ETFE Football Stadium Will Soon Be Minneapolis Showcase

by grmeyers

Originally published on Green Building Elements

When it opens this summer, US Bank Stadium in Minneapolis will feature the only ETFE (ethylene-tetra-fluoro-ethylene) roof on a sports facility in the United States. This resilient and transparent material, long used in Europe, will now provide Minnesota Vikings football fans with a comfortable experience inside the stadium and a clear view outside, even if the outdoor temperature is far below zero degrees Fahrenheit.

us bank stadium logo shutterstock_306699017In contrast to the preponderance of opaque domed stadiums in this country, some 60% of the Vikings’ facility has been covered with ETFE, not only letting in daylight, but allowing fans to gaze skyward and enjoy the view. Add to this, this dramatic stadium features five of the world’s largest operable glass doors, which can be opened if the weather outside is pleasant. These gargantuan doors measure 55 feet in width, angling from 75 feet to 95 feet in height, and weighing approximately 57,000 pounds each. Of note, the large door system also contains five smaller doors which can be used when the large doors re closed due to inclement weather.

Journalists were invited to sample

GRM Vikings ZT__8035As the stadium nears completion, a diverse group of journalists — specializing in everything from architecture to sports — had the opportunity to visit this 1.75 million sq. ft. structure, including 248,000 sq. ft. of ETFE roof, and listen to very articulate presentations from many on the design and development team, including leadership from the Minnesota Vikings.  I found no shortage of good stories to report, most which will follow later this month. Here I report on the old stadium, the new stadium, and this remarkable material, ETFE.

In other stories, I will report about:

  • Sustainability practices in design and construction
  • Strategy behind  this projected $1.1 billion inner-city facility
  • Economic impact & surrounding development
  • This development is a showcase for others to follow

The old stadium model

Minneapolis, known for its very cold winter weather, previously featured the Hubert H. Humphrey Metrodome, built downtown in 1982. It was the ninth oldest stadium in the NFL, featuring a fiberglass fabric roof, self-supported by air pressure. It was the third major sports facility to have this feature (the first two being the Pontiac Silverdome and the Carrier Dome).

vikings metrodome shutterstock_108070454

Preparation for the demolition of the Metrodome began the day after the final home game for the Minnesota Vikings on December 29, 2013. Demolition began January 18, 2014.

For those wanting a glimpse, here is how the roof to the Metrodome came down.


The new stadium model

usbankstadiumOwned by the Minnesota Sports Facilities Authority (MSFA), the multi-purpose US Bank Stadium is scheduled to host Super Bowl LII in 2018 and the NCAA Final Four in 2019. Some leap from the starting line!

Designed by Dallas-based HKS Architects, the US Bank Stadium features the largest transparent ETFE roof in North America, spanning 240,000 square feet. This will be the only stadium in the nation with a clear ETFE roof.

Vikings ETFE & cane IMG_6142Because of the angles of the roof, ETFE material on the south side accounts for 60% of the entire roof, while hard metal deck on the north side will account for the remaining 40%. 

ETFE basics

ETFE is a co-polymer resin which is extruded into a thin film. The light-weight material is transparent but can be treated to be translucent. It is durable and resistant to corrosion. In an architectural application ETFE is typically used in a multi-layer pneumatic system.

Longevity of ETFE

Vikings ETFE IMG_6211

ETFE beginning layer

This material does not degrade with exposure to UV light, atmospheric pollution, harsh chemicals, or extreme temperatures. The material has withstood extensive testing within extreme environments and is expected to have a 30 to 50-year life expectancy, requiring minimal maintenance. Presently, the true life-cycle of ETFE is not known as the oldest applications are just hitting the 30-year mark with little to no replacement of system components.

ETFE weight & strength

us bank stadium 2 Berg-150707-0965Despite its light weight (1/100 the weight of glass) ETFE is reported to handle snow/wind loads well. In sheet form, it can stretch three times its length without losing elasticity. Support rods are used with the stadium roof panels.

Cleaning ETFE

The surface of the foil is non-stick and non-porous, which allows the natural action of rain to clean the surface. Deposits of dirt, dust and debris remain unattached and are washed away in the rain, meaning ETFE effectively self-cleans with virtually no need to clean externally.

As Amy Wilson has written on Architen, “Originally invented by DuPont as an insulation material for the aeronautics industry, ETFE was not initially considered as a main-stream building material, its principle use being as an upgrade for the polythene sheet commonly used for green house polytunnels.

“The advantages of its extraordinary tear resistance, long life and transparency to ultra-violet light off-set the higher initial costs and 20 years later it is still working well. It wasn’t until the early 1980s, when German mechanical engineering student, Stefan Lehnert, investigated it in his quest for new and exciting sail materials, that its use was reconsidered.”

Indeed! Just take a look at this showcase taking place near the Mississippi River.

Images: Metrodome via Shutterstock; usbank stadium sign via Shutterstock; all other images via the Minnesota Vikings

Elon Musk proposes smart carbon tax

by grmeyers

Tesla founder and CEO Elon Musk addressed an audience at Paris Sorbonne University during the 2015 Council on Climate Change held in Paris.

His subjects: climate change, fossil fuels, the carbon cycle.

The video, including audience questions is here.


Advanced Infrared Camera Can Photograph Methane

by grmeyers

Originally published on CleanTechnica

A new camera has eliminated the guesswork about where greenhouse gases are being emitted. It can photograph and film methane.

This technology has been released by a team of researchers from Linköping and Stockholm Universities who have demonstrated how this remarkably advanced camera can record methane in the air around us.

Importantly, this technological advance can play an important role in global efforts to measure and monitor greenhouse gases.

camera shoots methane inventors104304_web

David Bastviken and Magnus Galfalk

According to a press announcement, the camera has been developed by a team that combined knowledge from many different fields of expertise, including astronomy, biogeochemistry, engineering and environmental sciences.

“This gives us new possibilities for mapping and monitoring methane sources and sinks, and it will help us understand how methane emissions are regulated and how we can reduce emissions,” said David Bastviken, Linköping University professor at Tema Environmental Change,  and principal project investigator. “So far the camera has been used from the ground and now we’re working to make it airborne for more large-scale methane mapping,”

So much for the dubious notion, “If you can’t see it, it’s not there.” Now it will be visible for all to see.

The news release reports several questions surround the powerful greenhouse gas methane, including its rapid but irregular increase in the atmosphere. There is also considerable uncertainty regarding methane sources and sinks in the landscape.

The new camera may help address these issues. The utility of the camera to both photograph and film methane has been demonstrated in a study that was recently published in Nature Climate Change.

“The camera is very sensitive, which means that the methane is both visible and measurable close to ground level, with much higher resolution,” said Magnus Gålfalk, Assistant Professor at Tema Environmental Change, Linköping University, who led the study.

The hyperspectral infrared camera weighs 35 kilos and measures 50 x 45 x 25 centimeters. It is optimized to measure the same radiation that methane absorbs, and which makes methane such a powerful greenhouse gas.

The camera can be used to measure emissions from many environments including sewage sludge deposits, combustion processes, animal husbandry, and lakes. For each pixel in the image the camera records a high-resolution spectrum, which makes it possible to quantify the methane separately from the other gases.

Longstanding complaints of methane leaks from natural gas production and distribution can also be recorded. It will be very interesting to report on the results.

Image via Linkoping University

Photons & Solar Panels

by grmeyers

Photons & Solar Panels

We talk plenty today about solar panels, but not many really grasp how they work – how they create electricity. In his book, Let It Shine: The 6,000-Year Story of Solar Energy, author John Perlin takes readers back to Albert Einstein in 1905 for perspective on the matter of light: “Einstein showed that light possesses an… Read more of this >>

Off-Grid Electrics raises $25 million to power African homes

by grmeyers

Off-Grid Electric Raises $25 Million To Power African Homes

Off-Grid Electric has raised $25 million in venture capital funding to launch an affordable mobile solar leasing platform in Tanzania. Meeting the energy needs of the poor This innovative renewable energy program is targeting households making as little as $1 a day. The solar electricity program uses mobile money – where customers pay with their mobile… Read more of this >>

Energy Entrepreneurs In Africa & India

by grmeyers

October 14th, 2015 by Glenn Meyers from CleanTechnica

The notoriously small amount of electricity available in Africa and India is now being addressed, thanks in part to the steady growth of energy entrepreneurs who happen to be selling electrical power by peddling bicycles.

A recent BBC program on The Forum featured the bicycle, and interviewed numerous business people, including Sameer Hajee, CEO at Nuru Energy, an international social enterprise targeting the global problem of energy poverty prevalent in Africa and India.

Nuru Lights p034ly50It is estimated more than 700 million people across Africa alone have little or no access to energy, with some 400 million residents of India facing similar energy poverty.

Seed funded by the World Bank in 2008, Hajee markets affordable LED lamps that can be easily recharged using a human-powered generator — in other words, pedal power. While bicycle-powered technology like this has been around for a while, what is most noteworthy about this platform is how it allows individuals to operate as independent businesses that provide people with needed electricity at a reasonable fee.

Nuru Energy products Products_Header

Nuru Energy co-created a unique off-grid recharging platform using human power to recharge both Nuru Energy’s portable LED Lights as well as other low-power devices, such as radios and mobile phones. According to the company, its Nuru POWERcycle is the world’s first commercially available pedal generator. It requires minimal human exertion (60 rotations per minute), and charges up to five Nuru Lights (NL1s) simultaneously in approximately 20 minutes.

The solar lantern is said to burn for 28 hours and can be recharged from multiple sources. Theses are impressive numbers for potential customers who have had to suffer through the toxic odors from kerosene lanterns. Nuru Energy adds these considerations:

“It is extremely efficient producing enough energy for 420 minutes of light for every minute of easy pedalling. Because it is human-powered, the POWERCycle is not affected by unpredictable weather conditions and can therefore recharge products anytime, anywhere.”

The POWERCycle not only provides reliable and clean power anytime, the company states this product is hundreds of times more efficient than current solar-based solutions. Plus it comes at a fraction of the cost. This is of particular importance where poverty levels are as extreme as they are in Africa and India.

Nuru Energy claims to use a “bottom-up approach” for every product it develops and the way in which products go to market. “We work with local organizations to recruit and train micro-franchise entrepreneurs, Nuru Energy Entrepreneurs, who sell Nuru’s LED lights to their community and then offer POWERCycle recharging services for a small fee, typically earning in 20 minutes what they previously earned in an entire day.”

12 solar facts you should know

by grmeyers

12 Solar Facts You Should Know

Lists are always fun, so here are 12 solar facts to put in your notebook so you can share the important stuff with anyone who’s interested. I have divided this list of facts into four categories that might help you to better keep track of things. Understanding Our Sun Solar History Solar Technology Solar Metrics But… Read more of this >>

Solar storage milestone in Texas

by grmeyers

Battery Storage Milestone In Texas

Younicos battery storage system will be state’s first integrated grid-scale solar storage asset. The news ledger about solar electricity storage continues expanding following an announcement from Berlin-based Younicos on its agreement with solar power supplier OCI Solar Power to provide a turnkey battery storage system at one of OCI Solar Power’s projects in Texas. According to… Read more of this >>

SunEdison Australia Taking Delivery Of Tesla Powerwall

by grmeyers

September 22nd, 2015 by Glenn Meyers

The Tesla Powerwall will be introduced to customers in Australia, through an agreement with SunEdison Australia.

According to SunEdison concern Energy Matters, this partnership agreement will slate SunEdison Australia as one of the first companies in the world to take delivery of the revolutionary Tesla Powerwall home battery system:

“The first Tesla Powerwall 7 kWh units will arrive on our shores in November this year; heralding the real start of Australia’s residential energy storage revolution.”

tesla powerwall 1436722888916383012

This is good news for Australian solar power system owners wanting to further distance themselves from the grid in support of renewable electricity and energy independence. This follows Tesla’s announcement that both Australia and North America would be the first markets to receive the batteries.

“The 7kWh daily cycling Powerwall is a compelling option for Australian residential solar users,” said Tesla in a statement.

SunEdison Australia says it will celebrate the arrival of the Tesla Powerwall with a competition — the major prize being one of the battery systems. To be notified when the competition is formally announced, pricing of the Tesla Powerwall and other pre-release updates on home battery storage systems, register here.

Initially, only the 7 kWh daily cycling version of the Powerwall will be available, however, the 10 kWh is expected to be made available be made available in early 2016, according to Energy Matters.

This clean storage device from Tesla Energy, is a wall-mounted, rechargeable lithium ion battery with liquid thermal control and incorporates a battery management system with smart DC-DC converter for controlling the flow of electricity.

Powerwall offers a 92% round-trip DC efficiency, 5.8 amp nominal, 8.6 amp peak output and 3.3kW continuous/peak power. Multiple 7kWh batteries can be installed, with up 63 kWh capacity total possible. A single unit weighs 100 kg and measures 1300 mm x 860 mm x 180 mm.

SunEdison Australia states it also intends offering advanced storage solutions from other leading manufacturers including Enphase Energy and Fronius as they become available.

Because of the high cost of electricity in Australia, and solar feed in tariff rates, Bloomberg New Energy Finance forecasts 33GW of battery storage will be installed in Australia by 2040.

Photo credit via TeslaEnergy

Source: CleanTechnica

Understanding biohybrids and energy

by grmeyers

What We Night Reap from Biohybrids (via

David Thomas has provided this article on the subject of biohybrids, an alternative way of  generating electrical energy from the sun using plants.   Thomas could not send the article as quickly as desired, as he was waiting for another scientist to interview. The call never came and Thomas finally…

Read more of this >>