PSIDA  Solar, Wind, and Waste to Methane RE Backup Facilities

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PVac Solar FAQ#2

Posted by [email protected] on May 21, 2014 at 4:40 PM Comments comments (87)

Even for  non-profit organizations that cannot directly use the 30% ITC,  is it possible to incorporate incentives through third party financing arrangements such as a Power Purchase Agreement (PPA)?

 --  Yes, but a true financial analysis would need to be performed.  While we can introduce NGO to groups who will do this, it is less expensive in the long run to take care of it themselves if they already have maintenance and can obtain good financing or have the money.

What Total Lifetime Costs increase or decrease the lifetime cost (utility price increases, Power output degradation,total operating and maintenance expenses over your system’s lifetime?  

 -- the systems are warrantied over a 30 year period.  Projected lifetime is 50 years with a 5% probability of replacing inverters and a 1% probability of replacing panels.   Replacement of hardware is unlikely, but a 0.1% probability exists.  Power output degradation over 20 years is less than 10%.  Operating expense is primarily administrative, maintaining a monitoring computer and possibly someone overseeing production.  This can be a typical maintenance function or allow access to anyone who wishes to look at the performance.  Great PR  to allow the schools access for school projects, keeps the monitoring interesting.

How is your PVac690 wired?  What is included in the PVac690?


Our PVac690 system would include 2 (345 watt) panels, 12.5' 10 AWG wiring harness, Inverter and Electrical Chaise and Mounting hardware.


In addition, you can order plug and play combiner boxes with 10 AWG coming in and 6 AWG copper coming out going to the plug and play disconnect box.  This eliminates any electrician requirements all the way to the disconnect box.


The mounting hardware is now part of the frame.   All wiring is plug and play using Anderson Power connectors.


All PVac systems are parallel wired.  Essentially plugging the harness between systems, 8 systems to a wiring harness delivering up to 32 Amps at 240 VAC to the combiner box.   6 AWG from combiner box (24 systems) carrying up to 96 amps



PVac Solar FAQ

Posted by [email protected] on May 21, 2014 at 4:00 PM Comments comments (4)

How much electricity will your solar installation generate over the lifetime of

 the system?  

 -- This depends on specific location.  For example - Berkeley, CA, USA will average 136,632 kWh (85.56 kW install) and Pleasant Hill, CA, USA will average 383,451 kWh (240.12 kW install) per year over a  30 plus year period.

Note that all of our power projections are based on a NASA database model for specific location.  So instead of giving you some kind of theoretical Peak power generation, we actually provide you with the monthly and annual average power projected.

 How does the lifetime cost of the solar electricity produced compare to what you

 would pay your current provider over that same period?   

 --The Level Cost of Electricity is used to compare your cost over a 30 year warranty period against your retail or wholesale cost of electricity.  Costs are capital , finance , installation, maintenance, administration and insurance costs.

 You determine your LCOE costs by taking all costs above and dividing by your annual projected costs times 40 or LCOE= (Total Costs)/(annual kWh*30).

How much roof area will be consumed for solar panels (xx-sqft) & how much annual electricity will the system produce?

  -- Size of a PVac system is 42" by 12' 10" .  Pitched roofs are straight forward.  Look at how many systems can be physically placed on your roof  effectively outside of shaded areas or areas with vents, air conditioning systems , chimneys or similar structures.

A flat roof includes the shading caused by use of our flat roof structures plus panels.

PSIDA does full shadow analysis for our customers indicating best layout for maximum power production at minimal cost.

How much oxidation reaction when first exposed to light & how much production capacity will they lose within first couple weeks after installation?

 --  PSIDA ZEV uses monosilicon wafer panels, no oxidation and no loss of power after first couple of weeks.  This is an issue with polysilicon and thin film solar panels.

How much will light-induced degradation impact on total electricity produced over its lifetime?

 --   The AR 10 layer nanomaterial coating on the tempered solar glass has a UV cutoff at 350 nm, the pellicle glass provides additional protection by having a UV cutoff at 400nm.  Over a 30 year period, the solar glass will maintain panel efficiency to within 95% of original value.  The Pellicle glass will maintain within 98% of original efficiency value.   Aka, 690 watt  times either .95 (Solar glass only) or .98 (Solar and Pellicle tempered glass).

How sensitive are our panels to very low levels of light?

 --   The use of 10 nanolayer films improves overall sensitivity to diffuse and low levels ofight.  The solar glass helps to increase overall annual power generation by 5 to 6% per year whereas the additional pellicle glass will tend to increase power production by an additional 1 to 3 points per year, aka, raises it to 6 to 9% overall power production increase per year due to low levels of light or diffuse light.

What is your panels Spectral Response during cloudy days, is it possible to capture energy in shorter wavelengths (blue) and longer wavelengths (red) of the solar spectrum?

 --  Spectral response at this time is primarily in the green/yellow regions.  This is a solar cell dependency.  While methods for shifting Infrared into this region has been proven in the laboratory it is not yet available on solar cells.  What is important to note is that with our tracking systems we still saw 60% of maximum power production in the early morning and late evening, aka, the Blue and Red high spectrum periods.

What is your panel Temperature Performance, how much efficiency loss do we expect when they become hot, what is your Normal Operating Cell Temperature (NOCT)2? Any advantage in your Solar Panel System Mounting Technology, can we deploy low tilt angles to reduce shadowing and reduce spacing?

 -- Note that there is a common misunderstanding even by people in the industry.  Temperature performance is related to the junction temperature not ambient air temperature.  Our panels are rated at Nominal Operating Cell Temperature (NOCT)   45+/-2 C,  Temperature Coefficient of Pmax -0.45%/C, Temperature Coefficient of Voc -0.33%/C, Temperature Coefficient of Isc 0.05%/C.

Note that Isc has the lowest coefficient, utilizing our MPPT algorithms correctly and maintaining a constant current output at VAC over temperature, we improve overall annual power production through our inverter technology related to temperature. 

Overall this means that in extremely hot temperatures, desert environments, we see a drop in efficiency from 17.77% to 17.27% in DC power output but total power output from DC rating to AC peak output only reduces from 96.4% to 96.2 %.

Our mounting approach has an advantage in reducing overall junction temperature, by using low profile, we shade flat roofs and pitched roofs..  Air flow and the  fact that the roof is shadowed behind the panel helps to keep the solar cells cooler.  The cell temperature heat is reduced through cooling of the backside reducing the greenhouse impact of the glass.  Since infrared, IR passes through silicon, it does not significantly impact the junction temperature.  Plus removal of UV gets rid of unwanted absorption of UV in the junction reducing heat buildup in the junction.

What Upkeep Maintenance Operation is required to maintain peak performance?

 -- Occasional cleaning.  Note that by using UV cutoff we reduce or eliminate the degradation of the plastic encapsulate.  In addition, our solar glass nanofilm traps UV for a short period of time in the film.  The energy of the UV breaks ionic bonds of dust and pollen which allows breeze and rain to remove it from the film on top of the glass.  In addition, the film is designed to be hydrophobic, thus rain sheets off the glass reducing dust spots.

It is the non organic films such as diesel fumes that must be cleaned .  Monitoring of performance in relation to projected average energy production helps to establish cleaning schedules for this type of "grease layer".

What amount of System monitoring, preventative maintenance, and regularly scheduled repairs are expected to avoid downtime and derive maximum value over the lifetime of your solar installations?

 --  Each PVac system is monitored using a WiFimesh approach developed for Cloud computing.  This eliminates data dropping and provides precise monitoring.  Preventive maintenance consists of occasional cleaning based on power performance.  The snap lock approach of our wiring systems eliminate the need to go back after installation and double check all wiring connections to make sure they have not loosened up.

Essentially the system is designed to be an "install and forget".  We are working on improved statistical analysis packages to reduce human monitoring and provide alarms indicating something needs to be done, similar to the check engine light on your car.

Is an Energy Management System (power monitoring, Preventive Maintenance, module cleaning, corrective maintenance) to ensure uninterrupted power generation?

 -- Yes.