$8 Million Battery Research Lab at University of Michigan Announced


A unique $8 million battery research lab at the University of Michigan will enable industry and university researchers to collaborate on developing cheaper and longer lasting energy storage devices in the heart of the U.S. auto industry.

Initial support for the lab includes $5 million from the Michigan Economic Development Corporation (MEDC), $2.1 million from Ford Motor Company and roughly $900,000 from the U-M College of Engineering. It will be housed at the U-M Energy Institute within the newly renovated Phoenix Memorial Laboratory—a project completed with $18 million in U-M funding.

“This kind of collaboration is essential to addressing complex challenges like sustainable energy and efficient transportation. I want to thank our campus leaders, MEDC and Ford for having such a singular focus on developing solutions to such challenging energy issues,” said U-M President Mary Sue Coleman. She announced the battery research lab at the dedication celebrating the renovation of the Phoenix Memorial Laboratory.

The new facility—for prototyping, testing, and analyzing batteries and the materials that go into them—promises to be a key enabler for Southeast Michigan’s battery supply chain. It will bring together materials scientists and engineers, as well as suppliers and manufacturers, to ease a bottleneck in battery development near the nation’s automotive capital.

“Michigan is the home and leader of the global automotive industry including the development of advanced powertrain technologies. The battery prototyping facility at the U-M Energy Institute will be a valuable resource for our automotive industry going forward,” said Nigel Francis, MEDC senior vice president, automotive, and senior automotive advisor to Gov. Rick Snyder.

At present, research labs—both in industry and at universities in the region—can test new battery structures and chemistries in “coin cells” that resemble those in a watch or hearing aid. But researchers need to be able to test whether their ideas will work in larger cells for more power-hungry devices from smartphones on up to electric vehicles. The new battery facility will let researchers take this step.

For Ford, the lab represents a unique, collaborative approach to basic research in the space of advanced automotive battery development.

“We need to be able to test hundreds of chemistries and cell designs, but they have to be tests that can translate from the lab to the production line,” said Ted Miller, who manages Ford’s battery research. “Ford has battery labs that test and validate production-ready batteries, but nothing this far upstream. This is sorely needed and no one else in the auto industry has anything like it.”

The new lab will be available for any firm to use. It will also allow students to utilize state-of-the-art equipment while working closely with experts

The Energy Institute envisions the new facility as a safe zone for non-competitive collaboration.

“This is open innovation,” said Mark Barteau, the DTE Energy Professor of Advanced Energy Research and director of the U-M Energy Institute. I believe that cooperation between university researchers and industry is essential to create advances that have real-world impact.

In his opinion, better technologies for energy storage are critical both for making electric vehicles desirable alternatives on a much larger scale, and for seamlessly integrating with the power grid renewable energy resources like solar and wind.

The facility will be open to non-automotive battery-makers as well. While prototyping is expected to be a big draw, the testing equipment will offer developers a way to predict how their batteries will fare in regular use and improve on their designs.

The analysis systems will be able to measure the battery while it’s running to determine how well it performs under expected operation. Measurements such as strain and temperature can identify mechanical and heat management issues that could decrease the battery’s performance and shorten its life.

Developers will also be able to do detailed post-testing analysis, revealing changes to the battery’s chemical microstructure after operating.

Original Article on The Daily Fusion

Northwestern Students Test Solar Cell Behavior at High Altitudes


Four undergraduate students from Northwestern University’s McCormick School of Engineering and Applied Science have taken photovoltaic cells somewhat closer to the energy source to find out how the proximity to the Sun affects their performance.

The team, led by Mark Fischer, who will graduate in June with a B.S. in mechanical engineering, cheered as the payload that was sent 97,000 feet into the atmosphere on a weather balloon parachuted back to Earth intact.

Fischer and fellow McCormick seniors Julian Minuzzo, Jingwei Lou and Sail Wu, who sent the solar cell experiment—with a video camera—up from an Indiana field May 23, were surprised by the answers to their simple questions.

When they reviewed the data and crunched the numbers, they found that the solar cell — a device that converts the energy of sunlight directly into electricity—did not, as expected, perform best at the highest altitudes. They assumed that closer proximity to the sun would mean more intense rays and better performance.

It turns out, the sweet spot for a high-altitude solar cell is between 50,000 and 60,000 feet above Earth’s surface.

“Solar cells are more efficient as they get colder,” Minuzzo said. “As altitude increases, the air temperature gets colder, but then you reach a point where it gets warmer again. The air is coldest between 50,000 and 60,000 feet.”

The findings could be important for future technologies like solar-powered aircraft and drones.

The project was a great learning experience for the students—not just about solar cells or weather balloons, but the value of careful preparation.

“There’s this moment where you count down—3, 2, 1—and let the balloon go, and there’s nothing you can do. It’s out of your hands,” Fischer said. “You launch it and cross your fingers and hope you did everything right.”

The experiment traveled 40 miles in one hour and 56 minutes before returning to Earth—31 miles from the launch site—recording data and images during the entire trip.

Original Article on The Daily Fusion

Green Mountain College Students Build Solar Garage


Students at Green Mountain College don’t just study solar projects, they design and build them.

This year students in the Renewable Energy and Ecological Design Program designed a solar-powered garage. The project not only taught students practical real-world experience in designing and building, it also will serve the college’s fossil fuel-free farm and could make electric car charging more viable in Vermont, where long cold winters and hilly terrain make plug-in cars less efficient.

The program received a $50,000 grant from Constellation Energy Resource’s “E2 Energy to Educate” program.

Students were involved in every aspect of the project from design to working with contractors, said Lucas Brown, Assistant professor of environmental studies with the college.

They learned to generate ideas and modify plans based on client feedback and implemented the building.

“One of the things we’re doing at Green Mountain College is we’re creating opportunities for students to get engaged and find real world solutions as part of the curriculum,” he said.

Projects like the garage give students confidence to go into the real world, equipped with skills and ready to start work immediately and understanding what it takes to create a project from the idea to construction.

“It’s this collision of ideas and values of sustainable design with the real world of construction and budgets,” Brown said.

Solar classIt started from the beginning, when 21 students in the class had to organize themselves into team and collaborate.

“It was good practice in consensus decision-making,” said student Connor Magnuson in a press release about the project.

The garage features and integrative design to optimize performance of electric vehicles in cold weather.

The students designed the garage to use recycled or repurposed materials. The building, which is situated on the college’s fossil-free farm, uses active and passive solar technology to charge an electric vehicle.

A fiberglass passive-solar south facing wall serves multiple functions including being used for early-season crop germination for the college’s farm where the building is located. It was meant to showcase integrative design and serve multiple purposes.

“It’s really a spectacular space,” Brown said.

The project will not only serve the school, it’s already had an impact on the students involved in the project. Audrey Jiunta, said the project bolstered a passion for design and construction.

“It was the most fulfilling thing I’ve ever done,” she said. “Finding a design that fit into the ecology and actually building it- that’s what I want to do now.”

She plans to travel to Guatemala in late May for an internship in the design-build field.

Original Article on Cleanenergyauthority

Morocco Gets Solar Research Center


The German Aerospace Center (Deutsches Zentrum für Luft und Raumfahrt; DLR) is developing plans for a solar power research and test center in Morocco on behalf of the Moroccan Agency for Solar Energy (Masen). The long-term objective of this new center is the development of a competitive solar power industry, that can replace coal as the backbone of the Moroccan electrical system. The project is part of the Moroccan Solar Plan, which envisages having solar power stations capable of generating 2000 megawatts by 2020.

The project is partially funded by the German Government and implemented by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH. In a country that enjoys long duration of sunshine hours and high irradiation like Morocco, solar power stations have the potential to provide a significant proportion of national power requirements.

The Moroccan town of Ouarzazate is a potential location for this solar research and test centre. Construction work on the first solar power station started at this location in May 2013 as part of the Moroccan Solar Plan. This will be a parabolic trough power plant with a capacity of 160 megawatts. By 2015 this capacity will be increased to 500 megawatts and the complex will then include a solar tower and a photovoltaic power plant. The DLR Institute of Solar Research is now developing a concept for a test center in which pilot and demonstration scale plants will be tested and evaluated, and also in which research and development work can be conducted towards efficient, cost-effective solar power stations to supply electrical power as well as desalination plants in Morocco.

Furthermore, DLR researchers on this project are also evaluating the potential added value of Concentrated Solar Power (CSP) and Photovoltaic (PV) technology to Moroccan industry. Therefore, training and further education in the construction and operation of solar power stations will also be a priority. Mustapha Bakkoury, the President of Masen, is placing emphasis on the build-up of research expertise in Morocco: “With the Moroccan Solar Plan, our country has sent out a clear signal about the development of solar energy. We are delighted to be able to rely on DLR’s expertise as we set up the Solar Research and Test Center. This initiative will enable us to further intensify cooperation between European and North African researchers and support the development of a competitive solar industry in our country.”

Experience in setting up research centers

Through many years of cooperation with its Spanish partner, CIEMAT, DLR has gained important experience through the joint construction and operation of the Plataforma Solar in Alméria. In addition, DLR has been building up its own research and testing infrastructure for many years, examples being the solar furnace in Cologne and the DLR solar tower in Jülich. “By virtue of our many years of research activity at the Plataforma Solar de Almería and our own facilities, we are familiar with the current status of research and development, as well as the infrastructure required for successful projects. DLR has an extensive network as a result of its numerous collaborative projects with partners from Morocco and other countries in northern Africa, in industry as well as in the research sector,” said Peter Heller, Head of the Qualification Department at the DLR Institute of Solar Research at the Almería site. “In the further education sector, we can draw upon the capacity building programme, ‘enerMena’, developed here at DLR.”

Electrical power around the clock

The DLR Institute of Solar Research is working on technologies for solar power stations, specifically in relation to Concentrated Solar Power (CSP). This technology involves the use of mirrors to concentrate solar radiation onto a point (tower power plant) or a line (parabolic trough power plant). The thermal energy collected here is then used to generate electricity in the same way as in a conventional steam power station. These power stations can generate between five and 250 megawatts of controllable, renewable electrical power. The thermal energy collected has an advantage over other renewable energies in that it is easy to store. This also means that these solar power plants can deliver electrical power around the clock, for example in the evening after the sun has set, and typically a time of peak consumer demand.


Masen (Moroccan Agency for Solar Energy), which was effectively set up in March 2010, is a limited company with public funding, and which was created by Law no. 57-09 for the implementation of the integrated Moroccan Solar plan and the promotion of solar resources in every aspect. Masen has three main missions: to develop solar power plants, contribute to the development of a national expertise, and be a force of proposition on the regional and international plans.

The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) is Germany’s assistance Agency through its project ‘GIZ Accompaniment of the Moroccan Solar Plan (GIZ APSM)’, which focuses on supporting industrial activities in Morocco’s nascent solar energy sector. GIZ provides technical assistance, which has been mandated by German Ministries to support Morocco in reaching development indicators. GIZ is active in Morocco since 1975. Its mission focuses on providing support for sustainable economic development and land use, the management of water resources, as well as the environment and climate change, including the promotion of renewable energy sources. GIZ projects are commissioned by the German Federal Ministry for Economic Cooperation and Development (BMZ), the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) the Federal Ministry of Defense, the Federal Ministry of Economics and Technology, the Federal Ministry of Education and Research and other international institutions.

Original Article on The Daily Fusion

Can Stanford Students Revolutionize Green Home Construction?


Stanford students are planning to revolutionize green home construction with a new standardized platform. A first home based on this concept is being built right now (you can even follow the progress via its very own YouTube channel). This solar-powered, zero-emission house is Stanford’s entrant in the Solar Decathlon, a biennial competition run by the U.S. Department of Energy. The 2013 competition will feature solar homes from 20 collegiate teams from four countries.

At the heart of the project is the Start.Core, a central unit that contains all the plumbing, utilities and appliances and manages the house’s energy usage. The team believes that a standardized unit like the Start.Core could transform green home construction.

“We want to inspire industry to think about houses that can be built more like cars,” said project manager Derek Ouyang, a double major in civil engineering and architectural design.

The ability to mass produce basic but critical elements will make it possible to improve quality control and upgrade equipment with new technology as it becomes available, while at the same time allowing customizability. “The Start.Core is like an engine for homes, and you can build any shell you want around it,” he said.

Most of the students had no carpentry experience before beginning the build, but they are gaining on-site training from five instructors from the Carpenters Union, one of the project’s sponsors. After a few hours on the site with the expert instructors, Ouyang said, most students feel very comfortable with the construction equipment.

Learning their way around a construction site, however, hasn’t been the only challenge.

“Every single day we run into five unexpected issues,” Ouyang said. “Most of them are structural. When you’re designing something using 3-D software, it looks really easy to drop in a beam or a screw. But then you finally get building, and you realize you can’t swing a hammer in the space where you planned to put a nail. I’ve spent most of my time so far going around the site figuring out on-the-spot design changes.”

Earlier this week, 100 6th-graders from nearby Nueva School visited for a tour of the house. A public house-warming ceremony is scheduled for Earth Day, April 22, and the team has plans for more educational tours this summer, when the core systems are fully integrated. Ouyang said that these outreach efforts will help people think about improving their day-to-day energy consumption.

“We’re packaging behavioral design into the Start.Core, to help people become net-zero as well,” Ouyang said. “The more aware you are of your daily energy usage, the more likely you are to improve your habits. That’s hard to do just based on an electric bill at the end of the month.”

This summer the team also will be fine-tuning the operating systems and confirming that the house is really operating at net-zero emissions.

Later this summer, the team will practice dismantling and re-assembling the house in preparation for the competition, which will be held October 3-13 at Orange County Great Park in Irvine, Calif.

Original Article on The Daily Fusion

HiFlex Researchers Develop Flexible Organic Solar for Mobile


A technology developed by the HiFlex research project promises flexible, lightweight, on-the-go charging for mobile electronics and remote applications. New organic photovoltaic module (OPV) is relatively cheap and can effectively function under various light conditions.

The project—a collaboration between  ECN, Fraunhofer Institute for Solar Energy Systems (ISE), TNO / Holst Centre, Technical University of Denmark (DTU),  Pera Technology / The UK Materials Technology Research Institute (UK-MatRI), Dr. Schenk and Agfa Gevaert—was supported by the European Commission as part of the FP7 Information and Communication Technologies (ICT) Programme.

The project has overcome a number of the key challenges towards the commercialisation of this technology as the modules are fully roll to roll (R2R) processed, indium free, and demonstrate good outdoor stability.

Jan Kroon from ECN, project coordinator for Hiflex says: “Our consortium has developed a relatively low cost module which will significantly accelerate the take up of OPV technology in the mobile electronics market and will also find future applications with other products such as leisure and building industries to name but a few.”

A key feature of the Hiflex project is the removal of indium tin oxide (ITO) which is used as a transparent conductive layer in other OPVs.  ITO is very expensive and there are concerns about future supplies of Indium, so removing ITO has been key to the cost effectiveness and long term viability of the Hiflex technology.  In addition, silver has also been removed from the production process of small credit card sized modules, further reducing costs and potential resource supply issues. Overall, the approach also demonstrates significantly lower embedded energy than competing technologies.

To ensure increased process efficiency and performance and to keep costs under control, testing tools have been built into the production process, which analyse the material for any faults. In particular Hiflex partner Dr. Schenk has installed their SolarInspect RollToRoll Metrology System within DTU’s (Technical University of Denmark) inline printing and coating system.

Kroon continues:  “We’ve made some technological breakthroughs in OPV development here, without losing sight of the user requirements, both in terms of the film’s performance and quality but also regarding production costs, which could limit applications if too high.”

The Hiflex consortium held a final dissemination event in Eindhoven in December 2012 to demonstrate the modules and discuss issues around OPV development and commercialisation.  As well as attracting other research and technology organisations, the event also attracted a good number of potential end users such as building products and solar canopy manufacturers in addition to mobile electronics producers.

Original Article on The Daily Fusion

GE Research Achieves CdTe PV Efficiency Record


Rather quietly, GE Research has bested First Solar for the cadmium telluride PV cell efficiency record.

Clocking in at 18.3 percent, the new record edges First Solar’s previous mark by a full 1 percent. First Solar (NASDAQ:FSLR) hit 17.3 percent about a year ago.

Presumably, this record was set using the PrimeStar Solar technology acquired by GE in the April 2011 acquisition of the Colorado firm. PrimeStar/GE uses (as did Abound) a close space sublimation (CSS) process for CdTe manufacturing, while First Solar uses a vapor transport deposition (VTD) process. (Note that the GE record is for a cell. First Solar still holds the module record at an NREL-measured 14.4 percent.)

General Electric announced plans to go into production in Colorado with 13 percent panels, and then backed off those plans in July 2012.  A spokesperson for the firm told GTM in an earlier interview that GE remains firmly committed to solar panel production and the plan is to revamp GE’s process to reach 15-percent-efficiency panels.

The test data was was reported in the most recent issue of Progress in Photovoltaics, but word of this record came from a GTM reader who spotted it on the NREL record solar cell efficiency chart. This is the NREL solar efficiency record chart that launched a hundred solar startups and has lured investors to bet on the learning curves of CIGS, a-si, OSCs, and CPV.

Once these records were the domain of labs, government-affiliated entities, or universities.

But Alta Devices’ flexible single-junction gallium arsenide (GaAs) photovoltaics hit 28.8 percent cell efficiencies. Startups such as Amonix (HCPV system), Solar Junction (III-V Triple Junction), and Solexel (thin-film c-Si) lead their respective chemistries. It’s certainly a testament to the risk-taking and smarts of these solar entrepreneurs and investors. It’s also a potential indictment of an underfunded energy research sector that has left VCs shouldering applied research.

First Solar has lost the lead in hero-cell efficiency, but still holds a bit of an edge in megawatts deployed — the firm’s 2012 guidance is for net sales of $3.5 billion to $3.8 billion at a module manufacturing cost below $0.70 per watt.

Continue Reading at Greentech Media

Micro Inverters: What You Need to Know

Are you thinking about installing solar panels on your home or business? You may just want to update your current system and add value to your investment. There are two types of inverters that you can install on your solar panel array. These may be either an array inverter, which will convert the DC current on your set up to AC, but it is less efficient than micro inverters. A micro inverter can convert the DC current on one or two panels. This will help you in getting the maximum efficiency out of your solar installation.

Getting Started With Micro Inverters on Your Solar System

It has been two decades since the first micro inverter was fabricated, and in this time there have been vast improvements. Now, you can find micro inverters for several types of set ups. These inverters can be linked to an internet gateway to help you monitor the efficiency of your solar array.

You can use a unit that connects a 60 cell unit, such as, the APS YC200 micro inverter. There are also others like the Enecsys micro inverter, which can handle some extreme temperatures and is a little more robust than the APS YC200 micro inverter, though not as cost effective.

If you want to have the internet monitoring capabilities you will also have to have an Internet Gateway Module. Both APS and Enecsys have Internet Gateway Modules for monitoring the efficiency and performance of your solar array. The units will allow you to access the statics of your system from any Internet connection and monitor performance and see any potential maintenance problems.

Getting Your Micro Inverters Connected to Your Grid

Once you have decided on the system that you want to implement, you will be ready to start the process of installation. It will be easiest if it is a new installation and you are mounting them on the racks as you go. You can string up to 15 can be daisy-chained together per string. What does this mean? This means that you can connect up to 15 units to connect to your power grid.

When you are installing the inverters and any other electrical equipment you want to make sure that there is no current, and that all power is disconnected from energy sources. You will need the cable, and connecting points to mount a daisy chain of micro inverters to your solar panels and disconnect switch.

First you will want to mount the micro inverters on the racks and run the cable and connections that you will need for each individual micro inverter. After the cables and micro inverters have been installed you will be able to start with connecting it to the disconnect switch, but if you want to have an Internet Gateway the module will need to be mounted before it is connected to the disconnect switch and meter.

The Internet Gateway can be mounted and connected to an array of panels and to the disconnect switch and meter. There are cable and wireless Internet Gateway modules that can be mounted to give you the information of the solar array you have setup.

If are using wireless; you will probably need to use a range extender that is connected to the solar panel array. In addition a wired Internet Gateway Module will need to have CAT5 cable to connect it to the internet.

You may even be able to return energy that you do not use back to the power grid of the power company with a Gird Tie Inverter, and save even more on your energy costs.

Original Article on Greener.Ideal

PV Inverters Market: 52.3 Gigawatts by 2018

Soaring oil prices and growing environmental concerns intensified the focus on alternate energy in recent times. The photovoltaic industry is a major benefactor of this growing interest, with large scale solar parks mushrooming in advanced and developing countries alike, propelled by favorable regulatory environment, Government subsidies, falling PV module prices, and the growing pressure on buyer rates. In particular, the feed-in-tariff (FIT) and micro-FIT programs in several countries, particularly Europe, reaped rich dividends in the form of increased solar installations. As a result, PV system installations grew at a healthy rate of over 30% over the last decade and are expected to continue at a robust pace through the year 2020, fostering a similar increase in demand for PV system components such as inverters.

While Europe remained the major growth driver for the global photovoltaic industry for most of the previous decade, the announcements of roll-backs in FIT subsidies created shockwaves that rippled throughout the worldwide supply chain. The Spanish Government triggered the trend in 2008, announcing deadlines for cut-backs in FIT incentives. With other Governments following suit, the unprecedented surge in demand drove a short term spurt in prices in 2010. The Eurozone crisis is expected to stifle regional Government support for solar installations in the near term, weighing heavily on the global market. At the same time, US Government is showing renewed interest in solar photovoltaic power, as part of its ‘green economy’ drive. The recent nuclear incident at the Fukushima plant prompted the Japanese Government to revisit its alternate energy infrastructure.

Photovoltaic Inverters are transforming from simple energy conversion devices into ‘Smart’ PV inverters with capabilities of intelligent energy storage and grid interaction, and reactive power that are fast becoming a core part of the fast expanding smart grid infrastructure. Due to issues related to grid imbalances factors such as increasing deployment of grid-tied PV inverters, the need for intelligent energy storage and disbursal systems and integration of solar power into the utility grid are driving demand for ‘smart’ PV inverters. Moreover, regulators are tightening inverter specifications and demanding that PV inverters play a greater role in grid stabilization, thereby improving the scenario for smart PV inverters in developed markets. Germany set the example for other European countries, by issuing the Low and Medium Voltage Directives for integrating solar power into the utility grid. The implementation of this directive is expected to propel the market share of smart and semi-smart PV inverters. In the medium-term, energy inverters are expected to constitute about half of the total of PV Inverter shipments, driven by Government subsidies and the development of cost-effective alternatives for the expensive lithium ion batteries in widespread use at present.

PV inverter manufacturers are displaying increasing propensity for disruptive technologies, as is evident from the huge growth in shipment volumes of microinverters and power optimizers in 2010. DC-to-DC power optimizers and solar microinverters are expected to cross the $1.0 billion mark in terms of revenues over the next few years, with shipments also projected to double over the period. These technologies offer enhanced power harvest besides enabling easier installation, improved monitoring and safety. Microinverters offer benefits for PV systems that are prone to shading and require constant re-orientation, as well as overcoming the single-point failure of central inverters. While solar microinverters are anticipated to find application in residential and commercial applications, power optimizers would be employed in large scale commercial projects that involve the deployment of central inverters. Despite this, the segment accounts for a fraction of the total PV inverter market, with penetration limited to less than 10% of the total market. The substantially high prices and technological immaturity of microinverters are the greatest barriers to their adoption, particularly in commercial applications. However, prices of the disruptive technologies are sliding downwards, as scales of economies are being realized through OEM contract agreements.

Europe dominates the worldwide PV Inverters market, as stated by the new market research report. The European market, led by Germany, France, Italy, Spain, Belgium, Greece and the Czech Republic, also accounts for the majority of the global installations. However, in light of the economic recession and subsequent Eurozone financial crisis, several Governments rolled back PV subsidies and incentives as part of their austerity measures, thereby culling demand in the region. In the near term, China and India are forecast to emerge as major centers of growth in the Asia-Pacific region, with China evolving into a major PV inverter manufacturing hub for the region. Government authorities in emerging Asia economies are also promoting PV system installation, driving the domestic demand for solar inverters. As a result, the market is expected to register healthy CAGR of over 25% through 2018.

Original Article on PVdepot.com

True Sine Wave or Modified Sine Wave Inverters?

Because the AC electricity from the electric grid is in the form of sine wave, the inverters we use aim to produce a current that is as close to sine wave as possible.  While modified sine wave inverters present an inexpensive alternative, there is no comparison to the clean, undistorted sine wave provided by pure sine wave inverters.

A pure sine wave inverter, also known as a true sine wave inverter, produces a clean, undistorted electrical output.  Depending on the manufacturer of the product, pure sine inverters have a perfect sine wave output that’s in phase with the AC grid of the utility company.  Because of the sinusoidal form, pure sine wave inverters are used for grid-tie solar systems and work for virtually any AC load.
Cotek SK3000-148, 3000 Watt 48V Pure Sine Wave Inverter

Because they produce no harmonic distortions in the frequency, pure sine wave inverters allow any electronic device to function well without overheating or creating an irritating “buzz” sound.  Though pure sine wave inverters are undoubtedly the best and most versatile kind of inverter, they are more expensive than modified sine wave inverters.

Pure sine wave inverters are necessary for highly sensitive products such as digital clocks, audio equipment, and video-game consoles.  As a general rule of thumb, if you’re powering any electronics, you’ll probably want to stick with a pure sine wave inverter.

The image below displays the difference between a pure sine wave and a modified sine wave.

The cheaper alternative to a pure sine wave inverter is a modified sine wave inverter.  A modified sine inverter converts DC electricity to a nonsinusoidal AC wave that is “modified,” or distorted.   When an inverter produces modified sine wave, the voltage output (represented in the Y axis of the image) essentially jumps from zero volts to positive, where it plateaus and drops back to zero, to negative voltage, and then back to zero again. This is signified in the image by the squared edges seen in the modified sine wave, which is contrasted by the smooth oscillation of a voltage that is produced by a pure sine wave inverter.  The modified sine wave is a stepped waveform that is designed to mimic a true sine wave.  Because it is not a clean form of energy, modified sine wave does generate a certain kind of interference called harmonic distortion (though not as much as a square wave).

Modified sine wave inverters can work for the majority of low-end appliances, but take caution when using them for your electronic devices.  Because these inverters do not produce a clean output, a “buzz” often accompanies modified sine wave inverters.  Highly sensitive electronic products that were intended operate with a clean AC waveform will certainly overheat when connected to a modified sine wave inverter.  Since modified sine wave inverters are less efficient than pure sine wave inverters, the excess energy produces heat that can be detrimental to some devices.  The impure energy produced by modified sine wave inverters can curtail the longevity of many appliances, and utterly destroy some electronics that were originally designed for clean AC.

Samlex America PSE-12125A, 1250 Watt 12V Modified Sine Wave Inverter

Though it would be wise to choose a pure sine wave inverter for a television, video-game console, or audio equipment (so they don’t overheat), a modified sine wave inverter is suitable for most rugged, low-end products.  At such a low cost, it makes financial sense to use a modified sine wave inverter if your equipment can handle it.
If your goal is merely to power some lights and a refrigerator, a modified sine wave inverter will surely satisfy your needs.  If there’s even a chance that you will be powering sensitive electronics with your inverter, opting for a pure sine wave inverter is highly recommended.  Don’t stress over what is compatible- with pure sine wave inverters, there is no hassle, no interference, no noise, and a longer lifetime for your appliances.

What are your thoughts on modified sine wave inverters?

Thomas Jackson

Original Article on Go Green Solar

Microinverters vs. Central Inverters

So you’re installing a brand new solar system.  Do you go with microinverters or stick with a central inverter?

What’s the function of an inverter?
The task of an inverter is to convert direct current (DC) to alternating current (AC), which is needed for the vast majority of electrical devices.   Solar energy comes in the form of direct current, which must be converted to AC for this reason.
Central Inverter
Traditionally, central inverters have been used in solar systems to convert DC to AC.  One central inverter is connected to multiple solar panels.
Central inverters are trusted by many because they have been around for so many years and people are familiar with them.  This technology has been around longer, so the collective amount of real-world use gives central inverters a certain kind of credibility in the industry.

SMA SB 3000US Sunny Boy Grid Tie Inverter 3250W with DC disconnect

The key benefit of a central inverter is cost.  The bottom line is that central inverters currently cost less per watt than microinverters.  This is why many home owners and most utility scale industrial applications opt for central inverters.  A good number of people argue that having a single conversion point simplifies grid management for such large applications.

Critics of central inverters point out that high voltage levels are centralized with these inverters and thus pose a safety hazard.
The main disadvantage of having a central inverter is that your system is “only as strong as its weakest link.”  If one panel is subject to shading or some other form of coverage, the energy output of your array can be decreased by fifty percent.  This setback has created an opportunity for microinverters to make their way into the market.
Microinverters convert the DC electricity from each panel to AC electricity.  They attach behind individual solar panels in the array, allowing each module to operate independently.  Microinverters can maximize the power produced by each panel, rather optimizing for the “weakest link” in an array.  Because of this, microinverters are particularly advantageous for systems in locations that might have shading or some form of coverage (i.e. dirt, snow, etc).
Using microinverters definitely has its advantages, predominantly for residential applications.  Microinverters, such as the Enphase M215 on the right, are desirable for DIY applications because they’re so easily installed.  Microinverters are easily scalable, meaning you can add to your existing system with little trouble.  Microinverters also allow for module level monitoring and comprehensive analytics, making it possible for you to view how much energy is being produced by each panel.  For these reasons, microinverters have become increasingly popular for residential applications, particularly in California.
The main disadvantage of microinverters is the price tag; they still cost more per watt than central inverters.  Dual microinverters have been introduced to address this issue.  Because dual microinverters connect with two panels at once, the cost per watt is cheaper than single microinverters.

Currently, Enphase Energy dominates the market for microinverters.  Enphase offers a fifteen year warranty on their microinverters.  Over the last several years, Enphase microinverters have made a remarkable breakthrough in the solar market.  Many believe that microinverter technology will continue to gain traction in the years to come.

What do you think?

As microinverters (and dual microinverters) become cheaper, what can we expect to see?  If microinverters become cheaper than central inverters, will central inverters eventually become obsolete?  Perhaps there will continue to be a place for both technologies, each with their respective applications.  I guess we’ll just have to wait and see!

Original Article on Go Green Solar