Monday, December 31, 2012

Snow load on Solar PV and max output

Here's how Snow can impact Solar PV production.

Inverters show that on a good day, they can produce their rated maximum of right about 4000W each.  This happens on cold days with good sun or even with some edge of cloud effect.

They have produced more peak power (Ppk) than the numbers shown above - about 4011 and 4012 for the individual inverters on colder January days.

Saturday, December 22, 2012

Solar PV Project

The shed was in for a few weeks and then it was time to do the Solar PV Project.

The idea to "go solar" comes from an intererest to both cut our electric bill (PECO charges about 16-17c per kWh in SE PA) and to help fuel the Chevrolet Volt we purchased in summer of 2012.  With a clear sky and southern exposure, the backside of the shed was always to be used for this Solar project.  Rather than a ground-mount for the entire Solar PV array, we went with a 1/2 roof and 1/2 ground solution.

In August, 2012, we started to choose the equipment.  I did want to use USA-made components and not choose items imported from other countries.  Our nation needs continued jobs and I felt it would be best to pay the premium for the locally-made products.  Saving $1-2K on the project wasn't worth the mindset of not supporting our nation.  My kids may, some day, work in an industry that we support and carry forward now.

First negative was that my township charged a permit fee based on per square-foot of the array.  The shed's permit was $25 and the solar permit was over $270.  They randomly chose to use .50/sqft for the permitting fee.  It seems they are gouging those who are putting in "one of them there fancy-dancy solar things".  There is national movement to try to make permitting of solar installations smoother and lower-fee to incent more people to do installs.

On to the Solar PV setup.  Total peak power capacity is 8.16KW based on the module numbers.  Maximum output is roughly 8.0KW when the inverters hit their maximum AC power.  Over time, modules will degrade and will not hit these maximums but for the first few years, I hope we can hit the 8.0KW peak output on many good sun days.

This system is a 32-module array - actually two 16 module arrays - made up of

- 32 SolarWorld SW 255 Mono-crystalline Version 2.0 panels.  Each can make up to 255W of peak power.
- 2 PowerOne Aurora PVI-3.6 inverters
- Schletter ground-mount racking
- Pro Solar roof racking

Step 1 - Install the modules on the roof.  That's Misty, the miniature poodle wondering when the rabbit will come out from under the shed. The rabbit moved from under the old shed to this new one quickly.

Step 2 - reviewing the installation, the cable combiner box really wasn't right on the roof.  This is to be removed and wires rerouted.  Don't put up with installation steps which can be done better.

Step 3 - with combiner box now removed and roof-mounting cut down, the team adds the ground mount modules.

You will also notice the lower array is positioned over the grass area.  The guys did come back and pushed the whole array back, using jacks, so that the lower edge is behind the wooden border.  I have to say the installation team was very helpful in making everything right.
Roof rack angle is 39* and ground mount angle is 35*.  Since they are not tiltable, they may not produce the maximum possible during the summer months' high-sun and daytime heat.  But I do know that they can produce at full power during December days' peak sun as we have already seen this happen soon after installation.

Finished arrays:

Step 4 - The team then added the wiring and internal components for the inverters.
Shown here are two inverters - one for the roof and one for the ground mount.
A combiner breaker box taking both inverters' output into one 240V power output.
Also, a production meter (for possibly tracking production for SRECs).
And lastly, a small breaker box so we can install some lights and plugs into the shed.

The power is routed to the house 18" underground in a pvc pipe and then connected up outside using a "service side" interconnection.  No internal wiring was done to backfeed into the main 200A service breaker box.  This photo shows the meters before commissioning.  PECO, our local electric company came out to install two "Detented" meters allowing for proper metering for Net-Metering.  With the original home meter, if the Solar PV produced electricity back to the grid, the meter would still "spin-forward" digitally and you would pay for the electricity you sent to the grid.  Nobody wants that.  Using two meters for a net-meter configuration allows proper billing.

The shed doesn't look too bad after all the work.  We don't have a lot of neighbors around and so the big array shouldn't stand out too much.
The array is a total of 8.16KW.  The inverter maximum output is 4KW each so the array really is a 8KW maximum power output system.  I have seen it hit the maximum of just over 4KW per array on a cold day in December so I know that it is working properly.  We have had a number of cloudy days since it was commissioned so hopefully soon, we will have some good sun to put out some serious output.  On Dec 3-5, before it was properly commissioned, we had the array on for two test days and each day, the array put out over 50 kWh each day.

This system was built by Smucker's Energy, LLC of Kinzers, PA

The new Garden Shed

The following photos were taken during the week of setting up for and delivery of a large garden/yard shed that some might call a small house.

This shed was built by Stolzfus Structures of Atglen, PA

First, remove old shed,  This little guy served us well.  It was a 8' by 16' shed we kept our mower and yard tools in for about 16 years.


Next, prepare the spot for the new shed.  A local contractor prepared the ground and brought in the whitestone for this pad.

Finished pad:
Even large sheds are delivered by truck.

Using two of these motorized mules, the shed was brought to the backyard.

After all the work was done - here is the shed placed on the pad, built-out by the shed company and ready for use.
Some may ask "why get a front-porch built onto a shed?"  Well, the porch will make for a nice sitting area during summer months.  We hope to put in some flower beds or bushes around the front of the shed to give it some appeal.
Next step is to put some of our garage items into the shed and make room in the house by putting rarely-used bins out in the shed on the 2nd floor's storage area.
After that, the shed's "back area" will be used for a Solar PV system.  Pictures to come.

Niagara Power Project educational video

Below is an interesting video for kids and adults about the power project that I spent much of my youth visiting, sledding on the reservoir and riding dirt bikes under some of the power long-lines that lead from the project.

A series of four videos which go back a few decades.
Video part-2 - missing from Youtube.
Power Vista visitor's center;