Solar Choice now has its own electric vehicle–the first of its kind ordered and purchased in Australia. The Mitsubishi i MiEV (“Mitsubishi Innovative Electric Vehicle”), will be parked and charging its batteries in the evening in Manly, NSW when it is not being used on official Solar Choice business. Those living in Sydney will be able to see Solar Choice’s new wheels cruising around the city. In addition to being CO2 emissions-free, the i MiEV is also noise-free: Although its decals and odd shape make it hard to miss when it drives past on the street, the vehicle makes virtually no sound while in operation, proving disconcerting for driver and pedestrians alike.

The first 100% Electric Vehicle in Australia produced for the mass market

Solar Choice Mitsubishi i Miev

The above claim to having ‘Australia’s first 100% electric vehicle’ does come with some qualification: Solar Choice’s i MiEV is the first volume-produced Electric Vehicle (EV) ordered and sold on Australian soil. Although other models of EVs (such as the high-end Tesla roadster) have already arrived in Australia, the i MiEV is the first EV on the Australian market that has been mass produced and is relatively affordable. At around $50k AUD, it isn’t as cost-competitive as a many cars on the market (although the price will doubtless come down as EVs become more common), but the car offers significant savings on the cost of fuel. i-MiEV owners will save hundreds or thousands of dollars in petrol per year, as the vehicle can be charged overnight on off-peak rates of 6c/kWh, totalling less than $1, on which the vehicle can be driven for up to 160km.

Features of the Mitsubishi i-MiEV

Solar Choice EV at Ocean Care Day 2011 in Manly, NSW. (Photo credit: Robynne Millward of Manly Environment Centre.)

The i MiEV has a number of features that make it innovative and allow it to be emissions-free while driving. The most vaunted of these features are the following:

-High-capacity, high-energy density litium-ion batteries means versatility in fuel sources. Having batteries instead of a fuel tank means that electricity is drawn from the electrical grid. In Australia, this of course means that power is ultimately sourced from fossil fuels (i.e. coal), but even taking this into account, the i MiEV only produces 30% of the emissions of a standard petrol-powered car of the same size. What’s more the electricity that charges its batteries need not necessarily come from the grid–if the car is charged using only a solar car port, or during the day at a home with large solar power array, for instance, then the electricity powering the car will be totally CO2 emissions-free.

Mitsubishi i MiEV electric vehicle charging station. (Image from http://global.ev-life.com/.)

-A 3-way battery charging system: two slow-charge modes (100V and 200V, 7-14 hours charge time) which can be accessed via any conventional home or car park power point, and one fast-charge mode which can have the ‘tank’ 80% full in 30 minutes using a specialised EV charger not yet widely available in Australia.

-Unusual chassis layout: The i MiEV is the 100% electricity-powered version of the Mitsubishi i, the company’s innovative and popular ‘minicar’ with an unusual ‘rear-midship’ design–its engine sits underneath the rear seat of the car, as opposed to in the front under the bonnet. This feature of the i’s design made it ideal for the placement of the batteries required to power the EV version’s electric engine. The fact that the i MiEV’s engine is powered by its battery as opposed to petrol allows it to be much smaller than it would be with otherwise–conveniently leaving room for all the parts that cannot be found in conventional automobiles–an inverter, a charger, and the battery bank.

-A small, high-efficiency motor that takes up much less space–and provides more torque–than a petrol-fired engine of comparable size. The i MiEV has surprisingly good pick-up for car with such a small engine!

A dial above the spedometer on the i MiEV's dashboard indicates when the car is using deceleration power to charge the engine. (Image from http://global.ev-life.com/.)

-Regenerative charging: The i MiEV’s re-channels the power produced in rolling downhill and braking to charge the car’s battery. The energy produced during long descents, for instance, can be seen on a ‘power meter’ on the car’s dashboard.

Are Electric Vehicles the future of personal transportation?

Solar Choice’s EV may be one of the first of its kind on the road in Australia, but as production capacity and demand for similar vehicles increases globally, they will undoubtedly cease to garner much attention. Much like the Toyota Prius petrol-electric hybrid went from head-turner to commonplace since its introduction in 1997, emission-free cars like the i MiEV, in an ideal world, will become a common sight. In fact, Chevrolet/Holden, Ford, and Nissan, plus a handful of other companies all have EV models in their product lines.

City of Sydney Solar Powered Electric Car (Photo: Minnie Bye)

In addition to replacing fossil fuel-based automobiles from the road, EVs could potentially revolutionise the way that electricity is stored and distributed in the grid, and make the relatively erratic nature of renewable energy production harnessable–if there were thousands or millions of EVs in operation in a nation, resting cars’ batteries could be used as a repository for electricity produced from solar power systems, and owners could be paid for the electricity drawn from their cars’ batteries into the grid at peak demand times. Technology like this is still a long way off, and will require a fair amount of forward-planning by governments and/or private grid owners–so let’s not hold our breath. Some private enterprises are already looking into ways to make this vision a reality: as we have written previously, developing grid infrastructure to accommodate renewables is one of the aims of companies like Better Place.

The Solar Choice team around the new i MiEV electric vehicle

Written by James Martin

Solar Choice Analyst

© 2011 Solar Choice Pty Ltd

Resources and Links:

Mitsubishi’s i MiEV portal page

See the article about Solar Choice’s new ride in the Manly Daily.

Related Solar Choice blog articles: Ford and Sunpower team up for Solar EV charging stations, Better Place: Electric Vehicle Charging Stations : Solar-Powered Carports

Solyndra solar tube technology has been widely praised as one of the most innovative approaches to solar electricity generation in the world. Solyndra modules utilise ordinarily lower-efficiency (compared to mono- and poly-crystalline silicon) thin-film CIGS photovoltaics technology in an ingenious configuration that enables higher module efficiencies, and simplifies and reduces the cost of array installation. Already widely used throughout the world in large-scale rooftop installations worldwide, the number of solar installations that utilise Solyndra panels has also been increasing steadily in Australia.

Solyndra 3MW rooftop solar system in Zellik, Belgium. (Image from Solyndra.)

(Update 2 October 2011: Since the writing of this article, Solyndra has filed for Chapter 11 bankruptcy. Panels are no longer available through the manufacturer in Australia.)

Solyndra’s technology has already seen significant uptake in a number of large-scale rooftop solar power installations. Among the thousand+ installations worldwide are a 3-megawatt (MW) installation in Zellik, Belgium, 1.5MW on the roof of a shopping centre in Rome, and a 488kW installation on the roof of the Norkus grocery store chain in New Jersey. To date, Solyndra has manufactured over 100MWs’ worth of its solar tubes worldwide–mainly for mid- to large-scale projects like these.

488kW Solyndra installation on Norkus foods chain roof, New Jersey Shore. (Image from Solyndra.)

Previously, when Solyndra solar tubes were first featured and explained on the Solar Choice site, Solyndra was only just beginning to make its way into the Australian solar photovoltaics (PV) scene. Since then a number medium, large, and even small-scale installations have appeared throughout the country. Solar Choice has overseen the installation of a number of systems using Solyndra’s technology, including a 10kW system in Manly, NSW.

Solyndra modules require no drilling, roof penetration, or special tools to install: modules come with Solyndra's customised snap-together mounting frames.

The signature design and construction of Solyndra modules makes them resistant to the effects of strong wind. Wind passes between the tubes instead of pushing against it, as is the case with traditional panels.

Higher efficiency solar power and more

Besides relatively high efficiency, Solyndra’s unique approach to solar power technology affords a number of bonus advantages for installers and owners. Many of these benefits are related to how the modules can be used on a rooftop. For example, Solyndra modules are self-ballasting; they come with snap-together mounting frames and install easily and quickly on no-slope or low-slope roofs–up to four times faster than ordinary solar panels, which require drilling and mounting brackets to secure the panels on the roof.

Solyndra modules thrive on reflective roofs by collecting diffuse sunlight

Solyndra panels are composed of a series of cylinders. Cylinders, by definition, have a continuous surface, so the CIGS thin-film photovoltaic material contained in Solyndra tubes runs all along the around the inside. At first glance, this may seem like a waste, as one side of the tubes will always be facing away from the sun. Paradoxically, this apparent disadvantage offers a great opportunity to take full advantage of the intrinsic photovoltaic characteristics of the properties of CIGS thin-film photovoltaics.

Thin-film photovoltaic materials are ordinarily known for their low conversion (sunlight-to-electricity) efficiency, but they are also more resistant to the effects of partial shading and are better at collecting diffuse/indirect light than conventional crystalline silicon flat panels. Plus, as you can see from the photos above and below, there are gaps between each tube, which means that light can pass between them, hitting not only the increased surface area that comes as a result of the tubes’ curved nature, but also the surface behind them (i.e. a roof or wall). Provided the surface behind a Solyndra module is reflective or lightly coloured, its rear part will collect the diffuse sunlight that would ordinarily not have occurred at all with a conventional flat panel. At the end of the day, modules can reach efficiencies of up to 14%–the same as the efficiency of many crystalline silicon panels.

Solyndra and energy savings go hand-in-hand: “Cool roofs”

As an additional benefit, a light-coloured roof has significant energy-saving properties that make pairing them with Solyndra modules an easy choice; they do not absorb as much heat as a dark roof would, and therefore cut down on the need for air conditioning in the summer. This would of course offer improved thermal comfort for occupants as well as financial benefits for owners/operators in hot climates by mitigating the need for air conditioning in the summer.

Solyndra is aware of this low-hanging fruit, and it is common practice to paint roofs as a part of the installation process. At the Blacktown, New South Wales RSL club, where Solar Choice recently oversaw the installation of a commercial-scale 100kW Solyndra system, roof-painting was one of the first steps in the process. (See pictures below.)

The roof of the Blacktown RSL has been painted white in preparation for the installation of 100kW of Solyndra solar modules.

Solar inverters on the Blacktown RSL commercial solar installation. (Photo by Iain McGregor, Solar Choice Commercial Tenders Manager.)

The sun shining through the clouds on the installation. (Photo by Rob Burnett, Solar Choice Broker.)

Another application for Solyndra: Solar Greenhouses

The shape and characteristics of Solyndra’s panels make them ideally suited for another application that not ordinarily associated with solar panels: Solyndra Solar Greenhouses.

Solyndra has put its solar tubes to use in greenhouses, where their ability to cast even shade on whatever lies underneath makes them perfect for use in greenhouse roofs. The panels above collect sunlight and generate electricity, while the plants below are allowed to soak up the sun’s beams without withering under its heat–a great example of building-integrated photovoltaics. One such greenhouse (598kW) is already in operation in Villa del Conte, Italy.

Solyndra solar modules used in the roof of a greenhouse in Italy. The slots between tubes provide even shading for the plants within while generating electricity from sunlight. (Image from Solyndra.)

Solyndra module 200 series

All 5 modules available in the Solyndra 200 series have the same dimensions (2.28m x 1.09m x 0.06m) and 31.8kg, but rated power ranging from 182 to 220W.

About Solyndra:

-Headquarters and Factory location-

Freemont, California, USA

-Components standards met/awards-

All Solyndra modules are accredited by the Clean Energy Council of Australia.

Solyndra has appeared on Massachusetts Institute of Technology’s ’50 Most innovative companies in the world’ list, the ‘Global Cleantech 100′ list, and has won a ‘Business Journal’ award for Emerging technology: Green/Clean Technology.

Solar Choice Commercial manages the tender process for a wide diversity of large-scale solar power projects throughout Australia, including for mining companies, restaurant groups, shopping centres, and rural solar farms. For professional management and consultancy on your solar energy project, contact our Commercial Tenders Manager, Iain McGregor, on 1300 78 72 73 for more information.

Written by James Martin

Analyst

© 2010 Solar Choice Pty Ltd

Resources and Links:

Solyndra homepage

One of the trickiest parts of maximising efficiency in a solar installation is dealing with variations in power output among panels and strings of panels in the same system. SolarEdge is a leading company that has developed a unique solution to the problem of irregularity in solar panel array output. It uses a solar system architecture that utilises per-module maximum power point tracking (MPPT) to tackle system efficiency from a holistic design perspective, providing an ingenious balance of system strategy for solar system efficiency and energy savings.

Centralised MPPT inverters 

In order to explain the innovative inverter technology that SolarEdge specialises in, it is first essential to understand how conventional solar system inverters function.

System losses can sometimes be attributed to the nature of industry-standard crystalline solar panels themselves, which are susceptible to partial shading and overheating, and sometimes attributed to the nature of conventional inverters, which do not perform MPPT for individual modules.

There are many potential reasons for variation amongst panels in an array: natural variance in a solar panel’s rated capacity is typically +/-3% of rated output, shading can happen on some parts of the array but not others, the array can heat up unevenly, and strings of panels on different sides of the same roof can generate different amounts of electricity at different times of day.

In a system with a centralised-MPPT, single-input inverter, total solar system array output will be limited by the panel that is producing the least amount of power–the weakest link is where the chain breaks. If an inverter has only one input for one ‘string’ of panels, you may have to deal with losses on a regular basis, or buy more than one inverter to improve the overall system efficiency.

Some inverters support MPPT at a string level, which does help to minimise losses, but the inverter still cannot ‘see’ into a string to monitor and control what individual panels are doing. This means that your system is not taking full advantage of all the power produced by your panels, which in turn means higher cost per watt of your system and extended payback periods for your solar investment.

An example of partial shading in a conventional multi-string inverter system (Image credit: pvsolarchina.com)

So in summary, the current industry standard multi-input inverter design approach, while much more efficient than inverter systems of the past, still only addresses the efficiency problem on a string level. Even when the inverter itself is functioning efficiently, variance between the panels within the array limits the potential overall system efficiency, and therefore, its usable electricity output.

SolarEdge Solar Power System Architecture: Holistic solar system design using module-level MPPT

The engineers at SolarEdge took a bird’s-eye-view approach to system design. An image on their homepage is telling of their methodical, thoughtful approach: transposed over a photograph of a Zen Buddhist rock garden read the words, “Good design always requires a holistic viewpoint. Take a step back, consider the details from above, and you get a better perspective on how to deal with the problems close up.”

Benefits of SolarEdge technology:

-Up to 25% increase in power output compared to single- and multi-input inverter system arrangements

-Superior inverter efficiency (up to 98%) – peak performance in both mismatched and unshaded conditions

-Flexibility in system design options: SolarEdge system architecture allows parallel uneven length strings, panels of different wattages and from different manufacturers (more inventory options); installation involves fewer components and less wiring, which means faster installation and better roof space utilisation than conventional systems

-Interactive, ‘from anywhere’ monitoring offers a new world of opportunities with regard to system troubleshooting maintenance

-The power optimizer (MPPT tracker) can be embedded into any module as a certified junction box–possible on-site or factory-based integration into solar modules

-Superior safety for installers and firefighters: Electric arc detection and termination features; safe module voltage when disconnected or off

-SolarEdge ‘Inverter Configuration Tool’ software means immediate installation feedback for quick system commissioning

How does SolarEdge distributed smart inverter technology work?

SolarEdge System Architecture Components:

Three components form the balance of system in SolarEdge’s ‘system architecture’.

-Module-embedded power optimisers, which monitor and regulate the power output of all the individual modules in an array, in order to maximise overall system output–these can be installed on-site, or may be pre-assembled in solar module factories of companies that are in a partnership with SolarEdge,

-A smart inverter, which inverts the DC power of all modules to grid compliant AC, and

-A monitoring system, data from which is accessible via the Internet.

SolarEdge System Architecture Features:

Module-level MPPT

The inverter uses a highly-optimised algorithm to keep each module at the same constant MPP, preventing power loss even under panel mismatch or partial shading. In fact, even panels from different manufacturers can be used simultaneously in the same array. (This offers intriguing possibilities for future applications in Building-Integrated Photovoltaics (BIPV); solar windows, solar walls, and rooftop solar arrays could all be routed through one inverter.) The algorithm also allows the system to react more effectively to changes in irradiance and temperature, a big benefit on cloudy days.

Highly Efficient DC Conversion

Each power optimiser performs a DC-DC power conversion (peak 99.5% efficiency) that allows it to boost or buck output voltage of modules in the array to ensure a fixed string voltage.

Fixed String Voltage

The voltage of a string is held constant at the optimal point for DC to AC conversion, regardless of the number of modules in a string, or external factors such as weather or shading. This feature means that there are fewer limits to system design and panel location, greater inverter efficiency and reliability, and lower installation costs.

Advanced Power-Line-Communication

A range of module-by-module status indicators (current, voltage, etc) are continuously measured and communicated by the power optimisers. Data are transferred through the existing DC power lines, meaning that there is no need for extra wiring. For ease in monitoring all the goings-on within the system, the inverter houses a LAN- and wireless-capable communications hub, enabling the owner or operator to view system performance in detail on a remote monitoring server from a computer or other even hand-held devices.

Performance data being recorded on a remote monitoring server also means that the system owner or operator can quickly identify and troubleshoot problems with your system, should any arise, minimising or eliminating the need for site visitations and associated travel charges.

SolarEdge: certifications, awards, and recognition

-ETL Mark: Proof of compliance with North American safety standards

-CE mark: Panel is compliant with European Union regulations

SolarEdge has also  been rewarded for its outside-the-box thinking with numerous awards, including the Climate Change Business Journal’s 2010 Business Achievement Solar Technology Merit Award, and the 2011 Red Herring Global 100 Award, where it was recognised for its achievements in the solar power optimisation field.

About SolarEdge

Founded in 2006, currently engaged in partnership agreements with module manufacturers and integrators in Europe, USA and Japan, which provide SolarEdge technology alongside their current services.

-Company Headquarters-

Hod Hasharon, Israel

Other offices in USA, Germany, and the Asia-Pacific region

Solar Choice is a solar installation comparison service: we don’t undertake our own solar array installations, but we do offer free independent solar quote comparisons of what’s on offer from trusted solar system installers nationally. Our installers may use components from different manufacturers, and if you’re new to solar power installations, you will probably want to know what distinguishes one company’s panels, inverters, batteries, and other system parts from those of their competitors. This article is one of a series written to help you make an informed decision about purchasing your solar power system.

Written by James Martin

Analyst

© 2010 Solar Choice Pty Ltd

Resources and Links:

Solar Edge homepage

Solar Edge: Company Presentation (pdf)

SolarEdge Power Optimiser: Module-embedded solution (pdf)

SolarEdge: Technology overview

Suntech is the largest manufacturer of solar photovoltaic (PV) modules and produces some of the most efficient and affordable commercially available solar panels in the world. Suntech’s 350-person strong research and development (R&D) team spans three continents and allows the company to stay at the technological forefront of the solar power industry. Although Suntech’s head office and manufacturing operations are located primarily in China, CEO Dr Zhongrong Shi is a PhD graduate of the University of New South Wales’s (UNSW) Photovoltaic Centre of Excellence, and the company’s Australian origins and ongoing Australia-based Research & Development are clearly a point of pride for Suntech.

Looking for Suntech solar panels? Request a free solar quote comparison to see which installers in your area use Suntech components.

Stepped warranties, Good performance in low-light conditions,
Positive manufacturer’s tolerance, and Current sorting

Suntech offers a range of solar panels, from less efficient standard silicon panels to industry-leading high-efficiency panels using the company’s newly introduced Pluto technology (also discussed below). No matter which of these technologies is used or the model under consideration, Suntech panels are characterised by a number of features that make them stand out from others in this increasingly competitive field. These characteristics are detailed below.

Standard Suntech Silicon Cells

High module conversion efficiency. Athough module efficiency varies slightly from model to model, Suntech standard poly- and monocrystalline silicon modules routinely achieve 14.9% efficiency, 2 to 5% more than many other panels on the market.

-Positive power tolerance. Suntech ensures its panels’ output reliability by guaranteeing that its solar panels will perform at their rated output or greater at the time of purchase: 0 to +5%. This is in contrast to an industry average of +/-3%.

-Better low-light performance. All solar panel arrays will be affected at some point by overcast skies and other sub-optimal lighting conditions. Suntech panels’ efficiency is up to 2.5% better in low-light conditions, thanks to their ‘edge-isolation’ technology, which essentially means shorter ‘fingers’ on the cells and therefore less wasted sunlight.

-TruPower process. All silicon solar cells are susceptible to material and performance degradation over time due to a phenomenon called ‘light-induced degradation’ (LID). Suntech’s TruPower process takes LID into account in determining nominal system wattage from time of production. This means higher output than most brands over the course of a Suntech cell’s lifetime.

-Stepped Warranty means more assurance over a panel’s lifetime. Most solar module manufacturers offer a two-step solar product warranty for module components and a 25 year manufacturer’s power output warranty for the cells themselves. Suntech warrantees are broken into four steps for more certainty over discreet periods: 10 (as of 15 July 2011), 12, 18, and 25 years, resulting in estimated comparative efficiencies of anywhere from 6% to 28% over the course of a panel’s lifetime. This means that the owner is able to more accurately estimate the returns from their solar system over the course of its lifetime.

Suntech warranties vs Competitor warranties

-Current sorting processes. Suntech modules of the same rated capacity are sorted and packaged by current, so that current mistmach losses are reduced by up to 2%.

In focus: Suntech Ad+–190W for residences

The Ad+ is one of four residential solar panels available in Australia. At 14.9% module efficiency, in combination with the other benefits as mentioned above, it offers market-leading value for money.

190s 24/Ad+ Suntech Solar Panel

-Product Specifications/Electrical Characteristics-

Standard test conditions are lrradiance 1000 W/m2, module temperature 25 °C, AM=1.5;

-Component standards met/awards-

-PV Cycle–Suntech participates in PV Cycle’s voluntary take-back PV recycling program

-CE mark–Panel is compliant with European Union regulations

-IEC–International certification for electrical equipment used in explosive environments

-Clean Energy Council–Suntech panels can be found on the CEC approved solar panel list

-Other products by Suntech-

Suntech Pluto technology is used in Sydney Town Hall's 48kW solar power array

Suntech offers a wide range of reliable silicon solar module products, with capacities between 180W and 280W and including polycrystalline and monocrystalline modules, allowing a great degree of solar system design flexibility.

Suntech’s most recent technological development is its Pluto technology, which uses super-fine ‘fingers’ (the conductive metal strips on the silicon cells) to effectively increase the cell area that can capture usable sunlight. Although not yet commercially available in Australia except for larger, iconic solar installations such as those on Sydney Town Hall and the Sydney Theatre Company, Pluto panels are becoming increasingly widespread in the EU, where limited roof-space means higher demand for high-efficiency panels.

Standard silicon cells (l) vs cells using Pluto technology (r). Note the fineness of the conductive 'fingers' in the Pluto cell.

About Suntech

-Company Headquarters-

Wuxi, China

-Factory locations-

China, USA

-Production capacity-

2.4GW capacity for modules, 1.2GW of in-house wafering and cell capacity by the end of 2011.

-Quote-

“Suntech has sold over 15,000,000 panels to thousands of customers in more than 80 countries. Our customers come to trust us as the reliable partner of choice, and with our industry-leading 10 year product warranty they know that Suntech products can provide the safest and fastest return on their investment.” Suntech APMEA President James Hu.

Solar Choice is a solar installation comparison service: we don’t undertake our own solar array installations, but we do offer free independent solar quote comparisons of what’s on offer from trusted solar system installers nationally. Our installers may use components from different manufacturers, and if you’re new to solar power installations, you will probably want to know what distinguishes one company’s panels, inverters, batteries, and other system parts from those of their competitors. This article is one of a series written to help you make an informed decision about purchasing your solar power system.

Written by James Martin

The Swiss-engineered Solar Impulse is set to make its first international flight on 2 May 2011 (yesterday in Australia as of the time of this writing, but today in Switzerland!) This is the first international flight of its kind: one powered solely by solar power.

The single-seater Solar Impulse made history last July when manned aircraft flew continuously for 26 hours relying on solar panels and batteries to propel it, without the aid of fossil fuels. The ultimate goal of the project, speculated to be set to take place sometime in 2012, is to fly around the powered only by solar photovoltaic power. The endeavour being taken up in the news at the moment is intermediate to these past smaller and future larger goals of the Solar Impulse project: a flight from Switzerland to Belgium, and then to France.

The mood of the Solar Impulse website is overflowing with unabashed enthusiasm for the spirit of adventure tied up with their undertaking. Interviews on the site with the engineers and pilots behind the project reveal fierce-eyed men with steady gazes talking directly into the camera about the magnitude of what the project is hoping to achieve: nothing less than a total revolution in the aviation industry to zero-emissions, supported by the swell of recent developments in the world of renewable energy. The team is hoping to accomplish what most would write off as impossible.

First flight of the Solar Impulse (from inhabitat.com)

Solar Impulse is the first vehicle capable of flying day and night without the need for fuel and without emitting CO2. Its wingspan is comparable to that of a Boeing 777, but weights only as much as an average family-sized sedan, making it the largest plane of its weight to ever be built. 7 years of intensive development were spent by a team of 70 people and 80 partners to develop the lightweight, carbon-fibre craft. The wings, embedded with 12,000 solar photovoltaic cells, supply the 4 electric engines with power whilst at the same time charging lithium polymer batteries. The batteries enable the craft to be flown at night.

Written by James Martin

Solar Choice Analyst

© 2010 Solar Choice Pty Ltd

Sources and Links:

Photos from inhabitat.com

CBS News, “Solar plane set to try first international flight”

Website for the Solar Impulse project

Related previous Solar Choice blog entries: Electric vehicles and solar power : New world land speed record for solar-powered car

Researchers at Boston College and the Massachusetts Institute of Technology (MIT) have produced a single technology that accomplishes what is currently only accomplished with two separate units: thermoelectric and photovoltaic solar electricity generation.

As we have pointed out previously in the Solar Choice blog, solar hot water systems are one of the most effective ways to reduce home energy costs; water heating accounts for 30 to 40% of the average household’s energy bills by using the sun to pre-heat water for showers, baths, and basins. Solar hot water systems absorb heat from the sun and concentrate, heating the water inside. Thermoelectric technologies, a broader category that encompasses solarthermal technologies, can utilise heat from the sun, fires or elsewhere to generate electricity. Solarthermal generation can be similar in principle to concentrating solarthermal electricity generation, except that concentrating solar thermal generation typically requires large swathes of land for mirrors and giant towers to spin turbines to generate power (much as in a conventional coal generation plant). Solarthermal of the type and scale developed under the MIT/BC project would not generate enough power to do so.

Solarthermal technologies have not been deployed as widely as photovoltaic technologies have. Photovoltaics solar panels convert sunlight directly into electricity, which can then be used by appliances in a home or fed into the electricity grid.

Solarthermal and photovoltaic technologies have always been manufactured in separate units. The combination of these methods of generation in the technological development at Boston College and MIT has the potential revolutionise the way that the power of the sun is utilised in homes and elsewhere. The team of researchers used nanotechnology (nanostructuring) to combine into one flat-bodied panel materials that have thermoelectric properties with photovoltaic materials that selectively absorb certain parts of the spectrum of light. The technology promises efficiencies up to 8 times higher than the previous record for solarthermal, and would not require large arrays of high-precision tracking devices to aim mirrors and concentrate sunlight, as is the case with many solarthermal technologies that are currently deployed, such as the solar towers in Spain and parts of the US.

There are a number of potential benefits associated with the use of solar photovoltaic/solarthermal technology: a panel would not require as much material to manufacture, and would not be affected so significantly by orientation with regard to the sun. It could also be integrated with a solar hot water system: water inside the panel would be heated by incoming light, whilst the exterior materials absorb the sunlight and convert it to electricity. This dual-action effect greatly increases the overall sunlight-to-useable energy efficiency of the unit, promising payback periods of up to one third shorter than those of conventional solarthermal panels, according to Zhifeng Ren, a co-author of the paper on the technology.

The hybrid technology would not be a replacement for solar hot water or solar photovoltaics, but instead would be “another way” of utilising the massive amount of solar power with which the earth is inundated on a daily basis, according to says Gang Chen, MIT’s Carl Richard Soderberg Professor in Power Engineering and director of the Pappalardo Micro and Nano Engineering Laboratories. œWith the use of other or new thermoelectric materials that can operate at a higher temperature, the efficiency may be improved further to be competitive with that for state-of-the-art amorphous silicon solar cells. This can potentially provide a different approach to realizing the $1-per-watt goal for solar-electricity conversion, says Li Shi, associate professor of mechanical engineering at the University of Texas, Austin.

Written by James Martin

Solar Choice Analyst

© 2010 Solar Choice Pty Ltd

Sources and Links:

Ecoseed.org, “MIT and Boston College researchers develop hybrid solarthermal technology”

MITnews, “Solar power, with a side of hot running water”

Boston College office of news and public affairs, “BC researchers report on solar-thermal flat panels that generate electric power” (top image also from this website)

Previous related Solar Choice blog entries: Solar Hot Water: an introduction : What type of solar panel is best for you? : What is grid parity and what does it mean for solar power? : Tilt angle and orientation for solar panels in Australia

New York city will soon have its first-ever net-zero energy, carbon-neutral building, to replace its current environmental education centre, Solar 1. The new building is to be rather cleverly named Solar 2.

Mock-up of Solar 2, green screen and green roof--image from Solar 1 website

All the stops have been pulled out for this impressive project, which will feature a 90kW dc  solar photovoltaic module array on a canopy that sits above the building itself. The project will also showcase some of

Mock-up of Solar 2, facing south--image from Solar 1 website

the best elements of building-integrated photovoltaics (BIPV) and passive solar and sustainable design, including

a green roof, rainwater collection and water conservation features, and a vegetative ‘green screen’ which will provide shade and attract birds and butterflies.

(You can read more about the project on the Solar 1 website.)

Written by James Martin

© 2010 Solar Choice Pty Ltd

Sources and Links:

GE Reports, “Turning New York into Solar City”

Solar 1, Solar 2 project page

Previous related Solar Choice blog entries: Building-integrated photovoltaics (BIPV)

A potentially major breakthrough for the future of solar photovoltaic power has been achieved at the Massachusetts Institute of Technology (MIT): organic solar cells that are transparent for visible light, but which collect infrared radiation for electrical power production. This promising technology could offer savings on construction costs as well as operational costs (i.e. less need for air conditioning during hot summers) for buildings.

In a previous Solar Choice blog entry, we discussed the future of BIPV, or building-integrated photovoltaics: solar photovoltaic cells that can be used in the place of building materials, simplifying solar system installation and eliminating the need for additional components such as solar panel array mounting brackets. Some of the multifunction technologies mentioned were photovoltaic awnings and windows, which integrate solar cells of different composition into glass, blocking light and creating shade from the sun while at the same time capturing sunlight for power generation. The new technology under development at MIT is another major step toward seamlessly working PV technologies into everyday building materials; another tool in the toolbox of sustainable building design.

An MIT News article about the technology references the academic journal article co-written by Richard Lunt and Vladimir Bulović in which the research results were published. It points out that at the moment one half to two thirds of the costs associated with a thin-film solar power are attributable to the installation itself, and up to half are due to the glass and structural structural of thin-film PV modules.

The amorphous PV technology has achieved a new high level of efficiency for organic, transparent cells–a level may become comparable to conventional silicon cells–but currently stands at 1.7%. At the moment, for similar technologies, this number stands at less than 1%.  Bulović admits that it will be a challenge to reach 12%, the conversion efficiency that is commonly achieved by modern mono- and poly-crystalline silicon panels. Getting to that point will require exitonic engineering to optimise the composition and configuration of the photovoltaic materials, Bulović says. He also speculates that it could be available as a practical, manufacturable building component within a decade, although as part of a ‘family of solutions’ to the world’s energy needs.

Written by James Martin

Solar Choice Analyst

© 2010 Solar Choice Pty Ltd

Sources and Links:

Applied Physics Letters (academic journal), “Transparent, near-infrared organic photovoltaic solar cells for window and energy-scavenging applications”

MIT News, “Turning windows into power plants” (Photograph of Richard Lunt by Geoffrey Supran, from this article)

Previous Solar Choice blog entries: BIPV : Thin-film flexible solar cells : What type of solar cells are right for you? : PV awnings, asbestos concerns

Prime Minister Julia Gillard has announced plans for a massive commercial-scale solar power for Australia’s Sunshine State. 44MW of supplementary solar power will be added on to a preexisting coal-fired Kogan Creek electricity generation plant in Dalby, south-west Queensland.

A visualisation of where the solar superheated steam generation section of the Kogan Creek plant will be located. The 44MW peak solar thermal generation will supplement the 750MW capacity of the main coal-fired plant.

The compact linear Fresnel reflector (or CLFR) technology for Kogan Creek Solar Boost Project is to be provided by the French firm AREVA Solar. CLFR uses long segmented sections of mirror to concentrate the sun’s energy onto one focal point, where water is heated, turned into steam, and used to spin turbines–much the same mechanism as coal-fired generation, but without any greenhouse gas emissions or other types of pollution. According to CS Energy, the project will be “the largest solar integration with a coal-fired power station in the world.”

Ongoing operation will be overseen by CS Energy, which has been operating the Kogan Creek Coal plant since 2007, when it was commissioned.

$34M of the funding for the addition will come from the Australian government’s Renewable Energy Demonstration Program, which has already provided partial funding for a number of other renewable energy projects.

About the project, PM Gillard said, “I am very confident this project is going to be a standout – a standout in Australia, a standout in the world – about how power generation can be changed to give us a cleaner-energy future,” adding “With the clean-energy future I want for our nation, I want it to be a norm.”

The Kogan Creek Solar Boost Project is separate from CS Energy’s Solar Flagship Project at the same site, the 600MW Solar Flair solar thermal project, which utilises Parabolic Solar Trough technology.

To see more about how the plant will operate, see the Kogan Creek Solar Boost Fact Sheet (pdf).

Although not associated with the project described above, Solar Choice Commercial does manage the tender process for a wide diversity of large-scale solar power projects throughout Australia, including for mining companies, restaurant groups, shopping centres, and rural solar farms. For professional management and consultancy on your solar energy project, contact our Commercial Tenders Manager, Iain McGregor, on 1300 78 72 73 for more information.

Written by James Martin

Analyst

© 2010 Solar Choice Pty Ltd

Sources and Links:

Cnet News – Green Tech, “Aussie coal partners with solar”

IBTimes UK, “Green light given for Kogan Creek”

ABC, “Gillard spruiks massive solar power project” (Third image from here)

CS Energy Kogan Creek power plant homepage

Kogan Creek Solar Boost Fact Sheet (pdf) (Second image from here)

CS Energy Solar Flair Project

Document on Solar Parabolic Trough Technologies

Previous related Solar Choice blog entries: Become a solar farmer : Western Australia’s Commercial-scale Solar Projects : Solar Flagship Projects