From pv magazine India
Held as part of REI’s 2018 conference program, at the India Expo Center in Greater Noida, just outside of Delhi, pv magazine’s Quality Roundtable brought a number of leading industry experts together, who highlighted the current weak points in India’s solar installations, their consequences, and the importance of system monitoring. They also discussed innovations in raw materials and solar tracking to maximize efficiency, as well as innovative financial instruments to reduce the cost of debt and scale up infrastructure investment.
Asier Ukar, senior consultant at PI Berlin, began the session by presenting case studies detailing 1.505 MWp of rooftop, and 50 MWp of ground mounted, PV projects in India.
Ukar voiced concerns over the findings from these projects, which included a lack of engineering, procurement and construction (EPC) and operations and maintenance (O&M) warranties in contracts; inaccurate module mounting; potential induced degradation (PID) in modules; no supervisory control and data acquisition (SCADA) systems for O&M; and inaccurate handling of modules, leading to damage during transportation.
The serious revelations about the poor quality of Indian PV projects set the tone for intensive deliberations by the distinguished panel, which comprised Rajaram Pai, business leader, E&I South Asia and marketing manager, DuPont Photovoltaic Solutions (South Asia and ASEAN); Rahul Sharma, senior manager, technical applications, Solar-Log; Jan Mastny, head of global sales, Leoni; Robin Li, director of technical service & product management, JinkoSolar; Shailesh Bijegaonkar, sales manager India, Stäubli; Jitendra Morankar, vice president global design applications, Nextracker; Vibhuti Garg, energy economist at The Institute for Energy Economics and Financial Analysis (IEEFA); and George Touloupous, director of technology and quality, Clean Energy Associates (CEA).
Improve quality, keep down costs
Dupont’s Rajaram Pai said project installers need to factor in the climatic conditions in the specifica areas of installation. If they do not plan for factors like salinity, PV modules will degrade much faster.
On innovations in raw materials to improve quality, while also keeping costs down, Pai told pv magazine, “Companies like DuPont are working to significantly increase the efficiency of PV modules by using fine lines of silver to be able to aggregate the electrons that are generated. That’s the front-side metallization paste where the efficiency is being increased while keeping the cost same or even reducing it.”
He continued, “This ensures that the contact is made much better and electrons generated as part of the photovoltaic activity are collected more efficiently. Secondly, tomorrow if you are going to have trackers, you are going to be using materials that can be light, don’t require maintenance and last for 25 years. Third, backsheets are being made robust by using things like polyvinylfluoride film, which has over 30 years of proven experience in the field and ensures that the outer layer doesn’t crack under severe environmental stress.”
Robin Li from JinkoSolar went on to say, “Manufacturers are using materials and processes so that the modules can withstand the harsh climatic conditions of India. For instance, JinkoSolar is using Tedlar backsheets for the Indian market. Also, module manufacturers have a liability towards the environment.”
Inverter failures can cause revenue losses of as much as 38%, said Rahul Sharma, Solar-Log, while discussing the importance of monitoring PV systems. Using case studies, he emphasized that without professional monitoring, slight yield losses from module failures are hard to distinguish from natural fluctuations throughout the year; however, even small yield losses translate into significant financial losses.
Regarding installations, Jan Mastny from Leoni outlined several issues affecting quality, including connector exposure to outdoor conditions, bad handling of cables, and improper attention to junction boxes and components. To overcome these, he said it was vital to find reputable project installers and suppliers, and to observe their quality-related processes and mindsets.
Constant low contact resistance between cables is key to the long term reliability and efficiency of PV systems, stressed Shailesh Bijegaonkar, Stäubli. “Technical failures like wrong or absent cable connections can have the biggest financial impact,” he said, adding, “Risk mitigation measures should be selected with an objective to minimize the levelized cost of electricity (LCOE) by optimizing the balance between the CAPEX and OPEX.”
Jitendra Moranka from Nextracker said that now is an excellent time for solar tracker providers in India, given the upward pressure on solar pricing. He added that India-specific challenges, such as land acquisition delays, hydrology and environmental impacts, a lack of skilled labor and high costs of grading, all contribute to issues, like row-to-row shading and construction variance.
The latest TrueCapture technology, continued Moranka, adapts tracking, based on machine learning, thus avoiding row-to-row shading and helping to increase yields. Particularly useful for India, which has many cloudy days, trackers using this technology detect the cloudy conditions and adopt a flat position, maximizing gains.
“Bifacial solar module pricing has started coming down, close to monocrystalline levels. Combining bifacial modules with solar trackers increases the overall gain by 8-9%. With respect to fixed-tilt, the gain increase is even higher at around 28%. Particularly, Southern India is a good market for solar trackers, where Nextracker sees 2-3 GW of potential,” Moranka told pv magazine.
Scaling up investment
To reduce the cost of debt and scale up infrastructure investment in a quest to ensure quality, Vibhuti Garg, from IEEFA, suggested using innovative financial instruments like bonds/masala bonds (green bonds), green climate funds/green banks, pension and sovereign funds (for capital recycling), the infrastructure development fund (IDF) and the Infrastructure Investment Trust (InvIT).
Falling tariffs are making earlier projects unviable, continued Vibhuti, who cautioned about reneging on existing contracts. Also, as there is risk of delivery or servicing debt obligation at very low rates, solar developers need to account for such risks appropriately in their bids.
Policy certainty in the long term helps to build developer and investor confidence. As such, the government should avoid policies like price caps and safeguard duties until domestic PV component manufacturing capacity is developed. He further suggested solar resource forecasting and grid integration planning as key for the Indian solar industry.
Summing up the way forward, CEA's George Touloupous, said that quality is of paramount importance, and is a factor which cannot not be negotiated on. As such, actors in the Indian solar market must become stricter in terms of quality assurance.
Key messages
Noting that responsibility for quality starts right from the tender stage, Asier Ukar said tender requirements should specify strict quality criteria across the entire value chain, with special emphasis on the long term durability of PV modules and DC cables, electromechanical installation and commissioning.
PV plants should also be designed to minimize LCOE, he said. Decisions aimed at a low initial investment provide benefits in the short term, but do not necessary lead to higher profitability. The yield simulations issued prior to financial close must be aligned with industrial best practices, in order to ensure the bankability of the project.
PV module suppliers must also provide evidence of quality, not only in regards to the basic IEC certification, but also considering Indian specific environmental stress factors. Incorporating factory audits and production supervision of PV modules as part of the tender requirements will prevent low quality modules from reaching projects.
Clear installation guidelines and a comprehensive BOM of the weather station should be another part of the tender requirements, in order to ensure a proper logging of all relevant environmental variables for an accurate performance ratio assessment. Furthermore, they must ensure that all PV plants are commissioned according to the best practices of the PV industry with regards to performance and safety, both at the system and component level. And, before starting the operational phase, the impact of the cleaning methodology on the PV module warranty must be assessed.
EPC and O&M contracts should also clearly specify performance warranties, along with the applicable pass/fail criteria, in order to reduce the risks for the solar power developers. However, for projects financed, constructed and operated by the same company, where EPC and O&M contracts may not exist, external third party inspection should be mandatory, since self-imposed quality control measures are usually not applied by the solar power developers.
The EPC must also be made liable for any installation failures; and the technical requirements for allowing a proper identification of the same must be annexed to the EPC contractors.
Finally, strong O&M reporting, including monitoring of the system availability, will contribute to accurate tracking of a PV plant’s behavior.
pv magazine also held a Quality Roundtable in Taiwan last week, the report of which will be available online shortly; and has two more planned for SPI in the United States this week, and at All Energy Australia, next week. Watch out for coverage from these quality events, and from our Future PV Roundtables, being held concurrently.
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