Solar Power plants have now actively become a major cost saving equipment for commercial and industrial power consumers. Since last one decade the cost of rooftop solar power has fallen by 75% , what I would like to call it, double grid parity in the present day. Simply put, this means the cost of producing solar power at rooftop of a factory or a large commercial building is less than half and in some states like, Delhi, one thirds of the cost of procurement of electricity from national grid through a distribution company.
So far so good, there are some underlying assumptions based on which any solar project is evaluated for its financial feasibility.
Common Assumptions in Solar Power projects cost benefit analysis sheets
Assumption No1 :- Solar Power plants will run consistently for the next 20-25 years
Assumption No2 :- Solar Power plants have no or very little running expense during its lifetime.
Assumption No.3 :- Solar power plants have an average production of 4 kWh/kW/day regardless of equipment used , quality of EPC & maintenance methodology.
Assumption No.4 :- Solar installers are responsible for all failures in the solar plant for the next 2 decades.
The probability of achieving timely payback and long term investment returns in lines with the excel sheet is really very sensitive to any of the above assumptions going wrong .
Some critical factors which decide longevity, consistency & Performance of Solar Power plants
1) Professional Operations & Maintenance Services: - According to a random "Performance Study" of 30 rooftop solar power plants in India, nearly all those solar power plants not having O&M contracts are losing almost half of their production and producing ~ 600 kWh / kWp/Year instead of anticipated 1200 kWh/kWp/Year. Before going in for the EPC contract , scrutinize well and ask the EPC about the anticipated solar power generation number and its strategy of Maintenance in the long run.
2) Lack of Performance Measurement Systems on site:- Solar Panels have a 25 year performance warranty but to measure performance we need to measure sunlight and do so with a fairly consistent accuracy.
3) Using Right tools: - Performance and longevity of solar power plants are ultra-sensitive to execution quality. We at Heliumfour solar use all tools & Shackles which are inevitable during the installation & Commission and followed by the maintenance services.
(a) Laser guided structure installation: - Solar panels are ultimately made of glass which is 3.2 mm thick. Incorrect or Inaccurate structural work can put unwanted stress on solar panels. The solar panels however high quality they may be, under stress and strain of temp gradients might develop micro cracks and greatly diminish the performance and the effects of which will be visible in a couple of years of performance.
Laser Alignment on RCC roofs Structural metal shed LASER alignment Structure grouted on mother slab
(b) Electronic Hydraulic MC4 crimping :-Solar panels are connected to each other using a patented connector called MC4. In conventional solar power projects these connectors are subjected to voltages of upto 1000 volts and current of 15 amps DC . According to NREL ( National Renewable Laboratories , USA) 45% of the reported solar power plant failures and more than 90% of the fire accidents can be traced back to poor MC4 management . Below is a video on how we deal with this critical point using a " Made in Germany " crimping tool which ensures failure proof crimping of these connectors and eliminating human errors .
(c) PV Insulation Tester :- Leakage in insulation due to cracked / damaged dc cables ,broken glass of solar panels & inverter side can lead to inverter failures and also is unsafe for the operator . Checking solar PV systems for compromised insulation both during the commissioning stage & during maintenance is absolutely essential for proactively preventing the system from failing.
Above Testing results of 2 bad strings and Testing results of 2 healthy strings
(d)Thermographic inspection using Thermal Camera :- Fire Hazard / Flashing in solar power plants is a real threat. Here at HeliumFour Solar we are a strong proponent of a design philosophy of using smaller capacity solar inverters . This in addition to saving DC cable losses and increasing the redundancy contributes a lot in keeping abnormal heating at connection points a bay. Thermographic inspection both during the project stage and maintenance is crucial for the life cycle of a solar plant like any other electrical installation especially when there is a large number of inter connections in the field.
(e) Fluke ground-Tester :Why is grounding important ? Grounding system is required to protect human life as well as protection of outdoor equipment against excessive touch voltages & lightning strikes and to keep transferred potential to a minimum. To provide the low resistance of the earth grid or path to neutralize the surge voltage and impact. After the earthing/grounding has been done it's important to measure its resistance to rely on both human life and the expensive equipment.
It's quite possible values may fall in the acceptable range and with passage of time, in a couple of years become more and more resistive. We at HeliumFour Solar use ,3 point method for earthing resistance value measurement and use globally best quality ground tester from FLUKE , USA.
(f) Professional monitoring and control for decentralized energy systems up to the megawatt range :-
There is no match for proactive monitoring and intelligent data crunching for achieving desired results . Typically for medium and large sized commercial solar rooftops , both short term (or day to day monitoring ) and long term monitoring mechanisms are required . Measurement of all energy flows , logging them and eventually, analytics play a crucial role in minimizing the breakdown losses .