urban infrastructure

Vertical-axis wind turbines

February 19, 2025 By EarthWise Leave a Comment

Nearly all wind turbines in use today are horizonal axis wind turbines. They are a familiar sight with their three giant rotor blades spinning about an axis high above the ground attached to a nacelle containing the gearbox and generator.

A vertical-axis wind turbine has its rotor shaft transverse to the wind; that is, the shaft rises up from the ground and the gearbox and generator are located close to the ground.

This type of wind turbine does not need to be pointed into the wind, which eliminates the need for wind-sensing and orienting mechanisms. It is also considerably quieter in operation than horizontal axis wind turbines. Vertical-axis wind turbines have enjoyed minimal success to date because of a variety of problems including reliability issues and complications related to how they respond to changing wind conditions.

A next-generation vertical wind turbine is going on trial in Australia as part of a research collaboration between Flinders University in South Australia and the start-up company VAWT-X Energy. The 6KW prototype will be installed at a field site in Australia’s Fleurieu Peninsula.

According to the developers, the new turbine design will be as efficient, or even more efficient, as existing horizontal turbines and will be able to thrive across diverse environments including being part of urban infrastructure where their relative quiet is a real advantage. Such turbines would be more accessible for applications like off-grid power and sustainable energy solutions for small businesses and farms. The developers claim the technology can also be scaled up for large-scale windfarms.

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Progress with new-look wind turbine

Photo courtesy of VAWT-X Energy.

Earth Wise is a production of WAMC Northeast Public Radio

Sinking Cities | Earth Wise

October 24, 2022 By EarthWise Leave a Comment

Sea levels across the globe are rising as a result of the changing climate. Two factors are largely responsible: the melting of ice sheets in the polar regions and the fact that as the oceans get warmer, the water in them expands.

Estimates are that by 2050, there will be over 800 million people living in 570 cities that will be at risk from rising sea levels. The rising waters can drown neighborhoods, put people’s lives at risk, and wreck entire economies. Unless global emissions can be reduced sufficiently, sea levels will continue to rise.

A new study, published in the journal Nature Sustainability by Nanyang Technical University in Singapore in collaboration with the University of New Mexico, ETH Zurich, and NASA’s Jet Propulsion Lab, has focused on yet another aspect of the threat to coastal cities. They have found that many densely populated coastal cities worldwide are even more vulnerable to sea level rise because much of their land is sinking.

The researchers processed satellite images of 48 cities from 2014 to 2020 using a system called Interferometric Synthetic Aperture Radar. They found that land subsidence varied on a neighborhood and even individual block level but across all the cities studied, there was a median sinking speed of 6/10” a year. Some places had land that is sinking at 1.7” per year. Meanwhile, the global mean sea-level rise is about .15” per year.

The increasing prevalence of industrial processes such as the extraction of groundwater, and oil and gas, along with the rapid construction of buildings and other urban infrastructure are leading to the sinking of the urban areas.

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Rapid land sinking leaves global cities vulnerable to rising seas

Photo, posted October 24, 2015, courtesy of Jeffrey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ecology And Designing Future Cities

January 4, 2016 By WAMC WEB

When most people hear the word ‘ecology’ – chances are it conjures up images of scientists working in distant, wild landscapes, such as old growth forests or remote mountain lakes. Increasingly, however, ecological studies are focused on urban and suburban areas.