perovskite solar PV

Will New Technologies Give Critical Boost to Solar Power?

perovskite solar PVPromising new technologies, including more efficient photovoltaic cells that can harvest energy across the light spectrum, have the potential to dramatically increase solar power generation in the next two decades. But major hurdles remain.

Today, despite recent progress, solar power accounts for about one percent of the world’s energy mix. Yet the International Energy Agency (IEA) says that solar energy, most of it generated by decentralized “rooftop” photovoltaic systems, could well become the world’s single biggest source of electricity by mid-century.

So how do we get from here to there?


The Best Pipeline is a Pipeline that does not get Built


 Slowing or stopping the building of fossil fuel pipelines is an important part of efforts to decrease emissions. In addition to a series of delays for pipelines originating in Canada, Russia has recently been forced to cancel a major pipeline to Europe.
Russia’s annexation of Crimea and ongoing destabilization of the Ukraine has resulted in the cancellation of the $29 billion, 63 billion cubic meter South Stream gas pipeline project. Gazprom confirmed that the pipeline is being diverted through Turkey and Greece, instead of going through Bulgaria, Serbia, Hungary, Slovenia, Italy, Serbia, Bosnia and Herzegovina, Croatia, and Austria.

Although European countries have been trying to reduce their dependence on Russian energy, they still get 33 percent of their gas supplies from Russia. In 2014 they will receive 155 bcm from Russia in 2014, half of which will flow through Ukraine, and the rest through Nord Stream, Yamal and other, smaller pipelines.

Russian difficulties building the South Stream pipeline are a scaled down version of the difficulties being faced by the Canadian government as it seeks to find a way to export its tar sands oil. All of canada’s pipeline projects, including the southbound Keystone XL, the westbound Northern Gateway, the eastbound Energy East pipeline and the northbound Arctic Gateway, have met with strenuous opposition. As has the Edmonton to Burnaby pipeline know as the Kinder-Morgan.

Each day that a fossil fuel pipeline is prevented from being built is a victory for the growth of clean energy and efforts to curtail emissions. A report this fall showed how delaying the Keystone pipeline in North America prevented $17 billion in new investments in the tar sands of Canada. These investments would have produced carbon equivalent to 735 coal-fired power plants.

The more pipelines we have the more carbon will be burned and the more emissions will rise. If we are to have a chance of staying within the internationally agreed upon 2 degree temperature increase, three quarters of existing fossil fuel reserves must be kept in the ground. In this context it makes little sense to keep building more pipelines.


Engineer Reimagines Solar Energy With Stick-On Panels

stick-on solar
These peel-and-stick solar cells could revolutionize the way we harness the immense energy of the sun.

Editor’s Note: Xiaolin Zheng is one of National Geographic’s 2014 Emerging Explorers, part of a program that honors tomorrow’s visionaries—those making discoveries, making a difference, and inspiring people to care about the planet.

The catalyst for Xiaolin Zheng’s groundbreaking work in solar energy began with an offhand comment her father made years ago at her parents’ apartment, a 13-story complex in the northeast China city of Anshan.

“In China, the rooftops of many buildings are packed with solar energy devices,” says Zheng. “One day my father mentioned how great it would be if a building’s entire surface could be used for solar power, not just the roof, but also walls and windows.”

An invention from Zheng’s research team at Stanford University might someday make that possible. They have created a type of solar cell that is thin, flexible, and adhesive—a solar sticker, in effect, that could help power everything from buildings to airplanes.


google NRG

The Strange Thing About Google’s Decision To Stop Renewable Energy Research

google NRG
From left, Rick Needham of Google and David Crane of NRG Energy field questions during 2014 dedication of Ivanpah Solar Electric Generating System, the world’s largest solar thermal plant.

Two senior Google engineers have written a confusing article explaining what they learned after Google stopped its advanced research and development effort into renewable energy technologies in 2011.

The answer they offer — that their effort was not on track to deliver renewable R&D breakthroughs that by themselves would reverse climate change — has always been obvious and thus makes very little sense as a reason for giving up on such an important effort, as we will see.

More likely, Google saw renewable energy prices coming down so quickly as global deployment accelerated that they realized their chances to make money in the R&D arena were much smaller than they thought. And they clearly understood that the real action in advancing renewable energy was in deployment, which Google continued to fund at a far greater level than they ever invested in R&D.


Report finds more info on solar, mini-grids needed to address energy gap

Practical ActionPractical Action has released a report that outlines gaps in the evidence that the UK-based NGO claims is tainting the energy debate in favor of the world’s richer population. More information and policy support for solar and mini-grids is in demand to help close the energy gap.

The United Nations’ goal of affordable energy for all is not being supported by policy, investment and debate: This is a finding of a report written by Lucy Stevens for Practical Action, published yesterday. The report finds that this environment “has not changed significantly in ways that benefit the poor.” In producing Enabling Access for the Poor, the NGO hopes to shift the debate by focusing on the evidence from a poor person’s perspective.


Kansas energy standards

Next legislative session could be end for Kansas’ renewable energy standard

Kansas energy standardsRepublicans may have gained enough seats in the Kansas House to end the state’s renewable energy standard, and activists on both sides of the issue are preparing for a fight in the next legislative session.

The policy, known as the renewable portfolio standard, requires utility companies to get 20 percent of their power from renewable sources by 2020. The standard was passed in 2009 as part of a compromise that included building a coal-fired plant in Holcomb, a project that has not developed because of federal regulations.

Supporters say the standard has been critical for developing the burgeoning wind energy industry in Kansas and that scuttling it would stall growth.

Opponents say the standard will lead to electric rate increases for consumers and that renewable energy should compete with fossil fuels in the free market rather than be mandated by the state.


rooftop solar

Do We Risk Having Two-Tier Access to Renewable Energy?

rooftop solarSolar energy access in the United States varies wildly from state to state. Texas gets enough sunlight per year to power the entire world via solar energy, and yet has one of the lowest solar capacities in the country. The Northeast is the “second most solar-friendly region in the country” despite receiving the least sunshine.

At the heart of it is state-level regulatory policy. Florida’s is described as ‘hostile’, while New York State has embraced renewables. As solar energy prices tumble, do state regulations risk creating a two-tier access to cheap renewable energy?

The new renewable

In the past renewable energy has been easy to dismiss on an economic basis. As a new technology, it has necessarily been more expensive than older, more established fossil fuels. It requires new infrastructure — which, in the wake of the 2008 financial crash, spending on was always going to take a backseat — and primitive technology is inefficient.

Soitec-Fraunhofer ISE multi-junction CPV cell hits world record 46% conversion efficiency

 record-breaking solar efficiency
New world record-breaking solar cell on a 100 mm wafer yielding approximately 500 concentrator solar cell devices. Image: Fraunhofer ISE / Alexander Wekkeli

A Soitec multi-junction solar cell for use in concentrator photovoltaic (CPV) systems has become the company’s latest cell to reach a world record for conversion efficiency at 46%, according to Fraunhofer Institute for Solar Energy (Fraunhofer ISE).

The Germany-headquartered research institute once again collaborated with Soitec on the new cell, along with CEA-Leti, a division of the French research and technology organisation. The three parties were also involved in the most recent record-breaking CPV cell last year.

The efficiency of the new cell has been independently verified under standard test conditions by the Japanese National Institute of Advanced Industrial Science and Technology (AIST). The multi-junction cell’s efficiency was measured at a concentration of 508 suns under a Fresnel concentrator lens. So-called multi-junction cells, based on III-V semiconductor compound materials, allow the materials at each junction to respond to different wavelengths of light.


SolarCity installation

Why More Solar Panels Should Be Facing West, Not South

SolarCity installation
Workers for SolarCity installing solar panels in Camarillo, Calif. A study of 110,000 California houses with rooftop solar systems confirmed that a vast majority of the panels are pointed south, which has its drawbacks. Credit J. Emilio Flores for The New York Times

For years, homeowners who bought solar panels were advised to mount them on the roof facing south. That captures the most solar energy over the course of the day, which benefits the homeowner, but does so at hours that are not so helpful for the utility and the grid as a whole.

Mount them to catch the sunlight from the west in the afternoon, and the panels’ production over all would fall, but it would come at hours when the electricity was more valuable.

But that idea is slow to take hold. A new study of 110,000 California houseswith rooftop solar systems confirmed that a vast majority of the panels were pointed south because most of the panel owners were paid by the number of kilowatt-hours the panels produced. Pointing them southward maximizes production over all, but peak production comes at midday, not in late afternoon, when it would be more helpful.



US Solar Policy — #SolarChat Review

#solarchatA couple weeks ago, I was the “featured journalist” on a massive #SolarChat on Twitter, the biggest yet. Senator Harry Reid joined in, as did the CEO of the Solar Energy Industries Association, Rhone Resch; OFA Climate Change Campaign Manager JackShapiro; Founder of Climate Hawks Vote RL Miller; and Greentech Media Senior Editor Stephen Lacey. The topic was US solar policy.

During our one-hour chat, #SolarChat rose to the top of Twitter’s trending charts. TweetReach provided some numbers about the event, but it is limited to only the first 1,500 tweets, so it actually under-represents the impact. Nonetheless, even with that limitation, it showed that we brought in nearly 7 million impressions from 335 contributors. The contributors came in from at least 11 countries and 27 US states.


cheaper solar power

Solar-Power System Is Easy to Install, and Therefore Much Cheaper

cheaper solar power
Researchers from the Fraunhofer Institute install novel, flexible solar panels with an adhesive backing and quick-connect cables.

Ordinarily, installing and connecting a new array of rooftop solar panels takes days, weeks, or even months because the hardware is complex and various permits are needed. Yesterday, on a frigid day in Charlestown, Massachusetts, researchers completed the process in about an hour.

Homeowners can install the system themselves, by gluing it to a rooftop. The permitting is handled by a combination of electronic sensors and software that communicates with local jurisdictions and utilities.

Installation and permit-related expenses currently account for more than half of the overall cost of a new solar power setup. “By simplifying the system so that it’s like installing an appliance, we envision that the soft cost will be virtually eliminated,” says Christian Hoepfner, director of the Fraunhofer Center for Sustainable Energy Systems, which developed the system. Doing so would lower the cost of a typical residential solar installation from $22,000 to as little as $7,500, he says.

Reconsidering the Rebound Effect

520-reboundThe rebound effect from improving energy efficiency has been widely discussed—from the pages of the New York Times and New Yorker to the halls of policy and to a voluminous academic literature. It’s been known for over a century and, on the surface, is simple to understand. Buy a more fuel-efficient car, drive more. Invent a more efficient bulb, use more light. If efficiency improves, the price of energy services will drop, inducing increased demand for those services. Consumers will respond, producers will respond, and markets will re-equilibrate. All of these responses can lead to reductions in the energy savings expected from improved energy efficiency. And so some question the overall value of energy efficiency, by arguing that it will only lead to more energy use—a case often called “backfire.”

Fool’s gold as a solar material?

520-Fools-Gold-solar-PV-materialAs the installation of photovoltaic solar cells continues to accelerate, scientists are looking for inexpensive materials beyond the traditional silicon that can efficiently convert sunlight into electricity.

Theoretically, iron pyrite—a cheap compound that makes a common mineral known as fool’s gold—could do the job, but when it works at all, the conversion efficiency remains frustratingly low. Now, a Univ. of Wisconsin-Madison research team explains why that is, in a discovery that suggests how improvements in this promising material could lead to inexpensive yet efficient solar cells.

“We think we now understand why pyrite hasn’t worked,” says chemistry Prof. Song Jin, “and that provides the hope, based on our understanding, for figuring out how to make it work. This could be even more difficult, but exciting and rewarding.”

Although most commercial photovoltaic cells nowadays are based on silicon, the light-collecting film must be relatively thick and pure, which makes the production process costly and energy-intensive, says Jin.

A film of iron pyrite—a compound built of iron and sulfur atoms—could be 1,000 times thinner than silicon and still efficiently absorb sunlight.

Like silicon, iron and sulfur are common elements in the Earth’s crust, so solar cells made of iron pyrite could have a significant material cost advantage in large scale deployment. In fact, previous research that balanced factors like theoretical efficiency, materials availability and extraction cost put iron pyrite at the top of the list of candidates for low-cost and large-scale photovoltaic materials.

In the Journal of the American Chemical Society, Jin and first author Miguel Cabán-Acevedo, a chemistry graduate student, together with other scientists at UW-Madison, explain how they identified defects in the body of the iron pyrite material as the source of inefficiency. The research was supported by the U.S. Dept. of Energy.

In a photovoltaic material, absorption of sunlight creates oppositely charged carriers, called electrons and holes, that must be separated in order for sunlight to be converted to electricity. The efficiency of a photovoltaic solar cell can be judged by three parameters, Jin says, and the solar cells made of pyrite were almost totally deficient in one: voltage. Without a voltage, a cell cannot produce any power, he points out. Yet based on its essential parameters, iron pyrite should be a reasonably good solar material. “We wanted to know, why is the photovoltage so low,” Jin says.

“We did a lot of different measurements and studies to look comprehensively at the problem,” says Cabán-Acevedo, “and we think we have fully and definitively shown why pyrite, as a solar material, has not been efficient.”

In exploring why pyrite was practically unable to make photovoltaic electricity, many researchers have looked at the surface of the crystals, but Cabán-Acevedo and Jin also looked inside. “If you think of this as a body, many have focused on the skin, but we also looked at the heart,” says Cabán-Acevedo, “and we think the major problems lie inside, although there are also problems on the skin.”

The internal problems, called “bulk defects,” occur when a sulfur atom is missing from its expected place in the crystal structure. These defects are intrinsic to the material properties of iron pyrite and are present even in ultra-pure crystals. Their presence in large numbers eventually leads to the lack of photovoltage for solar cells based on iron pyrite crystals.

Science advances by comprehending causes, Jin says. “Our message is that now we understand why pyrite does not work. If you don’t understand something, you must try to solve it by trial and error. Once you understand it, you can use rational design to overcome the obstacle. You don’t have to stumble around in the dark.”


Apple, Google among Green Power Leadership Award recipients

520-green-energyThe U.S. Environmental Protection Agency (EPA) has announced the recipients of its annual Green Power Leadership Awards for achievements in advancing the nation’s renewable energy market and reducing greenhouse gas emissions. The 19 Green Power Partners receiving the award were chosen from more than 1,300 partner organizations that comprise EPA’s Green Power Partnership, including utilities, renewable energy project developers, and other green power suppliers.

EPA, through the Green Power Partnership, works with partner organizations to use green power as a way to reduce the environmental impacts associated with conventional electricity use. The Partnership currently has more than 1,300 partner organizations voluntarily using billions of kilowatt-hours of green power annually. Partners include a wide variety of leading organizations such as Fortune 500 companies, small and medium sized businesses, local, state, and federal governments, and colleges and universities.