SOME FUN FACTS ABOUT ENERGY USE

Energy Efficiency Starts at Home
TV blasting, air conditioner humming - that's no time to start the dishwasher, do laundry, or bake a cake.

 Studies show how consumers can save energy by running their appliances at the optimal time of the day - or have smart monitors do it for them. The "smart" home of the near future will communicate with the electricity grid to know when power is cheap, tell appliances when to turn on or off, and even alert when renewable energy resources are available to offset peak demand.

 The idea is that eventually our appliances and homes are going to be able to 'talk' to the grid.

The goal is to reach 50% energy savings for new construction and 40% savings for building retrofits.

Cooling Efficiently in All Climates
Nothing runs up the energy bill like air conditioning. Air conditioning currently accounts for 15% of all electricity use in the United States, and can be as much as 70% of use during hot summer days.

Researchers borrowed ancient cooling ideas and combined them with outside-the-box thinking to come up with a radically new kind of air conditioning. The system first dehumidifies the air, and then sends it through an evaporative cooler to produce cool, dry air in any climate. The keys are paper membranes that separate the air from the water and the liquid desiccant, and a re-routing mechanism that uses a thermal cycle to refresh the desiccant and vent moisture away. The technology has the chance to lower air-conditioning energy bills by 40% to 80%, because it uses water rather than electricity to perform most of the process.

More Efficient Buildings
Forty percent of the nation's energy is used in buildings - from hospitals to factories, restaurants to office complexes.

Our nation's architects and engineers are looking to find ways to reduce by 50% the energy intensity of large hospitals, schools, and retail buildings.

U.S. hospitals spend more than $5 billion annually on energy, equaling about 2% of a typical hospital's operating budget.

Schools Finding Big Energy Savings
New schools and those going through a renovation can demonstrate an average energy savings of 30%. Among cost-saving measures, the blueprints called for pretreatment of humid air rather than over cooling the entire airflow; aligning the new schools on an east-west axis, with large, efficient, south-facing windows; and smart monitors to assure that only the lights that are needed are turned on.

The potential savings are monumental, amounting to some $75,000 per year, per school. In the United States there are about 100,000 public schools. This year, $14 billion will be spent constructing about 750 new schools and renovating others. If all the new and renovated schools followed green-school designs, the savings would be more than $50 million the first year, compounded each succeeding year. And the average school is built to endure 50 to 100 years.

NEW BATTERY ADVANCEMENTS

New batteries can recharge in 10 minutes

Researchers  say they've developed a lithium-ion battery using nanoparticles that has more energy capacity and recharges more quickly.

Scientists report using porous silicon nanoparticles in place of the traditional graphite anodes has yielded superior battery performance, holding three times as much energy as graphite-based designs and recharging within 10 minutes.

This discovery opens the door for the design of the next generation lithium-ion batteries.

The new batteries, which have applications from cell phones to hybrid cars, could be commercially available within two to three years.

Previous silicon anode designs using tiny plates of the material quickly broke down from repeated swelling and shrinking during charging/discharging cycles.

Using this design, porous silicon nanowires less than 100 nanometers in diameter and just a few microns long are used, and the tiny pores on the nanowires allow the silicon to expand and contract without breaking.

This also increases the surface area of the battery, allowing lithium ions to move in and out of the battery more quickly, improving performance.

SOLAR CELLS CAN BE MORE EFFICIENT

Simulating more efficient solar cells

Using an exotic form of silicon could substantially improve the efficiency of solar cells.

Solar cells are based on the photoelectric effect: a photon, or particle of light, hits a silicon crystal and generates a negatively charged electron and a positively charged hole. Collecting those electron-hole pairs generates electric current.

Conventional solar cells generate one electron-hole pair per incoming photon, and have a theoretical maximum efficiency of 33 percent. One exciting new route to improved efficiency is to generate more than one electron-hole pair per photon.

This approach is capable of increasing the maximum efficiency to 42 percent, beyond any solar cell available today, which would be a pretty big deal.

There is reason to believe that if parabolic mirrors are used to focus the sunlight on such a new-paradigm solar cell, its efficiency could reach as high as 70 percent.

In particular, the probability of generating more than one electron-hole pair is much enhanced, driven by an effect called "quantum confinement.”

But with nanoparticles of conventional silicon, the paradigm works only in ultraviolet light, this new approach will become useful only when it is demonstrated to work in visible sunlight.

SOLAR PV INSTALLATION IMPROVEMENTS

Electrical Systems and Services, Inc is always looking at new and improved solar PV installation techniques. These improvements not only allow for better and longer lasting solar systems, but in most cases decrease the overall cost of the system, with quicker installation times.

No two solar sites are precisely alike; both the built and natural environments affect an installation’s specifics. A thorough site survey quantifies these factors, and a quality system requires tailoring the design to the site specifics. Working with PV rack companies can take much of the guesswork out of the process, as they will provide engineered designs to meet wind uplift forces, snow load, and soil or roofing material types. 

Roof-Mounted PV Arrays

Because of space limitations, ground-level shading, and the excavating and trenching required for pole and ground mounts, the least expensive and most frequent location for PV arrays is on a roof.

Roofs can be classified as either low- or steep-sloped—low slope generally means a roof with a pitch of less than 3:12 (less than 14°). Low-sloped roofs are often mistakenly referred to as flat roofs, but no roof is ever really flat, as a pitch is needed for shedding water. Even a roof that appears flat will have a pitch of at least 0.5:12.

Top-Down Innovations

On steep-sloped roofs, modules are almost always flush-mounted—mounted parallel to the roof plane. The most common technique for flush-mounting steep roof arrays is “top-down mounting.” Anodized aluminum rails are used to support modules, and stainless steel or aluminum compression clips hold the modules onto the rails, usually with a bolt and nut captured by slots in the rails. This speeds up installation, eliminating bolting through the mounting holes on the back of module frames as was once common. Now, installation is easily accomplished with the modules in position on the rails from above—thus, the description “top-down”. 

Recent design improvements in top-down mounting decrease materials and reduce labor. They include automatic grounding   and one-tool installation, all of the bolts have the same size head, so one wrench fits all bolts. Snap-in nuts attach standoffs and top-down clips, the rails are height-adjustable, and there’s a built-in channel for wire management. In addition, both the mid- and end-clips have a universal design, meaning that regardless of module-frame dimensions, a single clip works with any module and the clips don’t have to be specified in advance.

Structural Attachments

Structural attachments from the array to the roof are a critical part of the installation. The attachment type and method will vary based on the roofing type (shingle, metal, tile, etc.) and with the roof’s structural design (wood trusses, structural insulated panels, metal, etc.). 

Preventing roof leaks and meeting building codes for live and dead loads (including wind uplift, rack and array weight, and snow loads) are primary concerns. A properly installed array will meet these concerns and maintain the roof warranty. In nearly all installations, every roof penetration needs to be flashed for waterproofing. On a composition (asphalt) shingle roof, the metal flashing fits underneath higher rows of shingles, so water runs over the top of the flashing and around the roof penetration. For years, many installers relied solely on sealant for penetrations, but new structural attachments make installing flashed penetrations simple and quick. 

LED LAMPS ARE NOT ALL EQUAL

Buying “the Wrong” LED Tube Lamps can be Expensive

Electrical Systems and Services, Inc is always concerned that our customers are well educated on what's new as well as comparing products. Many times when we get asked to bid on a project, we go over and above the demand by offering the customer several different options.One of the more common recent lighting upgrades ESS has done has been the T12 to T8 or T5. With a little more dollars up front, we can usually show the customer how money will be saved in the long haul, using LED's 

When making purchasing decision on energy efficient lighting, it is not uncommon for people to choose LED tubes lights on price alone. With conventional lamps where all things are equal, per-lamp price is a reasonable yardstick. However, with LED T8 lamps all things are everything but equal. Per-lamp price alone is inadequate to reflect the real cost of a retrofit project. Experienced lighting professionals are now considering  these factors when calculating the true cost of a retrofit project:

• ·         Per-lamp price
• ·         Per-lamp installation labor cost (50% labor saving is a lot)
• ·         Per-lamp accessories cost (for new tombstones, wirings, or an external driver)
• ·         Per-lamp rebate (available only for qualified LED products listed with LDL or DCL)
• ·         Per-lamp incentive (for it has strict requirements and expiration date)
• ·         Per-lamp energy difference (18W LED T8 saves 18% more energy comparing to 22W LED T8.)
• ·         Warranty (Rebate lists routinely call for 5-year warranty, thus a 3-year warranty is no longer acceptable.)
• ·         UL label (IFAR 1598C will be the standard in Feb, 2013, and many LED T8’s will lose their listing.)

With this holistic view for your retrofit project, buying a “lesser” LED T8 may be the wrong choice. Saving money by using a single-end lamp that only carries a 3-year warranty won’t get you the rebates. Also, you will need to use non-shunted tombstones, which your fixture may not have. Lastly, change-out time is greater since the fixture will require the electrician more labor time.  Now, how much did you really save with the “lesser” LED tube with that 3-year warranty, additional 4-watt higher on power consumption and without any rebate qualification, no UL1598C classification and requiring 50% more labor time on replacing fixture tombstone? You actually end up paying a lot more on a project basis with this “lesser” LED tube even though its per-lamp cost is cheaper.

ELECTRICAL SYSTEMS AND SERVICES HAS JOINED FORCES WITH FOCUS ON ENERGY AS A TRADE ALLY

ELECTRICAL SYSTEMS & SERVICES HAS BECOME A TRADE ALLY PARTNER WITH FOCUS ON ENERGY

Focus on Energy Trade Allies deliver products, services and knowledge about energy efficiency and renewable technologies directly to customers. A Focus on Energy Trade Ally has the opportunity to work with the many programs that Focus on Energy offers, saving customers energy and money. In addition, Focus on Energy Trade Allies gain access to a wealth of resources and other exclusive benefits.

As a Focus on Energy Trade Ally, Electrical Systems and Services will be working closely

with Focus on Energy representatives. This will give you access to resources, information and training on the latest energy technologies and program opportunities.

Here is an example of a program offered by Focus on Energy

Small business owners understand the importance of the bottom line. The Focus on Energy Small Business

Program helps business customers protect that bottom line by taking advantage of our easy and affordable installation of money-saving energy efficiency upgrades.

Participating small business owners will receive a free energy assessment which shows the building’s

energy use and recommendations for energy efficiency improvements that can reduce operating costs.

After reviewing the energy assessment and recommendations for ways to save with Electrical Systems and Services, the business owner may decide to install a free package of energy savings

measures or pursue a $129 co-pay package of enhanced energy saving measures.

The Small Business Program is available to small businesses of participating utilities with an average

peak monthly electric demand under 100 kW. or around 24,000 kWh per month.

Ways to Benefit

The Focus on Energy Small Business Program offers:

■ FREE energy assessment by Electrical Systems and Services, showing savings opportunities

■ Immediate energy savings from a direct install

■ Information about Focus on Energy incentives

■ Lower monthly energy costs

Small business owners will have the option of having Electrical Systems and Services, Inc. install the following packages:

FREE ENERGY SAVING PACKAGES

1. CFLs (dimmable, non-dimmable, globes)- Unlimited
2. CFL reflectors- Unlimited
3. Cold drink vending machine controllers- Unlimited
4. LED “OPEN” sign (neon sign replacement)- 1 maximum
5. Faucet aerators- Unlimited
6. Water-saving showerheads- Unlimited

$129 Gold Energy Savings Package:

All measures from the FREE Energy Savings Package, plus:

1. 42-watt CFLs- Unlimited
2. LED exit signs- 5 maximum
3. De-lamping of redundant fixtures- Unlimited
4. Occupancy sensors- 5 maximum
5. Interior and exterior hardwired fixtures- 5 maximum of each fixture
6. 4′ T12 to T8 fluorescent lighting retrofits* (maximum applies to 4′ and 8′ T12s)- 80 lamp maximum
7. 1″ and 2″ hot water pipe wrap- 10 foot maximum

*Additional copay applies to 8′ T12s

PLEASE CONTACT ELECTRICAL SYSTEMS AND SERVICES, INC. TO SCHEDULE YOUR FREE ENERGY ASSESSMENT.

MORE SOLAR INFORMATION

Cell Type & Efficiency. 

If you have limited mounting space, PV module efficiency is a key consideration. Modules with crystalline silicon PV cells—as opposed to thin-film—will likely be required, since thin-film modules produce about half of the wattage per square foot.

Within the crystalline module category, there are variances in power density (watts per square foot). Average power density is about 12.7 W per square foot, but some modules have higher power densities:

Using a module with higher power density means getting more power out of your usable mounting area. For example, let’s say our shade-free mounting area measures 20 feet by 10 feet, for an area of 200 square feet. Without considering module dimensions, choosing a module with a 12 W per square foot power density will yield a 2,400 W array; selecting a module that yields 18 W per square foot results in a 3,600 W array—a 50% improvement.

The downside is that modules with higher power densities typically are more expensive per watt (about 7% to 12% more). Decreased installation and racking costs for higher-efficiency modules may—or may not—amount to much. In most cases, if you have plenty of installation space, you won’t likely want the more expensive modules.

Bifacial modules that produce power from both the front and back of the module  report two values for module efficiency. These modules have clear backing, allowing some light to pass through, and can generate some energy from the reflective light that hits the back of the module. These modules can be good choices for awning and carport installations that can take advantage of reflected light.

Module Size & Dimensions. 

This will determine array layout—how many modules can fit in the available space. Differing roof planes, such as trapezoids (created by hip roofs) require carefully choosing modules with appropriate dimensions, so that roof space is maximized without hanging modules off the roof’s edges. Required setbacks for local fire department guidelines, accessibility for maintenance, module mounting infrastructure, and module interconnections and string layout will also influence what size modules will work in an array at your site.

CONTACT ELECTRICAL SYSTEMS AND SERVICES, INC.

TO SCHEDULE A FREE SITE SURVEY FOR YOUR SOLAR 

PROJECT.

AUSBILDUNG IN DEUTSCHLAND

If you know German, you will know that "Ausbildung in Deutschland" translates to English meaning "Training in Germany".

For the fourth year, ESS has participated in the International exchange program held by Gateway Technical College in Racine. This year ESS hosted one student, Laura Steigerwald of Johannesberg, Germany. She spent 3 days at ESS learning many aspects of the business. One of their "assignments" was to write and post on our blog, a story about the German educational system and how it differs from the American system. She did a lot of writing, in between all of the other activities, and came up with the wonderful blog post. Please enjoy her blog and many thanks to Gateway for having this unique program. 

Apprenticeship in Germany

Hello my name is Laura Steigerwald, I’m from Germany. At the moment I’m doing a student exchange and in this week I’m doing a job sharing at ESS. During the time in America I recognized that our education system in Germany is different.

I’m doing a apprenticeship as an industrial clerk in the second year. A common apprenticeship takes 3 years – it’s a dual system. The company works very closely with the school. And I get paid during the apprenticeship.

The school is responsible for the theory and general education. They offer subjects with reference to the profession. Also, sports are important because we don’t move very much in the office.

The company is responsible for the practical part. During our apprenticeship we go thru all the different departments to understand the processes of a company and to learn all the different tasks. For example Marketing, Human Resources, Accounting, Sales, Purchasing etc.. For the most companies it also very important to improve our English. So we have not only at school English lessons – but also in-house lessons. Furthermore, I can apply for a stay abroad for two month – for example to come to Turkey or Holland.

The Aim is to train their students so that they are able to work in every of their departments. And you have the chance to work in that company after the apprenticeship. In my opinion it is a chance to find my favorite department.

Posted by Laura Steigerwald of Johannesberg, Germany

NEW SOLAR TECHNOLOGY

Solar cells made from black silicon

Solar cells convert three-quarters of the energy contained in the Sun's spectrum into electricity - yet the infrared spectrum is entirely lost in standard solar cells. In contrast, black silicon solar cells are specifically designed to absorb this part of the Sun's spectrum - and researchers have recently succeeded in doubling their overall efficiency.

The Sun blazes down from a deep blue sky - and rooftop solar cells convert this solar energy into electricity. Not all of it, however: Around a quarter of the Sun's spectrum is made up of infrared radiation which cannot be converted by standard solar cells - so this heat radiation is lost. One way to overcome this is to use black silicon, a material that absorbs nearly all of the sunlight that hits it, including infrared radiation, and converts it into electricity. But how is this material produced?

Black silicon is produced by irradiating standard silicon with femtosecond laser pulses under a sulfur containing atmosphere. This structures the surface and integrates sulfur atoms into the silicon lattice, making the treated material appear black. If manufacturers were to equip their solar cells with this black silicon, it would significantly boost the cells' efficiency by enabling them to utilize the full Sun spectrum.

Researchers have now managed to double the efficiency of black silicon solar cells - in other words, they have created cells that can produce more electricity from the infrared spectrum.

This enabled the scientists to solve a key problem of black silicon: In normal silicon, infrared light does not have enough energy to excite the electrons into the conduction band and convert them into electricity, but the sulfur incorporated in black silicon forms a kind of intermediate level. You can compare this to climbing a wall: The first time you fail because the wall is too high, but the second time you succeed in two steps by using an intermediate level.

The researchers have already successfully built prototypes of black silicon solar cells and their next step will be to try and merge these cells with commercial technology.  They hope to be able to increase the efficiency of commercial solar cells - which currently stands at approximately 17 percent - by one percent by combining them with black silicon. Their starting point is a standard commercial solar cell: The experts simply remove the back cover and incorporate black silicon in part of the cell, thereby creating a tandem solar cell that contains both normal and black silicon.

The researchers are also planning a spin-off: This will be used to market the laser system that manufacturers will be able to acquire to expand their existing solar cell production lines. Manufacturers would then be able to produce the black silicon themselves and include it in the cells as standard.

JUST TO REMIND YOU

Here are the five most practical and popular ways that solar energy is used:

IN NO SPECIAL ORDER.

1.       Small portable solar photovoltaic systems.

      We see these used everywhere, from calculators to solar garden products; portable units can be used for everything from RV appliances while single panel systems are used for traffic signs and remote monitoring stations.

2.       Solar pool heating. 

      Running water in direct circulation systems through a solar collector is a very practical way to heat water for your pool or hot tub.

3.       Thermal glycol energy to heat water. 

      In this method (indirect circulation), glycol is heated by the sun's rays and the heat is then transferred to water in a hot water tank.
This method of collecting the sun's energy is more practical now than ever. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in three years or less.

4.       Integrating solar photovoltaic energy into your home or business power. 

      In many parts of the world, solar photovoltaics is an economically feasible way to supplement the power of your home. In Japan, photovoltaics are competitive with other forms of power. In the US, new incentive programs make this form of solar energy ever more viable in many states. An increasingly popular and practical way of integrating solar energy into the power of your home or business is through the use of building integrated solar photovoltaics.

5.       Large independent photovoltaic systems. 

      If you have enough sun power at your site, you may be able to go off grid. You may also integrate or hybridize your solar energy system with wind power or other forms of renewable energy to stay 'off the grid.'

ADVANCEMENTS IN SOLAR CELL TECHNOLOGY

Microwave ovens may help produce lower cost solar cell technology

The same type of microwave oven technology that most people use to heat up leftover food has found an important application in the solar energy industry, providing a new way to make thin-film photovoltaic products with less energy, expense and environmental concerns.

Engineers have for the first time developed a way to use microwave heating in the synthesis of copper zinc tin sulfide, a promising solar cell compound that is less costly and toxic than some solar energy alternatives. All of the elements used in this new compound are benign and inexpensive, and should have good solar cell performance.

Several companies are already moving in this direction as prices continue to rise for some alternative compounds that contain more expensive elements like indium. With some improvements in its solar efficiency this new compound should become very commercially attractive.

These thin-film photovoltaic technologies offer a low cost, high volume approach to manufacturing solar cells. A new approach is to create them as an ink composed of nanoparticles, which could be rolled or sprayed - by approaches such as old-fashioned inkjet printing - to create solar cells.

To further streamline that process, researchers have now succeeded in using microwave heating, instead of conventional heating, to reduce reaction times to minutes or seconds, and allow for great control over the production process. This "one-pot" synthesis is fast, cheap and uses less energy, researchers say, and has been utilized to successfully create nanoparticle inks that were used to fabricate a photovoltaic device.

This approach should save money, work well and be easier to scale up at commercial levels, compared to traditional synthetic methods. Microwave technology offers more precise control over heat and energy to achieve the desired reactions.

Keep checking back for more information on the non-stop improvements being made almost daily in all of the renewable energies.

MANY TYPES OF SOLAR INSTALLATIONS ARE AVAILABLE

Solar Energy Systems Come In A
Variety Of Installation Types

The type of racking or mounting systems impacts how well your solar panels function. When shopping for solar for your business, or home these are the most common mounting options you’ll find on the market:

Flat Roof Solar Panel Installation  

A flat roof installation is the easiest way to go solar on your building. It offers flexibility for orienting and tilting the solar panels for ideal solar collection. This installation type is more common on commercial installations and is perhaps one of the least complicated. These are the three most typical mounting options in flat roof installations:

Ballasted Mount:

Some solar systems use weights (called ballasts) to hold the solar array to the roof instead of bolting it down. Ballasted systems are often preferable because they do not penetrate the roof, but only work for large system in low-wind zones.

Mechanically Attached:

Traditional rooftop systems are mounted to the posts secured in the roof beams. Special roof leak protection is added to each penetration to stop leaks. These attached systems work for any size, and hold tight even in windy areas.

Hybrid Mount:

Often referred to as a minimally attached system, the hybrid mount uses some structural attachments combined with typical ballasted design. This results in minimal roofing penetrations but a little more security where needed.

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Pitched Roof Solar Panel Installation 

Perhaps the most common type of solar panel installation seen in residential solar systems, the pitched roof mounting option means installing panels on non-flat (or angled) roofs. Due to the angle and complexity of solar equipment used to keep solar panels in place on a pitched surface like a residential roof, makes this type of installation the most difficult.

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Ground Mount Solar Panel Installation: 

Some buildings are not well-suited to solar installations because of location, size, or orientation. In these cases, where surface area permits, a ground-mounted system is an option. The installation for these types of systems involves a wedge structure made of steel that anchors the solar panels to a concrete foundation.

Electrical Systems and Services, Inc can work with you to determine which of the installation techniques would be best for your type of roof or property, and provide your system with the best results. Contact ESS to set up free, no obligation, building and property survey.

WINDOWS CAN GENERATE ELECTRICITY

Transparent solar cells for windows that generate electricity

Scientists are reporting development of a new transparent solar cell, an advance toward giving windows in homes and other buildings the ability to generate electricity while still allowing people to see outside.

There has been intense world-wide interest in so-called polymer solar cells (PSCs), which are made from plastic-like materials.

PSCs are lightweight and flexible and can be produced in high volume at low cost. That interest extends to producing transparent PSCs. However, previous versions of transparent PSCs have had many disadvantages.

They describe a new kind of PSC that produces energy by absorbing mainly infrared light, not visible light, making the cells 66 percent transparent to the human eye. They made the device from a photoactive plastic that converts infrared light into an electric current.

Another breakthrough is the transparent conductor made of a mixture of silver nanowire and titanium dioxide nanoparticles, which was able to replace the opaque metal electrode used in the past.

This composite electrode also allowed the solar cell to be fabricated economically by solution processing. The suggestion is that the panels could be used in smart windows or portable electronics.

ENERGY EFFICIENCY RANKINGS

US Lags in Ninth Place on Energy Efficiency Among Top 12 Global Economies

The United Kingdom comes in first in a new energy efficiency ranking of the world's major economies, followed closely by Germany, Japan, and Italy, according to the first-ever International Energy Efficiency Scorecard published by the nonprofit American Council for an Energy-Efficient Economy (ACEEE). The report finds that in the last decade the U.S. has made "limited or little progress toward greater efficiency at the national level," putting it in 9th place out of 12 economies around the globe.

The rankings are modeled on ACEEE's time-tested approach to energy efficiency ranking of U.S. states, and include 12 of the world's largest economies: Australia, Brazil, Canada, China, France, Germany, Italy, Japan, Russia, the United Kingdom, the United States, and the European Union. These 12 economies represent over 78 percent of global gross domestic product; 63 percent of global energy consumption; and 62 percent of the global carbon-dioxide equivalent emissions.

On a scale of 100 possible points in 27 categories, the nations were ranked by ACEEE as follows: (1) the United Kingdom; (2) Germany; (3) Japan; (4) Italy; (5) France; (6) the European Union, Australia, and China (3-way tie); (9) the U.S.; (10) Brazil; (11) Canada; and (12) Russia.

WHAT IS THE DIFFERENCE?

Monocrystalline vs Polycrystalline Photovoltaic Cells

You may have heard the terms monocrystalline and polycrystalline used to describe photovoltaic cells, but what does that mean and how does it affect a cell’s performance?

Basic Anatomy of a PV cell

A lump of pure silicon

The main ingredient in most photovoltaic cells is silicon – the same element that makes computer chips possible.  Silicon is the second most abundant element in the Earth’s crust, but unfortunately it is normally found in the form of silica – you might know it as sand.

Various methods exist to extract the pure silicon, but the most common is carbothermic reduction, where the silica is heated to 1700°C in the presence of carbon.  As the silicon cools it forms crystals.

The speed at which the silicon cools is one of the critical factors that determine the crystal size: the slower the silicon cools, the larger the crystals.  With care the silicon can be extracted as one large crystal.  As you might imagine, that’s more difficult, which means it’s more expensive.

The difference between monocrystalline vs polycrystalline solar cells is simply that one is produced from a single crystal of silicon and the other is produced from a piece of silicon consisting of many crystals.

Practical Differences

So what is the impact on cell performance?

Since polycrystalline cells contain many crystals, they have a less perfect surface than monocrystalline cells.  This means that they absorb slightly less solar energy and produce slightly less electricity per square foot. On the plus side, the process of creating the silicon for a polycrystalline cell is much simpler, so these cells are generally cheaper per square foot.

On balance, the cost of monocrystalline vs polycrystalline based panels per Watt of power output works out about the same, but the polycrystalline panels will be slightly larger than equivalent monocrystalline panels.  This is generally not a problem unless you have a very limited area available for the installation, in which case you will want to maximise the power output per square foot.

Monocrystalline and polycrystalline can also look different.  Monocrystalline cells will usually have a perfectly uniform appearance, but polycrystalline cells will appear “grainy” – think of how a granite worktop looks and you’ll get the idea.  From a distance this will not be noticeable, so if they are going on your roof this is unlikely to worry you.

 So which should I choose?

At the end of the day, unless you are very space constrained, your choice of panel will probably be dictated by factors other than whether they are made up of mono or polycrystalline cells.

The price per Watt is an important factor, and that is largely unaffected by the choice of monocrystalline versus polycrystalline cells.  In some circumstances, the area available for the installation may be a factor that pushes you to go for monocrystalline cells.

But the most important thing is to make sure that you choose a reputable installer and manufacturer.  Your panels will most likely give you many years of trouble free operation, but for your own peace of mind you will probably want to choose a manufacturer that is likely to be around for long enough to honor the terms of the guarantee – which may be up to 25 years!

Please contact Electrical Systems and Services, Inc should you have any questions or would like to schedule a site survey to see the potential your home or business could have with a solar system installed.

MAYBE IT'S TIME FOR YOU TO THINK SOLAR?

U.S. SOLAR MODULE DEMAND EXPECTED TO DOUBLE IN 2012

The U.S. market for solar panels is likely to double in 2012, thanks to government policies and falling prices, although new tariffs on panels imported from China could contribute to slower growth in 2013, according to a new study.

U.S. developers are likely to install 3,300 megawatts of solar panels this year, nearly double the amount installed in 2011. More than 500 megawatts of solar power were installed in New Jersey, California, Arizona, Massachusetts and other states in the first quarter 2012 alone, in what is usually a slow time for solar installations due to winter weather.

The global solar power market has been turbulent for manufacturers, as prices have plunged amid an over supply of panels. But the falling prices, as well as faster development for large scaled solar powered plants, have driven strong demand for solar equipment.

Government subsidies, such as the federal rebate of 30% of the cost of each solar system, and state and local incentives have been driving growing demand for solar. The lowering prices have also played a role in the increase of interest for solar projects.

Average solar module prices fell by one- half in 2011, to about 94 cents a watt. That followed a 2010 drop of 27% in prices. The lower panel prices, combined with lower prices for other components, led to a drop in total solar systems installation costs. This was true in both large scale utility solar systems, as well as residential roof top installations.

Electrical Systems and Services, Inc is proud to be a NABCEP certified installer and part of this growing market. Now is the time to contact Electrical Systems to have a Free, No obligation assessment to your business or residence to see if this is the right time for you to go Solar.  Please contact us, so we can get yours scheduled.