Posts tagged with "carbon footprint":

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Washington, D.C., debates renewable energy goals

Last week, District of Columbia councilmember Mary Cheh introduced the Clean Energy DC Act of 2018, legislation that, if enacted, would require 100 percent of the electricity sold in the District to come from renewable sources by 2032. The act also specifies new guidelines for retrofitting existing buildings that emit substantial greenhouse gases into more energy efficient structures. The bill must be reviewed by committees before a vote takes place, which would probably happen sometime in the fall. In the wake of the United States' withdrawal from the Paris Climate Agreement, many U.S. cities have set their own sustainability goals, and the attempts have taken various forms, including a pledge by Saint Paul, Minnesota to make all of its buildings carbon neutral by 2050. Under the watch of D.C.'s Department of Energy and the Environment (DOEE), the New Building Emissions Standards proposed by the act would regulate the energy performance of the District's buildings and introduce benchmarks for future construction. Regulations would include cover energy usage and energy efficiency, among other topics. An incentive and financial assistance program would be set up, while penalties would be issued for buildings that fail to comply. Cheh’s office told AN that the act does not intend to create prescriptive policies aimed at restricting the building industry, but the Washington, D.C., chapter of the American Institute of Architects (AIA|DC) expressed that that is a concern. They note that the current proposal "contains ambiguity and leaves the setting of performance criteria up to D.C. DOEE staff without clear opportunity for stakeholder input,” according to an earlier comment. “The legislation puts a large administrative burden on D.C. DOEE staff to set the standards, track compliance, and enforce the requirements of the program," said the AIA|DC in a statement. "The mandate for private property owners to upgrade existing building systems and performance without accompanying financial assistance could be problematic, leading to legal challenges and potentially adversely impact development.” Despite these comments, the AIA|DC said that it is proud that the city intends to lead the nation in setting a new standard for clean energy. This is not the first time that Washington’s building sustainability efforts have come under the spotlight. Last year, the city was dubbed the “quiet capital of sustainable design” by Huffington Post. They reported that in 2016, the city’s volume of certified green buildings per capita was almost eight times that of Massachusetts, and over 11 times the average for the top ten greenest states. D.C. was later named the world’s first LEED Platinum City in recognition of the city’s efforts in reducing greenhouse gas emissions and promoting clean energy in the built environment. One innovative green building currently under construction in D.C. is the American Geophysical Union (AGU) Headquarters. Its “net zero” design means it generates as much energy as it uses. Design features include a photovoltaic array, a radiant cooling system, a green wall, a direct current electrified grid, a water reclamation cistern, and a municipal sewer heat exchange system. The building is seeking the Net Zero Energy Building (NZEB) Certification by the International Living Future Institute.
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Saint Paul, Minnesota pledges to make its buildings carbon neutral by 2050

Saint Paul, Minnesota has set an ambitious goal to reduce its carbon footprint by making all public buildings carbon neutral by 2030 and all private buildings carbon neutral by 2050, as first reported by Twin Cities Pioneer Press. St. Paul officials found that 52 percent of all carbon emissions were related to structures and the energy needed to power, heat, and cool buildings, according to Pioneer Press. Another 37 percent derived from transportation-related emissions. In an effort to encourage a reduction in a building’s carbon footprint, St. Paul has created a competition for private building owners called “Race to Reduce”. Participants monitor and compare their energy use to comparable structures across the city. The city council also recently approved a resolution that outlines general goals such as inspiring a culture of energy stewardship, working with major institutions such as colleges to set energy goals that align with the city, and promoting efficiency in large buildings. Another key aspect is lowering the energy burden on low-income households, ensuring that no household spends more than four percent of its income on energy costs, said Russ Stark, St. Paul’s chief resilience officer, to Pioneer Press. Small changes such as switching off air conditioning at night, as well as buying more renewably-sourced energy from community solar gardens, will help the city achieve its goal. Under the Trump administration and its decision to pull out of the Paris Climate Agreement, cities around the U.S. have been setting their own clean energy goals and emission reduction projections. St. Paul joins cities like Seattle and Boston, which have both declared a goal of becoming carbon neutral by 2050. Former New York City Mayor Michael Bloomberg has pledged $4.5 million to help cover the U.S.’s commitment to the Paris climate agreement.  
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Is mass timber really sustainable?

This is an article from our special November timber issue. We like to blame a lot of things for climate change—namely coal and cow farts—but if we were to search for a worthy scapegoat, architects might end up looking in the mirror. The building sector is responsible for 44.6 percent of U.S. carbon dioxide (CO2) emissions. And, with an estimated 1.9 trillion billion square feet to be built in the next 33 years, those emissions will not subside without significant intervention. On the flip side, for architects anyway, this means the power to reduce carbon emissions is quite literally in your hands. “No designer—I think—wakes up and says, ‘I want to make the world worse today,’” William McDonough, architect, designer, and sustainable development leader said. “To make the world better, that’s our job.” Identifying successful ways to build sustainably can be difficult in a haze of greenwashing and checklist-style certifications, but many environmental experts, architects, and scientists are looking to mass-built timber as a reliable way to reduce carbon and fossil fuel output. A recent study, “Carbon, Fossil Fuel, and Biodiversity Mitigation with Wood and Forests,” stated that using wood as a building-material substitute could save “14 to 31 percent of global CO2 emissions and 12 to 19 percent of global FF [fossil fuel] consumption by using 34 to 100 percent of the world’s sustainable wood growth.” Building with timber reduces the overall carbon footprint in several ways. First, wood is a renewable resource, and growing a tree is a low-impact method of production (i.e. it uses photosynthesis rather than a plethora of machines). Second, trees are grown in abundance all over the United States and don’t need to be imported from abroad, reducing the amount of energy expended on shipping. “Right now we harvest less than half of what we could and still be well within the threshold of sustainability,” Kathryn Fernholz, the executive director at Dovetail Partners, an environmental nonprofit, explained. “That’s not the same in every single scenario, but in general in the U.S., we have an abundance of wood.” Third, and perhaps counter-intuitively, many environmentalists believe that harvesting trees allows forests to become more efficient at carbon sequestration. The logic is simple: When a tree is harvested, it stores carbon, then when another tree is planted in its place, it also will store carbon, making that plot of land’s carbon sequestration infinitely multipliable as trees are planted, grown, and harvested. “There is a widely held belief that cutting down trees is bad and causes loss of forest, but a strong market for wood products would cause us to grow more forests,” Fernholz said. “The vast majority of deforestation is land conversion, using the land for something else like development or agriculture. We know what resources we have and we monitor them and adjust. Forestry is not in the same place it was a hundred or even fifty years ago when deforestation was an issue.” While that stance of de-and reforestation is under debate among environmental experts, across the board, timber is generally a more sustainable building material because it is a renewable resource (provided that responsible forest practices are used). This includes the energy consumed to produce cross-laminated timber (CLT) in factories, which have a carbon emissions advantage over steel because the wood does not need to be heated over 2,700 degrees Fahrenheit like steel or concrete—in fact, unless the wood is kiln dried, heat isn’t need at all. Although embodied carbon is typically measured per building, because different amounts of each material are used in different scenarios, Wood for Good, a campaign by the timber industry to promote the material, claims that a ton of bricks requires four times the amount of energy to produce as a ton of sawn softwood (wood used for CLT); concrete requires five times, steel 24 times, and aluminum 126 times. “Reporting carbon emissions for wood includes a range of different assumptions and methods,” explained Kathrina Simonen, an associate professor of architecture at the University of Washington and director of the Carbon Leadership Forum. “So sometimes it ends up negative and sometimes it ends up positive. It can be confusing.” She is optimistic, however, that research is close to resolving the differences. Responsible forestry practices are already underway, with harvest occurring on long rotations so that the forest has time to regenerate itself and care can be taken to avoid removing other plants, roots, and branches in the process. Lastly, “Wood can be a durable good, as we've seen in ancient wooden buildings like the Temple at Nara, Japan [originally built in 745 AD and rebuilt in 1709],” McDonough said. “In [wood’s] history, it is often put into a cycle of use and reuse that can take it from large numbers to smaller and smaller [components].” Its ability to withstand centuries and to be disassembled and then reassembled into other buildings and furnishings keeps it out of the landfill and in a perpetual cycle of use until it can ultimately be returned to the environment in some form. Although well over 90 percent of one-to-three-story residential buildings are already wood-built, there are only a handful of mid-rise and tall timber buildings across the United States, a result of building codes that often prohibit timber-built structures larger than four to six stories. However, thanks in part to innovative wood products, including CLT, nail laminated timber (NLT), and glue laminated timber (glulam), wood construction can be used in buildings as tall as 40 stories. A study by consulting and engineering company Poyry and the New England Forestry Foundation shows that the greatest potential for timber-built is in mid-rise (six to 14 story) buildings, as it also tends to be more economical to build with timber at that scale. According to the Soft-wood Lumber Board, over two-thirds of the square footage in the mid-rise sector could be made with mass timber. These statistics combined, in addition to the taller structures that mass timber can create, have the potential to make a sizable dent in our CO2 and fossil fuel emissions. Like virtually everything in architecture, though, it is all in the details; for timber to be sustainable it has to be done correctly, from responsible forestry practices to environmentally safe glues and binders to craftsmanship and the design itself. “It is tremendously exciting. Building with wood creates diverse opportunities—there are different species and materials that all can work,” Fernholz said. “However, it is important to recognize that some things can come from wood, but nothing replaces good design and planning.”
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Colorful Carbon Footprint Maps Illustrates Energy Usage Trends

University of California, Berkeley has released a new set of interactive maps illustrating national energy usage.  The visually striking if troubling images reveal a stark urban/suburban divide regarding carbon footprint, with the latter contributing far more in emissions than their city-dwelling counterparts. Average Annual Household Carbon Footprint (Source: UC Berkeley CoolClimate Network (2013) The maps were produced as part of the school's CoolClimate Network.  The three correspond to average annual household carbon footprints, household energy carbon footprint, and vehicle miles traveled respectively. Hovering your mouse over a particular region allows for a more detailed breakdown of the three categories.  The data suggests an inverse relationship between population density and carbon footprint size, which is to say that more densely populated cities tend to be more energy efficient. A further look at the numbers suggests that much of this correlation can be explained by the high transportation costs pervasive in suburbia. Average Household Energy Carbon Footprint (Source: UC Berkeley CoolClimate Network (2013) Yet before New Yorkers or any other urbanites grow too smug, the net effect of this relationship may be largely null.  The denser cities that demonstrate a relatively lower carbon footprint tend to be the very areas that  spawn the extensive suburbs possessing problematically higher ones. The correspondence between usage and population density is not applicable when only suburbs are taken into account, and in fact the opposite correlation tends to be true. Researches claimed that this finding can be explained largely by economic factors. Curious users can see how their household stacks up against their own neighbors or any other region in the country by filling out the Network's CoolClimate Carbon Footprint Calculator. Average Vehicle Miles Traveled by Zip Code (Source: UC Berkeley CoolClimate Network (2013)