VATIS Update Non-conventional Energy . Apr-Jun 2014

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New and Renewable Energy Apr-Jun 2014

ISSN: 0971-5630

VATIS Update New and Renewable Energy (formerly Non Conventional Energy)* is published 4 times a year to keep the readers up to date of most of the relevant and latest technological developments and events in the field of New and Renewable Energy. The Update is tailored to policy-makers, industries and technology transfer intermediaries.

* This update has been renamed as 'VATIS Update: New and Renewable Energy' from Jan-Mar 2015 onwards.

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Solar capacity in India crosses 2,500 MW

According to a report by Ministry of New and Renewable Energy (MNRE), India, the total grid-connected solar capacity, commissioned under the National Solar Mission, crossed the 2,500-MW mark and stood at 2,632 MW as on March 31, 2014. Of the total, a little over a third of capacity was commissioned in Gujarat. A total capacity of 947 MW was commissioned during fiscal 2013-14 and Madhya Pradesh added highest capacity of 310 MW during the year. Of the commissioned, higher contribution came from state-policy driven projects at 1,322 MW, followed by MNRE projects at 688 MW, REC Scheme at 491 MW and the rest came from RPO (renewable purchase obligation), private sector rooftop and central government organisations.Gujarat (916 MW) topped the cumulative capacity table, followed by Rajasthan (730 MW), Madhya Pradesh (347 MW) and Maharashtra (249 MW), among others.

“The solar market potential remains as large as ever, even in a slower-growing economy. As power shortfalls continue, peak shortage is a critical problem that has stifled industrial growth, and back-up generation is becoming increasingly expensive. The diesel price hike of 50 paise a month since January 2013 has resulted in about 15% increase in diesel prices over the last 13 months, making solar a very attractive option,” said Raj Prabhu, CEO and Co-Founder of Mercom Capital Group, India. While the total new capacity addition in renewable sector for 2013-14 is awaited, January 2014 saw two milestones — the total grid-interactive renewable energy capacity in the country crossed 30,000 MW and the total installed capacity of wind segment crossed 20,000 MW.

GE invests in India’s largest solar power plant

GE Energy Financial Services, the United States, is making its first investment in a solar power project in India, providing $24 million for a 151MW solar photovoltaic power project developed by Welspun Renewables Energy Pvt. Ltd. (WREPL), India. WREPL is one of the leading clean energy generating companies. The company’s Neemuch solar farm, one of the world’s largest solar plants, first started to generate energy in August 2013, almost eight months ahead of schedule. The plant is located on an 800-acre site in Neemuch, on a 500-meter-high barren land ridge in the Indian state of Madhya Pradesh. It provides enough power to supply 624,000 homes displacing an estimated 216,372 tons of carbon emissions annually and has reached a capacity utilization factor of 26%, thereby placing it among India’s top generating projects.

Power from the project is sold to the Madhya Pradesh state utility, helping the country meet its target of 20% energy generation from renewable sources by 2020. “We have been working to empower the country through our efficient solar energy projects, which will help meet the country’s energy requirements in a sustainable manner. The combination of our renewable project development expertise and GE’s financial strength and risk management will help achieve the ambitious goals set by the government to expand the use of renewable energy in India,” said Mr. Vineet Mittal, Vice Chairman, WREPL.

Raghuveer Kurada, business leader for India and South East Asia at GE Energy Financial Services, added that with its geography, strong economic growth and commitment from the highest levels of government, India has gained incredible potential for the development of solar power. The Neemuch project has enabled GE to exceed $10 billion in cumulative renewable energy investment commitments worldwide including $1.8 billion in solar power commitments in seven countries around the globe.
Source: http://www.renewableenergy

Wind power gains momentum in China

According to a research by Lin Boqiang, director of China Center for Energy Economics Research (CCEER), in 2013, growth momentum of wind power began to improve, with average wind curtailment rate down by 6% compared to the same period of previous year and the curtailment power reduced by 4.6 billion kilowatt-hours compared to 2012. Electricity output up 34% year on year, wind power projects distribution optimized. China added 14.49 million kilowatt of on-grid wind power generation capacity in 2013, hitting a total of 77.16 million kilowatt, up 23% over previous year. Wind power installed capacity generated 134.9 billion kilowatt hours of electricity in 2013, up 34% year on year, contributing to 2.6% of the country’s total generated electricity. New capacity increased by 30.69 million kilowatt, making a total of 137 million kilowatt. Capacity under construction totaled at 60.23 million kilowatt.

The above-mentioned statistics show that the installed capacity of wind power in China kept increasing from 2013, continuing the 30% year-on-year generation capacity growth. These achievements could not have been possible without the wind power administration reform. In 2013, China quickened changes in wind energy industry administration functions, with all approval of wind power delegated to local government. This measure has significantly improved the flexibility and enthusiasm of wind power construction, and has brought more than quantitative growth.” Besides quantitative growth, in 2013 China’s wind power industry had attached more importance to optimizing distribution, having accelerated wind power development in the middle-east and south regions,” said Shi Lishan, deputy director of the New Energy and Renewable Energy, Department of the National Energy Administration (NEA), China.

Currently, the center of wind power construction is shifting to the east and the south, and wind power subsidy efficiency has been increased. For instance, the price of sulfur-removed coal fired power in Guangdong is around RMB 0.5 Yuan, and the benchmark price of wind power is RMB 0.61 Yuan, with subsidy of RMB 0.1 Yuan/kilowatt-hour, lower than that in the three northern regions, conducive for the local development of wind power. Wind curtailment rate down by 6% points, the three northern regions seen apparent improvement.According to statistics, in 2013, the average of wind curtailment rate across China was reduced to 11%, 6% points lower than the previous year; main regions, except Hebei’s Zhangjiakou, that had suffered wind curtailment and power supply limitation had seen apparent improvement, particularly the three northern regions. The reduction of wind curtailment rate can effectively improve the operation efficiency of wind turbines and therefore improve economic benefits.

“China most attractive market for clean energy”

The Pew Report, “Who’s Winning the Clean Energy Race?” 2013 Edition, has found that China remains the leading destination for investors, even as global clean energy investment fell 11%. “Despite a slow recovery from a global recession and damaging policy uncertainty, the clean energy industry has established itself as a $250 billion component of the world economy,” said Phyllis Cuttino, director of Pew’s clean energy program. While there was an overall decline in investment, there are signs that the sector is reaping the rewards of becoming a more mature industry. Prices for technologies continue to drop, making them increasingly competitive with conventional power sources. Key clean energy stock indexes rose significantly in 2013, with public market financing up by 176%.

The curtailment of incentives in Europe weighed heavily on worldwide investment, while uncertainty about U.S. policy in the wind sector dragged down overall renewable energy capacity additions. In a study of contrasts, investment in the larger and more established markets of G-20 countries declined by 16% as investment in non-G-20 markets grew by 15%, with promising sectors emerging in countries such as Chile and Uruguay. Renewable energy investment in the Asia/Oceania region, which includes Australia, China, India, Indonesia, Japan and Republic of Korea, continued to grow steadily in 2013, increasing 10% to US$102 billion. China remains the leading regional and global market, attracting US$54.2 billion in 2013, with a nearly fourfold growth in solar power to an unprecedented 12.1 gigawatts (GW). With an additional 14.1 GW of wind, China installed more than 35 GW of new renewable power generating capacity.

Japan experienced the fastest investment growth in the world, increasing 80% to almost US$29 billion and moving to third from fifth place among G-20 nations. This reflects its priority on renewable power since the Fukushima nuclear disaster. Most striking was a near doubling in the country’s solar sector, which received US$28 billion in investment, almost 30% of the G-20 total. For the first time, more solar than wind energy was installed globally. 40 GW of solar generating capacity were added, an increase of 29%, raising the total to 144 GW. Wind capacity additions declined by more than 40%; the United States accounted for more than half of that drop. Current projections indicate that solar will be the leading clean energy technology in both investment and capacity for the next several years. Energy efficient and low-carbon technologies, which include smart meters and energy storage devices, grew 15% to US$3.9 billion.

Palm oil biodiesel programme in Malaysia

MALAYSIA’s B5 biodiesel programme will be fully implemented nationwide this July – three years after the initial phase launch in the central region in the Peninsula. The B5 biodiesel is a blend of 5% palm oil or palm methyl ester (PME) and diesel. For this palm biodiesel initiative, the PME requirement for the entire B5 programme is estimated at 500,000 tonnes per year to support both the subsidised and non-subsidised sectors in the country. “This initiative is also envisaged to effectively reduce domestic palm oil inventory to below one million tonnes, and provide a floor price to support CPO prices at RM2,000 per tonne,” saidYung Chee Liang, senior research officer at Malaysian Palm Oil Board (MPOB).

The B5 implementation was launched in phases, starting with the central region (Putrajaya, Kuala Lumpur Selangor, Selangor and Malacca) between June and November 2011. Next was the southern region (Johor) in July 2013, followed by the northern region (Perlis, Kedah, Penang and Perak) in October, the eastern region (Kelantan, Pahang and Trengganu) in January, and finally, Sarawak, Sabah and Labuan this July to complete full national coverage. Meanwhile, the B5 programme has been fully implemented among the subsidised sectors such as retail stations, fleetcard, skid tanks and fisheries in the central region since Feb 15, 2012.

“There is a need to install more in-line blending facilities at another 26 depots for the full implementation of B5 nationwide. There are currently over 1,500 retail stations in the central and southern regions selling the B5 biodiesel,” said Yung. On pricing, further subsidy from the Government would be expected to ensure the price of B5 is similar to that of diesel. Another issue to tackle is the need to finance the construction of in-line blending facilities for petroleum companies. For full implementation of B5, an RM300mil for in-line blending facilities for 35 petroleum depots or terminals is estimated, while additional subsidies may be required when the main PME feedstock – crude palm oil (CPO) – price is higher than that of diesel. At the same time, it is important for on time completion of the blending facilities, as well as to iron out the challenges of logistics and supply in Sabah and Sarawak.

Malaysia to rebalance renewable energy incentives

The Sustainable Energy Development Authority (SEDA), Malaysia, has revised the feed-in tariff (FiT) digression rates and bonus rates, which will apply to new renewable energy projects in order to rebalance developer interest toward the biomass and biogas at the expanse of the solar sector. “For biomass and biogas, the principle is to improve the feed-in-tariff rates to make it more attractive to the RE developers, as the take-up rate has been rather sluggish in the past two years,” said Badriyah Abdul Malek, Chief Executive at SEDA. Under the country’s Renewable Energy Bill, SEDA allocates FiT budget – split between biogas, biomass, small hydro and solar photovoltaic – on a first-come, first-served basis, every six months. Digression rates are supposed to reflect the falling cost of technologies while developers can earn an enhanced rate for fulfilling certain criteria, relating to construction and local content.

However it has not worked out that well in practice. The scheme was stymied right from the get-go because the initial FiT rates embedded in the 2010 Renewable Energy Bill, were based on 2009 prices. By the time the first tranche of FiT quota became available in early December 2011 the FiT rate for solar bore no relationship to cost and, as a result, practically all solar quota was snapped up within 24 hours. The initial solar digression rate of 8% for solar, which started apply in the FiT quota released in December 2012, was also way out of kilter. It would have taken until 2021 for the solar FiT to reflect the decline in solar module prices during 2011 and, of course, prices continued to fall rapidly before reaching a more stable point toward the end of last year.

The flip side has been the distinct lack of enthusiasm shown by developers for biogas and biomass projects. Given Malaysia’s verdant equatorial landscape, its 5-GW of estimated biomass potential should have been an obvious target for early development. Under the Tenth Malaysia Plan, the goal is from renewable energy to account for 5.5% (985-MW) of total generating capacity in 2015, rising to 11% (2,080-MW) by 2020. The country has also pledged to reduce the carbon intensity of its economy to 40% below 2005 levels by 2020. Given the relatively small and fixed nature of Malaysia’s FiT budget, which is funded by a 1% levy on electricity bills of customers on the Malaysian Peninsular, over-generosity to the solar sector was always going to be an expensive way of achieving these goals.


Researchers develop solar cells made of tin

Researchers from Northwestern University (NU), the United States, and the University of Oxford, the United Kingdom, are experimenting with tin as an alternative to lead in the production of perovskite solar cells, which convert light energy directly into electricity. Perovskite is a mineral composed mainly of calcium titanate, whose structure is ideal for solar conversion. Most perovskite solar cell development has relied on lead to absorb sunlight, but the new studies, make the case for using tin because it’s a less toxic material than lead. Tin is an inexpensive, abundant material and its use in solar cells would drive costs down, while alleviating the kind of geopolitical supply chain issues, that bedevil other solar cell materials.

Solar panels are quickly becoming a global product. While the cost of solar panels varies widely, depending on their type and efficiency, overall, they’re becoming more affordable. According to Cost of Solar, solar panels are about half the price they were in 2000 and 100 times the price they were in 1977.Today, solar costs about $0.70 to$0.73 per watt, although factoring in the “soft costs” of solar – things like installation and obtaining permits – can drive the prices up to about $4.72 per watt. One of the studies focused on using tin in solar cells to drive down cost is from researchers at NU. Their design for a new solar cell consists of five layers. The first two layers are of conducting glass and a layer of titanium dioxide. Then there’s the sheet of tin, followed by a coat of the electrical circuit. Finally, there’s a gold cap, which forms the back contact electrode of the cell.

“This is a breakthrough in taking the lead out of a very promising type of solar cell. Tin is a very viable material, and we have shown the material does work as an efficient solar cell,” said inorganic chemistMercouri G. Kanatzidis. Scientists in the U.K. have done similar experiments with using tin in perovskite solar cells and also report success with the material. The one downside to using tin in lieu of lead in solar cells is less efficiency. The U.K. team reported that their prototype demonstrated about 6% efficiency at turning sunlight into electricity – the U.S. team’s design achieved about the same – but researchers believe with more development that the solar cells can reach an efficiency closer to 20%.

New solar cell efficiency records

Panasonic Corporation, Japan, has announced that it has achieved a conversion efficiency of 25.6% in its HIT solar cells, while Trina Solar, China, has announced its Honey Ultra monocrystalline silicon module reached a new record of 326.3 watts. According to Panasonic, the previous record for the conversion efficiency of crystalline silicon-based solar cells of a practical size (100 cm2 and over) was 24.7%, as announced by Panasonic in February 2013 (cell area: 101.8 cm2). This new record is also an improvement of 0.6 points over the previous record for small area crystalline silicon-based solar cells (cell area: 4 cm2) of 25%.The high conversion efficiency rate was made possible through proprietary heterojunction technology and the high temperature properties of the company’s HIT solar cells, as well as adopting a back-contact solar cell structure, with the electrodes on the back of the solar cell to allow more efficient utilisation of sunlight.

Trina Solar has announced its State Key Laboratory of PV Science and Technology has developed a new high-efficiency Honey Ultra solar module.The Honey Ultra monocrystalline silicon module reached a new record of 326.3 watts, which has been independently certified by certification institution TUV Rheinland, according to Trina Solar. The monocrystalline silicon module is composed of 60 high-efficiency Honey Ultra monocrystalline silicon cells of 156 mm x 156 mm, fabricated with a technology developed by Trina Solar and currently in pilot production. According to Trina, this result sets a new world record for p-type monocrystalline silicon modules.

“As an advanced research and development facility, our State Key Lab of PV Science and Technology enables us to execute on our commitment to the commercialisation of new high-efficiency solar cells and highly reliable modules,” said Dr. Zhiqiang Feng, Vice President ofTrina Solar. This new Honey Ultra module is a key milestone for Trina Solar’s State Key Laboratory of PV Science and Technology since its accreditation in November 2013 and follows the company’s development of a new Interdigitated Back Contact cell capable of delivering an industry-leading efficiency of 24.4%.

US researchers develop indium gallium phospide

Yale University, the United States, has developed indium gallium phosphide (InGaP) solar cells on gallium phosphide substrates. The aim of the researchers’ work was to create a top-cell option for multi-junction cells with four or more junctions in monolithic or spectrum-splitting architectures. It is hoped that such arrangements will be able to achieve conversion efficiencies up to almost 60%. Such top cells need an energy bandgap of around 2.0-2.4eV. Gallium phosphide has such a bandgap, but unfortunately the 2.26eV gap is indirect, leading to inefficient conversion of photons into electrical energy. The InGaP alloy system has a transition from indirect to direct bandgap when the indium fraction exceeds 30%. However, the increase in indium content also leads to a reduction in the bandgap.

In fact, there are two valleys in the GaP bandstructure – a direct ‘gamma’ (Γ) valley giving a gap of 2.78eV and the indirect ‘chi’ (Χ) valley. In InGaP, the bandgap between the Γ valley and the valence band decreases at 19meV/% of indium. The Χ gap reduces more slowly at 1.7meV/%.The Yale group explored how moving the composition towards the crossover point increases conversion efficiency. In germanium solar cells such ‘pseudo-direct’ proximity between the smallest indirect gap (0.66eV) and direct gap (0.8eV) leads to improved conversion.Previous work with InGaP has tended to grow the material on gallium arsenide (GaAs) substrate. Unfortunately, the InGaP is then placed under tensile strain, which “leads to faceted trenches and cracks, and extremely thick graded buffers are required to minimize these efficiency-diminishing defects”.

The Yale group chose GaP substrates so that the InGaP was under compressive strain to avoid these problems.The epitaxial structures were grown on p-GaP substrates in a Veeco Mod Gen II solid-source molecular beam epitaxy (MBE) chamber. The use of a gallium arsenide phosphide (GaAsP) graded buffer reduced threading dislocations that arise from the lattice mismatch between the substrate and overlying epitaxial structure. The compressive grading was achieved using between 10 and 16 steps of 360nm thickness and increased arsenic molar fraction of 4% points per step. The aim was a grading rate of strain over buffer thickness of 0.4%/μm. The indium aluminium phosphide (InAlP) window layer was lattice-matched to the InGaP active emitter/base material.The main improvement of the InGaP structure is an increase in short-circuit current density (Jsc), leading to a 2x improvement in conversion efficiency (η) over a GaP cell.

A solar module with innovative substring optimizer

Scandinavian-German manufacturer Innotech Solar (ITS), has developed a new photovoltaic module that uses in-laminate integrated circuits (IC) to deliver yields that are up to 20% higher than those supplied by standard modules. The ‘SmartPlus’ module exploits the full potential of an installation, even when individual cells are shaded or soiled. As a result, roofs that were previously considered unsuitable even for smart modules now offer attractive prospects for solar power generation. “In standard modules, if a single cell underperforms due to factors such as shading or soiling, this compromises the yield of the entire string. However,intelligent microchips laminated into our new SmartPlus modules ensure that PV installations generate the maximum possible output power right down at cell level – not just at module level as is the case with conventional power optimizers,” said Knud Clausen at Innotech Solar.

“This has the added advantage that rows of modules in both flat roof and ground-mounted systems can be placed much closer together, despite the partial shading this causes, without concerns that significant yield will be lost. More energy can therefore be generated from the same area – not only compared to standard modules, but other smart modules too,” said Clausen. The I/V curve of the SmartPlus modules also means that they are well suited to other applications, such as off-grid solar systems. Three chips are installed in the laminate of each SmartPlus module, replacing both the bypass diodes and the junction box. Each chip optimizes the output of 20 solar cells connected in series.

The IC technology has been used successfully for over 20 years in servers and communications technology with proven durability and reliability. Calculated over the entire lifetime of a solar installation, it is possible to achieve a yield increase of up to 20%, depending on installation and shading conditions.Innotech Solar has rigorously analysed the performance of the new SmartPlus module in varying shading situations under laboratory conditions. The company is also conducting climate chamber tests at the Photovoltaik-Institut, Germany, in order to verify the long term performance of the modules.


Wind turbines gain size via surgery

Engineers from GE, the United States, have managed to increase the rotor diameter of wind turbines a staggering 40% by trimming and augmenting their blades using traditional surgical techniques. Increasing the size of wind power turbines has been a key imperative for renewable energy engineers over recent decades, given that larger rotors are capable of harnessing the wind’s energy far much heightened efficiency.According to a recent survey by Environmental Science & Technology, the dimensions of the average commercial wind turbine have increased tenfold over the past three decades, from around 15-metres in 1980 to over 150-metres today.

GE’s engineers, have now developed a method for increasing turbine sizes, which is akin to a surgical procedure, and involves the dismemberment of existing blades to augment their length via the insertion of custom-manufactured extensions. Mark Johnson, engineering leader at GE, led a team of researchers in successfully performing augmentation surgery on a standard 37-metres long wind blade. The blade is first secured into a fixture before being cut down the centre and divided into two separate halves. A 7-metres extension piece with suction side inserts is then placed in between the dismembered sections, and attached to both of them via the addition of pressure side inserts, in a process which bears an uncanny resemblance to surgical limb repair.

According to GE’s engineers, the new method is capable of increasing rotor diameter by 40% and can boost the power production of wind turbines by over 20% by allowing them to harvest energy from winds moving at slower speeds. The research project has already obtained a slew of 16 patent applications, while the augmented blades have managed to pass the barrage of stringent tests set by the International Electrotechnical Commission. These include static strength tests, and fatigue tests involving over 6 million cycles.

A new concept to improve power production

Wind energy is one of the most promising renewable energy resources in the world today. Dr. Hui Hu and his group at Iowa State University (ISU), the United States, studied the effects of the relative rotation directions of two tandem wind turbines on the power production performance, the flow characteristics in the turbine wake flows, and the resultant wind loads acting on the turbines. The experimental study was performed in a large-scale Aerodynamics/Atmospheric Boundary Layer (AABL) Wind Tunnel available at Aerospace Engineering Department of ISU. Their work, entitled “An experimental study on the effects of relative rotation direction on the wake interferences among tandem wind turbines”, has been published in SCIENCE CHINA Physics, Mechanics & Astronomy, 2014.

In a typical wind farm, the wind turbine located in the wakes of upstream turbines would experience a significantly different surface wind compared to the ones located upwind due to the wake interferences of the upwind turbines. Depending on the wind turbine array spacing and layout, the power losses of downstream turbines due to the wake interferences were found to be up to 40%. Therefore, how to improve the power production of downstream wind turbines in a wind farm is one of the most significant research topics in recent years. Extensive experimental and numerical studies have been conducted recently to examine wind turbine aeromechanics and wake interferences among multiple wind turbines in order to gain insight into the underlying physics for higher total power yield and better durability of the wind turbines.

While most of the wind turbines in modern wind farms are Single Rotor Wind Turbine (SRWT) systems, the concept of Counter-Rotating Wind Turbine (CRWT) systems has been suggested in recent years. Since azimuthal velocity would be induced in the wake flow behind a wind turbine with its rotation direction in the opposite direction to the upstream rotor, the downstream rotor should rotate in the same direction as the swirling wake flow for a CRWT system in order to extract wind energy in the wake flow more efficiently. Researchers conducted a comprehensive experimental study to quantify the effects of the relative rotation direction of two tandem wind turbines on the wake interferences among the turbines. During the experiments, the model turbines were set to operate in either co-rotating or counter-rotating configuration. The turbine power outputs, the static and dynamic wind loads acting on the turbines, and the turbulence characteristics in the wake flows behind the turbines were measured and compared quantitatively. Contact: Dr. Hu Hui, Iowa State University, USA. E-mail:

Automatic self-optimization of wind turbines

Specialists for learning systems at Siemens Corporate Technology (CT), Germany, has developed the self-optimization software for wind turbines in cooperation with Technische Universität, Germany, and IdaLab GmbH in the ALICE project (Autonomous Learning in Complex Environments), which is funded by Germany’s Ministry of Education and Research. The researchers presented the results of their work at the CeBIT trade show (March 10-14) in Hanover. Their solution enables turbines to produce around one percent more electricity annually under moderate wind conditions, while also reducing wear and tear.The researchers demonstrated a wind turbine unit that uses its own operating data and gradually increases its electrical output.

The scientists’ approach combines reinforcement learning techniques with special neural networks. A neural network is a software algorithm that operates in a way similar to the human brain. For several years now, Siemens CT has been developing neural networks in order to model and predict the behavior of highly complex systems, such as wind farms, gas turbines, factories, or even stock markets. The software programs learn from historical data, which also enables them to forecast the future behavior of a system. A model can thus be created that predicts the electrical output of a wind turbine under specific weather conditions. The researchers examined a large amount of very noisy data to identify relevant attributes that would enable the efficiency of a wind turbine to be improved by changing settings such as rotation speed.

Patented neural networks were then used to create a so-called reinforcement learning policy from the analysis results. The system thus learns to change certain wind turbine settings in a manner that ensures the maximum possible amount of electricity is generated in a given situation. After just a few weeks, the system is able to define and store the optimal settings for common weather occurrences. After an additional extended period of training, it can even regulate electrical output under rare and exceptional weather conditions. The technology has been successfully tested at a Spanish wind farm in 2013.Ongoing analyses of relevant operating parameters ensure the system can continually improve itself through repetition. The methods used, can be employed in many other fields, which means additional Siemens products can also be taught to optimize their own operation.

Patent issued for wind turbine comprising a main bearing

A patent by the inventor Henrik Stiesdal (Odense, DK), Denmark, filed on July 1, 2009, was published online on April 15, 2014, according to news originating from Alexandria, Virginia, USA, by Vertical News correspondents. The patent’s assignee for patent number 8696302 is Siemens Aktiengesellschaft (Germany).The following quote was obtained by the news editors from the background information supplied by the inventors:” A wind turbine comprises as main components a tower, a nacelle, a wind turbine rotor containing a hub and wind turbine rotor blades as well as a generator having a stator and a rotor arrangement and being typically arranged inside the nacelle. The rotor arrangement of the generator is at least indirectly connected to the wind turbine rotor for moving the rotor arrangement relatively to the stator arrangement for electrical power generation.”

There are different types of drive configurations of wind turbines to transfer the rotation of the wind turbine rotor to the rotor arrangement of the generator. But virtually in each configuration at least one main bearing is required. Such a main bearing or such main bearings are subject to different loads during operation of the wind turbine. It is not unusual that after a certain period of operation of a main bearing wear appears or the main bearing fails. As a consequence replacement of the main bearing is required. For replacement of a main bearing typically the wind turbine rotor has to be removed. This is not only an immense technical effort, but causes additionally a lot of costs. It is therefore an object of the present invention to provide a wind turbine as well as a method as initially mentioned in such a way, that the replacement of a main bearing is simplified and preferably less expensive.

This object is inventively achieved by a wind turbine comprising a rotatable main shaft having a centre axis and being at least indirectly connected to a wind turbine rotor of the wind turbine and at least one main bearing supporting the rotatable main shaft at least indirectly against a first stationary or fixed part of the wind turbine, wherein fastening means are provided for fastening the wind turbine rotor to the first or a second stationary or fixed part of the wind turbine during replacement of the at least one main bearing and tappet means are provided which are able to act on the at least one main bearing and permit a movement of the at least one main bearing relatively to the first stationary part in the direction of the centre axis. The fastening means permit to fix the wind turbine rotor on a stationary part of the wind turbine during replacement of the at least one main bearing.


World’s first tidal turbine started production

A community-owned tidal power turbine in the Bluemull Sound between Yell and Unst islands in the United Kingdom, has started exporting energy to the local grid.The turbine will power up to 30 homes, R.S. Henderson’s ice plant and Cullivoe Harbour’s industrial estate in the north of Yell.It is a joint project developed by tidal energy company Nova Innovation, the United Kingdom, in partnership with North Yell Development Council (NYDC). The turbine has received funding from the Scottish Government’s community and renewable energy scheme (CARES) and Shetland Islands Council.

It was first installed in April and has been undergoing trials and tests. Speaking at the All-Energy Conference, Scottish energy minister Fergus Ewing confirmed that the turbine was now producing power. “For the first time, anywhere in the world, a community-owned tidal turbine is generating electricity. It will have a positive impact on the North Yell community and economy,” said Fergus Ewing, Scottish energy minister.

“Nova 30 turbine has been successfully deployed and generating electricity for the local grid.It marks a major achievement for the wider Scottish tidal industry with over 80% of Nova’s supply chain Scottish-based. “By working in close partnership with the North Yell community and our suppliers, we believe that this project demonstrates the growing confidence in the marine sector and strengthens Nova Innovation’s leading position in the emerging global marine energy industry,”said Simon Forrest, Nova’s managing director. Scottish Enterprise has worked closely with Nova to help the company grow, and its director of renewables and low carbon technologies Seonaid. The successful deployment of this device is an important step in the development of technologies in the tidal industry.

Swivel solution for tidal turbine

Underwater technology system expert, MacArtney, Denmark, will be supplying a custom swivel solution for a new next generation Scottish tidal turbine.The firm has been selected to supply the custom designed Moog Focal swivel solution for the SR2000, a larger commercial scale turbine, developed by tidal energy pioneer, Scotrenewables Tidal Power (SRTP), Scotland.” Marine renewable energy is a key strategic focus of the MacArtney Group and we are proud to contribute to the sweeping development of technology taking place at the EMEC in these years,” said Jens Henrik Gadeberg, Sales Manager at MacArtney. SRTP’s innovative floating tidal energy converter the Scotrenewables Tidal Turbine (SRTT) is a floating hydrokinetic tidal stream system designed for ease of installation, operations and maintenance, coupled with efficiency, robustness and survivability in harsh offshore environments.

Nine different scale models and a 250 kW prototype known as the SR250, have been tested extensively over the past 10 years – both offshore and in a laboratory environment.The SR2000 builds on the success of SR250. It’s a larger commercial scale turbine more suited for tidal array deployment. This next generation turbine will reach a rated power of 2MW, making it one of the most powerful tidal turbines in the world.The main structure of the SR2000 comprises a floating cylindrical tube to which dual horizontal axis rotors are attached on retractable arms. The rotors extract the kinetic energy of the tidal flow, which is converted to electricity though a power take-off system for export to shore.

SRTP has developed an innovative and unique single point catenary mooring system featuring a patented mooring turret for the new turbine. At the heart of this turret and comprising a key element in the overall SR2000 system, sits a custom designed Moog Focal swivel supplied by MacArtney. The swivel allows the SR2000 to self-orientate in the tidal flow, while signal transfer and electricity flow to the onshore grid, is handled using a single marine export cable. The MacArtney Group is a global supplier of underwater technology systems to offshore operators, surveyors, the renewable energy sector, ocean science institutes and navies globally. Contact: MacArtney A/S, GI. Guldagervej 48, 6710 Esbjerg V, Denmark.

River currents to produce electricity

A new type of technology that uses river currents to generate electricity is coming to the United States. In fact, the prototype will be tested this summer. The RivGen® Power System, developed by Ocean Renewable Power Co. (ORPC), the United States, includes a large turbine that is placed at the bottom of a river. “It’s essentially an underwater wind turbine. It harnesses moving currents, they spin the turbines and the generator converts that into electricity,” said Monty Worthington, Director of Project Development.

The system has undergone tests in tidal areas off the coast of Maine where it was developed, but Alaska will be the first place where it will be tested in a river. “This was specific for Alaska’s remote communities. We wanted to build a smaller turbine that would interface with diesel micro-grids and reduce diesel use in rural communities, but there’s many worldwide opportunities for this as well,” Worthington said.

The system is headed to the Kvichak River across Cook Inlet, where it’s hoped to begin producing power for the village of Igiugig by mid-July. “Most residential homes are paying between $6,000 and $12,000 a year, depending on the size of the home and the number of occupants. And then public buildings like the utility and the clinic are around $20,000 a year.” village resident Alexanna Salmon said.The Alaska Energy Authority helped to fund the project. If successful, it could provide a new means of cheap, renewable energy for many parts of rural Alaska.

New-age water wheels harvest hydrokinetic energy

Capturing the energy contained in the water flowing in the Northwest’s rivers is nothing new – hydropower dams have been doing just that since the 1930s. But new turbine technology can create electricity without using dams or reservoirs, which carry environmental impacts. Instream Energy Systems, Canada, is testing out a turbine in the Roza Canal, just south of the Yakima Canyon, the United States. “We are creating power from moving water without the need for damming or diversions. The testing we’re doing in Roza will help us develop our next-generation technology,” said Shannon Halliday, director of business development at Instream. Instream worked with BAE Systems, the United Kingdom, on the turbine design. They first installed their equipment in the canal in August 2013 for a monthlong test. Engineers have now put their turbine back in the canal and set up monitors to track it all summer long.

The company chose to test its technology in the Roza canal because it is a good example of the canal systems found around the West, where the technology could be deployed. To install it without interfering with water delivery operations, the company built a large steel structure stretching across the top of the canal, which includes a walkway for the engineers. The turbine is mounted on this structure and the blades are rotated into the water. The turbine is designed to produce 25 KW, but at normal canal conditions it’s expected to produce enough electricity to power eight to 10 homes when the canal is running. For now, however, that power is just used on site by the engineers to run computers and data-monitoring equipment. Eventually, Instream hopes to build commercial turbine farms through canal systems that could power hundreds or thousands of homes.

Instream first test site in British Columbia was in a river used by bull trout and rainbow trout. Studies found that the fish easily navigate around the turbine blades. The fish can sense the change in water movement similar to other in-stream obstacles. The Bureau of Reclamation and the Department of Energy, the United States, are supporting the study of this turbine technology. It’s part of a larger initiative to encourage development of innovative technologies to capture energy from moving water in tidal estuaries, rivers and canals, which is known as hydrokinetic energy. Instream hopes to start work on a commercial project within the next two years and the data gathered in the Roza canal is the next step toward those potential power production options.


New fuel cell to eliminate waste at biodiesel plants

A researcher from Michigan State University (MSU), the United States, has developed a new fuel-cell concept, which will allow biodiesel plants to eliminate the creation of hazardous wastes while removing their dependence on fossil fuel from their production process. “The platform, which uses microbes to glean ethanol from glycerol and has the added benefit of cleaning up the wastewater, will allow producers to reincorporate the ethanol and the water into the fuel-making process,” said Gemma Reguera, MSU microbiologist. With a saturated glycerol market, traditional approaches see producers pay hefty fees to have toxic wastewater hauled off to treatment plants.

The results have been published in the journal Environmental Science and Technology, showed that the key to Reguera’s platform is her patented adaptive-engineered bacteria – Geobacter sulfurreducens.Geobacter are naturally occurring microbes that have proved promising in cleaning up nuclear waste as well in improving other biofuel processes. Much of Reguera’s research with these bacteria focuses on engineering their conductive pili or nanowires. These hair-like appendages are the managers of electrical activity during a cleanup and biofuel production. First, Reguera along with a team of other MSU students, evolved Geobacter to withstand increasing amounts of toxic glycerol. The next step, the team searched for partner bacteria that could ferment it into ethanol while generating by products that ‘fed’ the Geobacter.

It took some tweaking, but they eventually developed a robust bacterium to pair with Geobacter, which removes any waste produced during glycerol fermentation to generate electricity.The hungry microbes are the featured component of Reguera’s microbial electrolysis cells (MECs). These fuel cells do not harvest electricity as an output. Rather, they use a small electrical input platform to generate hydrogen and increase the MEC’s efficiency even more. The promising process already has caught the eye of economic developers, who are helping scale up the effort.

Next-gen fuel cell by Suzuki

Suzuki Motor Corporation, Japan, has introduced its Gen4 air-cooled fuel cell power unit, designed for easy integration into two-wheel and four-wheel vehicles. The Gen4 fuel cell power unit incorporates the necessary ancillary components to enable vehicle manufacturers to more easily integrate the system into their products. Incorporating Intelligent Energy’s latest proprietary fuel cell technology, Gen4 is a power-dense, compact and self-contained system. Rated for continuous operation at 3.9kW and capable of providing in excess of 4kW for short periods, the power unit has been designed as a prime-mover power source for smaller fuel cell electric vehicles and also as a range extender for larger vehicles.

Gen 4 has been subject to a comprehensive development process to satisfy demanding automotive requirements based upon an extensive operational and performance test programme, including shock and vibration testing and repeated thermal cycling over a range of operating temperatures. By making Gen4 available as a self-contained fuel cell power unit, we are able to offer new and existing customers a simple solution, reducing time to market for a broad range of zero-emission production vehicles without the high cost and risk associated with in-house development,” said James Batchelor, MDat Intelligent Energy.

Fuel cells to recover high-purity helium

The University of Hawaii at Mānoa’s Hawaii Natural Energy Institute (HNEI), the United States, together with Sierra Lobo Inc., the United States, has demonstrated the recovery of high-purity helium from hydrogen/helium mixtures produced at rocket engine testing sites using proton-exchange-membrane fuel cells. The National Aeronautics and Space Administration (NASA) uses a large amount of helium gas–about a million cubic feet per launch to purge hydrogen from their fuel lines. Helium gas, contaminated with hydrogen, is expensive and energy-intensive to purify and recover. Capitalizing on expertise at HNEI, Sierra Lobo technologists challenged the team to use proven fuel cell technology to develop an efficient recycling process for helium.

HNEI demonstrated that contaminated gas streams with up to 50% hydrogen can be refined to produce 99.995% pure helium. A pilot-scale Helium Reclamation System was designed and built by Sierra Lobo and its performance was validated on-site at the NASA Stennis Space Center in Mississippi. HNEI developed a chemical reactor model to estimate the PEMFC size needed to attain a specific helium purity for different hydrogen concentrations and processing rates. The model was used by Sierra Lobo to size fuel cell technology used in the pilot-scale separation system.


Cost efficient water-splitting photocatalyst

Researchers at National Institute for Materials Science (NIMS), Japan, have discovered a new photocatalyst, Sn3O4, which facilitates the production of hydrogen fuel from water, using sunlight as an energy source. Technology that allows the direct conversion of sunlight, an ultimate renewable energy, into chemical energies (i.e., fuels) that can be condensed and transported is not yet available. As such, solar energy is not ready at present to be utilized in place of conventional fossil and nuclear fuels. Many water-splitting photocatalysts, such as titanium dioxide (TiO2), can decompose water and produce hydrogen fuel when absorbing ultraviolet light. However, due to their inability to absorb visible light, which accounts for more than half of solar energy, their practical use in the conversion of solar energy is limited.

While the development of new photocatalysts that can split water by absorbing visible light has been worked on globally, there are cost- and environment-related issues because many of the available photocatalysts contain expensive rare metals, such as tantalum, or high concentrations of lead, which is very toxic. Led by Hideki Abe and Naoto Umezawa, researchers discovered a novel photocatalyst by integrating both theoretical and experimental sciences. The NIMS team searched for oxides containing divalent tin ions (Sn2+) based on the theoretical prediction that such substances may have an electronic structure conducive to water-splitting photocatalytic reactions under the presence of visible light.

As a result, they found a tin oxide, Sn3O4 (Sn2+2Sn4+O4), that is made up of divalent tin ions (Sn2+) and tetravalent tin ions (Sn4+). Their experiment revealed that this substance facilitates a water-splitting reaction leading to the generation of hydrogen when exposed to visible light which does not activate TiO2.Since tin oxides are relatively non-toxic, inexpensive and abundant, they are widely used as transparent conductive materials. The discovery of the Sn3O4 catalyst is expected to greatly contribute to the reduction of environmental load and costs associated with hydrogen fuel production, and to the realization of a recycling-oriented society founded on the use of solar energy. Results of this research has been published in the online journal of Applied Materials & Interfaces.

Researchers develop fuel created from seawater

The Naval Research Laboratory (NRL), the United States, has developed a technology for simultaneously extracting carbon dioxide (CO2) and hydrogen from seawater and converting the two gases to a liquid hydrocarbon fuel, as a possible replacement for petroleum-based jet fuel. Fueled by the liquid hydrocarbon, the research team demonstrated sustained flight of a radio-controlled P-51 replica of the legendary Red Tail Squadron, powered by an off-the-shelf, unmodified two-stroke internal combustion engine.NRL operates a lab-scale fixed-bed catalytic reactor system and the outputs of this prototype unit have confirmed the presence of the required C9-C16molecules in the liquid.

“This system is the first step towards transitioning the NRL technology into commercial modular reactor units that may be scaled-up by increasing the length and number of reactors. This is the first time technology of this nature has been demonstrated with the potential for transition from the laboratory, to full-scale commercial implementation,” said Dr. Heather Willauer, research chemist at NRL. NRL has made significant advances in the development of a gas-to-liquids (GTL) synthesis process to convert CO2 and H2 from seawater to a fuel-like fraction of C9-C16 molecules. Using an NRL electrolytic cation exchange module (E-CEM), both dissolved and bound CO2 are removed from seawater at 92% efficiency by re-equilibrating carbonate and bicarbonate to CO2 and simultaneously producing H2.

In the first patented step, an iron-based catalyst has been developed that can achieve CO2 conversion levels up to 60% and decrease unwanted methane production in favor of longer-chain unsaturated hydrocarbons (olefins). These value-added hydrocarbons from this process serve as building blocks for the production of industrial chemicals and designer fuels.In the second step, these olefins can be converted to compounds of a higher molecular using controlled polymerization. The resulting liquid contains hydrocarbon molecules in the carbon range, C9-C16, suitable for use a possible renewable replacement for petroleum based jet fuel. The predicted cost of jet fuel using these technologies is in the range of $3 to $6 per gallon, and with sufficient funding and partnerships, this approach could be commercially viable within the next 7 to 10 years.

Researchers unlock new hydrogen fuel production process

Hydrogen fuel production has been a relatively problematic issue for the fuel cell industry in recent years. While fuel cells have been gaining more attention and popularity, they are often considered inefficient because of the problems relating to hydrogen production. Current production methods are both expensive and inefficient as a significant amount of electrical power is required to power these methods. Scientists around the world have been focusing on discovering new hydrogen production methods in order to make hydrogen itself a more viable form of renewable energy. A team of researchers from Universite Claude Bernard Lyon 1 (UCBL), France, traveled to the American Geophysical Union (AGU), in order to share their findings concerning a new hydrogen production process they had discovered.

The team combined aluminum oxide, water, and olivine, a common mineral, in a high pressure device known as a diamond anvil cell. The device was able to heat these materials to 300°C, while also applying a great deal of pressure. Through this process, the researcherswere able to produce hydrogen fuel. The aluminum oxide introduced to the process acts as an accelerating factor, allowing the process to produce hydrogen fuel at a more rapid rate than would be considered normal. The process itself is based on one found deep within the ocean. Olivine is found in abundance on the sea floor and tends to react with water and oxygen when under high pressures.

Normally, this process is responsible for the creation of a mineral known as serpentine. The waste product of this process is typically hydrogen.The natural process tends to take a significant amount of time to accomplish itself, which is why the research team has focused on accelerating the process. By increasing the rate at which hydrogen fuel is produced, researchers believe that they can help make hydrogen a more attractive form of clean energy, thereby bringing more attention to fuel cell technology.

Porous silicon made using solar energy

According to the engineers from Penn State University (PSU), the United States, mechanical porous silicon manufactured in a bottom up procedure using solar energy can be used to generate hydrogen from water. The team also sees applications for batteries, biosensors and optical electronics as outlets for the new material. “The surface area of this porous silicon is high. It is widely used and has a lot of applications. The standard method for manufacturing porous silicon is a subtraction method, similar to making a sculpture. Silicon is an important material because it is a semiconductor. Typically, porous silicon is produced by etching, a process in which lots of material is lost,” said Donghai Wang, assistant professor at PSU. Researchers used a chemically based method that builds up the material rather than removing it.

They started with silicon tetrachloride, a very inexpensive source of silicon and then treated the material with a sodium potassium alloy. “The bonds between silicon and chlorine in silicon tetrachloride are very strong and require a highly reducing agent. Sodium potassium alloy is such an agent,” said Wang. Once the bonds break, the chlorine binds with the sodium, potassium and silicon, potassium chloride and sodium chloride – table salt – become solid, forming a material composed of crystals of salt embedded in silicon. The material is then heat-treated and washed in water to dissolve the salt, leaving pores that range 5-15 nanometers. Because sodium potassium alloy is highly reactive, the entire procedure must be done away from the oxygen in the air, so the researchers carried out their reaction in an argon atmosphere. Their report has been published in the journal Nature Communications.

Because these silicon particles have lots of pores, they have a large surface area and act as an effective catalyst when sunlight shines on this porous silicon and water. The energy in sunlight can excite an electron that then reduces water, generating hydrogen gas. This process is aided by the material’s larger-than-normal band gap, which comes from the nanoscale size of the silicon crystallites. The researchers are also looking into using this porous silicon as the anode in a lithium ion battery. The PSU team looks to have a really interesting material. It’s a long way from a product, but the seeming simplicity common chemicals and low energy inputs looks very attractive.


Biofuel-to-hydrocarbon conversion technology

Vertimass LLC, the United States, has licensed an U.S. based Oak Ridge National Laboratory (ORNL) technology that directly converts ethanol into a hydrocarbon blend-stock for use in transportation fuels. The technology offers a new pathway to biomass-derived renewable fuels that can lower greenhouse gas emissions and decrease U.S. reliance on foreign sources of oil.” Vertimass is very pleased to be partnering with ORNL to commercialize this revolutionary technology that can broaden the market for alternative fuels,” said William Shopoff, Chairmanat Vertimass. The technology developed by ORNL uses an inexpensive zeolite catalyst to transform ethanol into hydrocarbon blend-stock. The resulting liquid can be blended at various concentrations into gasoline, diesel and jet fuels without negatively affecting engine performance.

After mixing with petroleum-derived fuels, the blend-stock does not require modifications to the existing distribution infrastructure. The blend-stock can be mixed into gasoline at higher concentrations than ethanol’s current limit of 10%; plus it can be added to diesel and jet fuel. It’s completely consumer-transparent. Vertimass anticipates that the ORNL technology will be in demand by existing corn-based ethanol production plants, as well as new refineries coming online that aim to convert non-food crops such as switchgrass, poplar wood and corn stover into biofuels. The technology could also supply a source of renewable jet fuel required by recent European Union (EU) aviation emission regulations.It could also be incorporated into new plant designs to further reduce operating costs.

Preliminary ORNL analysis in collaboration with the National Renewable Energy Laboratory (NREL), the United States, shows the catalytic technology could be retrofitted into existing bio-alcohol refineries at various stages of ethanol purification. The direct conversion process produces minimal amounts of ethylene by-product, making the technology more cost-effective than previous approaches. The ORNL team’s lab-scale tests also indicate the catalyst can operate at relatively low temperatures and pressures and can be regenerated under mild conditions, helping the technology withstand long periods of operation without significant degradation.

Multifunctional nanoparticles for cleaner biofuel

Scientists from the U.S. Department of Energy’s Ames Laboratory, have created a faster, cleaner biofuel refining technology that not only combines processes, it uses widely available materials to reduce costs. They have developed a nanoparticle that is able to perform two processing functions at once for the production of green diesel, an alternative fuel created from the hydrogenation of oils from renewable feedstocks like algae. The method is a departure from the established process of producing biodiesel, which is accomplished by reacting fats and oils with alcohols. Conventionally, when producing biodiesel from a feedstock that is rich in free fatty acids like microalgae oil, the fatty acids must be separated first that can ruin the effectiveness of the catalyst, and then the catalytic reactions can be performed that produce the fuel.

“By designing multifunctional nanoparticles and focusing on green diesel rather than biodiesel, we can combine multiple processes into one that is faster and cleaner. Contrary to biodiesel, green diesel is produced by hydrogenation of fats and oils, and its chemical composition is very similar to that of petroleum-based diesel. Green diesel has many advantages over biodiesel, like being more stable and having a higher energy density,” said scientist Igor Slowing.Researchers first saw success using bi-functionalized mesostructured nanoparticles. These ordered porous particles contain amine groups that capture free fatty acids and nickel nanoparticles that catalyze the conversion of the acids into green diesel.

Nickel has been researched widely in the scientific community because it is approximately 2000 times less expensive as an alternative to noble metals traditionally used in fatty acid hydrogenation, like platinum or palladium.Creating a bi-functional nanoparticle also improved the resulting green diesel. Using nickel for the fuel conversion alone, the process resulted in too strong of a reaction, with hydrocarbon chains that had broken down. The process, called “cracking,” created a product that held less potential as a fuel.” A very interesting thing happened when we added the component responsible for the sequestration of the fatty acids. We no longer saw the cracking of molecules. So the result is a better catalyst that produces a hydrocarbon that looks much more like diesel, It also leaves the other components of the oil behind, valuable molecules that have potential uses for the pharmaceutical and food industries,” said Slowing.

Using algae as biofuel

According to engineers at the U.S. Dept. of Energy’s (DoE), Pacific Northwest National Laboratory (PNNL), a continuous chemical process is under development that can produce useful crude oil minutes after pouring in harvested algae, which is a lush green paste with the consistency of pea soup. In the process, a slurry of wet algae pumps into the front end of a chemical reactor. Once the system is up and running, out comes crude oil in less than an hour, along with water and a byproduct stream of material containing phosphorus that can end up recycled to grow more algae. With additional conventional refining, the crude algae oil can convert into aviation fuel, gasoline or diesel fuel. And the wastewater processes even further, yielding burnable gas and substances like potassium and nitrogen, which, along with the cleansed water, can also end up recycled to grow more algae.

While researchers have eyed algae a potential source of biofuel, and several companies have produced algae-based fuels on a research scale, the fuel ends up being expensive to make. The PNNL technology harnesses algae’s energy potential efficiently and incorporates a number of methods to reduce the cost of producing algae fuel. “Cost is the big roadblock for algae-based fuel. We believe that the process we’ve created will help make algae biofuels much more economical,” said Douglas Elliott, who led the research. PNNL scientists and engineers simplified the production of crude oil from algae by combining several chemical steps into one continuous process. The most important cost-saving step is the process works with wet algae. Most current processes require dried algae, which ends up being a very expensive process. The new process works with algae slurry that contains as much as 80-90% water.

“Not having to dry the algae is a big win in this process; that cuts the cost a great deal. Then there are bonuses, like being able to extract usable gas from the water and then recycle the remaining water and nutrients to help grow more algae, which further reduces costs,” Elliott said. The system runs at around 350°C (662°F) at a pressure of around 3,000 PSI, combining processes known as hydrothermal liquefaction and catalytic hydrothermal gasification. Such a high-pressure system is not easy or cheap to build, which is one drawback to the technology, though the cost savings on the back end more than makes up for the investment. “It’s a bit like using a pressure cooker, only the pressures and temperatures we use are much higher. In a sense, we are duplicating the process in the Earth that converted algae into oil over the course of millions of years. We’re just doing it much, much faster,” said Elliott.

Oilseed straw as new biofuel source

Researchers at the Institute of Food Research, the United Kingdom, are looking at how to turn straw from oilseed rape into biofuel. Preliminary findings are pointing at ways the process could be made more efficient, as well as how the straw itself could be improved. Straw from crops such as wheat, barley, oats and oilseed rape is seen as a potential source of biomass for second generation biofuel production. Currently the UK produces around 12 million tonnes of straw. Although much is used for animal bedding, mushroom compost and energy generation, there still exists a vast surplus. Straw contains a mix of sugars that could be used as a source of biofuels that do not compete with food production but instead represent a sustainable way of utilising waste.

However, the sugars are in a form that makes them inaccessible to the enzymes that release them for conversion into biofuels, so pre-treatments are needed. The pre-treatments make the complex carbohydrates more accessible to enzymes that convert them to glucose, in a process called saccharification. This is then fermented by yeast into ethanol. Professor Keith Waldron and his team have been looking at the steps needed to unlock the sugars tied up in the tough straw structure. In particular, they have looked at the pre-treatment stage, focusing on steam explosion, which involves ‘pressure-cooking’ the biomass, to drive a number of chemical reactions. A rapid pressure-release then causes the material to be ripped open, to further improve accessibility.

They varied the temperature and duration of steam explosion and then used a variety of physical and biochemical techniques to characterise what effects varying the pre-treatments had on the different types of sugars before and after saccharification. The amount of cellulose converted to glucose increased with the severity of the pretreatment. Saccharification efficiency is also associated with the loss of specific sugars, and subsequent formation of sugar breakdown products. These findings will help improve the efficiency by which straw can be converted to biofuels. It may even be possible to improve the straw itself, for example to reduce the uronic acid content in the biomass. In the main, oilseed rape has been bred to improve oilseed yield and disease resistance, without paying much attention to the straw.


Offshore Wind Energy Generation: Control, Protection, and Integration to Electrical Systems

The offshore wind sector’s trend towards larger turbines, bigger wind farm projects and greater distance to shore has a critical impact on grid connection requirements for offshore wind power plants. This important reference sets out the fundamentals and latest innovations in electrical systems and control strategies deployed in offshore electricity grids for wind power integration.

Grid Integration of Wind Energy, 3rd Edition

This timely update provides detailed treatment of the integration of wind power into electrical power systems, including brand new material on offshore wind power farms and technologies

This third English edition is based on new material from the fourth and fifth German editions (Windkraftanlagen: Systemauslegung, Netzintegration und Regelung, 5. Auflage, published by Teubner B.G. Gmbh, July 2009). It answers the question of how, with the proper control and direction, wind turbines can be made to operate more similarly to conventional power plants. The revised third edition addresses the engineering challenges of cost effective transmission and distribution of wind power, such as technical, economic and safety issues.

Solar Engineering of Thermal Processes, 4th Edition

This revised Fourth Edition offers current coverage of solar energy theory, systems design, and applications in different market sectors along with an emphasis on solar system design and analysis using simulations to help readers translate theory into practice. An important resource for students of solar engineering, solar energy, and alternative energy as well as professionals working in the power and energy industry or related fields.

For the above three books, contact:John Wiley & Sons Singapore Pte. Ltd., 1 Fusionopolis Walk, #07-01, Solaris South Tower, Singapore-138628. Tel: +65-6643-8333; Fax: +65-6643-8397; E-mail:


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