Posts Tagged: climate change

How re-thinking traditional building materials can lead to new strategies for carbon capture and utilization

Samples of concrete curing in a carbonation chamber in the lab of Professor Daman Panesar (CivMin). A new collaboration between her team and the Canada Green Building Council will investigate new ways to sequester carbon in building materials. (Photo: Dr. Runxiao Zhang)

One of the most powerful tools for mitigating the impact of climate change could be a material that is so common we tend not to think about it very much — concrete.

Daman Panesar (CivE) has been named the Erwin Edward Hart Professor in Civil Engineering. Her research focuses on new ways to improve the performance of concrete structures, from bridges to buildings. (Photo: Tyler Irving)

Prof. Daman Panesar. (Photo by Tyler Irving)

Burying Carbon in Buildings: Advancing Carbon Capture and Utilization in Cementitious Building Materials is a new collaboration between a team of researchers led by Professor Daman Panesar (CivMin) and the Canada Green Building Council. It is funded by a recently-announced $1.7 million contribution by the Government of Canada.

Concrete is the world’s most widely used building material, and it can impact carbon emissions both as a burden and also a benefit. Firstly, the production of cement — one of the key components of concrete — produces relatively large amounts of carbon emissions, so mitigating these could make a big difference. But over its lifetime, concrete also has the ability to uptake carbon from the air.

“Currently, several low-carbon concrete framework documents have been produced worldwide and most of these roadmaps have set 2050 carbon reduction targets related to several levers, such as clinker-cement ratio, alternative fuel use, and carbon capture, storage and sequestration,” says Panesar.

While there has been preliminary work on several carbon utilization approaches, few have been implemented on a large scale. Panesar and her team will examine the challenges associated with scale-up of these strategies, and explore new technologies that can effectively turn built infrastructure into a carbon sink.

“Natural carbonation of concrete occurs by a chemical reaction between the constituents of concrete, particularly cement, and atmospheric carbon dioxide and it has the potential to occur throughout the life of the concrete,” says Panesar.

“However, accelerated or enforced carbonation approaches are relatively new technologies, which can also be referred to as carbon capture and utilization technologies, and can be introduced at different life stages, such as during manufacture or at end-of-life.”

Some examples of carbonation processes that will be explored and assessed include: CO2 injection, elevated CO2 exposure, mineral carbonation using recycled or waste CO2, industry by-products used to replace cement and subsequent CO2 curing, as well as the potential for synthetic treated aggregates.

“All of these techniques need further understanding of the implications and potential for negative emission technologies such as carbon capture utilization approaches,” says Panesar.

Another challenge for both new and existing structures is that any change to the formulations of concrete — for example, using lower-carbon components or absorbing more CO2 during curing — cannot come at the expense of its required structural and material design properties, such as strength and durability.

“For example, considering natural carbonation processes, the mechanism related to the potential for increased vulnerability of reinforced concrete elements to steel corrosion, concrete degradation and shortened service lives is fairly well understood.” says Panesar.

“For existing infrastructure, the situation becomes more complex because there is a need to account for and interpret the role of age-related cracking on the CO2 uptake of concrete, as well as in conjunction with other predominant degradation issues in Canada, such as freeze-thaw cycles.”

Finally, researchers will need to come up with benchmarks and other standardized tools to accurately account for the carbon uptake in building materials.

“Currently, there is no harmonized measure of concrete carbonation, and the differences in measurements and reporting add an extra dimension of complexity when trying to compare between different concrete formulations and/or CO2 uptake technologies,” says Panesar.

“Carbon accounting is critical to enable us to determine the relative environmental impacts of the various approaches and to be able to estimate or forecast the impacts of deploying these new technologies in the coming decades.”

One of the strengths of the new collaboration is that it provides a built-in pathway for new research findings to get translated into industry, as well as into new policies and regulations.

“As the national organization representing members and stakeholders across the green building spectrum, CAGBC can access industry expertise to help advance research and mobilize the sector to implement market solutions,” says Thomas Mueller, President and CEO of the Canada Green Building Council.

“We are proud to partner with the University of Toronto on a project that has the potential to significantly reduce embodied carbon emissions from the cement industry. The results will contribute to the collective effort to decarbonize construction.”

By Tyler Iriving

This story originally published by Engineering News


CivMin’s Prof. Marianne Touchie is research recipient of Dean’s Strategic Fund

As the University of Toronto implements energy retrofits to buildings across its three campuses to meet its aggressive greenhouse gas emission reduction targets, one group of researchers will use the opportunity to improve the well-being of students, faculty, and staff.  

The research project entitled ‘Wellbeing and The Built Environment: A New Framework for U of T Campus Building Performance Assessment’ is a successful applicant to the Dean’s Strategic Fund.  

Professor Marianne Touchie

Prof. Marianne Touchie

The project is being led by Civil & Mineral Engineering’s Prof. Marianne Touchie along with co-applicants John Robinson of the Munk School of Global Affairs and Public Policy and the School of the Environment, Alstan Jakubiec of The Daniels Faculty of Architecture, Landscape and Design as well as Blake Poland from the Dalla Lana School of Public Health.  

Using tools to measure things like indoor air quality and temperature, as well as an app accepting real-time feedback from building inhabitants, the project aims to create a new standard for holistic building performance.  

Not only will it assess environmental and economic benchmarks, but it intends to measure the impact of these retrofits on people working and living in these buildings.  

Prof. Touchie took some time to tell us more about the three-year project.  

What is the project all about?  

We want to inform the retrofit process by trying to link specific aspects of the built environment to wellness outcomes of the people living and working in these spaces. We plan to do this through pre- and post-retrofit assessments using indoor environmental quality measurements and inhabitant feedback. 

The university is investing millions and millions of dollars in energy retrofits, but while we are making that investment, the question is whether we can integrate other changes to the building that would improve the wellness of students, faculty, and staff more broadly.  

What are some examples of the improvements you would make?  

Potentially improving accessibility to spaces, making spaces more thermally comfortable or looking at ways in which we could provide more control to inhabitants. As many of the planned retrofits are to the building mechanical systems, I hope we will be able to provide suggestions of how we can better operate these systems to improve the quality of the indoor environment and address inhabitant concerns that come up in the pre-retrofit assessments.  

How do green retrofits improve the mood and productivity of people inhabiting the buildings? 

The jury is still out on that one. There are some studies suggesting green buildings create a better indoor environment, but there is also a lot of contradictory research.  

This is a complex topic with many distinct aspects of the individual, the space, the building, and the broader community all impacting how the inhabitant feels. Previous research has tended to focus on thermal comfort, visual comfort, or indoor air quality independently, and what we are really trying to do is to bring all those elements together into a common framework.  

Earth Sciences Centre

The Earth Sciences Centre is one location on campus where research will take place over the next three years.

And it is not just the objective quality of the indoor environment that we are interested in, but instead seeing what impact these conditions have on the well-being of the inhabitants.  

While these retrofits are designed to reduce GHG emissions to mitigate climate change and reach U of T’s climate positive by 2050 goal, through this project we are hoping to find ways to leverage these retrofits to also be “people positive” by retrofitting spaces to improve comfort, productivity, health for students, staff, and faculty. 

 

 

 

What results are you most interested in seeing out of this project?  

There are a few things I would like to see come out of this project. From a scientific perspective, I hope this project will contribute to the growing body of knowledge on how aspects of the built environment influence inhabitant wellbeing. From a methodological perspective, I hope that the assessment methods we develop through this project can be integrated into the University’s building retrofit process, both to inform what needs to be addressed through the retrofit and then to verify predicted improvements after retrofit completion to ensure we are meeting our goals related to both the climate and the campus community.  

The U of T Exam Centre.

The University of Toronto Exam Centre is one of the buildings that Touchie’s team will monitor over the next three years.

When are you expecting to begin your research? 

We have already begun the planning process among the co-applicants and will be kicking off the project soon with a wonderful group of people from across the university working with us on this including Facilities and Services and representatives from the Dean’s and Vice Dean’s offices, as well as our industry partner, the International WELL Building Institute

We plan to develop the assessment approaches this year and then begin to conduct pre-retrofit evaluations starting in early 2023.  

Will people notice this research project going on across campus?  

We will target spaces that are common throughout the campus so they might see us in classrooms, offices, and residences. We are also going to combine long-term measurements with inhabitant responses. So, you may see monitoring equipment in particular spaces or calls for participation in the study.  

Depending on what the professors allow us to do, we would love to come in to explain the study to students and point out what sort of measurements we will be doing in the classrooms. 

How can people get involved?  

Keep an eye out for opportunities to participate in the study. We would also be interested in hearing from faculty or staff who know of a space in one of the planned building retrofits that impacts many people in our campus community (e.g., a large classroom or open plan office space). The initial candidate building list includes Earth Sciences and the Exam Centre with more to be identified soon.  

Final thoughts?  

One aspect of the study that I am really excited about is testing the large-scale use of a technique called Photovoice which we will use to prompt respondents to take photos of aspects of the campus-built environment that add to or detract from their wellbeing.  

We are looking to integrate students, staff and faculty perspectives this way as it is a much richer data source than survey responses.  

I am hoping we will be able to crowd source images and perspectives on features of a particular building to determine what the most important aspects are to address through retrofits.  

By David Goldberg


CivMin study: Electric vehicles can fight climate change, but they’re not a silver bullet

Sales of passenger electric vehicles are growing fast, but a new analysis from U of T Engineering researchers shows that on its own, electrifying the U.S. fleet will not be enough to meet our climate change mitigation targets. (Photo: microgen, via Envato)

Today there are more than 7 million electric vehicles (EVs) in operation around the world, compared with only about 20,000 a decade ago. It’s a massive change — but according to a group of U of T Engineering researchers, it won’t be nearly enough to address the global climate crisis. 

“A lot of people think that a large-scale shift to EVs will mostly solve our climate problems in the passenger vehicle sector” says Alexandre Milovanoff, lead author of a new paper published today in Nature Climate Change. 

“I think a better way to look at it is this: EVs are necessary, but on their own, they are not sufficient.” 

Around the world, many governments are already going all-in on EVs. In Norway, for example, where EVs already account for half of new vehicle sales, the government has said it plans to eliminate sales of new internal combustion vehicles altogether by 2025. The Netherlands aims to follow suit by 2030, with France and Canada to follow by 2040. Just last week, California announced plans to ban sales of new internal combustion vehicles by 2035.

Milovanoff and his supervisors, Professors Daniel Posen and Heather MacLean (both CivMin) are experts in life cycle assessment — modelling the impacts of technological changes across a range of environmental factors. 

They decided to run a detailed analysis of what a large-scale shift to EVs would mean in terms of emissions and related impacts. As a test market, they chose the United States, which is second only to China in terms of passenger vehicle sales. 

“We picked the U.S. because they have large, heavy vehicles, as well as high vehicle ownership per capita and high rate of travel per capita,” says Milovanoff. “There is also lots of high-quality data available, so we felt it would give us the clearest answers.” 

The team built computer models to estimate how many electric vehicles would be needed to keep the increase in global average temperatures to less than 2 C above pre-industrial levels by the year 2100, a target often cited by climate researchers. 

“We came up with a novel method to convert this target into a carbon budget for U.S. passenger vehicles, and then determined how many EVs would be needed to stay within that budget,” says Posen. “It turns out to be a lot.” 

Based on the scenarios modelled by the team, the U.S. would need to have about 350 million EVs on the road by 2050 in order to meet the target emissions reductions. That works out to about 90% of the total vehicles estimated to be in operation at that time. 

“To put that in perspective, right now the total proportion of EVs on the road in the U.S. is about 0.3%,” says Milovanoff. 

“It’s true that sales are growing fast, but even the most optimistic projections suggest that by 2050, the U.S. fleet will only be at about 50% EVs.” 

The team says that in addition to the barriers of consumer preferences for EV deployment, there are technological barriers such as the strain that these vehicles would place on the country’s electricity infrastructure. 

According to the paper, a fleet of 350 million EVs would increase annual electricity demand by 1,730 TWh, or about 41% of current levels. This would require massive investment in infrastructure and new power plants, some of which would almost certainly run on fossil fuels. 

The shift could also impact what’s known as the demand curve — the way that demand for electricity rises and falls at different times of day — which would make managing the national electrical grid more complex. Finally, there are technical challenges to do with the supply of critical materials, such as lithium, cobalt and manganese for batteries. 

The team concludes that getting to 90% EV ownership by 2050 is an unrealistic scenario. Instead, what they recommend is a mix of policies, including many designed to shift people out of personal passenger vehicles in favour of other modes of transportation. 

These could include massive investment in public transit — subways, commuter trains, buses — as well as the redesign of cities to allow for more trips to be taken via active modes, such as bicycles or on foot. They could also include strategies such as telecommuting, a shift already spotlighted by the COVID-19 pandemic. 

“EVs really do reduce emissions, but they don’t get us out of having to do the things we already know we need to do,” says MacLean. “We need to rethink our behaviours, the design of our cities, and even aspects of our culture. Everybody has to take responsibility for this.” 

By Tyler Irving

 

This story originally published in Engineering News


Going with the flow: Alumna Jenny Hill aims to improve stormwater management in Toronto and beyond

Jenny Hill (CivE PhD 1T6) advises everyone from landscape architects, to professional civil engineers, to condominium developers, on how to put more water back into the ground and the air. (Photo credit: Yuestas David )

Jenny Hill (CivE PhD 1T6) advises everyone from landscape architects, to professional civil engineers, to condominium developers, on how to put more water back into the ground and the air. (Photo credit: Yuestas David )

Before Jenny Hill took on her current job — working to prevent catastrophic city-wide flooding in the Greater Toronto Area — she worked in a police forensics lab. She thinks her role now is more exciting.

“Forensics is not what people think,” she says. “None of us carry guns, we don’t do a dozen different tests to solve a crime. We have to do very routine tasks, which quickly becomes repetitive.”

In her spare time, Hill pursued a master’s degree in landscape architecture, and eventually moved to Toronto to work in the field. But she quickly discovered that her U.K. training wasn’t completely transferable, and began considering the related field of environmental engineering.

“I decided to reach out to a few professors at U of T, just to get a feel for what was going on,” she says. Soon, she found herself in the lab of Professor Jennifer Drake (CivMin), a leading expert in stormwater systems and management.

Urban stormwater is a critical issue for many large cities, including Toronto, which experienced catastrophic flash floods in both 2013 and 2018. Part of the challenge is that asphalt, concrete and rooftops are normally impervious to water. Heavily paved urban landscapes prevent rainwater from draining into the underlying soil — instead, the built environment channels it into low-lying areas, which quickly become overwhelmed.

Hill focused her research on designing infrastructure that could help absorb excess rain and release it at a more gradual pace. In particular, she looked at the performance of various types of green roofs using the Green Roof Innovation Testing Laboratory (GRIT Lab) at the John H. Daniels Faculty of Architecture, Landscape, and Design.

Green roofs are often touted as a potential solution to urban flooding: a 2009 Toronto bylaw mandated the construction of green roofs on all new buildings. But according to Hill, the law omitted any performance-based specifications, limiting its effectiveness.

“It simply says that you have to have one,” she explains. “You know the turf grass you can roll out onto a lawn? You can purchase a similar product, roll it onto the roof membrane and call it a day, but that alone doesn’t have much absorbent capacity.”

A key finding of Hill’s research was how the composition of the soilless planting medium affects a green roof’s performance in adequately meeting the stormwater retention needs of the city. “The planting medium is a key component of a green roof, it influences the performance in relation to stormwater management, and the resiliency of the planting,” says Hill.

Today, Hill works as a research scientist at the Toronto Region Conservation Authority (TRCA), which is mandated to ensure the conservation, restoration and responsible management of the region’s water, land and natural habitats. In this role, she advises everyone from landscape architects, to professional civil engineers, to condominium developers, on how to put more water back into the ground and the air.

Green roofs are only a small part of the strategy. Hill and TRCA promote feasible, sustainable solutions such as implementing underground stormwater crates and the planting of more tree pits.

They also advocate for floodable landscapes: areas such as the public parks that line ravines throughout the city of Toronto that are specifically designed to flood during heavy rain events. The idea is to contain waters in these recreational areas rather than allowing them to destroy homes and businesses. But Hill acknowledges that it can be a hard sell.

“The public are afraid of flooding, and rightly so,” she says. “They think you’re bringing the flooding to them, but that’s not the case. We can’t easily stop having excess stormwater in the city. We have to decide where to flood; do you want it in your park or in your basement?”

Hill is currently focusing her research on the practice and development of floodable landscapes  around the world — she cites the Netherlands as a useful model — with the aim of implementing more of them throughout Toronto.

Looming over all her work is the threat of climate change, which will likely increase the frequency and intensity of flooding events. Hill says that while floodable landscapes, green roofs, and other low-impact developments will make a positive difference in managing floods, they may not be enough on their own.

“I think that climate change is serious enough that we’re going to need all of these green infrastructure measures, and the pipes.” she says. “It’s not an ‘either or’ situation. We will need all of the engineering.”

By Liz Do


This story originally appeared on U of T Engineering News


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