Reasons For Under Performance

 

                                           

                                           


#4  FINE-TUNING:  At the heart of every PV system is the inverter – a precision electrical device that converts DC current from the modules into AC current required on the electrical grid.  In addition to converting the energy, the inverter plays an extremely critical role in introducing the flow of electrons into the grid in a manner conforming to the utility’s technical requirements.  An inverter that is under-sized, poorly matched or improperly tuned and configured will absolutely deliver under performance.  Ambient temperature extremes – up or down, fluctuating grid voltages and frequencies, varying input voltage, etc. are all potential factors causing inverters to disconnect from the grid.  Such disconnects can last for seconds or days – depending upon the type and reason for the disconnect.  The result:  lost revenue.  Again, lack of knowledge and the ability to fine-tune the details of the inverter, module and system configuration will almost certainly guarantee under-performance.


All of the above is equally true with wind.......the devil is in the details.




 


                                           


A common misconception exists that utility scale solar PV plants are profitable and easy to build and maintain…….


The truth is that PV plants can be profitable and they can be easily built and maintained -  but that is not true of all PV plants…….in fact, your plant may be among those that are not profitable...


It’s a fact that over 30% of all installed PV plants are not operating and producing at optimal levels.  The result?  Lost revenue to the investor / owner.  And, because most utility scale plants comprise the asset base for many private equity, insurance and retirement funds, the ultimate losers are the fund investors. 


The main reason solar PV plants fail to perform optimally is simple:  lack of attention to detail in four (4) key areas.


Following are the 4 areas where details make the difference between correct performance and under performance:


 


                                              


#1  DESIGN: Optimal performance is a result of qualified engineering work and component matching.  Just because an inverter is made by a large, well-known German manufacturer does not mean its specifications match those of the modules and other components.  Operating temperature range, input variability, grid fluctuations, etc. all impact power, performance and reliability.  Finally, string design, wire and cable selection and grounding techniques are all critical decisions that make the difference between optimal and sub-optimal performance.


 


                                           


#2  CONSTRUCTION & COMPONENT QUALITY: To meet FIT deadlines, plants are sometimes built at night, or in the rain or in the dead of winter or with hired labor that has never before touched a solar module.  The plant may look good on the outside and it may qualify for a feed-in-tariff, but what is hiding beneath the surface has potential for under performance.


Additionally, no matter what the original design called for, it frequently happens that for reasons of availability, price, timing or poor planning, either the modules or the inverters or both are substituted for other brands at the last minute.  While a plant will function with multiple varieties of hardware, conversion efficiency is compromised when components are substituted due to availability without consideration for compatibility.  A solar PV plant can only perform at high levels when the design quality, construction quality and the component quality are carefully matched and integrated.


 


                                           


#3  MAINTENANCE:  Here is a fact related to PV plant maintenance: 


In general, maintenance personnel for PV plants are not the same people that designed the plant.  In many cases, perhaps most, O&M personnel are not electrical engineers, rather, they are trained for visual inspections, data recording, fuse installations, module cleaning, landscape maintenance, etc.  In most cases, routine plant maintenance personnel are neither trained nor qualified to properly configure and fine-tune the plant to its optimum performance capability.  As a result of this, a large percent of installed, utility scale PV plants are running at Performance Ratios below 80%.  The skills required to fine-tune a plant to produce > 80% are unique and generally beyond the skill level of certified, electrical engineers.


General, routine maintenance of PV plants is very important.  Every plant uses highly complex electronic equipment along with thousands of mechanical connections, contacts and supports.  All of these are tied together with kilometers of cabling and wire.  The effects of time, moisture, heat, cold, dust, vegetation, animals, poor quality and poor design will ultimately have its effect.  Proper maintenance of the obvious and the not-so-obvious are essential for producing a high Performance Ratio.