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Sun Volt

Sun Volt Solar

earth, the final frontier

Clean Energy, Clean Environment

We are at a cross roads in human history, we can choose to continue on as we have been, or we can make a change to improve our future and quite possibly the future for several generations to come. We are here to promote energy independence, a better environment, a secure future and a higher return on investment for your hard earned dollar. It is what I believe in, it is why I am in the solar business.

NYSERDA funds PV rebate program through 2015

06 Aug 10 | Solar Electric

The New York State Energy Research and Development Authority (NYSERDA) has updated it’s PV rebate program, formerly known as PON 1050, now known as PON 2112.  In the new program, 2 million dollars per month is allocated to PV installations.  Rebates are capped at various levels, 7 KW DC for residential, 25 KW for non-profits, and 50 KW for government installations.  The cash rebate is $1.75 per installed watt, however, if demand exceeds 2 million dollars in any particular month, that amount can be adjusted downward.

The prices of PV panels have dropped from the highs seen two years ago, leveling off in the $2-3 per watt range.  The balance of system parts also have more options available, so system prices are still edging downward, slowly.  Eventually, those prices will bottom out and begin to climb as energy prices in general increase.

Installation season is in full swing, so if you would like to get in on the action, give us a call.

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06 Aug 10 | Solar Electric | Comments (0)

New York A7557A fixes some of it’s net metering law

30 Jul 10 | Solar Electric, Wind Power

New York legislature has fixed at least one issue with the net metering law (PSL 66) with A7557A, which was signed by the Governor last March.  The law took effect yesterday.  Here are some of the issues addressed:

  1. Removed the requirement that solar generating equipment not exceed customer’s peak load.
  2. Removed the requirement that wind generating equipment not exceed customer’s peak load.
  3. Make certain provisions for commercial customers to pay for the installation of safety equipment

Increasing solar and wind generating capacities are a step in the right direction.  If a customer has a resource that is available to be used to generate power for other electrical customers, there is no reason not to take advantage of it.

The utility companies buy this power at wholesale rates and sell it for retail to the next few customers down the line.  Everyone wins.

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30 Jul 10 | Solar Electric, Wind Power | Comment (1)

Off grid solar system for construction site

18 Jul 10 | Solar Electric

This was a unique and fun project.  A fellow is constructing an off grid home in upstate NY.  His idea, since the house is going to be off grid anyway, why not put in a temporary system to power tools and such while building the structure.  When the house is completed, the system can then be moved inside.  He is also living onsite in a yurt, so having electricity available to charge laptops, run the well pump and other things that most of us take for granted would be a great side benefit.

To start, he purchased a portable saw mill and began clearing the lot.  Using trees he cut down on site, he built this temporary power shed to house the inverter, charge controller and batteries:

Temporary power shed made from onsite harvested and milled lumber

We used a bit of left over rubber roof membrane to water proof the roof prior to installing the PV panels.  The PV panels are Sharp NU-235F1 mounted on Unirac rails.

Power shed with roofing and solar panels attached

The inverter is a Xantrex XW-6048 with a XW-MMPT solar charge controller.  Also used are the XW power distribution panel, the XW control panel and generator start panel.  Since this system is going to be used in the finished house, we choose the larger inverter.  This house has a well that is 380 feet deep and uses a Goulds 1 1/2 HP submersible pump.  This pump is the largest single draw in the entire system, starting surge of about 5,000 watts and using 2,100 watts when running.  The 6 KW inverter is able to handle this without problem.

Balances of system parts, off grid system

The batteries are  16 Surrette S-530 flooded cells.

The wall between the batteries and the inverter has 30 pound roof felt to act as a corrosive barrier between the batteries and the electronics.  Ventilation is copious.  The tarp is placed over the opening when the system is not in use.

The house itself is in progress, with the foundation completed and the floor slab being prepared for pouring soon.

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18 Jul 10 | Solar Electric | Comments (0)

XsunX thin film solar advances

15 Mar 10 | Solar Electric, Technology

Thin Film Photovoltaics (TFPV) have the potential to dominate the PV market in years to come. TFPV is less expensive to manufacture due to reduced use or elimination of the raw material Silicon, the key ingredient in all wafer PV technology.  TFPV is also the key to building integrated PV (BIPV), peel and stick laminates and other low profile PV solutions.  Many commercial building architects and owners prefer low profile PV systems to the mounting of large PV arrays, which increase weight and wind loading and lower aesthetic appeal for some people.

The downside to TFPV is lower efficiencies, on the order of 7-9% for most commercially available modules.  This adds to the array area and adds expense and labor to a PV installation.

XsunX, Inc., manufacture of Thin Film Photovoltaics is working on boosting TFPV efficiencies to 19-20%.  Several development laboratories have seen efficiencies of 19% or greater in lab testing.  The difference between lab tests of specific PV modules made in tightly controlled conditions and mass manufactured modules is the purity of the substrate materials.  In conventional TFPV manufacturing, substrate is manufactured in a continuous roll process, making large quantities of low grade material.  These rolls are then cut up into 125 x 125 mm cells and installed in modules.  What XsunX is proposing is using a proven automated manufacturing process very similar to that used in the making of computer hard drives.  Smaller 125 x 125 mm solar cells will be manufactured individually instead of in large rolls.  Other parts of the process include a proprietary co-evaporation chamber which will speed the process and minimize contamination.

According to CEO Tom Djokovich, the cross industry system has the capability of making 600 million CIGS units per year, which equals 3 GW of solar cells.  With a 12% efficiency, the cost per watt will be about $0.80 wholesale.   Currently XsunX is developing the manufacturing machinery for this process as well as building their own thin film manufacturing plant.  They expect the first small production run in the end of 2010.

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15 Mar 10 | Solar Electric, Technology | Comment (1)

Smart grid and renewable energy

05 Mar 10 | Conservation, Solar Electric

I have been reading up on the smart grid technology.  I find it interesting for several reasons.  Our energy conversion to electricity is very inefficient, around 32% for the entire electrical grid in the United States.   Because of this, we are using much more energy than we need to generate electricity.

The aims of the smart grid are:

  • Self-healing from power disturbance events
  • Enabling active participation by consumers in demand response
  • Operating resiliently against physical and cyber attack
  • Providing power quality for 21st century needs
  • Accommodating all generation and storage options
  • Enabling new products, services, and markets
  • Optimizing assets and operating efficiently

According the the US Department of Energy website.

Renewable energy critics often cite the very small percentages that renewables currently contribute to electrical generation in the US.  The other argument against installing photovoltaics is their low efficiency, between 14-16 percent in most commercially manufactured silicone modules.  Others argue that the cost is too high and the reliability is low.  All of those statements are true in the context of the artificially low prices we are paying for energy today.  If the real costs of energy were reflected in one’s electric bill, the cost per kWh would be in the $0.25 to $0.40 range.  Currently, unsubsidized photovoltaic electricity is $0.218 per kWh ($7.31 per watt installed, over 25 year life span).  Our current utility electric rates are about $0.15 per kWh.  If only the Federal income tax refund were taken (30% of the installed system cost), that brings the cost down to $0.152 per kWh.

Behind the meter solar generation is much more efficient than conventionally produced power.  A coal, oil or natural gas fired power plant dumps about half the energy consumed into the environment as waste heat.  Another 10 percent or so is consumed as resistive losses in transmission lines, then there is the energy required to produce the fuel, mining, pumping, transportation, etc.  That is what is required to use whatever fossil fuel the power plant is burning.  The amount of original energy from the sun needed to produce a unit of fossil fuel (e.g. gallon of oil, cubic foot of natural gas, ton of coal, etc)  is almost incalculable.  If we were to compare solar energy inputs, photovoltaic panels are far more efficient than any fossil fuel could ever be.

Photovoltaics also produce peak power during peak demand times, which can help reduce costs associated with Time Of Use (TOU) metering.  They are a distributed generation technology, which spreads the failure risk out over many points of generation, reducing transmission losses as well.  A battery backup couple with a solar and or wind system will keep power on indefinitely if properly sized.

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05 Mar 10 | Conservation, Solar Electric | Comments (5)

What happens to a solar system when it snows?

01 Mar 10 | Solar Electric, Solar Hot Water, solar thermal

I have good customers, they ask good questions.  One such question asked of me lately has been “what happens to my solar system when it snows?”  Since I have both a solar thermal system and a photovoltaic system on my house, I can tell them.  Enough sunlight gets through the snow that the panels begin to heat up.  This, in turn, causes the snow to slide off.  Here is a picture of a ground mounted system after receiving over two feet of snow:

Ground mounted PV array after blizzard

Ground mounted PV array after blizzard

It helps that the panels are tilted to 40 degrees, roof mounted systems likely will not shed snow like this.  Still, on a roof mounted system, the snow will melt off, it might take a little longer.  The only system I would be careful of in this climate would be an evacuated tube collector.  Because the tubes have a vacuum, no heat is transfered to the glass envelope, which is really good for collecting heat, but not so good for melting accumulated snow off the collector.

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01 Mar 10 | Solar Electric, Solar Hot Water, solar thermal | Comments (0)

WEEB Grounding devices

28 Jan 10 | Solar Electric

On our last project, a ground mounted PV system supported by a post and beam frame, I used  Unirac WEEB grounding system (UGC-1) on the Unirac rails.  WEEB stands for “Washer, Electrical Equipment Bond.”

Unirack UGC-1 WEEB ground clip between two Sanyo HIP-205N PV panels

The electrical inspector was not familiar with the product or the concept.  I showed him the spec sheet from Unirac, which details how the grounding clip creates one electrical path through the mounting rails for the ground.  Basically, the ground clip pierces the aluminum finish on the panel frame and the aluminum surface of the mounting rail.  With that electrical connection established, a ground wire is run between all of the mounting rails and connected to the grounding electrode system.  Keep in mind, that systems should have a continuous grounding path back to the service panel ground bar and cannot be bonded to the neutral or negative conductor of the PV system.

Not all electrical inspectors would accept this method and it is not currently part of the NEC, so it is better to check with them first.  Otherwise, it saves a lot of time, effort and materials to use WEEB grounds.

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28 Jan 10 | Solar Electric | Comments (0)

Prism Solar Technologies

28 Dec 09 | Solar Electric, Technology

Prism Solar Technologies is continuing to grow their manufacturing facility located in Highland, NY. They took over the PLASMACO plant last March, which coincidentally, had much of the equipment and clean rooms needed to manufacture their product. PLASMACO was a subsidiary of Panasonic corporation, they manufactured Plasma screens for TV’s and computers.

What Prism Solar makes is a proprietary holographic planar concentrator™ (HPC) film that, when used in conjunction with conventional silicon photovoltaic cells, increases the cell efficiency by about 40%. According to their website, the increased efficiency allows for use of 30-50% less silicon during the manufacture process, making the the cost around $1/watt.

Here are the advantages of HPC technology:

  • Less silicon reduces cost per watt
  • Passive tracking from holographic effect produces more energy from diffuse and reflected light.
  • Cooler operation than conventional PV module, most unusable light passes through module without being turned into heat.
  • Bifacial PV cells can increase module performance when mounted over a reflective surface.
  • Lower embodied energy, the energy required to manufacture the HPC film is much less than that required to mine and process silicon.

They have four prototype modules on line in Tucson, AZ connected to Enphase inverters. One can look at the module performance on the Enlighten website. There is also a specification sheet for a 160 watt module.

According to their latest press release, they are about to create 175 new jobs in the Hudson Valley (although there is nothing on the careers page yet). All of that is good news for the solar industry and I look foward to seeing their product out in the field. I must say, it certainly looks cool.

holographic optical photovoltaic panel

I previously wrote about them here.

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28 Dec 09 | Solar Electric, Technology | Comments (0)

System verification for Enphase Inverters

16 Dec 09 | Solar Electric, Technology

In New York State, there is something called the Standardized Interconnect Requirements (or SIR) that governs how utility companies handle grid connected renewable energy systems such as Photovoltaic and Wind energy systems.

Among the requirements, usually known as “Step 5,” a verification that the system meets UL 1741 is required. This means that after a power outage, the inverter stays off for five minutes before it begins exporting power to the grid. For most inverters, the verification procedure is simple, turn off the breaker feeding the inverter for a short period, then turn it back on. Watch the LED indicators on the inverter and time how long it takes to come on line and produce power. If it is 5 minutes or longer, the system passes.

enphase energy M210 inverters

enphase energy M210 inverters

The problem with the [e] Enphase inverters is there are many of them, they are located with the solar panels, and it would be difficult to watch the LED start flashing green especially if the inverters are under a PV panel bolted to the roof. Therefore, an alternative verification procedure must be effected. One suggestion by the utility company was to use a clamp on ammeter to measure the AC current in the branch circuit between the inverters and the panel. One small problem was that some “leakage current” had been detected in previous tests of this nature.

I sent an e-mail off the [e] Enphase Energy, Inc. They responded very quickly with the following suggested verification procedure:

  1. Turn off the breakers to the array.
  2. Turn on the breakers to the array and make a note of the time down to the second.
  3. Using a clamp on ammeter, verify that the array is not producing current until 5 minutes have passed. During the non-producing period, the ammeter will show a slight current draw of 0.056 Amps +/- 5% for each installed inverter. In this case, there are 10 inverters in each string, therefore the clamp on ammeter will show 0.56 Amps +/- 5%.
  4. After 5 minutes have passed, the ammeter will show the array producing power by indicating greater than the quiescent current noted in step 4.

The test should be run when the array is in full sunlight so the AC current meter will obviously indicate the array is exporting power to the grid since AC current meters do not indicate the direction of current flow.

The second method proscribed by Enphase involves using the utility meter. This can only be used in arrays that are large enough to get the meter spinning, and should only be performed in full sunlight.

  1. Observe service meter and note direction it is turning while consuming power.
  2. Turn off main service breaker and all other breakers feed the various household loads, simulating a power outage.
  3. Turn on main service breaker and breaker feeding the inverter(s) only and note the exact time.
  4. Observe service meter. A very slight movement forward direction indicates the inverters are consuming a small amount of power in their monitoring circuit.
  5. After five minutes have passed, the meter will begin to turn in the opposite direction, indicating the inverters are exporting power.
  6. Close the breakers to the rest of the household loads.

Finally, if the inverters are ground mounted and the LED indicators can be readily observed, this procedure can be followed if the first two do not satisfy the utility company.

  1. Turn off the breaker feeding the branch circuit, if it is not already off, then turn back on.
  2. Observe the inverter(s) status LED, is should begin to flash red when AC power is applied then flash green when the inverter(s) begin to produce power. Time the period of the flashing red LED with a stop watch, it should be 5 minutes or greater.

This can be done for each individual inverter, or for each inverter string as the (utility company) representative present desires.

According to the manufacture, the system complies with the requirements of UL1741, which states that if the inverter detects that the grid has gone out of specification or has completely shut off, then the inverter will “cease exportation” of power. The inverter is allowed to draw current but cannot produce power. Therefore the small amounts of current indicated on an AC ammeter is not leakage current, rather it is the inverter consuming a small amount of power prior to in beginning operation.

Update: From Scott at Enphase Energy:

I had a brief, follow-up comment about one portion of the article. During the 5-minute wait time specified by UL-1741, the Microinverter is not consuming power. It is circulating reactive current in the A/C-filter section of the device.

I just wanted to make sure that the statement of “the inverter consuming a small amount of power prior to in beginning operation” was not potentially misinterpreted as tare-loss, with an Enphase customer thinking that he was losing some of that hard-earned energy during the 5-minute period.

No, we wouldn’t want them to think that, especially after I preached about unshaded locations and voltage drop during the sales presentation.

I have noted that these inverters come on line in 5 minutes and 20 seconds or so after a power outage.

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16 Dec 09 | Solar Electric, Technology | Comments (0)

DIY photovoltaics

14 Dec 09 | Solar Electric

I saw this article on MSNBC:

Solar technology is going where it has never gone before: onto the shelves at retail stores where do-it-yourselfers can now plunk a panel into a shopping cart and bring it home to install.

I suppose this was inevitable.  However, before a homeowner simply plugs a solar panel into a house, a agreement is needed with the servicing utility company.  Not doing the proper paper work can result in having the electric service disconnected.  Something the article touches on briefly.

Installing one solar panel will generate about 160-175 watts of power, depending on the temperature.  This is enough to run a desktop computer, a few lights and a flat panel TV.  Obviously, if the homeowner is serious about solar electric, a larger system is needed.

One other thing the article noted:

If you want more solar power, you can snap another panel to the first, kind of like Legos.

However, each time you snap another panel on the system, the entire system needs to be re-permitted by the utility, at least in New York State.

It will be interesting to see how this idea develops.

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14 Dec 09 | Solar Electric | Comments (0)
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