without trackers, the Center for Study of Science, Technology and Policy (CSTEP) conducted an analysis using the PVSyst V6.62 platform. First, a simulation for a 1 MW solar plant was done. Then the performance of an actual power plant with the same capacity was evaluated using emerging trackers and module technologies.
The assumptions and results of the analysis are illustrated in Figure 2 and Figure 3, respectively. As seen in Figure 3, a 1 MW plant with a poly Si solar module without trackers generates the lowest energy (1,772 MWh). However, when trackers are employed, the same plant generates almost 25% more output. The combination of bifacial panel and tracker offers the highest generation (2,308 MWh) and has the lowest cost of energy (INR 2.90/ kWh).
Conclusion
The ability of the emerging technologies to enhance the performance and cost-effectiveness of solar power plants makes a strong business case for their large-scale uptake. The Indian government should consider deploying these to fully harness the country’s huge solar resource, and drive the 2030 RE target of 450 GW.
MANJESH NAYAK
DIRECTOR / CFO, OORJAN CLEANTECH PRIVATE LIMITED
Over the last decades, solar photovoltaic projects have been increasingly adopted in a bet to transition to renewable sources of energy. As reported by IRENA, about 48% of the renewable additions in 2020 have been in Solar photovoltaic (PV) capacities.
So far, the crystalline silicon panel technology has dominated the solar photovoltaic market, particularly in utility-scale projects. However, in recent years, newer technologies have been adopted to make the most of the sun’s irradiation.
Floatovoltaics
“Floatovoltaics” are solar PV systems installed on reservoirs, dams, and other water bodies. These can be installed in huge capacities without using valuable real estate. Studies show that it generates up to 10% more due to the cooling effect of water. Further, floating solar farms reduce water evaporation as they limit air circulation and block sunlight; thus, helping in water management. Floatovoltaics also lower water treatment costs by reducing algae growth.
Bi-facial modules
Bi-facial modules, that can capture sunlight from both front and rear, seem to be the way forward. There is a strong shift towards this technology worldwide. A report says, bifacials accounted for about a third of utility-scale projects installed during the second half of 2020 in China. Similarly, over a Gigawatt of installations across Europe, Africa and South America and the United States are using bifacial modules. Preliminary results of an ongoing three-year investigation by the National Renewable Energy Laboratory (NREL) suggest that this emerging technology provides a considerable boost in energy gains up to 9% more energy as compared to monofacial modules.
Half Cells
Another new technology seeing quick adoption is half cells, mainly, since no major changes are required from a manufacturing view point. As the name suggests, it involves cutting a fully processed cell into half with advanced laser machines. Half cells improve module performance and durability.
Multi busbars
Multi-busbars solar cells are metallised with thin strips printed on the front and rear of a solar cell; these are called busbars (BB). Busbars conduct the Direct Current generated by the cell. The increased number of busbars has several advantages ranging from higher potential for cost saving to reduced series resistance losses and also additional rise in efficiency.
PV monitoring Drones
Continuous inspection and monitoring of the solar parks is important to take timely preventive and corrective action and maintain plant performance. Traditionally, monitoring was done through manual inspections; however, drones are finding their way in. Due to a range of surveillance and monitoring capabilities, the possibility of longrange inspection and easy control, Drones are finding wide acceptance. Drones efficiently capture the necessary data using sensors and send them to the cloud for analysis – faster and more accurate.
Robotic cleaning
Cleaning is a very crucial activity to maintain the PV plant performance. To ensure timely cleaning, optimise the use of water resources and comply with the tightening environment and labour laws, robotic cleaning is gaining popularity. Considering the current technologies, the larger the solar park, the more economical and effective it is to deploy the waterless robotic cleaning technology.
AYUSH SINHA
ASSOCIATE, ANALYTICS, AMPLUS SOLAR
Solar power is the energy of the future. It is renewable, reliable, and fuels the vast majority of life on the earth. But, in recent years, less than 2 percent of the world’s electricity has come from solar power. One of the main reasons behind this is the relatively low efficiency of solar panels. On average, a solar panel converts 15-20% of the incident sunlight (irradiation) into electricity. The factors determining solar efficiency include insulation resistance, environmental factors, type and design of solar panels. Although efficiency has not improved much in recent years, there are various existing and upcoming technological advancements in this field that can enhance large-scale PV project performance.
The solar panels are most effective when the sun’
s rays hit them head-on rather than at an angle. That is why solar panels are installed at a fixed angle that gets the maximum direct sunlight at their specific latitude. But, the angle of the sun’s light changes depending on the time of day and season. Photovoltaic trackers or PV trackers move solar panels along tracks that follow the arc of the sun. The trackers ensure that the sun’s rays always hit the panels head-on, so they are always performing at their peak. These systems do use about 5-10% of the energy produced by the panels, but the gains outweigh the losses. It has been observed that they can boost the generation of a solar panel by up to 40%, depending on the geographic location. They are generally too heavy to be used on rooftops, but they are used in other settings.
Solar efficiency reduces at high temperatures, as the electrons get excited due to the heat, they have less room to absorb energy from the sun. They work best in moderate conditions. Agrivoltaics, in which solar panels are installed over crop fields, helps in reducing the problem of overheating as the crops release water through the leaves. The water cools down the surrounding area and brings the plant’s temperature down. Floatovoltaics, in which solar panels are kept over bodies of water, which are also cooler than the air, helps keep the panels cool. The most commonly used material for solar panels is silicon. According to the Shockley-Queisser limit, the maximum possible efficiency for silicon p-n junction cells is 33.7 percent. However, researchers have found other materials that can offer higher efficiency. Perovskite, a compound of calcium, titanium, and oxygen, offers the possibility of achieving efficiency levels close to 30% as the raw materials are less expensive and fabrication methods do not require high temperatures and such high precision as silicon cells do. A film of carbon nanotubes, when added over a solar cell, can trap the thermal radiation bouncing off the surface of the cells and channel it into narrow bandwidth photons that can be easily converted to electricity.
While all these technologies can enhance efficiency, and some of these are already being used commercially, the challenge to make these technologies feasible lies ahead.
