construction

Better Paint For Cooler Buildings | Earth Wise

August 20, 2020 By EarthWise 2 Comments

A research team led by scientists at UCLA have developed a super-white paint that reflects as much as 98% of incoming heat from the sun. Such paint, if used on rooftops and other parts of buildings, could have a major impact on reducing the costs of keeping buildings cool.

Passive daytime radiative cooling is a well-known method to keep buildings cooler. By having building surfaces reflect sunlight and radiate heat into space, building temperatures can be significantly lowered. This in turn cuts down on air conditioner use and associated carbon emissions.

A roof painted white will result in lower indoor temperatures than a darker roof. But a white roof will do even more: it can reject heat at infrared wavelengths that are invisible to our eyes. This results in even more radiative cooling.

The best performing white paints currently available reflect about 85% of incoming solar radiation. The rest is absorbed by materials in the paint. The new research has identified simple modifications in paint ingredients that lead to a major increase in reflectivity.

Current reflective white paints use titanium dioxide, which absorbs UV radiation and therefore heats up under sunlight. The researchers studied replacing it with other substances such as barite – an artist’s pigment – or with powdered Teflon, both of which allow the paint to reflect more of the sun’s radiation.

Many cities are encouraging the use of cool-roof technologies on new buildings. Using the most reflective coatings possible on rooftops, if applied on a sufficiently large scale, could have a real impact on climate change as well as saving significant amounts of energy used for running air conditioners in buildings.

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UCLA-led Team Develops Ways to Keep Buildings Cool with Improved Super White Paints

Photo, posted August 15, 2012, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

New Jersey And Offshore Wind | Earth Wise

July 28, 2020 By EarthWise Leave a Comment

New Jersey intends to become a major hub for offshore wind in the United States. The state recently announced a plan to build a 30-acre port along the Delaware River for assembling and deploying wind turbines, as well as an additional 25 acres for manufacturing facilities. The new port is expected to cost as much as $400 million and create 1,500 jobs in southern New Jersey.

The port will be located on an artificial island that was built by the U.S. Army Corps of Engineers early in the 20th century. The island is already home to three nuclear reactors. No bridges exist between the island and the Atlantic Ocean, so turbines that are built at the staging facility could be hoisted upright and towed out to sea without obstruction. Some components are as tall as 500 feet and when fully constructed on the ocean, the turbines selected for New Jersey’s first offshore wind project will be more than 850 feet tall.

A second phase of the program would add over 150 acres to accommodate extensive manufacturing facilities for turbine components like blades and nacelles.

Construction on the port is expected to start next year. New Jersey has pledged to produce 7,500 megawatts of offshore wind energy by 2035 and to generate 100% of its electricity from renewables by 2050. Apart from deploying offshore wind, New Jersey wants to have a significant piece of the supply chain for what is likely to be a growing industry along the northeast coast. The state views offshore wind as a once-in-a-generation opportunity to not only protect the environment but also greatly expand its economy in a way that has immediate impacts and long-term growth.

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New Jersey Announces $400 Million Offshore Wind Port

Photo, posted September 18, 2010, courtesy of Vattenfall Nederland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Largest U.S. Solar Project | Earth Wise

May 28, 2020 By EarthWise Leave a Comment

The largest solar project to date in the U.S. has received final approval from the Department of the Interior. A $1 billion, 690-megawatt solar array will be built on federal land in the Mojave Desert in Nevada. The project includes battery energy storage and is expected to produce enough electricity to power more than a quarter million homes. It will also offset the greenhouse gas emissions equivalent to about 83,000 cars a year.

The current largest U.S. installation, the Solar Star Farm in Southern California, completed in 2015, generates 579 megawatts of power.

Construction of the Gemini Solar Array is expected to start sometime this year and be completed by 2022 or 2023. The first phase of the project will cover 11 square miles of desert land about 30 miles northeast of Las Vegas.

Some conservation groups have fought against the project, saying that it will destroy thousands of acres of habitat for endangered desert tortoises as well as other rare plant and animal species. The groups agree that solar energy is a good thing but are convinced that the location selected is the wrong one.

Interior Department representatives note that the Gemini Project will provide jobs and economic growth at a time when many Americans in general and Nevada citizens in particular are struggling with the impact of the COVID-19 pandemic.

The project is projected to generate $713 million in economic activity and employ about 2,000 people during construction. However, once it is up and running, it will employ just 19 full-time workers.

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The Largest Solar Project in the U.S. Gets Green Light

Photo, posted January 26, 2014, courtesy of Jannes Glas via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Emissions-Free Cement

October 29, 2019 By EarthWise Leave a Comment

The production of cement – which is the world’s leading construction material – is a major source of greenhouse gas emissions, accounting for about 8% of global man-made emissions.

Cement production produces carbon dioxide in two ways: from a key chemical process and from burning fuel to produce the cement. The process of making “clinker” – the key constituent of cement – emits the largest amount of CO2. Raw materials, mainly limestone and clay – are fed into huge kilns and heated to over 2,500 degrees Fahrenheit, requiring lots of fossil fuel. This calcination process splits the material into calcium oxide and CO2. The so-called clinker is then mixed with gypsum and limestone to produce cement.

A team of researchers at MIT has come up with a new way of manufacturing cement that greatly reduces the carbon emissions. The new process makes use of an electrolyzer, where a battery is hooked up to two electrodes in water producing oxygen at one electrode and hydrogen at the other. The oxygen-evolving electrode produces acid and the hydrogen-evolving electrode produces a base. In the new process, pulverized limestone is dissolved in the acid at one electrode and calcium hydroxide precipitates out as a solid at the other.

High-purity carbon dioxide is released at the acid electrode, but it can be easily captured for further use such as the production of liquid fuels or even in carbonated beverages and dry ice. The new approach could eliminate the use of fossil fuels in the heating process, substituting electricity generated from renewable sources.

The process looks to be scalable and represents a possible approach to greatly reducing one of the perhaps lesser known but nevertheless very significant sources of greenhouse gas emissions.

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New approach suggests path to emissions-free cement

Photo, posted March 26, 2014, courtesy of Michael Coghlan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Decline Of Earth’s Largest Freshwater Creatures

September 23, 2019 By EarthWise Leave a Comment

While nearly 70% of the globe is covered by water, only 2.5% of it is freshwater. The rest is saline and ocean-based. And only 1% of our freshwater is easily accessible, with much of it locked away in snowfields and glaciers.

Despite freshwater only making up a small fraction of all water on the planet, it’s home to one third of all vertebrate species. Some have survived hundreds of millions of years, but many of the world’s largest freshwater creatures – including fish, reptiles, amphibians, and mammals – may soon find themselves on the brink of extinction.

According to a study recently published in the journal Global Change Biology, scientists from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries and international colleagues have quantified the global decline of freshwater megafauna for the first time. In four decades since 1970, the global populations of these freshwater giants have declined 88% – twice as much as the loss of vertebrate populations on land or in the oceans.

Freshwater megafauna include all freshwater animals that weigh 30 kilograms (about 66 pounds) or more, such as certain dolphins, beavers, crocodiles, turtles and sturgeons.

Overexploitation is one of the main threats to freshwater megafauna. (These animals are often targeted for their meat, eggs, and skin). The other main threat is the loss of free-flowing rivers. Many of the world’s large rivers are already highly fragmented, which impacts access to spawning and feeding grounds. The research team says another 3700 large dams are planned or under construction, including 800 in habitats rich with freshwater megafauna, including the Amazon, Congo, and Ganges river basins.

Current conservation measures are clearly failing our freshwater creatures.

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88 percent decline of big freshwater animals

Earth’s largest freshwater creatures at risk of extinction

Photo, posted March 25, 2012, courtesy of the U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Scottish Wind Power

September 5, 2019 By EarthWise Leave a Comment

Scotland is a windy country. Most wind turbines in the European Union produce electricity at an average of 25% of their maximum rated power as a result of the variability of wind resources. The west and northern coasts of Scotland have an average capacity of 31% or more. Some wind farms in Scotland have achieved more than 50% capacity over the course of a year.

As of the end of last year, Scotland had more than 8 GW of installed wind power capacity. This included 7.8 GW of onshore wind and 623 MW of offshore wind generators. Estimates are that more than 11 GW of onshore wind could be installed in Scotland. The total offshore potential is far greater than that but would be much more expensive. There are multiple large-scale wind farms proposed or under construction in Scotland.

All of this growth in wind power has led to some remarkable results. During the first half of 2019, wind turbines in Scotland produced enough electricity to power every home in the country twice over. Scottish wind farms generated nearly 10 million megawatt-hours between January and June, which is equal to the consumption of 4.5 million homes during that period. That is enough to take care of all of Scotland’s homes plus a large portion of northern England’s.

Scotland has set a target of generating half of its electricity from renewable sources by 2030 and decarbonizing its energy system almost entirely by 2050. The recent performance of its wind power installations shows that the country might be able to reach its goal much sooner than anticipated.

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Scotland’s Wind Farms Generate Enough Electricity to Power Nearly 4.5 Million Homes

Photo, posted March 27, 2017, courtesy of Ian Dick via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mass Timber

June 10, 2019 By EarthWise Leave a Comment

Mass timber is a type of construction typically characterized by the use of large solid wood panels for wall, floor, and roof construction. Large structural panels, posts, and beams glued under pressure or nailed together in layers, with the wood’s grain stacked perpendicular for extra strength – are prized as innovative building materials, superior to concrete and steel in many ways. Mass timber has pushed the perceived boundaries of wood construction, leading to building heights and spans that traditionally have required concrete, steel or masonry for structural support. The move to mass timber has become something of a construction revolution and many see it as a significant part of a climate change solution.

The question is just how green is mass timber construction? How sustainable is it in terms of the forest management, logging, manufacture and transportation of wood products involved?

A number of environmental groups are very skeptical. There is not yet comprehensive data on the subject. Only recently have interdisciplinary scientists begun to study the potential climate impacts of the wide use of mass timber.

Despite these questions, the mass timber industry is taking off. Demand for mass timber posts and beams has led to new sawmills opening in the U.S. Northwest and many new jobs for loggers.

The aesthetics and economics of mass timber are both very attractive compared with conventional large-scale construction materials. The real unknowns relate to the environmental impact of its widespread use. If that can take place in a sustainable and environmentally conscientious way, it would be very important in the fight against climate change. Carbon dioxide emissions from the building industry account for more than a third of global emissions, primarily from the concrete and steel industries.

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As Mass Timber Takes Off, How Green Is This New Building Material?

Photo, posted March 19, 2018, courtesy of Freres Lumber Co via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Weather-Responsive Traffic Signals

April 17, 2019 By EarthWise Leave a Comment

We all spend time sitting at red lights – sometimes it seems like a whole lot of time. There is a fair amount of science applied in the design of traffic signals that at least has the aim of easing congestion and improving traffic safety.

Signals in modern cities are timed using optimization models that analyze multiple factors including traffic volume and speed with the goal of safely getting as many vehicles as possible through intersections. It sure doesn’t seem that way in many places, but that is the intent in any case.

But a real problem with these models is that they assume normal conditions including weather conditions. In places that experience real winter conditions, the assumptions of traffic models fail. If the road surface is covered with snow and ice and visibility is poor, variables like speed and stopping distances become very different.

Researchers at the University of Waterloo in Canada collected data from real-world intersections and ran computer simulations to determine the effects of adjusting traffic signal behavior in bad weather (as well as in the presence of other conditions such as accidents or construction.) They found that such adjustments could reduce traffic delays by as much as 20%.

Cities with computerized signal systems are already equipped to remotely and inexpensively adjust the timing of traffic lights. To gain the benefits of smarter signals, there would need to be video cameras and a certain amount of artificial intelligence software that would be able to automatically tweak the timing of lights in response to traffic changes caused by weather, accidents or construction.

It sounds like a great idea.

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Weather-responsive intersections could ease traffic congestion

Photo, posted September 22, 2009, courtesy of Tristan Bowersox via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving Beaches With Seagrass

February 22, 2019 By EarthWise Leave a Comment

Almost a quarter of the Gross Domestic Product of places around the Caribbean Sea is earned from tourism. Preserving the beaches in the region is an economic imperative. With increasing coastal development, the natural flow of water and sand is disrupted, natural ecosystems are damaged, and many tropical beaches simply disappear into the sea.

With such high stakes, expensive coastal engineering efforts such as repeated replenishing of sand and the construction of concrete protective walls are common strategies. Rising sea levels and increasingly powerful storms only increase the threat to tropical beaches.

Researchers from The Netherlands and Mexico recently published a study in the journal BioScience on the effectiveness of seagrass in holding onto sand and sediment along shorelines.

Seagrasses are so-named because most species have long green, grass-like leaves. They are often confused with seaweeds but are actually more closely related to flowering plants seen on land. Seagrasses have roots, stems and leaves, and produce flowers and seeds. Seagrasses can form dense underwater meadows and are one of the most productive ecosystems in the world. Seagrasses provide shelter and food to an incredibly diverse community of animals, from tiny invertebrates to large fish, crabs, turtles, marine mammals and birds.

The researchers performed measurements of the ability of seagrass along Mexico’s Yucatan Peninsula coastline to keep sand in place and prevent erosion. They found that the amount of erosion was strongly linked to the amount of vegetation. Quite often, seagrass beds have been regarded as a nuisance, rather than a valuable asset for preserving valuable coastlines. The study opens opportunities for developing new tropical beach protection schemes in which ecology is integrated into engineering solutions.

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Seagrass Saves Beaches and Money

Photo, posted October 13, 2010, courtesy of NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

U.S. Offshore Wind Powering Up

February 26, 2018 By EarthWise Leave a Comment

After many years of false starts and delays, the offshore wind industry in the U.S. finally seems to be gaining momentum. According to the Department of Energy, more than 25 offshore wind projects with a generating capacity of 24 gigawatts are now being planned. Most of these are off of the Northeast and Mid-Atlantic coasts.

Trends Influencing Our Cities

February 23, 2018 By EarthWise Leave a Comment

The Environmental Protection Agency removed its information hub about climate change last year. In response, 17 cities reposted the information on their own city government sites. This is indicative of the fact that cities are increasingly taking on a leadership role in environmental, social and economic change.

Surging Wind Power In The U.S.

June 16, 2017 By EarthWise

So far, it has been a big year for the U.S. wind industry, which experienced its fastest first-quarter growth since 2009. In total, about 2,000 megawatts of new capacity was installed, enough to power about 500,000 homes. With this addition, wind now produces 5 1/2% of the country’s electricity.

Natural World Heritage Sites

May 5, 2016 By WAMC WEB

Natural world heritage sites exemplify the world’s greatest areas of natural beauty, ecology, geology, and biodiversity. They are recognized internationally for their value as places with significance that is “so exceptional as to transcend national boundaries and be of common importance for present and future generations of all humanity.” Many of these areas also are a vital source of food, fuel, and water for rural communities, and provide a revenue stream for national economies through tourism and recreation. The livelihoods of some 11 million people are directly dependent on these areas.

Reduced Waste From Modular Construction

March 10, 2016 By WAMC WEB

Our nation’s landfills are overflowing and we are constantly seeking ways to reduce the amount of waste that needs to go into them. Usually, we are thinking about food waste, plastics, glass and paper. However, one of the largest sources of waste generation is actually construction and demolition waste. Estimates are that between 25 and 40% of the national solid waste stream comes from these activities and very little of it gets recycled.