Can we get more power out of a solar cell? These UK physicists think so

warwick solar cell

Physicists at the University of Warwick published new research in the Journal Science that could literally squeeze more power out of solar cells by physically deforming each of the crystals in the semiconductors used by photovoltaic cells. The paper entitled the “Flexo-Photovoltaic Effect” was written by Professor Marin Alexe, Ming-Min Yang, and Dong Jik Kim who are all based in the University of Warwick’s Department of Physics.

The limits of a solar cell

The Warwick researchers looked at the physical constraints on the current design of most commercial solar cells which place an absolute limit on their efficiency. Most commercial solar cells are formed of two layers creating at their boundary a junction between two kinds of semiconductors, p-type with positive charge carriers (holes which can be filled by electrons) and n-type with negative charge carriers (electrons). When light is absorbed, the junction of the two semiconductors sustains an internal field splitting the photo-excited carriers in opposite directions, generating a current and voltage across the junction. Without such junctions the energy cannot be harvested and the photo-exited carriers will simply quickly recombine eliminating any electrical charge.

That junction between the two semiconductors is fundamental to getting power out of such a solar cell but it comes with an efficiency limit. This Shockley-Queisser Limit means that of all the power contained in sunlight falling on an ideal solar cell in ideal conditions only a maximum of 33.7% can ever be turned into electricity.

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The new approach

solar cell

Image of the crystal deformation.

There is however another way that some materials can collect charges produced by the photons of the sun or from elsewhere. The bulk photovoltaic effect occurs in certain semiconductors and insulators where their lack of perfect symmetry around their central point (their non-centrosymmetric structure) allows generation of voltage that can be actually larger than the band gap of that material (the band gap being the gap between the valence band highest range of electron energies in which electrons are normally present at absolute zero temperature and the conduction band where electricity can flow). Unfortunately the materials that are known to exhibit the anomalous photovoltaic effect have very low power generation efficiencies, and are never used in practical power-generation systems.

The Warwick team wondered if it was possible to take the semiconductors that are effective in commercial solar cells and manipulate or push them in some way so that they too could be forced into a non-centrosymmetric structure and possibly therefore also benefit from the bulk photovoltaic effect. For this paper they decided to try literally pushing such semiconductors into shape using conductive tips from atomic force microscopy devices to a “nano-indenter” which they then used to squeeze and deform individual crystals of Strontium Titanate (SrTiO3), Titanium Dioxide (TiO2), and Silicon (Si). They found that all three could be deformed in this way to also give them a non-centrosymmetric structure and that they were indeed then able to give the bulk photovoltaic effect.

Professor Marin Alexe from the University of Warwick said:

“Extending the range of materials that can benefit from the bulk photovoltaic effect has several advantages: it is not necessary to form any kind of junction; any semiconductor with better light absorption can be selected for solar cells, and finally, the ultimate thermodynamic limit of the power conversion efficiency, so-called Shockley-Queisser Limit, can be overcome. There are engineering challenges but it should be possible to create solar cells where a field of simple glass based tips (a hundred million per cm2) could be held in tension to sufficiently de-form each semiconductor crystal. If such future engineering could add even a single percentage point of efficiency it would be of immense commercial value to solar cell manufacturers and power suppliers.”

— Solar Builder magazine

SunPower buys SolarWorld Americas to ramp up P-Series panel production

sunpower logo

In the latest episode of As the Solar Industry Turns, SunPower is acquiring 100 percent of SolarWorld Americas. You may recall SolarWorld Americas being one of the companies that hit a rough patch and filed a 201 trade petition that launched the #TrumpTariffs now in place. SunPower plans to inject fresh capital into the SolarWorld Americas facility and implement high-efficiency P-Series solar panel manufacturing technology.

“The time is right for SunPower to invest in U.S. manufacturing, and SolarWorld Americas provides a great platform for us to implement our advanced P-Series solar panel manufacturing technology right here in our home market,” said Tom Werner, SunPower CEO and chairman of the board. “P-Series technology was invented and perfected in Silicon Valley, and will now be built in SolarWorld Americas’ factory, helping to reshape solar manufacturing in America.”

SunPower plans to ramp SolarWorld Americas operations to capitalize on strong U.S. market demand. The company will invest in factory improvements and increased working capital, while retrofitting a portion of the facility to produce P-Series solar panels, in addition to continuing to produce and ship SolarWorld Americas’ legacy products. Like SolarWorld Americas, SunPower has spent decades perfecting its technology and manufacturing processes, and this announcement marks the company’s return to U.S. manufacturing. The agreement is subject to necessary U.S. and German regulatory approvals and other closing conditions. At closing, which is expected in the next several months, SunPower will become the largest U.S. solar panel manufacturer.

“This is a smart move for SunPower,” said Vikram Aggarwal, CEO and founder of EnergySage. “As our latest report shows, SunPower has typically been the most expensive panel brand offered to consumers, while SolarWorld has been among the lowest priced. This acquisition gives SunPower the ability to better serve both quality-driven and price-conscious consumer segments, particularly those looking for American-made products. It should also help the company minimize the impact of Trump’s solar tariff.”

“SunPower is the solar industry technology leader,” said Jürgen Stein, CEO of SolarWorld Americas. “We are delighted that SunPower has agreed to inject fresh capital and their industry leading P-Series technology into SolarWorld Americas operations here in Hillsboro. Our hundreds of long-time employees are excited to be part of this next chapter in SolarWorld Americas’ long history. We are thrilled about this acquisition as it means quite simply, that our company can look forward to redoubled strength as it continues to innovate and expand into the future. This outcome is ideal for SolarWorld Americas and its employees.”

 

— Solar Builder magazine

Meteocontrol, viasys are collaborating on solar site monitoring solution for North America

Meteocontrol

Meteocontrol North America, a subsidiary of meteocontrol GmbH in Germany, and viasys Intelligent Video GmbH are collaborating is to offer PV-system operators a turn-key solar monitoring solution at a great value and provide North American customers with professional technical support.

Consolidating the systems will result in cost savings for customers because video surveillance can be integrated into meteocontrol’s monitoring portal without the need for any additional infrastructure in solar farms, since the systems can share the same network components, cabling and control cabinet.

“The challenges involved in securing and monitoring solar parks are impressively similar,” said Anson Moran, CEO of meteocontrol North America. “The solution is optimized alarm management. We will conduct high-level data assessments using video, data analysis and artificial intelligence.”

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“The collaboration will solidify our reputation as a reliable partner because our product portfolios complement each other perfectly,” said Martin Schneider, Managing Director of meteocontrol GmbH. “Through our new collaboration with viasys Intelligent Video, we will be able to provide additional value to the market.”

Interlocking the viasys and meteocontrol systems will simplify the technical operation management of solar parks and make them even more secure. When the viasys security system is integrated into an operation manager’s portal view, for example, they will be able to see what is happening near the system at any time and track it with precision all the way up to the access control. The meteocontrol monitoring portal signals the operating status in the status message and provides information as to whether the security system is active.

“There are also other developments in the pipeline,” adds Moran. “The operation manager should be able to receive the alarm messages directly in the ticket system, log them there and create the report for the investor. The messages will no longer need to be processed separately from monitoring in the security control room. We also want to set up an O&M camera-based “Awareness System” designed to provide operation managers with the required view of the system on site without the need to invest in an extensive and complete perimeter security system.”

— Solar Builder magazine

Massachusetts’ first community solar plus storage project now operational

Massachusetts community solar

Sterling, MA residents, elected officials and solar and energy storage professionals joined Origis Energy USA and Sterling Municipal Light Department at today’s Sterling Community Solar + Energy Storage project dedication event. The project marked the first solar plus storage project in operation in Massachusetts. (Photo: Business Wire)

Origis Energy USA and Sterling Municipal Light Department (SMLD) serving the Town of Sterling, Mass., completed the Sterling Community Solar + Energy Storage project, which is the first community solar plus storage and the first operational solar plus storage installation in Massachusetts, the project couples a 1 MWac rooftop solar installation with a 1 MW/2 MWh energy storage system to deliver an annual base load of 1.7 MWh in dispatchable clean energy to the town’s ratepayers. It was developed and is owned by Origis Energy USA, delivering power and storage benefits to SMLD through a Power Purchase Agreement.

Sterling, Mass., residents, elected officials and solar and energy storage professionals joined the two companies at the celebration under a “Community First” theme, highlighting the collaborative effort the project represents for the Town of Sterling and the many professionals involved with its completion. The dedication of permanent signage marking the installation location served as a focal point for the event.

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A strong proponent of the project, Matt Stelmach, Chairman of the SMLD Board of Commissioners, said, “The Town of Sterling embodies the independent spirit of the Commonwealth of Massachusetts. Through the leadership of the Sterling Municipal Light Department, we now mark another milestone in our renewable energy leadership. We thank our ratepayers for their continued support and thank the Light Department staff and all of the professionals, led by the Origis Energy team, who have worked to install this important energy system.”

The Sterling Community Solar + Energy Storage project utilized community solar program guidelines from the Massachusetts Department of Energy Resources (DOER) to craft a subscription program for ratepayers in line with state policy.

“We are so pleased to offer residential customers this opportunity to participate in our new Community Solar Program,” said Sean Hamilton, Manager, Sterling Municipal Light Department. “This program allows them to receive up to 25% of solar kwhr’s based on their total bill at a rate that will be protected for 25 years. We have achieved our goal with the Sterling Community Solar + Energy Storage of competitive electricity rates while tapping the grid benefits of battery storage technology.”

Construction on the solar plus storage facility began in January and was completed the end of March. Just over 4000 Tier 1 solar panels are now located on commercial property owned by RockBreakers LLC and managed by Vincent J. CampoBasso, a resident of Sterling, MA. The battery system, Tier 1 lithium ion equipment, is located at ground level onsite.

“Every step of the way the Sterling team empowered our team and all those working with us to ensure we met the accelerated construction deadlines of this project” said Josh Teigiser, Director of Development & Energy Storage, Origis Energy. “Again, SMLD is providing a leadership example of renewable energy deployment. This progressive solar plus storage project demonstrates the viability of this technology for other municipalities in Massachusetts and leaders throughout the country and abroad.”

— Solar Builder magazine

Details on 11 MW solar portfolio now live throughout Washington D.C.

WGL solar project

At a solar project ribbon cutting ceremony, WGL Energy joined DC Mayor Muriel Bowser and project partners to commemorate the completion of a 11.8 megawatt solar system project with the DC Department of General Services (DC DGS). The DC DGS solar project is among the largest municipal onsite solar energy projects in the country. WGL Energy president Sanjiv Mahan pictured to the left of Mayor Bowser. (Photo: Business Wire)

WGL Energy Systems, a WGL company, joined Washington, D.C. Mayor Muriel Bowser and project partners today to commemorate the completion of a 11.8 megawatt (MW) solar system for Washington D.C.’s Department of General Services (DC DGS). The expansive portfolio of onsite solar projects, which includes electric capacity installed across 40 properties owned and operated by WGL Energy, supplies power to several schools, hospitals, recreation centers and more, including the Police Training Academy, St. Elizabeth’s Hospital, and Ballou Senior High School, through rooftop and carport systems throughout the nation’s capital. The completion of the solar project is expected to save taxpayers millions in reduced electricity costs while avoiding greenhouse gas emissions in the District.

The ribbon cutting ceremony took place at a project site, HD Woodson High School, one of the largest solar systems in the city. Through its partnership with WGL Energy, the DC DGS is able to fulfill its pledge to bring new solar development to the District of Columbia. Together, WGL Energy, with a group of talented project team members including Sol Systems that served as the developer of the project, closely collaborated with DC DGS and worked diligently to make one of the largest municipal onsite solar projects in the United States a reality.

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“WGL Energy commends the District of Columbia and the DC DGS for their energy leadership in the region, and their dedication to providing innovative energy options that will benefit local businesses, residents, students and community members for many years to come,” said Sanjiv Mahan, president of WGL Energy. “We are proud to support this significant energy milestone with city leaders as part of our Earth Day celebration. WGL Energy is dedicated to delivering diverse energy solutions to our customers, and we look forward to continuing our long history supporting the District with energy answers from across the energy spectrum.”

WGL Energy Systems, which has more than 250 MW of distributed generation projects installed or under contract across 21 states and the District of Columbia, owns and operates the facility under 20-year power purchase agreements (PPAs), and receives the renewable energy credits (RECs). WGL Energy operates 64 solar projects throughout Washington, D.C., with a combined capacity of over 14 MW.

Over the 20-year term of the PPA, which allows DC DGS to benefit from stable and lower-cost electricity, D.C. taxpayers are expected to save $25 million in reduced electricity costs, according to estimates. The projects, a system of 22,075 solar panels that are anticipated to generate more than 14,977 megawatt hours (MWh) of electricity this year, will avoid greenhouse gas emissions equivalent to taking 2,387 cars off the road for one year.

The project started in January 2016 with a vast majority of sites designed, engineered and generating electricity for the city by July 2017. According to DC DGS estimates, the combined projects created more than 150 temporary jobs during construction and design, as well as a projected five permanent jobs for ongoing operation and maintenance.

— Solar Builder magazine