cooling effect

Floating Solar In New York’s Capital Region | Earth Wise

June 8, 2021 By EarthWise Leave a Comment

We have previously talked about installing solar arrays on the surface of bodies of water. The idea is especially attractive in places like Japan where land resources are scarce. There are several floating solar installations in the UK and the idea is starting to catch on elsewhere as well.

It is quite possible that the largest municipally owned floating solar array may get built in the city of Cohoes in New York’s Capital Region if a project under consideration for federal funding moves forward.

The proposal is for an installation of 8,000 solar panels to cover about 2/3 of the 10-acre Cohoes reservoir. Cohoes has wanted to erect a solar installation to generate power for its buildings but needed to find suitable vacant land. The 10-acre manmade reservoir could be an excellent location for a floating solar array.

Cohoes would be the first community in the US to build and own a floating array on a manmade reservoir and could serve as a model for municipalities across the nation. Such a project makes additional use of land that is already municipal property. According to the city, the 3.2-megawatt array would generate over 4 million kilowatt hours of electricity per year, saving the city $300-350,000 annually.

Cohoes is seeking $4.59 million in federal funding to support the project and has the support of U.S. Representative Paul Tonko for possible inclusion in the 2022 federal budget.

Apart from generating electricity, putting solar panels on the surface of a reservoir reduces evaporation, lowers algae growth, and actually improves solar panel performance because of the cooling effect of the water.

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Cohoes reservoir could be a floating solar power pioneer

Photo courtesy of Michael Coghlan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Air Pollution Reduction And Global Warming | Earth Wise

April 13, 2021 By EarthWise Leave a Comment

The world is dealing with two serious problems affecting the atmosphere: the growing levels of carbon dioxide leading to a warming climate and the effects of air pollution on human health. It turns out that these two things are connected in complicated ways.

Countries around the world are racing to mitigate global warming by limiting carbon dioxide emissions. The combustion of fossil fuels as well as wood and other biomass produces sulfate aerosols, which are associated with acid rain as well as many human health problems. Air pollution causes an estimated seven million premature deaths per year worldwide, so reducing it is imperative.

The complication is that sulfate aerosols in the upper atmosphere actually have a cooling effect on surface air temperatures. Aerosols create bigger clouds and increase light scattering, both of which result in less sunlight reaching the surface. Large natural sources of sulfate aerosols – such as volcanic eruptions – can temporarily cool the earth until they settle out of the atmosphere.

There are many kinds and sizes of atmospheric aerosols, making predicting their effects and behavior difficult. For example, black carbon aerosols from forest fires tend to suppress cloud formation by warming the air and making tiny water droplets evaporate. However, sulfate aerosols from burning fossil fuels make clouds grow larger.

Analysis has shown that air pollution has actually reduced the amount of warming that has taken place to date. A new study by Kyushu University in Japan looked at the long-term climate effects of reductions in sulfate aerosols. The loss of cooling effect from light-scattering aerosols as emissions are reduced is a factor that cannot be ignored.

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Air pollutant reductions could enhance global warming without greenhouse gas cuts

Photo, posted January 23, 2021, courtesy of Wutthichai Charoenburi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cooling Down Urban Heat Islands

November 6, 2019 By EarthWise Leave a Comment

Researchers have known about and studied the urban heat island effect for quite some time. Since large cities began to emerge in the 19th century, it has been understood that various aspects of the urban environment lead to warmer temperatures than the surrounding countryside.

Researchers led by a group at Portland State University in Oregon have been utilizing a new way of studying the urban heat island effect. They have used citizen science volunteers in 24 cities around the world to map temperatures in the cities at ground level in great detail using mobile sensors attached to slow-moving vehicles. Previous studies have used data from satellite or stationary sensors. They have learned that the urban heat island effect is more complicated, more varied, and subtler than the earlier data indicated.

They found that there are six things that affect urban heat. Three are living — the volume of the tree canopy, the height of the tree canopy, and the ground level vegetation. Three are human-built — the volume of buildings, the difference in building heights, and the coloring of the buildings.

Buildings can have both negative and positive effects. Tall buildings that cast shade actually lower relative afternoon temperatures, while densely packed shorter buildings, like the big-box stores in suburban areas, lead to hotter afternoon temperatures. The studies show that increasing the difference in building heights in an area creates more air circulation, which has a cooling effect.

The study also showed that urban heat is a social justice issue. Lower-income neighborhoods largely barren of trees have considerably higher temperatures than more affluent, tree-shaded areas.

Such detailed research can be used to guide decisions in urban planning with regard to trees, building heights, and the color and type of surfaces in our urban spaces.

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Can We Turn Down the Temperature on Urban Heat Islands?

Photo, posted July 21, 2009, courtesy of Daniel Dionne via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.