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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.

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 (0)

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)

New York to revise its net metering laws

27 Feb 10 | Conservation, Environment, Incentives, Solar Electric

Both the New York Assembly and the Senate has passed amendments to NY’s net metering rules.  The amendment (A.7557A/S.6700) is designed to increase the net metering for non-residential customers by correcting restrictions to the 2008 net metering regulations.   The original 2008 allowed for interconnections up to 2 MW but the wording was ambiguous and most new net metering accounts were residential since 2008.  By allowing larger commercial systems, businesses will be able to take advantage of solar and wind energy, helping to meet NY State’s goal of 25% renewable energy by 2013.

Net metering allows the owner of an on-site renewable energy system to receive a credit on his or her utility bill for any unused power supplied to the electric grid by the system. The credit then offsets the power received from the grid when the customer consumes more energy than the system is generating. In addition to acting as a hedge against rising energy costs and reducing overall stress on the electric grid, on-site renewable energy sustmers provide numerous environmental, public health, and economic development benefits to local communities.

This is the basis for all grid connected PV systems.  It is good that the government of NY realizes the benefits of renewable energy and are taking steps to help implement it here.

The question is, will all of this renewable energy replace fossil fuel based generation, or will it merely increase the energy capacity and thus use in NY?  There are indications that the latter is normally the case, unless fossil fuel based energy becomes too expensive for the average person of business.   After the energy efficiency increases in the 1970’s and 80’s, many people began building larger houses because they could now afford it.  History will repeat itself unless the true costs of energy are passed on to the end consumer and not the taxpayer.

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27 Feb 10 | Conservation, Environment, Incentives, Solar Electric | Comments (0)

How will Solar change the electrical contractor business

16 Feb 10 | Solar Electric

I read an interesting article yesterday regarding how the solar industry will change the job of electricians.  My experience is thus:  Electricians get asked a lot of questions about solar (photovoltaics mostly) by their customers.  Some attempt to give good answers, some may even look into doing solar installations a little, but most are not interested.  At least right now.

In the future, perhaps solar installation training will become part of electrical apprenticeship programs.  The main skill sets that a solar installer has, which an electrician does not, is the site analysis, system design and intimate knowledge of available incentives and grants.  System design is getting easier with the advent of microverters.  In new construction, at least some of the system design aspect should be up to the architect, e.g. a roof facing true south tilted at latitude.  In retrofitting existing buildings, however, compromise is often the case.  With performance based incentives, such as what is available in New York state, that can increase the system’s cost.

In general, green construction requires an integrated approach.  All of the various systems need to work together to reduce or eliminate traditional energy inputs.  Electrical contracting is but one part of that equation.  There are many other green technologies available to electricians, such as reduced power lighting, variable speed motor controllers, energy efficient appliances, smart building systems, etc.

The article is an interesting read and brings out many good points.

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16 Feb 10 | Solar Electric | 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)

Solar Hub

26 Jan 10 | Solar Electric

Solar Hub, any technical information you need about PV panels or inverters.

This makes panel and inverter selection much easier.  Downloading then reading .pdf files from manufacture’s web sites takes time and clogs up a hard drive.  This way, you can find out all of the critical information ahead of time.  Of course, any installation will need to have spec sheets on hand for the electrical inspector, the utility company, etc.

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26 Jan 10 | Solar Electric | Comments (2)

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)

Solar Power: Save money, increase the value of your home

20 Dec 09 | Sales, Solar Electric, Solar Hot Water, solar thermal

I have been going over some of the bills from the last few years. My utility company, Central Hudson Gas and Electric has been increasing the cost of electricity by 9% annually.

central hudson electric rates

Nine percent per year seems like quite a bit, especially since inflation has been running around two to three percent. The increases of fuel costs and energy products in general has far outpaced inflation. Projected out 25 years, the cost per kWh is $1.53! I don’t expect it to get that bad, but one never knows.

Here are some solar facts:

Based on conditions here in NY state:

  • The average home owner chooses to install a 4 KW DC photovoltaic system. This generates 4500 to 5000 KWh per year.
  • With rebates and incentives, the final system cost is about $10-11K.
  • Over the course of the system life (25 years), the electricity generated will cost $0.09 per KWh. Currently, NY electricity averages $0.158 KWh (increasing at 9% per year).
  • Without inflation, that equals a savings of $29,000.00.

Also, based on conditions in NY state:

  • the average home owner chooses to install an 80 SF/80 Gallon solar hot water system. This will supply a family of four with 80% of their hot water annually.
  • With rebates and incentives, that system cost is around $3,800.
  • Over the course of the system life (25 years), the energy converted by this system will cost $0.03 per KWh. Currently, NY electricity averages $0.158 KWh (increases 9% per year)
  • Without inflation, that equals a savings of $16,500.00.

Of course, these are long term investments. In order to realize this type of savings, a homeowner will have to stay put for 25 years. That is a rarity these days.

Solar systems retain almost all of their pre-incentive/rebate value when added to a structure as a capital improvement. Here is a list of residential home improvements and the values added to a typical house:

  1. Two story addition: 94%
  2. Bathroom remodel: 93%
  3. Major Kitchen Remodel: 91%
  4. Solar System: 90%
  5. Basement finish/remodel: 89%
  6. Siding: 88%
  7. Roof Replacement: 85%
  8. Deck: 84%
  9. Hot tub: 84%
  10. Family room addition: 82%
  11. Sun room: 75%
  12. Garage addition: 70%
  13. Backup power generator: 58%

Of course, if the rebates and incentives are considered, then the installation of a solar system is cash positive from day one. What this means is the homeowner pays $11-12K but gets $32,000 of additional home value. I can’t think of a better deal than that.

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20 Dec 09 | Sales, Solar Electric, Solar Hot Water, solar thermal | 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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