Sustainability

SECURING THE PLANET FOR FUTURE GENERATIONS

“The cumulative scientific evidence is unequivocal: Climate change is a threat to human well-being and planetary health.”

– UN Intergovernmental Panel on Climate Change “Climate change is the existential threat to humanity. Unchecked, it is going to actually bake this planet. This is not hyperbole. It’s real. And we have a moral obligation.”

– U.S. President Joe Biden

In February 2022, the Sustainable Engineering Initiative at NYU Tandon was founded. The initiative, directed by Associate Professor Miguel Modestino (CBE), is devoted to developing comprehensive and tangible engineering methods of addressing the vast array of environmental challenges now facing the world.

The initiative’s researchers, who include faculty across multiple departments, will be focused on a framework they call AMRAd: avoiding emissions and pollutants whenever possible; mitigating them when total avoidance isn’t possible; remediating in cases where mitigation is insufficient, such as when dealing with situations that developed before 1970s-era environmental protections were put into place; and, finally, developing engineering adaptations to situations beyond human control, such as when localized flooding occurs, almost inevitably carrying contaminants.

Modestino and the other researchers involved will be applying the framework to a variety of areas, such as clean transportation, industrial decarbonization, efficient and resilient power grids, disaster risk analysis, environmental justice, and others. This initiative is a direct result of Dean Jelena Kovačević’s strategic plan, which focuses on areas of research rather than siloed departments.

Modestino is joined in the initiative by more than 20 other researchers, spanning departments and centers across the school.

André Taylor

André Taylor receives DOE Solar Energy Technology Office Award

Professor André Taylor (CBE, SEI) was selected to receive a $300,000 award from the U.S. Department of Energy Solar Energy Technologies Office (SETO) to advance solar photovoltaics research and development to help eliminate carbon dioxide emissions from the energy sector.

Taylor’s project, “Passivated and Conductive Back Contacts for Bifacial Cadmium-Telluride PV,” will generate novel approaches to fabricating next-generation cadmium-telluride (CdTe) solar cells using two-dimensional nanomaterials that are highly conductive and can be used as transparent contacts. The process will enable the use of low-cost processing techniques, like spraycoating and slot-die coating; their tunable surface properties could lead to higher-efficiency CdTe PV.

“Among the industry problems this work addresses is the issue of the back contact, which affects performance. The question is, how do you find a material with ideal performance with CdTe systems? We think these 2D nanomaterials confer that kind of performance,” said Taylor.

He added that the novel element of his work will be the use of these nanomaterials in concert with CdTe. “We have been working on both the techniques and materials to extend this work,” he said.

Shifting the sun

Tandon researchers developed a film for solar cells that shifts the light spectrum by up to 95 percent to increase efficiency.

Solar cells are a key feature of creating a sustainable energy ecosystem for the future. Existing solar arrays and cells can produce clean energy from the most abundant source in nature. But increasing their efficiencies while lowering cost to replace coal and gas as energy sources still requires technological advancements — advancements that we need sooner rather than later.

Now, a team of researchers led by Professor and Chair Eray Aydil (CBE), is tackling one facet of solar cells’ inefficiency — the nature of light itself.

The issue with silicon solar cells is that they are not the best match for the solar spectrum. Only certain wavelengths can be efficiently utilized with existing cells. For example, ultraviolet and blue light aren’t converted to electrical power as well as infrared light. This means that a great deal of the potential energy that could be captured is wasted.

The solution Tandon researchers came up with involved, essentially, “Changing the sun,” according to Aydil. They developed a film that can be used in the solar cells to shift the light spectrum, turning ultraviolet and blue light (from the less efficient band of the spectrum) into near-infrared light (the more efficient source for solar cells).

Changing the light spectrum has other benefits to the cells. UV rays can cause the cells to degrade more quickly, which would require them to be replaced more frequently, increasing the cost of electricity. UV rays can also cause overheating due to the excess energy they carry, decreasing their efficiency and contributing to their premature degradation. By shifting these rays into the near-infrared part of the spectrum, the new film can solve multiple issues with a single fix.

Industry Assistant Professor Tega Brain, Industry Associate Professor Benedetta Piantella, and Adjunct Assistant Professor Alex Nathanson (M.S. ‘19)

Surf the web on solar lightwaves

To address the climate emergency, the U.S. needs to make an unprecedented energy transition across all sectors. This has implications for systems that we take for granted, even those of the internet or “the cloud.” The energy demands of the cloud are perhaps less obvious than those of other systems of infrastructure. After all, the shiny digital interfaces we interact with daily mask a backend of massive data centers and sprawling transmission networks — and where the energy requirements of these infrastructures, as well as the devices and systems connected to them, are responsible for greenhouse gas emissions equal to that of the global airline industry. The energy demand of the Internet is growing rapidly, especially with the expansion of computational approaches like blockchain and AI. The carbon footprint of a single Ethereum, proof-of-work transaction is equivalent to nearly 329,000 credit card transactions, and the training of a neural network uses more energy than five cars across their entire lifetimes. A new project, Solar Protocol, developed by a team of Tandon researchers, spotlights how the transglobal trafficking of data through the web is a major consumer of energy and driver of climate change, as well as explores possible responses.

Developed by Industry Associate Professor Tega Brain (IDM, SEI); Industry Associate Professor Benedetta Piantella (IDM, CUSP); and Adjunct Professor Alex Nathanson (IDM), Solar Protocol comprises a web platform hosted across a network of solar-powered servers, set up and maintained by volunteers around the world. The project demonstrates what the team calls “energy-centered design,” an approach to UX design that foregrounds the carbon implications of digital experiences and that prompts designers to consider these effects as a key part of the design process. Designers are highly innovative and are well positioned to respond creatively to constraints like the need to make web experiences light-weight and with low data requirements. As a workable system that spans the planet, Solar Protocol also investigates the politics of the web and different ways to route web traffic. In stark contrast to large-scale, high-volume web services that algorithmically direct network traffic to whichever server gives the quickest response time, usually the closest geographically, Solar Protocol uses the distribution of solar energy across the planet to determine where to send web traffic in the network. By sending web traffic to whichever server is in the most sun at the time, the system is also dynamically moving the computational work required to generate and send the website, to the place where there is the most naturally available energy. In this way, the sun becomes the “logic” used to automate decisions in the digital network.

By considering the energy demands of the whole computational stack, from hardware to software to interface design, Solar Protocol imagines an internet that operates in concert with our shared environmental conditions.

Tandon researchers are exploring gas hydrate crystallization in nanopores to understand the impact of warming oceans on methane emissions.

LEARN FROM THE WATERS

Below the seafloor

A vast amount of the powerful greenhouse gas methane is sequestered as frozen crystals in the world’s oceans. Of great concern among experts is the growing risk that, as the Earth warms and ocean temperatures rise, these highly disruptive, potent greenhouse gasses will ‘flee’ their frozen confinement..

To understand the stability of these crystalline hydrocarbon deposits, Associate Professor Ryan Hartman (CBE) is launching an investigation into how this “fire ice” forms within a medium of sedimentary mineral deposits and remains in solid form under specific pressures and temperatures.

Hartman had previously studied how unusual sea-floor symbiosis between worms and their microbial neighbors keep these deposits under wraps. He discovered that this natural ecosystem involving feather duster worms (Sabellidae, Annelida) and both heat-generating and heat-absorbing bacteria (Archaea) that consume methane enclathrated — or locked into a crystalline structure — by hydrates in deep marine environments play a key role in maintaining equilibrium that keeps hydrates frozen.

Seeking to examine the influence that subtle temperature fluctuations may have on the dynamic stability of the hydrate deposits, the investigators found that feather duster worms, which thrive around crystalline hydrates, by selectively consuming heat-generating bacteria called methanotrophs that metabolize methane, put the brakes on the potential melting of these crystal structures (releasing trapped methane) due to the microbes’ exothermic metabolism.

The team simulated the ecosystem by solving the associated energy balance and methane hydrate dissociation kinetics. They examined and analyzed the dissociation rate — the rate at which frozen hydrates disassembled into molecular components — and found that the symbiosis established among methanogens (methaneproducing bacteria), methanotrophs, and feather duster worms indeed stabilizes methane hydrates at depths where the crystals are exposed to the ocean and its living organisms.

Now, they are exploring gas hydrate crystallization in nanopores — pores or cavities in a substance whose dimensions can be measured at the nanometer scale. In oceans worldwide, hydrate crystals form within the nanopores of sedimentary materials from the arctic permafrost to a range of deep marine environments.

Ryan Hartman

The heterogeneous materials have profound implications for energy and climate change, particularly in deeper waters, where these structures dominate: while they are vital, energy-rich entities that form spontaneously from water and small hydrophobic molecules under specific temperature and pressure conditions, they also keep highly volatile greenhouse gasses under frozen “lock and key.”

The organisms helping clean up a Superfund site

Scientists sampling the Gowanus Canal’s “black mayonnaise.”

Photo credit: Matthew Seibert

Greenhouse gasses are not the only pollutants that affect the waters, of course. Take one look at the Gowanus Canal, a Superfund site in Brooklyn where the water is so dirty, it is uninhabitable to life. Well, most life. Assistant Professor Elizabeth Hénaff (TCS, SEI, CUSP, C2SMART) has been uncovering a community of extremophiles, a type of microorganism capable of living in extreme conditions that have the ability to break down the pernicious waste, at the bottom of Brooklyn’s Gowanus canal. These microbes reproduce with enormous speed, the ratio of time being 20 years in 20 minutes of our perception.

Researchers Elizabeth Hénaff and Ian Quate during a trip to collect samples.

Photo credit: Josh Johnson

And these creatures are not just thriving in such an environment — they may be helping to clean it up. If these creatures can eat the industrial waste that makes the canal so inhospitable, then they’re unique biology could be utilized to clean up other waste from polluted bodies of water. Hénaff believes that these extremophiles could hold some secrets to a sustainable solution for severe pollution, and a way to harness evolution for the earth’s benefit.

Goodbye Stick, Hello Carrot

Miguel Modestino

In a world where the Environmental Protection Agency’s ability to regulate greenhouse gasses has been limited by the supreme court, engineering solutions must be matched with policy solutions. In an op-ed, Professor Miguel Modestino (CBE and Director of the SEI), gave his advice to the United States’ government to help incentivize industry to convert to sustainable energy, even if they can’t be forced to through law.

“Low profit margins advocate for fossil fuel use in the short-term due to the upfront investment in retrofitting manufacturing plants with new equipment, but in the long term, renewables are poised to confer lasting revenue benefits,” explained Modestino, adding that while the federal government “may not be able to mandate change through regulation, [it] can encourage change through incentives, thus allowing the chemical manufacturing industry to retrofit itself to be more efficient and sustainable through the use of renewable power at scale.”

He suggests a robust program of increased government funding for research, development and demonstrations, and tax rebates or other financial subsidies that could help shift the green revolution forward, even in the face of setbacks. The full article can be found at engineering.nyu. edu/news/goodbye-stick-hellocarrot

Protecting communities from flooding

If polluted water, like that from the Gowanus Canal, rises onto the city streets, it creates a new host of problems. Specifically, the bacteria and microbes that floodwater leaves behind. When Hénaff, Assistant Professor Andrea Silverman (CUE, CUSP, SEI), and Industry Associate Professor Tega Brain (IDM, SEI) set out to study the microbiome of city streets after flooding, seeking to discover how sewage and other contaminants were affecting flood-prone neighborhoods worldwide, they were faced with a dilemma: there was no way to predict when flooding might occur so that they would know where and when to take samples.

Tandon researchers are part of the FloodNet consortium deploying ultrasonic sensors in low-lying NYC areas prone to hyperlocal flooding.

The group joined forces with Research Assistant Professor Charlie Mydlarz (CUSP) to design and deploy a series of sensors that would gather data and alert them to the presence of hyper-local flood events. With support from C2SMART, Tandon’s U.S. DOT Tier 1 University Transportation Center, the team collaborated with the Science and Resilience Institute at Jamaica Bay (SRIJB) led by Brooklyn College and the Advanced Science Research Center at the City University of New York (CUNY) to form a consortium called FloodNet. The City of New York has incorporated the network into its own flood resiliency plan and, as Mayor Eric Adams announced on September 1 — the anniversary of Hurricane Ida’s landfall in NYC — FloodNet will expand to 500

Andrea Silverman

Tega. Brain

Charlie Mydlarz

sensors citywide. It is the first systematic, continuous, and accessible record of regular and catastrophic street-level flood events in the city.

FloodNet sensors can detect flood depths as low as 0.5 inches. Given the hyper-local and distributed nature of urban flooding, the sensors were designed to be affordably built and easy to install to allow deployment of a large, distributed sensor network. Additionally, the sensors are:

• Flexible for multiple use cases and scenarios (not requiring power or connectivity infrastructure)

• Easy to construct with a simple open-source design (allowing community participation in construction and deployment)

• Accessible via open-source firmware, software, and hardware design files publicly available online at a GitHub repository

NYC Mayor Eric Adams holds an ultrasonic sensor at a press conference about the city leveraging data from the growing FloodNet sensor network to power decision-making.

The consortium has launched a realtime dashboard on its online interface at FloodNet. nyc to integrate, store, and disseminate sensor data and other flood-related data streams (including comments from community members, and tide and rainfall data) to a range of stakeholders, including community members, city agencies, researchers, weather forecasters, and reporters.

Undergraduates Sophie Weiss and Dorothy Zhang and recent graduate Christina Curry

Confronting the Anthropocene

When the Association for Environmental Studies and Sciences (AESS) held its annual conference, with the theme “Hopeful Strategies for the Anthropocene,” a trio from Brooklyn was there to present their work.

The Anthropocene refers to our current geological age — a time when human activity and demands exert a major influence on climate and the environment. With U.N. experts predicting that there may be 11 billion people on the planet by 2100, it’s evident that the world’s scientists, technologists, engineers, and sustainability experts must devise ways to mitigate those human effects.

The AESS — an organization of environmental educators and STEM professionals who value interdisciplinary approaches to research, teaching, and problem-solving — convened its latest conference with that in mind.

Former Industry Assistant Professor Alice Reznickova, whose area of expertise is sustainable urban environments, encouraged her students to submit proposals for inclusion in the highprofile event, and in late June, three of them headed to Towson, Maryland, not only to hear scholarly presentations on such topics as sustainable food systems and environmental justice but to present their own research.

Christina Curry, who graduated with a B.S. in May and who will be pursuing her graduate degree in Urban Planning at NYU Wagner, presented her Tandon capstone project, a study entitled “The Effects of Vegetal Elements on Perceptions of Safety of Urban Pedestrians.”

“Literature on this topic has been mixed, but even though no definitive conclusions have been drawn yet, we do know that how people perceive an area’s safety will affect how they use public spaces,” she explains. “Because of urban greening trends, I decided to focus on a space’s vegetation. How does it feel when a street is tree-lined? Can the same level of greenery feel comforting by day but threatening by night?”

Curry concluded, after analyzing her survey results, that pedestrians perceive well-lit, active, moderately vegetated

areas to be the safest — while overly vegetated and unvegetated settings both contributed to feelings of unease. “Of course, factors like lighting and whether or not someone is walking unaccompanied are exceptionally important, the presence of vegetation is preferable, and its placement should be considered alongside the other design elements of a site,” she asserts.

Undergraduates Sophie Weiss (TCS) and Dorothy Zhang (CSE) participate in the VIP team Solutions for Sustainable Futures, and their presentation focused on the ways in which multi-semester interdisciplinary programs like VIP can enhance undergraduate education.

Students in the VIP program choose a hands-on project of real-world importance and work on it almost the entirety of their academic careers, earning credit each semester. Because the projects are multidisciplinary, students from all majors can participate, and a motivated person can take on increasingly responsible roles as their school years progress, tracing the trajectory they might take over the course of their professional lives.

Weiss and Zhang’s team currently consists of 24 students pursuing various projects related to sustainability education, food security, waste management, and urban design, and in their presentation, they discussed how an initiative like VIP works, including student recruitment, project selection, and assessment and evaluation. They showcased examples of each of the projects, highlighted the different competencies developed by students, and spoke openly about barriers they had faced.

“Sustainability education is on the rise, and this type of initiative can nurture meaningful connections between students, support interdisciplinary collaborations, promote leadership development, and act as a catalyst to bring a large number of students into real-world sustainability work,” they say.

They were, as their advisor pointed out, the only undergraduates to be invited to present at the conference.