China leads solar PV demand in Asia Pacific region with 2.9GW installed in 2011

The sleeping giant has finally awoken, according to the latest report from NPD Solarbuzz as PV installations in China reached 2.9GW in 2011, a massive 500% increase over 2010. The Asia Pacific region as a whole saw demand increase 165% year-on-year, reaching a total of 6GW. Like Germany, NPD Solarbuzz noted that 2.8GW of installations in the region were installed in the fourth quarter alone.

According to the market research firm, China has quickly emerged as the dominant force in the region, with 48% of 2011 demand. A planned year-end 13% FIT reduction led to a surge in installations in the fourth quarter, reaching 1.7GW, NPD Solarbuzz noted.

“The China PV market was reshaped in 2011 by the release of the national FIT,” said Ray Lian, analyst at NPD Solarbuzz, “Approximately 1GW ground mount projects were installed in the Qinghai province alone. However, the explosive growth could well be followed by policy adjustments in 2012 as the Chinese central government takes action to control the growth rate.”

However, the market research firm noted that low factory gate module prices and favorable project returns have led to a project pipeline that reached 20GW and in direct comparison the project pipeline estimates for the US.

Japan

Other major markets in the Asia Pacific region include Japan and India. Though dependent on the residential market (70% plus of installations), Japan installed 1.2GW in 2011, an increase of 30% over 2010.

However, NPD Solarbuzz expects the Japanese market to grow 40% in 2012 as a new FIT law aimed at large-scale PV projects should increase demand, though highlighted that the actual 2012 rates have yet to be announced.

Many forecasters had previously touted Japan to once again become a major growth market but a forecasted growth of 40% could disappoint many in the PV industry, especially considering the growth in overseas module suppliers moving into the Japanese market in anticipation of strong growth.

India

According to NPD Solarbuzz, demand in India increased by 125% in the fourth quarter, as install deadlines loomed in the first quarter of 2012. The market research firm expects 600MW to be grid connected in the first quarter under the National Solar Mission and Gujarat Solar Policies.

In 2012, the Indian market could begin to approach 1GW, driven by new installations under the National Solar Mission and new state-level policies.

"While rapid PV price declines have greatly improved project economics over the course of 2011, many Indian developers have suffered setbacks due to difficulties associated with financial closure, land acquisition, and power evacuation facilities. Now developers will need to race to meet their installation deadlines or face the prospect of losing their PPAs, leading to a surge of activity in December and January," added NPD Solarbuzz analyst Chris Sunsong.

Australia

Australia’s PV installations fell 10% quarter-on-quarter as incentive schemes were closed down. NPD Solarbuzz expected first quarter 2012 installs to make further declines of around 20%.

Worse, the market for 2012 is forecast to fall by 30%; however, the market is forecast to pick up in 2013 as large-scale ground-mounted systems begin to come online.

Thailand, Korea and Taiwan

Other emerging markets in Asia added 500MW of demand in 2011, largely driven by Thailand, Korea and Taiwan, noted the market research firm. Further growth of more than 50% is expected in 2012 as new markets in Malaysia and the Philippines evolve.

Government incentives and continued declines in module prices are set to underline the growth potential in this rapidly emerging important market for the PV industry.

Ref: Solarbuz.com

 

Scientists create first solar cell with over 100 percent quantum efficiency

Researchers from the National Renewable Energy Laboratory (NREL) have reported the first solar cell that produces a photocurrent that has an external quantum efficiency greater than 100 percent when photoexcited with photons from the high energy region of the solar spectrum.

The external quantum efficiency for photocurrent, usually expressed as a percentage, is the number of electrons flowing per second in the external circuit of a solar cell divided by the number of photons per second of a specific energy (or wavelength) that enter the solar cell. None of the solar cells to date exhibit external photocurrent quantum efficiencies above 100 percent at any wavelength in the solar spectrum.

The external quantum efficiency reached a peak value of 114 percent. The newly reported work marks a promising step toward developing Next Generation Solar Cells for both solar electricity and solar fuels that will be competitive with, or perhaps less costly than, energy from fossil or nuclear fuels.

Multiple Exciton Generation is key to making it possible

A paper on the breakthrough appears in the Dec. 16 issue of Science Magazine. Titled “Peak External Photocurrent Quantum Efficiency Exceeding 100 percent via MEG in a Quantum Dot Solar Cell,” it is co-authored by NREL scientists Octavi E. Semonin, Joseph M. Luther, Sukgeun Choi, Hsiang-Yu Chen, Jianbo Gao, Arthur J. Nozikand Matthew C. Beard. The research was supported by the Center for Advanced Solar Photophysics, an Energy Frontier Research Center funded by the DOE Office of Science, Office of Basic Energy Sciences. Semonin and Nozik are also affiliated with the University of Colorado at Boulder.

The mechanism for producing a quantum efficiency above 100 percent with solar photons is based on a process called Multiple Exciton Generation (MEG), whereby a single absorbed photon of appropriately high energy can produce more than one electron-hole pair per absorbed photon.

NREL scientist Arthur J. Nozik first predicted in a 2001 publication that MEG would be more efficient in semiconductor quantum dots than in bulk semiconductors. Quantum dots are tiny crystals of semiconductor, with sizes in the nanometer (nm) range of 1-20 nm, where 1 nm equals one-billionth of a meter. At this small size, semiconductors exhibit dramatic effects because of quantum physics, such as:

• Rpidly increasing bandgap with decreasing quantum dot size,

• Formation of correlated electron-hole pairs (called excitons) at room temperature,

• Enhanced coupling of electronic particles (electrons and positive holes) through Coulombic forces,

• And enhancement of the MEG process.

Quantum dots confine the charges and harvest excess energy

Quantum dots, by confining charge carriers within their tiny volumes, can harvest excess energy that otherwise would be lost as heat – and therefore greatly increase the efficiency of converting photons into usable free energy.

The researchers achieved the 114 percent external quantum efficiency with a layered cell consisting of antireflection-coated glass with a thin layer of a transparent conductor, a nanostructured zinc oxide layer, a quantum dot layer of lead selenide treated with ethanedithol and hydrazine, and a thin layer of gold for the top electrode.

In a 2006 publication, NREL scientists Mark Hanna and Arthur J. Nozik showed that ideal MEG in solar cells based on quantum dots could increase the theoretical thermodynamic power conversion efficiency of solar cells by about 35 percent relative to today’s conventional solar cells. Furthermore, the fabrication of Quantum Dot Solar Cells is also amenable to inexpensive, high-throughput roll-to-roll manufacturing.

Such potentially highly efficient cells, coupled with their low cost per unit area, are called Third (or Next) Generation Solar Cells. Present day commercial photovoltaic solar cells are based on bulk semiconductors, such as silicon, cadmium telluride, or copper indium gallium (di)selenide; or on multi-junction tandem cells drawn from the third and fifth (and also in some cases fourth) columns of the Periodic Table of Elements. All of these cells are referred to as First- or Second-Generation Solar Cells.

MEG, also referred to as Carrier Multiplication (CM), was first demonstrated experimentally in colloidal solutions of quantum dots in 2004 by Richard Schaller and Victor Klimov of the DOE’s Los Alamos National Laboratory. Since then, many researchers around the world, including teams at NREL, have confirmed MEG in many different semiconductor quantum dots. However, nearly all of these positive MEG results, with a few exceptions, were based on ultrafast time-resolved spectroscopic measurements of isolated quantum dots dispersed as particles in liquid colloidal solutions.

The new results published in Science by the NREL research team is the first report of MEG manifested as an external photocurrent quantum yield greater than 100 percent measured in operating quantum dot solar cells at low light intensity; these cells showed significant power conversion efficiencies (defined as the total power generated divided by the input power) as high as 4.5 percent with simulated sunlight. While these solar cells are un-optimized and thus exhibit relatively low power conversion efficiency (which is a product of the photocurrent and photovoltage), the demonstration of MEG in the photocurrent of a solar cell has important implications because it opens new and unexplored approaches to improve solar cell efficiencies.

Another important aspect of the new results is that they agree with the previous time-resolved spectroscopic measurements of MEG and hence validate these earlier MEG results. Excellent agreement follows when the external quantum efficiency is corrected for the number of photons that are actually absorbed in the photoactive regions of the cell. In this case, the determined quantum yield is called the internal quantum efficiency. The internal quantum efficiency is greater than the external quantum efficiency because a significant fraction of the incident photons are lost through reflection and absorption in non-photocurrent producing regions of the cell. A peak internal quantum yield of 130% was found taking these reflection and absorption losses into account.

More information: Peak External Photocurrent Quantum Efficiency Exceeding 100% via MEG in a Quantum Dot Solar Cell, Science 16 December 2011: Vol. 334 no. 6062 pp. 1530-1533. DOI: 10.1126/science.1209845

Paint-On Solar Cells Developed

A team of researchers at the University of Notre Dame has made a major advance toward this vision by creating an inexpensive "solar paint" that uses semiconducting nanoparticles to produce energy.

"We want to do something transformative, to move beyond current silicon-based solar technology," says Prashant Kamat, John A. Zahm Professor of Science in Chemistry and Biochemistry and an investigator in Notre Dame's Center for Nano Science and Technology (NDnano), who leads the research.

"By incorporating power-producing nanoparticles, called quantum dots, into a spreadable compound, we've made a one-coat solar paint that can be applied to any conductive surface without special equipment."

The team's search for the new material, described in the journal ACS Nano, centered on nano-sized particles of titanium dioxide, which were coated with either cadmium sulfide or cadmium selenide. The particles were then suspended in a water-alcohol mixture to create a paste.

When the paste was brushed onto a transparent conducting material and exposed to light, it created electricity.

"The best light-to-energy conversion efficiency we've reached so far is 1 percent, which is well behind the usual 10 to 15 percent efficiency of commercial silicon solar cells," explains Kamat.

"But this paint can be made cheaply and in large quantities. If we can improve the efficiency somewhat, we may be able to make a real difference in meeting energy needs in the future."

"That's why we've christened the new paint, Sun-Believable," he adds.

Kamat and his team also plan to study ways to improve the stability of the new material.

NDnano is one of the leading nanotechnology centers in the world. Its mission is to study and manipulate the properties of materials and devices, as well as their interfaces with living systems, at the nano-scale.

This research was funded by the Department of Energy's Office of Basic Energy Sciences.

Ref: Science Daily

The way towards Cop 18 in Qatar

Countries at the United Nations climate change negotiations have publicly acknowledged their current pledges to reduce carbon emissions will not result in limiting global warming to less than two degrees Celsius.

To bridge this shortfall, delegates at the 17th Conference of Parties (COP 17) climate talks proposed on to address this so-called "emissions gap" at COP 18 in Qatar next year.

Documents negotiated in Durban, South Africa acknowledged the science-based emissions reduction target of 25 to 40 percent by 2020. Those reductions and that timeline are what is needed to stay below two degrees Celsius. The draft text says this would be the target to be agreed on at COP 18.

"We need agreement on that science-based target next year at the latest," said Karl Hood, Minister of Foreign Affairs of the Caribbean island of Grenada and representing the Alliance of Small Island States.

"And we want those targets to legally come into force before 2017."

Hood told IPS waiting to close the gap until after 2020 is "unacceptable" and a "disaster for small island states" who are already suffering the impacts of climate change.

The world has months to curb emissions from burning fossil fuels before two degrees Celsius of warming will be impossible to stay below. Delay a few years and the extraordinary emission cuts needed could bankrupt the world's economy and reverse development gains in most countries, climate experts warned at the largely deadlocked United Nations climate change conference here.

"We're here to warn policy makers that we are dangerously close to not being able to meet the less than two degrees Celsius target," said Bill Hare, Director of Climate Analystics, a non-profit climate science advisory group based in Germany.

The current pledges made by countries to cut emissions after the Copenhagen climate talks in 2009 will result in global warming of 3.5 degrees Celsius, said Hare a climate scientist. Two years later, those pledges remain essentially unchanged and that means the world's options to stay below two degrees Celsius are narrowing Hare said in press conference during the COP 17 negotiations that conclude Friday.

"To put it bluntly, the longer we wait, the less option we will have, the more it will cost ...and the bigger threat to the world’s most vulnerable," he said.

Global emissions of fossil fuels have increased 49 percent since 1990 and reached a record of about 48 gigatonnes (billion tonnes) of CO2 in 2010 and likely 50 gigatonnes (Gt) of CO2 this year, he said. Thanks to the moderating affect of the oceans, the world has warmed only 0.8 degrees Celsius on average, however, many parts of the world are much warmer than that.

The science shows that global emissions need to fall to 44 Gt by 2020 and continue to decline by two percent per year, a rate that our fossil fuel-dependent world will find "extremely challenging" but still doable, he said.

If countries live up to their pledges made in Copenhagen global emissions are likely to rise nine to 11 Gt above the 44 Gt target creating an "emissions gap" that is quite considerable, said Niklas Höhne, Director Energy and Climate Policy of Ecofys, an energy consulting organization.

"Our results are in agreement with the United Nations Environment Programme (UNEP) Bridging the Emissions Gap Report released at the opening of the Durban climate talks," he told IPS.

The new UNEP report calculates a similar emission gap and outlines the way reductions can be made between now and 2020 to bridge that gap. Shockingly many of the items under intense debate at here at the COP 17 — biofuels, agriculture, carbon credits for forest protection, carbon capture and storage — are not considered important pathways to reduce emissions by scientists.

"With biofuels you have to be very sure they won't result in a net increase in emissions," said Höhne.

A number of new studies of palm oil biodiesel and maize ethanol show their net emissions are higher than fossil fuels when their entire lifecycle is calculated.

Biofuels are unlikely to be a significant method for reducing emissions, agreed Höhne. Agriculture is in the same category. Farming practices could be altered to reduce emissions but based on analysis using various reduction scenarios they would only be a small part of the "bridge.”

The emissions gap can only be bridged with a combination of improving energy efficiency in all sectors, significant increase in renewable energy including biomass power and shifting from coal to natural gas. The cost of making this shift is relatively low at 38 dollars a ton of CO2 avoided.

Ref:The Madison Times