Which Are The Best Practices And Technological Challenges in Rooftop Solar + Storage System Deployment


There is a lot of value that energy storage can bring to rooftop solar. Rooftop solar with storage systems is a win-win solution for both end consumers as well as the DISCOMS. A few hurdles will have to be addressed before the market can see a scale-up in rooftop solar + storage projects. Despite drastic fall in battery prices, a Solar + Storage system still costs at least 3 to 5 times more than a solar PV system alone. Grid-tied energy storage application is fairly new technology and there is insufficient publicly available field data on the performance and reliability of each energy storage technology and integration algorithm.  The bulk of the data are proprietary, making it difficult to take a long-term view of the technology risks. This issue is further compounded by several competing storage technologies and huge advancements being made by various manufacturers. The gaps in data and analysis capabilities can deter investments and hamper the growth of energy storage deployment.  Open knowledge sharing can bolster the development of best practices in Solar + Storage system deployment and could spark further improvements across such assets in the long run.

Read what the expert has to say,

It is evident from the falling prices of Li-ion batteries that we (the clean energy industry) is arriving towards a position of becoming more reliable and also cost effective for large scale adoption. We are seeing this across the market with rise in BESS tenders for large utility projects to allow RTC clean energy supply. However, for decentralised installations it is especially important to size the system appropriately with battery/energy management systems (BMS/EMS) to allocate the flow of energy from the generation sources. The BMS will manage the energy supply to loads at the facility on the basis of energy source priority, we usually consider solar as priority 1 (primary source) while the battery is priority 2 (secondary source) and the existing diesel generator/utility grid will become the backup (tertiary source). A critical factor in ensuring that this is done in an optimised way is to run a detailed load analysis at the facility. 

Another point is that batteries are becoming cheaper, so much so that they are now reaching parity to the commercial sector where the utility tariff is Rs.11/unit. So we are looking for sectors where there are high energy rates and providing them with clean energy solutions, while also working with some PSU’s to ensure that these companies have a detailed energy assessment service to support this transition. As batteries have been cheaper than using diesel (Rs.25/unit) we are continuing to work with facilities with heavy diesel use in the reduction of the gen-sets and their effluents. There is a fair amount of reduction in the past year alone, from Rs.18/unit to Rs.12/unit, which contributed to the improvements in technology and also increased the scale of adoption. 

A best practice would be, to ensure that the EPC company is providing you with the right system size and best technology option, because although the prices are becoming competitive the entire system will need to be maintained/replaced if not done right. U-Solar has piloted a project with Big Basket and from this large off-grid system in Kataria, we are learning more about the O&M for battery based systems and are continuing to improve the processes in their operations.

By: Sanjeev Jha, Head of Operations, U-Solar Clean Energy

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