Monday, December 26, 2011

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

Thursday, December 22, 2011

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

Friday, December 16, 2011

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

Sunday, December 11, 2011

1411 MW Wind capacity added in India during the first half of the Indian Financial Year

Wind power has shown remarkable growth over the past decade, with the global cumulative installed capacity reaching 215 GW by June 2011. By 2015, installations are predicted to grow at an annual average rate of 15.5%, with the annual installed capacity growing to 81.4 GW from the current 39.5 GW (2010), including offshore development. India has maintained its position as one of the leading wind power nations, remaining at fifth position worldwide in terms of cumulative installations in 2011. The Indian wind industry has successfully weathered the economic slowdown encountered by many other nations and is moving towards achieving maturity. Presently, the country has a cumulative installed capacity of 15,567 MW. The capacity addition for FY 2011-12 is expected to be around 3,000 MW, out of which 1,411 MW has already been achieved. According to the estimates, the annual capacity increase for the Indian wind market is expected to reach 5000 MW by 2015.

Tremendous achivement is there in India in terms of capacity addition in Wind Energy. Based on some reliable sources, around 1411 MW wind power capacity has been added in India during the period from April-2011 to Sept-2011 of the FY 2011-12 which is the highest capacity addition during the first half of any Financial year in India.

Indian State wise capacity addition during the period April-2011 to September-2011 is as under.

Sl.No. -    Indian State      - Capacity (MW)   

 1.       Andhra Pradesh        -    11.50

2.       Gujarat                      -  251.00

3.        Karnataka                 -   93.30

4.        Madhya Pradesh        -   54.20

5.        Maharashtra               -  150.80

6.        Rajasthan                   -  226.35

7.         Tamilnadu                 -  624.30

             Total                        - 1411.45

About 14 WTG manufacturers were involved in this capacity addition in various capacities, major being Suzlon Energy, Enercon, Regn Powertech, Gamesa, Vesta Wind, Inox Wind, Letner Shriram, Gobal, RRB Energy etc. Mjor addition is done by Suzlon Energy with 510.35 MW, Enercon added 315.20 MW, Regen Powertech added 199.50 MW, Gamesa with 165.75 MW and Vestas Wind with 86.10 MW.

This clearly shows the intensity of WTG capacity addition going on India which will continue in the later par of the financial year as well.

Despite the financial crisis affecting the western world, Indian Renewable Energy Sector shows strong growth which may be the reason for major forign players investing in India along with the domestic WTG manufacturers.




Wednesday, December 07, 2011

JNNSM Phase I Batch 2 -Solar Power reaching the Grid Parity in India


This was a fantastic news for all of us involved in Grid based Large Solar photovoltaic Projects. Jawaharlal Nehru National Solar Mission (JNNSM) is bringing Indian solar sector to the new heights. The turning point is that for the first time Solar Photovoltaic Power in India is closing to the grid parity with the lowest bid being Rs.7.49 ($ 0.146) per kilowatt hour (/kWh). I could sense the enthusiasm when I visited the SOLARCON conference at Hyderabad, where the speculations were there that this time the bids will be still coming down from the previous one. Lot of US and European based companies had set up booths at SOLARCON like Solar Semiconductor, Azure Power, BERGEN Power, SunEdison etc.

Aggressive bidding has taken place at the JNNSM Phase 1 Batch II. A very aggressive bidding round was seen at the Scope Complex Auditorium for the Batch II of Phase 1 of the Jawaharlal Nehru National Solar Mission (JNNSN). Solar Direct Emerges was the lowest bidder at Rs.7.49/kWh, while Green Infra was the highest bidder at Rs.9.39/kWh.

Other developers such as Welspun - it quoted three projects at Rs.7.97, Rs.8.05 and Rs.8.14/kWh; SunEdison at Rs.9.28/kWh; Mahindra Bids at Rs.9.34/kWh; Sai Sudhir at Rs.8.22/kWh; VS Lignite at Rs.8.54/kWh; and Sunborne Energy at Rs.8.99/kWh.

Meanwhile, Punj Lloyd offered no disount this time. Inderpreet Wadhwa led Azure Power and quoted a very aggressive price of Rs.7.91/kWh (50 megawatts); Sujana Energy at 9.09/kWh; and Kiran Energy quoted Rs.9.34/kWh for a 50 MW project. Green Infra emrged as the highest bidder, having quoted Rs.9.39/kWh.

This has set a trend on the one side making solar energy closer than ever to grid parity while on the other it has presented a big challenge for these projects to achieve financial closure and prove viability.

This bidding for the Solar PV project allotment under the second round of JNNSM phase I and the results from the bidding has shown signs of solar becoming genuinely cost competitive with grid power. While sub 10 bids were obviously expected, the bid price falling below 8 was indeed amazing for many developers and experts.

The Rs 10.59/kWh bid during the first round of bidding during the previous year, resulted in serious discussion over whether the developers are trying to pull wool over the eyes of the general public and more importantly the lender community.
Similar to the previous year results, the new numbers that were out yesterday too has resulted in a lot of debate. With severe penalty clauses in the second round this year and considerable learning during the last year, the discount that could be offered was never expected to cross 50% but all the assumptions and predictions are here to be bulldozed in the solar PV industry. Though the numbers might seem unreasonable at first sight, if one gives a proper thought over it, we would understand that these developers had every reason to submit such lower quote.

As earlier said, the French company Solaire Direct created shock in the industry with an unimaginable Rs7.49/kWh which was just close to grid parity.

Solardirect is the second largest solar power company in France. The company has quoted the so called ‘rock bottom’ price possibly as a part of market entry strategy as they have big plans of entering and growing in the Indian market. The latest report on photovoltaic support schemes released by the French government has caused haywire in the industry since the government threatens to severely curtail incentives including a potential annual cap of 500 MW. The French company has a pressing need to expand their market presence and India being one of the most promising market, the company had shown serious interest in the country with an anticipated target of 25 MW in the year 2011-2012. Also, the company has now saved loads of money which they would otherwise have spent on marketing. They have managed to hit all the headlines and gained extremely significant visibility in the country and all without any phenomenal marketing investments. All the revenues saved could come handy when they implement and operate the historic Rs 7.49/kWh project. The calculative risk and the low bid price is all a part of the market entry strategy.

Welspun Solar, with three different bid prices emerged second only to Solairedirect. Three different price levels and a 50MW clean sweep – and there is definitely some serious thought process behind their high discount bids. For Welspun, solar is of strategic importance and they are well on their way to become the bid daddy of Solar PV power generation sector in India. Project allotments in the first round of JNNSM phase I and projects from Gujarat state policy would have given them very good learning’s and confidence to go all out to secure 50MW and do not forget, they are on the fray to get projects allotted in Karnataka policy too. With past experience (something which is a rarity in the niche solar PV sector in India), the company definitely would have working relationships with EPC companies, module makers, inverter and other BoS manufacturers, lenders etc. The past experiences and associations comes in handy not only for Welspun, but a similar situation exist for a few other renowned solar PV developers like Azure Power, Mahindra Solar, Kiran Energy, Sai Sudhir Energy, Sun Edison India, Green Infra and Sun Borne Energy. All these companies have made the early mover advantage to their fullest benefit and managed to get projects allotted by quoting competitive yet viable prices.

There can be a number of arguments to justify the low bid prices, but we have to wait and see that how these companies are achieving financial closures with these lower tariffs.

Export-Import Bank of America, OPIC will be one of the sought after destinations for many of the victorious developers other than Azure Power. It is however surprising to know that two other well known developers – Punj Lloyd and Acme Solar who were EXIM bank beneficiaries in their previous projects, did not quote competitive prices to emerge victorious.

Deadline for achieving financial closure in the second round of JNNSM phase I has been raised to 210 days (7 months) from the earlier 180 days (6 months). The timeline for the commissioning of the project is also extended by a month – to 13 months from the date of signing PPA from 12 months earlier in batch I. With one more month of additional time coming in as a cushion for the victorious developers, one would have to wait and watch the actions that are to unfold in the days to come.

Now the challenge is to accomplish the projects as per the schedules after signing the PPAs. Of course, most of these developers can benefit from their previous experience in India in setting up Solar Photovoltaic Projects. I am sure that Solar will overtake Wind Energy sector in India if this enthusiasm and spirit prevails which can replace several tons of carbon dioxide otherwise would have produced with fossil fuel based power plants.

Wednesday, November 30, 2011

Managing wind variability in a Wind Farm

As Texas’ electric grid operator prepares to add power lines for carrying future wind-generated energy, an electrical engineer at The University of Texas at Austin is developing improved methods for determining the extent to which power from a wind farm can displace a conventional power plant, and how best to regulate varying wind power.

“The cost of wind energy has become competitive with that of energy from fossil fuels because of technology improvements,” said Assistant Professor Surya Santoso. “Unfortunately, electric power generated from wind energy is intermittent and variable. That means we need to have better measurements of wind power plants’ output as we integrate wind energy into existing power systems. We also need to develop a way of managing wind power so it can be more readily called upon when needed.”

Texas has outstripped California since 2006 as the leading national producer of wind power, with most of the state’s renewable energy goal by 2025 focused on wind power. To help meet this goal, the state’s Electric Reliability Council of Texas is expected to add about 1,500 megawatts of new wind generation this year alone. In late September, Texas also awarded four offshore tracts along the Gulf Coast for wind power projects with a generating capacity of 1,150 megawatts.

Santoso is developing two strategies to manage and overcome the intermittent and variable behavior of wind power. With a two-year, $200,000 grant from the National Science Foundation, he and his students are developing computational methods to measure the actual capacity contribution of wind farms. This will allow system planners to calculate how much a wind farm can contribute to meeting expected power needs.

Santoso’s lab is also using the funding to establish the technical requirements of energy storage systems that would serve as temporary ”batteries” for releasing stored wind energy at optimal times.

“Having a proper energy storage system would allow you to harness free wind when it’s available, but release that energy at the time of your choosing with a desired power profile,” Santoso said. He noted that a wind energy storage system would also increase wind farms’ overall capacity contribution and reduce the likelihood of overloading transmission power lines that must carry energy from different power sources.


Ref: University of Texas at Austin (2007, October 19). Dealing With Wind
       Variability On The Wind Farm. ScienceDaily. Retrieved November 30, 

Sunday, July 31, 2011

Renewable Energy continued to grow strongly according to REN21 Report

REN21 report released in July 2011 captures that reality and provides a unique overview of renewable energy worldwide as of early 2011. The report covers both current status and key trends; by design, it does not provide analysis or forecast the future.


Global energy consumption rebounded in 2010 after an overall downturn in 2009. Renewable energy, which experienced no downturn in 2009, continued to grow strongly in all end-use sectors - power, heat and transport - and supplied an estimated 16% of global final energy consumption. Renewable energy accounted for approximately half of the estimated 194 gigawatts (GW) of new electric capacity added globally during the year. Renewables delivered close to 20% of global electricity supply in 2010, and by early 2011 they comprised one-quarter of global power capacity from all sources.

In several countries, renewables represent a rapidly growing share of total energy supply, including heat and transport. For example:

   In the United States, renewable energy accounted for about 10.9% of domestic primary energy production (compared with nuclear's 11.3%), an increase of 5.6% relative to 2009.

   China added an estimated 29 GW of grid-connected renewable capacity, for a total of 263 GW, an increase of 12% compared with 2009. Renewables accounted for about 26% of China's total installed electric capacity, 18% of generation, and more than 9% of final energy consumption in 2010.

   Germany met 11% of its total final energy consump­tion with renewable sources, which accounted for 16.8% of electricity consumption, 9.8% of heat produc­tion (mostly from biomass), and 5.8% of transport fuel consumption. Wind power accounted for nearly 36% of renewable generation, followed by biomass, hydropower, and solar photovoltaics (PV).

   Several countries met higher shares of their electricity demand with wind power in 2010, including Denmark (22%), Portugal (21%), Spain (15.4%), and Ireland (10.1%).

Trends reflect strong growth and investment across all market sectors. During the period from the end of 2005 through 2010, total global capacity of many renewable energy technologies - including solar PV, wind power, concentrating solar thermal power (CSP), solar water heating systems, and biofuels - grew at average rates ranging from around 15% to nearly 50% annually. Biomass and geothermal for power and heat also grew strongly. Wind power added the most new capacity, followed by hydropower and solar PV.

Across most technologies, 2010 saw further growth in equipment manufacturing, sales, and installation. Technology cost reductions in solar PV in particular meant high growth rates in manufacturing. Cost reduc­tions in wind turbines and biofuel processing technolo­gies also contributed to growth. At the same time, there was further industry consolidation, notably in the biomass and biofuels industries, as traditional energy companies moved more strongly into the renewable energy space, and as manufacturing firms continued to move into project development.

By early 2011, at least 119 countries had some type of policy target or renewable support policy at the national level, up from 55 countries in early 2005. There is also a large diversity of policies in place at state/provincial and local levels. Developing countries, which now represent more than half of all countries with policy targets and half of all countries with renewable support policies, are playing an increasingly important role in advancing renewable energy.

As policies spread to more and more countries, the geography of renewable energy use is also changing. For example, commercial wind power existed in just a hand­ful of countries in the 1990s but now exists in at least 83 countries. Solar PV capacity was added in more than 100 countries during 2010. Outside of Europe and the United States, developed countries like Australia, Canada, and Japan are experiencing gains and broader technology diversification, while (collectively) developing countries have more than half of global renewable power capacity.

China now leads in several indicators of market growth: in 2010, it was the top installer of wind turbines and solar thermal systems and was the top hydropower producer. India is fifth worldwide in total existing wind power capacity and is rapidly expanding many forms of rural renewables such as biogas and solar PV. Brazil produces virtually all of the world's sugar-derived ethanol and has been adding new hydropower, biomass, and wind power plants, as well as solar heating systems.

At least 20 countries in the Middle East, North Africa, and sub-Saharan Africa have active renewable energy markets. Manufacturing leadership continues to shift from Europe to Asia as countries like China, India, and South Korea increase their commitments to renewable energy. The increasing geographic diversity in markets and manufacturing is boosting confidence that renew-ables are less vulnerable to policy or market dislocations in any specific country.

One of the forces propelling renewable energy policies and development is the potential to create new indus­tries and generate new jobs. Jobs from renewables number in the hundreds of thousands in several coun­tries. Globally, there are more than 3.5 million direct jobs in renewable energy industries, about half of them in the biofuels industry, with additional indirect jobs well beyond this figure.

Also driving renewables development are state-owned multilateral and bilateral development banks, which have been pillars of investment in renewable energy during recent, troubled years for the world economy. More pub­lic money went to the renewable energy sector through development banks than through government stimulus packages during 2010.

Total investment in renewable energy reached $211 billion in 2010, up from $160 billion in 2009, continuing the steady annual increase seen since tracking first began in 2004. Including the unreported $15 billion (estimated) invested in solar hot water collectors, total investment exceeded $226 billion. An additional $40-45 billion was invested in large hydropower.

Asset finance of new utility-scale projects (wind farms, solar parks, and biofuel and solar thermal plants) accounted for almost 60% of the total and was the larg­est investment asset class. Investment in small-scale dis­tributed generation projects (mainly solar PV) amounted to $60 billion and accounted for more than 25% of total investment in renewable energy. For the first time, investment in renewable energy companies and utility-scale generation and biofuel projects in developing countries surpassed that in developed economies. China attracted more than a third of global investment during 2010, making it the leader for the second year in a row.

WIND POWER.

The market maintained its 2009 level, with 38 GW added for a total of about 198 GW. For the first time, the majority of new wind power capacity was added in developing countries and emerging markets, driven primarily by China, which accounted for half the global market. Trends include continued offshore devel­opment, the growing popularity of community-based projects and distributed, small-scale grid-connected tur­bines, and the development of wind projects in a wider variety of geographical locations. Average turbine sizes continued to increase in 2010, with some manufacturers launching 5 MW and larger machines, and direct-drive turbine designs captured 18% of the global market.

SOLAR PHOTOVOLTAICS (PV)

 The PV industry had an extraordinary year, with global production and markets more than doubling in 2010. An estimated 17 GW of capacity was added worldwide (compared with just under 7.3 GW in 2009), bringing the global total to about 40 GW - more than seven times the capacity in place five years earlier. The EU dominated the global PV market, led by Italy and particularly Germany, which installed more PV in 2010 than the entire world did the previous year. The trend toward utility-scale PV plants continued, with the number of such systems exceeding 5,000 and accounting for almost 25% of total global PV capacity. Cell manufacturing continued its shift to Asia, with 10 of the top 15 manufacturers located in the region. Industry responded to price declines and rapidly changing market conditions by consolidating, scaling up, and moving into project development.

CONCENTRATING SOLAR THERMAL POWER (CSP)

After years of inactivity, the CSP market has come back to life with nearly 740 MW added between 2007 and the end of 2010. More than half of this capacity was installed during 2010. Parabolic trough plants continued to dominate the market. Dramatic reductions in PV costs are challenging the growing market for CSP, at least in the United States, where several planned projects were redesigned to use utility-scale PV technologies. At the same time, project development is moving beyond the U.S. southwest and Spain to other regions and countries, particularly the MENA region.

SOLAR HOT WATER/HEATING

Solar heating capacity increased by an estimated 25 GWth in 2010 to reach approximately 185 GWth, excluding unglazed swimming pool heating. China continues to dominate the world market for solar hot water collectors. Europe's market shrank during 2010 due to the economic recession, despite the emergence of some new players, but it continued to rank a distant second. While virtually all installations in China are for hot water only, there is a trend in Europe toward larger combined systems that provide both water and space heating. A number of solar industrial process heat installations came online during 2009 and 2010 in China, Europe, the United States, and elsewhere.

BIOMASS POWER AND HEAT

 Biomass supplies an increasing share of electricity and heat and continues to provide the majority of heating produced with renewable sources. An estimated 62 GW of biomass power capac­ity was in operation by the end of 2010. Biomass heat markets are expanding steadily, particularly in Europe but also in the United States, China, India, and elsewhere. Trends include increasing consumption of solid biomass pellets (for heat and power) and use of biomass in combined heat and power systems. China leads the world in the number of household biogas plants, and gasifiers are used increasingly for heat applications in small and large enterprises in India and elsewhere. Biomethane (purified biogas) is increasingly injected into pipelines (particularly in Europe) to replace natural gas in power and CHP plants.

A Dynamic Policy Landscape

Renewable energy support policies continued to be a driving force behind the increasing shares of renewable energy, despite some setbacks due to the lack of long-term policy certainty and stability around the world in 2010.

National targets now exist in at least 98 countries. These targets represent commitments to shares of electricity production (typically 10-30%), total primary or final energy, heat supply, installed capacities of specific technologies, and shares of biofuels in road transport fuels. Many targets also exist at the state, provincial, and local levels. Although some targets were not met or were scaled back, many countries achieved or exceeded their targets set for 2010; two countries - Finland and Sweden - passed their targets for 2020.

Rural Renewable Energy

In even the most remote areas, renewable energy is increasing access to basic energy services - including lighting and communications, cooking, heating and cooling, and water pumping - and generating economic growth. PV household systems, wind turbines, micro-hydro powered or hybrid mini-grids, biomass-based systems or solar pumps, and other renewable technolo­gies are being employed in homes, schools, hospitals, agriculture, and small industry in rural and off-grid areas of the developing world.

The number of rural households served by renewable energy is difficult to estimate as the sector becomes driven increasingly by individual project promoters or private companies, but it runs into the hundreds of millions. Small solar PV systems provide power to a few million households, and micro-hydro configured into village- or county-scale mini-grids serves many more. Over 44 million households use biogas made in house­hold-scale digesters for lighting and/or cooking, and more than 166 million households now rely on a new generation of more-efficient biomass cookstoves.

Off-grid renewable solutions are increasingly acknowl­edged to be the cheapest and most sustainable options for rural areas in much of the developing world. This will have an impact on market development in the long term, especially if the barriers to accessing information and financing products are addressed.

This report predicts a good future for various Renewable Energy Technologies and through which we can hope for a more greener world as well.
Ref: REN21 Report






Saturday, June 25, 2011

Tool to Predict Solar Variability Effects for a better Grid Integration

The variability in the output of photovoltaic power systems has long been a source of great concern for utility operators worldwide. This is a real concern in tropical countries like India where the monsoon clouds will control the situation for 3 to 4 months. Once we can predict and model it, it will be a fine tool for the Utility Grid operators to control and switch other generators when needed to stabilise the Grid.

Currently, with solar plants accounting for a very small fraction of generation on most electrical grids these changes do not cause any problems for grid operators. However, if solar penetration levels increase in the future, as they likely will, such variability will pose problems for grid operators. A fast change in generation from cloud transients will need to be balanced by other sources of generation to balance load.

The power output fluctuations from solar panels during the cloud cover have to be predicted for addressing this issue. We hope that the latest innovation from the Department of Mechanical and Aerospace Engineering at the Jacobs School, San Diego can solve the problem to a greater extent.UC San Diego Professor Jan Kleissl and Matthew Lave, a Ph.D. student in the Department of Mechanical and Aerospace Engineering at the Jacobs School, have found the answer to these questions. They also have developed a software program that allows power grid managers to easily predict fluctuations in the solar grid caused by changes in the cloud cover. The program uses a solar variability law Lave discovered.

But Kleissl and Lave found that variability for large photovoltaic systems is much smaller than previously thought. It also can be modeled accurately, and easily, based on measurements from just a single weather station.

The finding comes at a time when the Obama administration is pushing for the creation of a smart power grid throughout the nation. The improved grid would allow for better use of renewable power sources, including wind and solar.

Also, more utilities have been increasing the amount of renewable energy sources they use to power homes and businesses. For example, Indian Ministry of New and Renewable Energy have come up with National Solar Energy Mission to add 20000 MW by 2020. Inspired by this announcement many MNCs and Indian companies have come up with proposal for solar farms.
Kleissl and Lave's finding could have a dramatic impact on the amount of solar power allowed to feed into the grid. Right now, because of concerns over variability in power output, the amount of solar power flowing in the grid at residential peak demand times in California, say -- is limited to 15 percent before utilities are required to perform additional studies. As operators are able to better predict a photovoltaic system's variability, they will be able to increase this limit.

Incidentally, Kleissl and Lave's research shows that the amount of solar variability can also be reduced by installing smaller solar panel arrays in multiple locations rather than building bigger arrays in just one spot, since a cloud covering one panel is less likely to cover the other panels, Lave said. "The distance between arrays is key," he said.

Kleissl presented the paper, titled 'Modeling Solar Variability Effects on Power Plants,' this week at the National Renewable Energy Laboratory in Golden, Colo.

His findings are based on analysis of one year's worth of data from the UC San Diego solar grid -- the most monitored grid in the nation, with 16 weather stations and 5,900 solar panels totaling 1.2 megawatts in output. Lave looked at variations in the amount of solar radiation the weather stations were receiving for intervals as short as a second. The amount of radiation correlates with the amount of power the panels produce.

Based on these observations, he found that when the distance between weather stations is divided by the time frame for the change in power output, a solar variability law ensues. "For any pair of stations at any time horizon, this variability law is applicable" says Lave. In other words, the law can be applied to any configuration of photovoltaic systems on an electric grid to quantify the system's variability for any given time frame.

But Lave didn't stop there. He developed an easy-to-use interface in MATLAB that allows grid planners and operators to simulate the variability of photovoltaic systems. Data can be input as a text file, but the interface also allows users to simply draw a polygon around each system on a satellite Google Map. Based on solar radiation measurements at a single sensor on a given day, the model calculates the variability in total output across all systems.

"It is as easy as painting by numbers," said Kleissl. "In Google Maps, photovoltaics show up as dark rectangles on rooftops. Draw some polygons around them, push the button, and out comes the total variability."

Kleissl said he anticipates this tool will be useful to figure out whether problems in voltage fluctuation may occur in power feeder systems with a large amount of photovoltaic arrays. At this point, the solar installations on almost all feeders are still far below the capacity that would cause any major issues. The tool developed by Lave and Kleissl could become key in solar installations in all parts of the world.

The model development was sponsored by DOE's High PV Penetration Program grant 10DE-EE002055. Further information is available at:

https://solarhighpen.energy.gov/project/university_of_california_san_diego and http://solar.ucsd.edu

Wednesday, March 16, 2011

New Questions arise after the Japanese Nuclear Crisis


Academics and nuclear experts agree the problems at the Fukushima Daiichi reactors are grave, and the solutions being proposed are last-ditch efforts to stem what could well be remembered as one of the world's worst industrial disasters.

Conditions at a stricken nuclear power plant in Japan have deteriorated so much that there is a growing consensus the crisis is greater than the Three Mile Island accident in 1979, and there are fears that it could get significantly worse.

All six reactors at the complex have problems; be it blown-out roofs, potentially cracked containment structures, exposed fuel rods or just the risk of explosion that has been great enough to force emergency measures. Of particular concern are a fire in a massive pool holding spent atomic fuel rods and a blast at the building housing the pool and reactor No.4. The pool is exposed to the elements, unlike the reactor core protected in steel and concrete.

The accident at the Three Mile Island nuclear plant in Pennsylvania in 1979 was the biggest in U.S. history. Half of the reactor core in one unit melted due to the loss of coolant, though it resulted in no immediate injuries.

The Chernobyl accident in Ukraine in 1986 was the worst in the industry's history, as an explosion led to a cloud of radioactive material being spewed over big parts of Europe.

Several experts said that Japanese authorities were underplaying the severity of the incident, particular on a scale called INES used to rank nuclear incidents. The Japanese have so far rated the accident a four on a one-to-seven scale against Three Mile at a five and Chernobyl at a seven.

But that rating was issued on Saturday, and since then the situation has worsened dramatically.

In the past few hours alone, the plant's operator Tokyo Electric Power Co, said that a fire broke out at the building housing the No.4 reactor -- the same reactor that houses the troubled spent fuel pool.

Kyodo News reported, citing TEPCO, that the fuel rods in the No. 1 reactor were 70 percent damaged and the rods in the No. 2 reactor were 33 percent damage. Meanwhile, just after 10 a.m. local time Wednesday, Japanese TV reported white smoke coming from the plant.

Separately, Japan's nuclear safety agency said two workers are missing and disclosed that there is a crack in the roof of the same building after an earlier explosion.

Europe's Nuclear Plan under Pressure

Japan's nuclear crisis in the wake of a huge earthquake is likely to increase opposition to plans for a major nuclear expansion in Europe and focus attention on the vast potential costs of a nuclear disaster.

The crisis will reignite concern over nuclear safety as Japan fights to avert a meltdown at crippled nuclear reactors, describing the quake and tsunami, which may have killed more than 10,000 people, as its biggest crisis since World War Two.

The disaster is a setback to the nuclear industry, which is enjoying a renaissance as public fears over nuclear safety have faded along with memories of the 1979 Three Mile Island accident in the United States and Ukraine's 1986 Chernobyl disaster.

Many countries plan new nuclear power plants, regarding nuclear as a clean alternative to expensive and dwindling oil and gas and saying new technology should allay safety fears.

But anti-nuclear campaigners around Europe have seized on the Japanese accident as evidence of the dangers of nuclear power and said governments should rethink plans for new plants.

"I think it will make a lot of governments, authorities and other planners think twice about planning power stations in seismic areas," said Jan Haverkamp, European Union policy campaigner for environmental group Greenpeace, which opposes new nuclear reactors and wants existing ones phased out.

French reactor maker Areva and nuclear power producers EDF and GDF Suez are important industry players. France's Alstom and Schneider Electric are also active in the sector, as are Switzerland's ABB and Germany's Siemens.

Chancellor Angela Merkel, whose government last year extended the operating lives of Germany's nuclear reactors, said the government was consulting with nuclear experts and watching the situation in Japan closely.

The Japanese radiation leak comes at a difficult time for Merkel, whose conservatives face three state elections in March where nuclear safety fears could help her opponents.

On Saturday, tens of thousands of anti-nuclear protesters formed a 45-km (27 mile) human chain from Stuttgart to a nuclear power plant that will be kept running longer because of the new policy. The protest was planned before the Japanese earthquake.

Oil will be needed to support Japan after the recent earthquake disaster. Russia has promise energy industry support to Japan, the easiest of which to implement is fuel. Clean up is going to take lots of horsepower from fuel. The Japanese electrical grid will be without electricity from nuclear generators for quite sometime. Bloomberg reported that Tokyo Electric is still seeking government approvals for a full restart of the Kashiwazaki Kariwa nuclear power plant (five reactors at 1,067 MW and two at 1,315 MW for a total 7,965 MW), which was shutdown after being damaged by an earthquake in 2007. The company posted its first loss in 28 years after it was forced to buy fossil fuels at record prices to make up for the lost nuclear output.

The Effect on Energy Industry

The 8.9 magnitude earthquake not only wiped out people's belongings in northern Japan, but also destroyed supply chains from various industrials. The nuclear power industry was especially hit hard due to the chain reaction resulting meltdown of the metal containers in the reactors. Numerous organizations and governments around world protect against nuclear energy as a major source of energy on this planet because it is simply not safe in such scale a disaster.

Countries such as USA, China, Japan and Australia are most susceptible to big earthquakes. It is reported that Southern California is way overdue for a big hit, it is not a question of "if" but "when." California has two operating plants: Diablo Canyon and San Onofre, both are vulnerable to earthquakes. This causes serious concerns in the region. Naturally, last week's earthquake changed the mentality of how people should approach renewable energy in the future. We will not likely give up nuclear energy, but the problem is that no safety rule is strict enough to guarantee safe operations if a big earthquake strikes. As a result, nuclear power will likely play a smaller role in the future energy market, while solar and wind energy are much more secure, safer and easy to distribute.

The Effect on Solar Industry

The earthquake also has impact on the solar energy industry. Japan accounts for 1/4th of global solar production, including solar panels and polysilicon. Most of these products are sold in domestic markets, some polysilicon is shipped overseas. The earthquake caused shutdown of production from Sanyo, Panasonic, the Kyocera Corp. and Sharp. Some facilities are not severely damaged, but what impacts the industry is the infrastructure. It is believed that at least 2-3 months will be needed to repair the power grid. Without electricity, the solar industry will remain shutdown for foreseeable future. The supply chain is not there any more. It will even take longer to repair the roads and ports in the northern coast.

Japan may have two weeks of inventory for panels and wafers. M. Setek, a solar wafer supplier, has completely shut down its facilities due to the damage caused by the earthquake. It supplies wafers to Sunpower. Companies benefiting the most are the polysilicon producers such as LDK solar and ReneSola. Both will fill the gaps left by Japanese companies. Sunpower, Sharp and Kyocera will likely have to place orders from LDK and SOL to solve the supply problem, and they may have to pay high price for the wafers. We believe Suntech power, Jinko Solar, and Trina Solar will not be affected by the shortfall, as they have long term contracts in place. Yingli green is a vertical integration company, so it is barely impacted.

The sentiment is shifting towards to solar energy as governments from Japan, China, France, Italy and Germany are considering boosting the solar energy shares in their renewable energy portfolios. People of these countries are putting lots of pressure on politicians to shift their energy policies to favor solar energy. In the next 2-3 months, new policies from the countries of major solar markets are expected to be enacted. The German government has indicated that existing nuclear plantoperations will not be extended as most Germans are opposed to nuclear power. It is certain that leaders in Japan will rigorously set policies to promote solar power as opposed to nuclear power in their next congressional meeting.


Saturday, February 26, 2011

Floating Solar Panels: Will it catch up?


Availability of space is a major problem for Solar Photovoltaic installations. This is more true in the case of big PV Power Plants where space is a constraint. Generally 4 to 5 acres of land area is needed for a MW of PV installation. This means that the total land area needed for a 50 MW installation is 250 acres which is a huge area. This is a concern for PV generation in areas where the density of population is high and the land value is costly. In my country, I faced this problem when I was trying to design a 1 MW Slar PV Power Plant in Thiruvananthapuram City area. We have only some roof tops available which is not sufficient for 1 MW PV module laying. The idea of laying PV modules in dam catchment areas and lakes are not new for the last several years. The important thing is to lay these modules without affecting the living organisms in water and to maintain it scientifically. The following scientific innovation will be interesting for any PV technologist to try and adapt it to suit to their environment after making proper technological changes.

The company Solaris Synergy believes that their invention provides cheaper electricity and better use of the land area.

Solar panels located on water surfaces have the advantage that they easily can be moved according to the sun’s movements and also prevent the water to the solar cells get too hot. A third advantage is that the water temperature is more constant than air temperature. Large temperature differences, such as in a desert is wearing much on solar cells semiconducting components, but this can be avoided by putting solar cells in water. The placement in freshwater prevents solar evaporation and inhibit algae growth.

Solar cells on water will probably be best placed on industrial ponds, for example at a water treatment plant where solar cells could then provide power to operate the treatment plant.

Developed by a Franco-Israeli partnership, this innovative solar power technology introduces a new paradigm in energy production. Solar power plays a dominant role in the world-wide effort to reduce greenhouse gases, it is considered a clean energy and is an efficient source of electricity. Yet several obstacles have been undermining the expansion of this sector and many of its actors are looking for a new approach towards the markets.

Soon after the design phase was over, at the end of March 2010, the fabrication of a prototype began and the team is now aiming to launch the implementation phase in September 2011. The tests will take place at Cadarache, in the South East of France, the site having a privileged position on the French electric grid and being close to a local hydro-electric facility providing the water surface to be used for the installation of the system. It will operate on-site during a period of nine months, while assessing the system's performances and productivity through seasonal changes and various water levels. The research team members believe that by June 2012, they will have all the information required to allow the technology's entry on the market.

As even leading photovoltaic companies struggle to find land on which to install solar power plants, the project team identified the almost untouched potential of solar installations on water. The water basins, on which the plants could be built, are not natural reserves, tourists' resorts or open sea; rather they are industrial water basins already in use for other purposes. By that, it is assured that the new solar plants will not have a negative impact on natural landscapes. "It's a win-win situation," declares Dr. Kassel, "since there are many water reservoirs with energy, industrial or agricultural uses that are open for energy production use."

After solving the question of space, the team also took on the problem of cost. "It sounds magical to combine sun and water to produce electricity, but we also have to prove that it carries a financial logic for the long run," explains Dr. Kassel. The developers were able to reduce the costs linked to the implementation of the technology by two means. First they reduced the quantity of solar cells used thanks to a sun energy concentration system based on mirrors, while keeping steady the amount of power produced.

Secondly, the team used a creative cooling system using the water on which the solar panels are floating. Thanks to this efficient cooling method, the photovoltaic system can use silicon solar cells, which tend to experience problems linked to overheating and need to be cooled down in order to allow the system to work correctly, unlike standard type more expensive cells. The particular type of solar cell used also allows a higher efficiency than the standard ones, achieving both reliability and cost reduction.

Still for the purpose of making the technology efficient and ready to market, the system is designed in such way that on a solar platform it is possible to assemble as many identical modules as needed for the power rating desired. Each module produces a standard amount of 200 kiloWatt electricity, and more power can be achieved by simply adding more modules to the plant.

The team also worked on the environmental impact of the technology. It works in fact as a breathing surface through which oxygen can penetrate to the water. This feature ensures that sufficient oxygen will maintain the underwater life of plants and animals. Dr. Kassel adds: "One of the implementation phase's goals is to closely monitor the possible effects of this new technology on the environment with the help of specialists" and "a preliminary check shows no detrimental environmental impact on water quality, flora or fauna. Our choices of materials were always made with this concern in mind."

*The project results from a collaboration between Solaris Synergy from Israel and the EDF Group from France. EUREKA provided the supporting platform which allowed to enhance both companies' partnership. After receiving the "EUREKA label" the project, called AQUASUN, found also support from the Israeli Ministry of Industry, Trade and Labor.

Floating solar power plants could be placed at hydroelectric plants, which already have infrastructure for electricity production.It is not realistic to place solar cells on the sea as waves will prevent the optimum angle to the sun. My State of Kerala, "The God's Own Country", is blessed with a lot of lakes and rivers. The catchment areas of our major dams can be utilised for PV module laying if we scientifically design the installations without affecting the fishes and other living organisms. This is one of the areas we need to stress upon for small scale generation of power utilising Photovoltaic technology.

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