Nope — these don’t look like the panels that grace the rooftops of homes and buildings to generate clean electricity. Parabolic troughs are solar thermal technology: they use the sun’s heat to directly generate energy. Photovoltaic (PV) panels take a different approach, using panel materials to create an electric current without utilizing heat. These parabolic troughs, and solar thermal electricity in general, are used in large, utility-scale solar farms.

They function by concentrating heat from the sun onto a receiver pipe in the center of the parabolic curve (see the horizontal grey pipe above). The curved surface allows the system to concentrate heat to 30-60 times its natural intensity, and this heat is transferred to the synthetic oil circulating through the receiver pipe. This heated liquid is then sent through a heat exchanger, producing steam that spins a turbine and generates electricity.

Solar trough predominate utility scale solar plants in the United States, and 2010 actually marks the 25th anniversary of the first solar trough technology implemented domestically. This solar plant in the Mojave Desert achieves daily net efficiencies close to 20 percent.

For a seemingly strange-looking solar technology, parabolic troughs play a fairly significant role in the solar market.

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The American Recovery and Reinvestment Act of 2009 made it possible for businesses to receive a cash grant worth 30 percent of the cost of renewable energy projects. At the end of the year, the grant reverts to a 30-percent tax credit, which is in effect through 2016. And since cash is king, especially in slow-growth economy, the fast-approaching deadline has businesses scrambling to get their solar energy projects underway.

It also has agencies that oversee big commercial solar installation, like the California Energy Commission (CEC), scrambling to keep pace with a barrage of solar project approval applications. As a result, eight utility-scale solar energy projects have been given the green light in roughly three months.

In order to qualify for the federal renewable energy grant, projects must be in construction or developers must have spent a minimum of five percent of construction costs by the end of December. Most experts are doubtful we’ll see the federal grant option again in the future.

The end of the line for federal renewable energy grants doesn’t necessarily spell the end for incentives for residential solar energy systems. There’s still the 30-percent tax credit. And, depending on where you live, solar rebates, tax credits and other incentives may be available to help homeowners and small businesses install solar panels.

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As clean energy developers aim to construct on California’s vast stretches of arid land solar energy plants the size of small villages, environmentalists have fought to protect two endangered species in the California: the desert tortoise and Mojave fringe-toed lizard.

On Monday, both sides got their wish. Solar Millennium LLC in Oakland, California — which will partner with Ferrostaal AG to build the largest solar thermal plant in the world — has agreed to fund a conservation project to provide refuge to the two animals during the plant’s construction.

And with that agreement in place, U.S. Interior Secretary Ken Salazar yesterday approved construction of the $6-billion Blythe Solar Power Project. To be sited 216 miles east of Los Angeles, the project is the sixth solar energy installation approved to be built on public lands. For its conservation efforts, Solar Millennium has gained the backing of the Natural Resources Defense Council (NRDC).

The Blythe solar power project will span over 7,000 acres and have a generating capacity of 1,000 megawatts (MW). In the future, additional capacity may bring that figure to 2,800 MW. Solar thermal plants differ from photovoltaic (PV) plants in that they use mirrors to concentrate the sun’s energy. The configuration at Blythe will focus the sun’s rays onto tubes that will carry heat into a boiler and eventually pass steam into a turbine. Photovoltaic (PV) plants, by contrast, use panels — or “modules” — that convert sunlight directly into electricity.

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Now, however, it seems the administration has warmed to the idea, today announcing a plan to install a small solar energy system atop the White House. The move reverses the decision by the Reagan Administration in 1986 to take down the solar water heater installed by Jimmy Carter in the late 1970s.

Speaking at the White House Council on Environmental Quality (CEQ) 2010 GreenGov Symposium, U.S. Energy Secretary Steven Chu and CEQ Chair Nancy Sutley did’t indicate which solar installation company would do the job. Aptly enough, however, it was revealed that American made solar technologies would feature prominently.

Obama will become the third U.S. President to install solar energy at the White House. As previously mentioned, President Carter installed a $30,000 solar water heater for the West Wing offices in the late 1970′s. Then, most recently, President George W. Bush installed a solar energy system that powers a maintenance building.

A number of variables related to the pending White House solar installation remain unknown. According to the Huffington Post, administration officials estimate the system will include anywhere from 25 to 75 panels and will generate 19,700 kilowatt-hours (kWh) of electricity each year. That would save a typical American household $2,300 on electricity bills each year — a hefty sum. Relative to the White House’s electricity consumption, however, these savings are likely to be modest. Nevertheless, kudos to the White House for putting it’s money where it’s mouth is by putting solar on it!

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The panel recommended the five-member CEC approve the three-part solar thermal project, stating the benefits of the plant would outweigh any negative impacts to the local environment. We are now in the midst of a 30-day period for public comment before the commission makes its final decision whether construction may proceed.

If completed, Ivanpah — at 392 megawatts (MW) — would be one of the largest solar thermal plants in the world. According to Brighter Energy, the plant will produce enough energy to power 140,000 homes and improve air quality by taking the equivalent of 70,000 cars off our roads.

A main reason the project gained the panel’s approval is that BrightSource Energy Inc. — the Oakland, California-based firm that is developing the project — scaled down the total size of the project and revised its plans to minimize environmental impacts. One such revision includes switching from a water-cooling system to an air-cooling system. Water in the desert is, after all, a scarce resource.

John Woolard, President and CEO of BrightSource Energy, had this to say following the CEC panel’s recommendation:

We look forward to a final decision from the Commission when we can begin constructing the Ivanpah project, providing good jobs for the High Desert community, producing clean energy for the state’s homes and businesses, and creating a model for environmentally-responsible energy projects.

According to the Mojave Desert Blog, the environmental impact of the project won’t be zero. You can expect to see the loss of some desert tortoise and other species. To allay these concerns, BrightSource Energy has agreed to fund land conservation projects elsewhere in the Mojave Desert. The issues involved underscore the interplay between local environmental impacts and the broader issue of climate change.

Amy Davidsen, U.S. Director of the Climate Group, is in favor of the plant because of what it can potentially do to help combat climate change.

“Large-scale solar technologies provide one of our best hopes for solving the problem of global climate change,” she said. “To meet this potential, we need to scale up the use of these technologies as soon as possible. Today’s proposed decision recommending approval of the Ivanpah project represents a major step toward the realization of this goal.”

If the commission gives final approval, construction is set to begin this coming fall, with the San Francisco, California-based engineering firm Bechtel heading up the effort. The energy produced will be sold to Southern California Edison (SCE) and, pending approval, Pacific Gas and Electric (PG&E). SCE gained such approval last Thursday from the California Public Utilities Commission (CPUC).

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The desert laboratory for testing new solar technologies is scheduled to be built on 25 square miles of the same test site used by the U.S. Government in the 1950′s to test the nation’s nuclear capabilities. The area stands approximately 65 miles northwest of Las Vegas. According to several government officials, who spoke to the Las Vegas Sun, the majority of the testing will focus on developing new solar thermal technologies.

This type of solar power setup entails using mirrors to direct the sun’s rays onto a liquid-filled tube or tower. The heat boils the liquid, creating steam that turns a turbine. Much of the new technology developed will focus on creating better ways to store the heat and reduce water consumption.

The testing facility is expected to allow the U.S. to develop and market new solar technology at a faster rate, with the end goal being to drive prices down, which is a key igredient to the widespread adoption of renewable energy. And if solar is a large part of that renewable energy future, what better place to make the epicenter of it all, says Reid, than Nevada with its 300+ sunny days a year.

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With a 97.5 percent efficiency rate, SolarEdge’s DC-AC inverters are among the most efficient on the market

The Escondido solar home plays host to 26 multi-crystalline PV modules, which were installed by Photon Solar Power, a solar installation company that serves customers in Colorado, San Diego and other parts of southern California.

According to the press release, solar energy professionals in the area may pay particular attention to this residential solar installation because it is the first grid-tied system in the U.S. to incorporate SolarEdge’s inverters. If successful, the installation could pave the way for many more solar homes to incorporate the company’s high-efficiency inverter technology.

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The solar developments began in 2005 when the city’s subway system opened the Stillwell Avenue Terminal: it was equipped with 2,800 solar electric panels mounted to its roof. The installation gained national attention two years later when the American Institute of Architects’ Committee gave the installation honorable mention on the 2007 Top Ten list of green projects, calling it “a catalyst for the revitalization of Coney Island.”

Also in 2005, 32 solar panels were installed on Coney Island’s signature ”Wonder Wheel” ride.

The NYC Transit Maintenance Facility is part of the MTA system that transports 2.4 billion New Yorkers each year.

The latest solar-power development on Coney Island came in April, 2010, when the New York Power Authority (NYPA) and Metropolitan Transit Authority (MTA) mounted solar hot-water panels atop the Island’s maintenance facility, the biggest rapid transit yard in the world. The 48 panels provide hot water — at temperatures as high as 240 degrees — for the washing of subway cars. The system also supplies hot water in the restrooms. NYPA’s President Richard Kessel found the installation very appropriate for Coney Island:

“It seems fitting that we’re pioneering this advanced solar-thermal technology in a community whose iconic attractions include the beach and sun.”

The NYPA has made efforts to reduce greenhouse gas emissions by over 34,000 tons a year, according to New York City Transit President Thomas Prendergast. This latest solar thermal (solar hot water) installation cost the NYPA $550,000, minus the $150,000 grant they received from the New York State Energy Research and Development Authority.

Predergast noted the solar thermal system, which replaced an old hot water tank, will save about $94,000 annually.

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Bowdoin’s goal is to use the system to offset emissions from its steam-to-water heat exchanger system, which uses natural gas to run the school’s dining hall. The solar hot water system is part of a broader initiative, the Climate Neutrality Implementation Plan (PDF), a strategy to help Bowdoin reach carbon neutrality by 2020. The solar hot water project would fall in the light green category depicted below.

The 960-square-foot, 24-panel solar water heating system will be installed atop Bowdoin’s Thorne Hall, which currently uses about 4,800 gallons of hot water per day — high, relative to the rest of the campus. According to ReVision Energy, a renewable energy consulting firm, during the first 10 years of operation the project will generate roughly 4.16 billion British Thermal Units (BTUs) — an amount of energy that would otherwise need to come from 268 million cubic meters of natural gas purchases.

S. Catherine Longley, Bowdoin’s Senior Vice President for Finance and Administration & Treasurer, views the solar hot water installation as a key step towards fulfilling the school’s goals. ”The solar hot water project, in conjunction with the installation of a cogeneration facility that also recently received state funding, will help the College move forward in meeting its carbon neutrality goals,” she said.

Read more on Bowdoin’s website.

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About a month ago, the Solar Rating and Certification Corporation (SRCC) OK’d the solar manufacturer’s 7000 series solar collector to receive an OG-100 certification. Many federal and state solar incentive programs require equipment to be SRCC-certified, so the announcement represents a milestone for the company.

Free Hot Water’s new solar thermal collector can output 1.65 kilowatts (kW) per hour equivalent, equal to about 28,000 BTUs per panel per day. Install these collectors, in other words, and you can use the sun to meet a good portion of your domestic hot water needs.

The federal government is currently offering a 30-percent tax credit for the installation of qualifying solar hot water systems (and solar electric systems). Beyond this, a number of state- and utility-sponsored solar hot water incentives are available across the country.

According to Renewable Energy World, in some states Free Hot Water’s new solar collector qualifies for a rebate that’s larger than the actual installed cost of the system.

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