Solar electricity or solar hot water?

If you are thinking about installing a solar panel system on your home, you may be wondering whether solar electricity or solar hot water is the way to go.  There are probably several factors that you are thinking about:

• Cost
• Efficiency
• Appearance
• Return on investment
• Energy savings
• Tax rebates and incentives

Comparing solar electricity (photovoltaic, or PV panels) to solar hot water systems, you can stand to save a lot of money with both.  In general, solar photovoltaic panels generate electricity for use throughout your home.  Using PV panels, you draw less on the grid and pay less to your electrical utility.  On the other hand, solar thermal panels save you money on the energy required to heat water for domestic use – bathing, washing dishes, laundry and more.

Here is a brief introduction to solar hot water:

For homeowners considering solar, solar hot water is less expensive than solar electricity systems.  In fact, many people make the switch to solar by going with solar thermal panels, rather than PV panels.  As a result, the return on investment for solar hot water is shorter than for traditional solar panels (5-8 years, compared to 10-15 years).

On the other hand, solar PV panels can save you significantly more money and energy over the life of a system.  Plus, with grid-tied systems, you can get credit on your utility bill for excess solar power generated via net metering.  Because all water heated with a solar hot water system is used on-site, there is no opportunity to extend your savings by selling excess solar-heated water to your community.

There are currently more options for financing solar PV panels than solar hot water systems, including solar panel leasing.  But both types of solar panels boost the value of your home and help you reduce your carbon footprint, while saving you money on your monthly utility bills.

So – whether you switch to solar electricity or solar hot water, you’re making a smart investment.  What would you do?

REC New Solar Technology

Renewable Energy Co. (REC) has recently developed new solar technology that allows its solar PV panels to achieve energy payback time in one year.

So-called energy payback time is the amount of time it takes for a photovoltaic (PV) solar module to produce as much energy as was used to manufacture it.  Efficient solar cells are just part of the equation.  REC’s solar technology uses a new method of producing silicon that requires much less energy and reduces the energy payback time to just one year.

What does this mean for solar PV panels?  Well, to start with, other solar manufacturers have only been able to produce cells with energy payback times of five years, or more.  REC, on the other hand, uses the Fluidized Bed Reactor (FBR) process that it developed to create granular silicon – a substance that uses much less energy to produce crystalline silicon.  The energy-saving manufacturing process requires only 10% of the energy required for traditional silicon processing.  This is because the FBR process does not use heating and cooling processes.

The FBR process was awarded the 2011 Solar Industry Award by Solar Industry Magazine on September 6, 2011.

Solar power in Nevada

All across the “Land of Enchantment” the state of Nevada is shining bright with a solar power future.  To the south, near Boulder City, over a million solar panels cover desert lands, generating utility scale solar electricity. Using First Solar panels, the project will generate enough clean electricity to power about 26,000 homes, saving 123,000 metric tons of CO2 with the positive environmental impact of taking 24,000 cars off the road.

Up north in the Truckee Meadows, smaller solar panel arrays are also sprouting up.  While on a scale smaller than the First Solar farm in the southern part of the state, distributed generation photovoltaic (PV) panels generate electricity for the property on which they are situated.

For example, NV Energy uses solar energy to keep the lights on at their Reno headquarters.  Not only is the company using solar power, it is adopting incentives to help residential and small business customers make the switch to the renewable resource, as well.  A new solar hot water incentive allows between $3,000 and $7,500 to off-set initial costs of the system.

To learn about the new NV Energy solar rebate programs, click here.

Sedona Red Rock High School in Arizona gets solar panels

Solar panels installed at Sedona Red Rock High School in Arizona were unveiled this week!  Using over 3,800 Kyocera Solar PV panels, Kinney Construction Services completed the solar electric system as part of the Sedona-Oak Creek Unified School District Alternative Energy Project.

The Sedona, Arizona school district is turning to solar power to help it save money and the environment.  In addition to the rooftop solar panels, the district is installing solar hot water and geothermal technologies.  What a great learning experience for the kids!  In fact, an educational PV monitoring system will show students exactly how much solar power is being generated in real time.

Mike Thomas, Project Manager of Kenny Construction Services, noted:

“The educational component for the students is going to be really intriguing.  Students will be able to compare different types of photovoltaic systems, including thin-film and multicrystalline technologies, and see the difference in electricity production of fixed versus tracking solar arrays.”

The 806 kilowatt PV panel system at Sedona Red Rock High School is just the beginning.  Solar panels will also be installed on the school district office and at West Sedona School.  At the high school alone, solar panels will offset CO2 emissions in the amount equivalent to taking nearly 200 cars off the road each year.  Solar energy generated would be enough to power over 125 residences.

World's largest building integrated PV system to be constructed in China

Yesterday, Astronergy (also known by the name of its parent company, Chint Solar) announced that the largest photovoltaic system in the world would be constructed in China next year.  To be located at the Hangzhou East Railway Station, the 10 MW solar panel system will be grid connected and fully building integrated.

The cost of the largest photovoltaic system will come from funds from the Golden Sun Program and National Solar Photovoltaic Building Demonstration Projects.  According to a press release:

The station, located in East Hangzhou, will serve as a hub for high-speed rail, subway, buses, taxis and other forms of transportation. The PV project will integrate grid-connected power generation into the building’s infrastructure and will make full use of the building surfaces and roofs, as well as other surfaces.

The solar panels at the Hangzhou East Railway Station will cover 148,000 square meters and will generate over 9,800,000 kilowatt hours (kWh) each year.  When it begins operating, the solar panel system will replace 3277 tons of coal and reduce CO2 emissions by 8095 tons.

Its exciting to think that the train station and the world’s largest photovoltaic system will be operational by the end of 2011.   The hope is that the project becomes a model for other solar installations across China.  Dr. Liyou Yang, CEO of Astronergy, stated:

“By bringing together two very necessary elements of sustainable cities- efficient transit and clean energy, we are setting an example for cities worldwide that sustainability is, in fact, achievable.”

Astronergy is a leader in renewable energy development with the goal of bringing its photovoltaic (PV) solar power product line to global markets.

Solar panels on top of Anheuser-Busch's Newark, NJ facility

Solar panels on the rooftop of Anheuser-Busch’s beer manufacturing plant in Newark, New Jersey help generate clean solar electricity for operations.  Famous for its Budweiser beer, Anheuser-Busch has installed 3,000 photovoltaic (PV) solar panels over 65,000 square feet of its facility’s rooftop.

Its the second time that the company has installed rooftop solar panels at its facility.  Last year, a solar array was added to Anheuser-Busch’s Fairfield, California brewery.  That makes it one of the largest users of solar power in the United States brewing industry!

Anheuser-Busch has entered a power purchase agreement with Orion Energy Systems, under which Orion installed and owns the solar panels on the rooftop and Anheuser-Busch will purchase reduced-cost, clean solar electricity from Orion.

Rooftop solar panels at Anheuser-Busch's facility in Newark

The general manager of the Anheuser-Busch Newark beer manufacturing plant, Kristopher Scholl, commented:

“New Jersey is quickly becoming the No. 2 producer of solar energy in the country and Anheuser-Busch is proud to be among the leaders in our state in use of this technology.”

Cheers to Anheuser-Busch for being a leader among beer manufacturers in solar energy!

Wal-Mart Solar Panels

Wal-Mart has fought against negative press regarding its mega-retail stores, competitive practices and even the way it treats is employees.  However, one news story that doesn’t get a lot of press is Wal-Mart’s efforts to go green.  For the past 3 years, Walmart has quietly been working with Environmental Defense Fund to promote thin film solar technology.  Since 2007, the retailer has funded solar research and development to create thin film photovoltaic cells with real-world applications.

And Wal-Mart is starting with its own retail outlets. The new thin film solar panels have been installed in California, Hawaii and Puerto Rico.  Another 20-30 Walmart stores in Arizona and California are slated for solar panel installation, as the corporation aims to go 100% green.  The thin-film solar panels will be manufactured by First Solar and MiaSolé.

Solar panels are being installed at Walmart’s California and Arizona in locations in part because of ample sunshine, but also because these states offer generous solar incentives and rebates. Thin film solar panels have been chosen because they are less expensive than “regular” PV solar panels, since they require less silicon and other materials.  They are easy to install and maintain, and are usually more efficient (they convert more sunlight into solar electricity) than their bulky counterparts.

Installing Walmart solar panels

What to expect from thin film solar installed at Wal-Mart:

• New solar panels installed at the proposed Walmart locations in California and Arizona will generate more than 22.5 kilowatt hours (kWh) of electricity each year
• The solar panels will offset 20-30% of the energy requirements of each retail outlet store
• The environmental impact will be the equivalent of taking over 3,000 cars off the road

And its just the beginning of Walmart’s solar efforts, which will have an impact on the way all retailers do business.  Kim Saylors Laster, Walmart VP of Energy states:

“By leveraging our global scale to become a more efficient company, we are able to lower our expenses and help develop markets for new technologies. Developing and incorporating new renewable energy sources, like thin film, reduces energy price risk and aligns very well with our commitment to solving business challenges through technology.”

With over 8,000 stores in the U.S. alone, Walmart can definitely lead by example if it continues installing solar panels across its properties.

Record-breaking solar panel efficiency

A new world record for PV solar cell efficiency was recently reached by Silicon Valley-based SunPower Corporation.  Last week, it claimed to have accomplished over 24% conversion from sunlight to electricity with silicon solar panels at its manufacturing plant in the Philippines.  U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) confirmed the solar panel manufacturer’s claim.

Aside from achieving this new world record, what is the significance of improved solar cell efficiency?

With higher conversion rates, more electricity can be generated from the same number of solar panels, which can save the user money.  More efficient solar panels also reduce the energy cost per watt and per kilowatt-hour.

In SunPower Corporation’s press release, its founder and chief technology officer, Dr. Richard Swanson stated:

“As we celebrate SunPower’s 25th anniversary this year, I am thrilled to see the company achieve technology milestones that were inconceivable only a few years ago.  SunPower’s research and development and engineering teams have increased cell efficiency by a full four percentage points over the last five years while radically driving down manufacturing costs. We are extremely proud of their continued success.”

Over the past 5 years, SunPower has been steadily increasing PV solar cell efficiency, making gains of more than four percentage points in that short period of time.

Founded in 1985, SunPower Corp. (Nasdaq: SPWRA, SPWRB) designs, manufactures and delivers the planet’s most powerful solar technology broadly available today. Residential, business, government and utility customers rely on the company’s experience and proven results to maximize return on investment. With headquarters in San Jose, Calif., SunPower has offices in North America, Europe, Australia and Asia. For more information, visit www.sunpowercorp.com.

PV solar panels convert sunlight into electricity

You’ve likely heard of photovoltaic (PV) solar panels.  But do you really know how photovoltaics work?  Just how do those blue-colored surfaces convert sunlight into electricity?  In other words, how do we tap into solar energy?

PV technology was “born” in 1854 through research of the Bell Telephone Company.  Within a decade PV solar panels were being used on spacecraft.  It wasn’t long before property owners in remote areas determined that they did not have to be connected to the grid in order to enjoy electricity – with installation of PV panels.  From there, even grid-connected customers have decided to minimize or eliminate their monthly electricity bills by going solar.

So, let’s review how photovoltaics work!

PV solar cells convert UV light photons into electricity. Photovoltaics do this through two distinct functions.  First, there is photogeneration of charge carriers (electrons and holes) in a light-absorbing material.  Then, separation of the charge carriers to a conductive contact to transmit the electricity.

The following video is a good primer of how photovoltaics work:

A solar panel array

The word “photovoltaic” is derived from “photo,” which means “light” and “voltaic” which means “electricity.  A solar module is a group of cells connected electrically and packaged into a frame (commonly known as a solar panel)  A number of solar panels grouped together is a solar array.

PV solar cells are made of semiconductor materials, like silicon, used most commonly these days.  When sunlight hits a solar cell, some of the energy is absorbed by the semiconductor material; energy knocks electrons loose and they can then freely flow.

The electric field(s) of PV solar cells can force the freed electrons to flow in a certain direction.  This flow is an electrical current.  With metal contacts on the top and bottom of a PV cell, the current can be drawn away for power usage.

No matter how large or small it is, most silicon PV cells produce about 1/2 volt direct current (under open-circuit, no-load conditions). The output of a PV cell depends on its efficiency and size (surface area), and is proportional to the intensity of sunlight striking the surface of the cell.

While there are a number of factors that contribute to the amount of electricity that can be generated by a solar cell, a general understanding of how photovoltaics work is important in determining whether and how much to invest in a solar array.

Stirling Engines Driven by Solar Energy (image from Salt River Project)

Its hard to imagine a better place for large scale solar power generation!  Last week, a new solar array in Arizona was launched using a unique concentrating solar power system: the SunCatcher from Stirling Energy Systems.

Sixty giant parabolic dishes – also known as solar collectors – concentrate solar heat at a hydrogen-filled piston, which drives a Stirling engine, generating electricity.  The dishes are covered with mirrors and track the movement of the sun across the sky.

The Peoria, AZ-based system, installed by Tessera Solar, will generate up to 1.5 megawatts (MW) of solar energy.

Just imagine the possibilities:

The new solar array in Arizona is perhaps but a drop in the renewable energy bucket of Tessera Solar.  The company has contracts to install over 1,500 megawatts of large-scale solar power generation in California and Texas.

Its SunCatcher technology is believed to deliver electricity more efficiently and with less use of precious water resources than other concentrating solar power systems.