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Infrastructure Transformation
“I can’t imagine a more pressing and urgent topic than the one we’ll be discussing today,” said Deanne Bell, founder and CEO of Future Engineers and moderator of the forum at the National Academy of Engineering’s October 2–4, 2021, annual meeting. “Addressing climate change requires cooperation on multiple levels, from policy to research to changing consumer habits, and the engineering community has its own unique roles and responsibilities.”
Bell was joined at the virtual event by five engineers who have considerable experience with engineering responses to climate change:
- Tim Lieuwen (NAE), Regents’ Professor, the David S. Lewis Jr. Chair, and executive director of the Strategic Energy Institute at the Georgia Institute of Technology
- Leslie Shoemaker, president of Tetra Tech
- Catherine Peters, George J. Magee Professor of Geosciences and Geological Engineering, chair of the Department of Civil and Environmental Engineering, and director of the undergraduate Geological Engineering Program at Princeton University
- Mohammad Shahidehpour (NAE), University Distinguished Professor, Bodine Chair Professor of Electrical and Computer Engineering, and director of the Robert W. Galvin Center for Electricity Innovation at the Illinois Institute of Technology
- Ken Washington (NAE), vice president of software engineering at Amazon
Through a series of brief presentations and responses to questions from Bell and the forum audience, the speakers discussed many of the
issues at the forefront of climate-related engineering practice and policy today.
TRANSFORMING THE ENERGY INFRASTRUCTURE
From a broad perspective, the energy infrastructure can be divided into three parts, said Tim Lieuwen of Georgia Tech. On one side are energy sources, such as renewable energy, electric power plants, fossil fuels, and so on. On the other side are energy users, such as cars, buildings, and manufacturing plants. In the middle is a part of the energy infrastructure that is considered less often—the carriers that store and transport energy. This is “like the plumbing and wiring of your house,” said Lieuwen. “It’s behind the walls. It’s in the crawlspace. You don’t see it, but it’s important to have those wires moving electricity around or those pipes moving water around.”
Today, roughly 40 percent of the energy used in the United States is moved via electricity and about 60 percent is moved via fossil fuels. Unlike electricity, fossil fuels have a dual role, in that they are both the source and the carrier of energy. The replacement value of the US energy infrastructure is about $13 trillion.
In evolving the energy system toward greatly reduced emissions of carbon dioxide, the source of energy and the carrier of energy can be separated. For example, solar or wind power could be used to generate hydrogen, or biological materials could be converted to liquid biofuels. In this way, the sources and the carriers of energy are decoupled, and fuels with a net zero impact on climate can be used for energy storage and transport.
A recent study done at Princeton University called Net Zero America demonstrated what a net zero economy would look like, where remaining releases of carbon dioxide are balanced by capturing carbon from smokestacks or from the atmosphere and sequestering it away from the atmosphere. In this study, minimizing aggregate societal costs requires much greater use of electricity, but fossil fuels still account for about a quarter of energy use, offset by large amounts of carbon capture and sequestration. This would represent a “massive new industry” heavily dependent on engineering, observed Lieuwen. This scenario
“is just one view, but it’s a compelling view if we want to minimize the overall cost.”
To avoid catastrophic harm to the Earth’s environment, the use of renewables and electric power will need to grow substantially, which will require that several significant societal decisions be made around the year 2030. One is the division between moving electricity around versus fossil and renewable fuels. Some groups would like to see a much greater use of electricity and put “the use of fuels as energy carriers in the rearview mirror,” Lieuwen said. “But exactly what that mix needs to look like is very much something for discussion.”
The other significant decision involves how to generate renewable energy. Today, the largest source of net zero electricity is hydropower from dams, but this source cannot be substantially expanded in the United States and other developed countries. On the contrary, said Lieuwen, some dams are starting to come down because of environmental issues and their devastating effects on the cultures of indigenous people.
The most rapidly growing source of renewable energy is wind, followed by solar photovoltaic energy. “In fact, wind is not alternative energy anymore,” Lieuwen pointed out. “Last year, wind produced around 8 percent of US electric power. There are days in Texas where wind was generating more than half their electricity.”
Another major source of net zero energy is nuclear power. Though tied up with political and regulatory issues, nuclear power already contributes a substantial portion of electricity generation in some countries, such as France, and it could play a larger role in the future. Smaller, modular-type reactors are also being developed in the United States and elsewhere, which could increase nuclear energy’s contribution to electricity generation. Massive expansion of nuclear energy is occurring in China, whereas Germany is essentially closing down its nuclear plants. In the United States, Georgia is the site of the only new nuclear builds in decades, which has created significant workforce challenges. Nuclear is “certainly doable,” Lieuwen said, but “it remains to be seen whether we can tackle the nontechnical regulatory issues.”
Some renewable fuels, like hydrogen, would require a large amount of new large-scale infrastructure. But some replacements for fossil fuels can be considered “drop-ins,” where the new fuel does not require
major changes to a car, airplane engine, or home furnace. Drop-in fuels can be made two ways. One uses biology; the other, chemistry. An example of the former is the extraction of methane from landfills and livestock operations, although such sources cannot be scaled up to very large scales. An example of the latter is the use of chemical methods to combine carbon from the atmosphere with hydrogen from water to produce fuels. It is currently much more expensive to make fuels this way than to buy gasoline, but new ways to reconfigure carbon and hydrogen atoms could yield as much synthetic fuel as desired.
Today, people have many different visions of the best combination of renewable energy sources. Inevitably, “there will be a mix,” said Lieuwen, including large-scale photovoltaic sites, distributed small-scale sources, and so on.
Engineering considerations will need to be thoroughly integrated into larger societal discussions about the energy infrastructure, Lieuwen observed, because energy systems are not just technical systems, they are sociotechnical systems. “There are millions of jobs tied up in these. There are significant equity impacts tied up in these…. Many of these systems have been foisted on some of the most vulnerable members of our society, those with the fewest resources, and we don’t want that to happen going forward.” As an example of these social challenges, Lieuwen cited the transition away from coal, which peaked at about 20 percent of energy generation in the United States and now is at about 10 percent. That transition involved massive societal disruptions that the country still has not entirely absorbed. Natural gas and oil now account for three times the percentage of energy generation as coal did at its peak, raising significant questions about jobs and who will be affected by the transition to renewable energy sources.
Considerations of equity also require discussions of engineering and society to be “more fine-grained,” said Lieuwen, “to understand the impacts and how they’re distributed.” Lifecycle analysis is needed to understand the costs of different energy systems and how these costs are borne and distributed across all income levels. “Really understanding the broader social contracts, the job impacts, the equity impacts, can move the needle. We’re going to see real motion by 2030.”
TRANSFORMING THE BLUE-GREEN INFRASTRUCTURE
Blue-green infrastructure occupies the interface of water and land, explained Tetra Tech’s Leslie Shoemaker. Building on work done in the area of low-impact development, blue-green infrastructure seeks to mimic the natural environment in urban areas through nature-based solutions to climate-related problems.
As an example, one way to implement blue-green infrastructure is through land-based infiltration areas that capture stormwater runoff and trap some of the toxins by filtering the water through natural vegetation. The solution may seem small scale, Shoemaker acknowledged. “How could one small patch of land that filters water from a parking lot or a building development be something that is going to change the world or address climate change?” But blue-green infrastructure is the sum of its parts. “It’s not the one small piece of green land. It’s the 10,000 pieces of green land that you put across an entire landscape and its additive impact on water, environment, and the resulting outcomes.”
On a larger scale, Los Angeles County, the most populous county in the United States, sends about 100 billion gallons of water into the ocean each year. In 2018 a ballot measure approved by voters dedicated about $300 million per year for blue-green infrastructure throughout the Los Angeles County area, bringing “tremendous benefit to all the communities in the county,” Shoemaker said. Many other places also are using blue-green infrastructure as a way to manage stormwater and produce other benefits. Detroit has a program that repurposes land, including abandoned properties, for green infrastructure; Philadelphia is using green in tandem with grey infrastructure to manage combined sewer overflows.
Shoemaker pointed out that many coastal areas are starting to experience flooding simply from a high tide or full moon. Hard engineering can address some of these potential catastrophes, but for many such challenges, hard engineering solutions are not available. Instead, natural solutions, such as flood barriers through wetlands or green-grey solutions, can help with some types of adaptation. These can allow communities to prepare and respond more quickly. They also can help
build a body of knowledge that enables the field to do continuous innovation, balance hard engineering approaches with nature-based solutions, and quantify benefits in terms of, for example, carbon capture and sequestration.
Working with rather than against nature has multiple benefits, Shoemaker said. It reduces heat in urban areas, improves air quality by adding more green vegetation, boosts quality of life by creating open parks and park environments, controls stormwater quantity and quality, and recharges groundwater. Planning for blue-green infrastructure thus resembles community or master planning more than it does traditional engineering. Still, “the engineering role has been phenomenal in providing the rigor and the quantification of the benefits of blue-green solutions, because without being able to quantify them you can’t integrate them into a risk mitigation strategy.” This ability to quantify benefits creates “a whole new way of doing business in the world of blue-green infrastructure.”
Good engineering also has enabled the leveraging of technology for instrumentation and control of blue-green infrastructure, which makes possible a move from static to active management of the infrastructure. For example, a dashboard can track where water is being stored across an entire watershed, with a control center to manage that water. “I can see which reservoirs are full, or which cisterns are full. We can release water in advance of storms, so that we can enhance the ability to capture more water to protect from floods. We can optimize how we manage water to improve water quality and react, making sure that we have the maximum benefit for our receiving water bodies. We can quantify the amount of carbon sequestration and track it as we go. We can even integrate disparate sources of information, like crowdsourced information, into how we manage our water systems.”
Assets can be managed across a region and across a municipality over long periods of time. Many of the municipalities Shoemaker works with are building robust and smart asset management systems that are integrated with financial planning, economic analysis, climate change mitigation plans, water management systems, and water quality controls.
As with the energy infrastructure, the implications of climate change for blue-green infrastructure are not evenly distributed across com-
munities. In the United States, marginalized communities are disproportionately affected by, for example, flooding, strong hurricanes, and other climate-related events. It is very difficult for them to be resilient and recover from these impacts. Important data science tools need to be developed to help communities prepare for and recover from impacts, Shoemaker observed. “We value and understand things and can take action when we have data.”
“Engineering has a big role to play in turning blue-green from an idea and a concept that’s been around for quite some time to a practical, on-the-ground, and highly innovative implementation,” Shoemaker said. “Climate change is a global challenge, and I see a new way of doing water management as integral to how we address it.”
IMPROVING THE ELECTRICITY GRID
The consequences of climate change are becoming increasingly obvious: large and intense wildfires, more destructive hurricanes, lethal heat waves. In addition, climate change is affecting the built infrastructure, said Mohammad Shahidehpour of the Illinois Institute of Technology. Ten times more large power blackouts have been occurring each year in the 2000s as compared with the 1980s and 1990s.
One contributor to climate change is the increasing urbanization of the world’s population. In 1950, about 30 percent of the global population lived in big cities; by 2050, that number is projected to increase to 70 percent. Many cities are not ready to build the infrastructure required by such a massive migration of people. The result will be growing issues with transportation, clean water and air, and electricity use.
The increased use of renewable forms of energy will cause profound changes to the electricity grid, according to Shahidehpour. The use of electricity varies dramatically over the course of the day as people get ready for work, engage in their jobs, and return home afterward. Solar and wind energy is available when the sun is shining or the wind is blowing but not at other times. Electrical systems and their operators can thus have great difficulty matching energy supplies to energy demand as both continually change.
One solution to this problem is to embed intelligence in the devices that use electricity and in the electricity grid itself. Smart dishwashers,
washing machines, electric vehicles, and other “smartware” can operate or store energy when renewable sources are plentiful or loads are low, reducing the need for additional generation and transmission infrastructure. Similar “levelization” of loads can extend to transportation, water use, and other basic utilities to provide basic human needs in a rapidly urbanizing world, Shahidehpour explained. “The future is going to depend a lot on how we control the load, how we socialize this issue, and how we teach customers to use electricity more intelligently.”
At the same time, smarter electricity grids can distribute power in more efficient and effective ways. New technologies can provide more reliable electricity supplies without the widespread disruptions that can occur in centralized systems. Holistic solutions will rely on distributed systems, enhanced transmission, increased energy storage, and load control.
A particularly promising way to manage power generation and loads is through the use of microgrids, said Shahidehpour. This is not a new idea—the first microgrid was built by Thomas Edison in New York in 1881. It offered two distinctive features: it was islanded, meaning that it could be separated and operated autonomously from other grids, and it used direct current. Although the US electricity grid eventually came to be based on alternating current, renewable energy typically takes the form of direct current, and in modern life many loads, such as for cellphones, laptops, and LED lights, use direct current.
Shahidehpour and his colleagues have converted the campus of the Illinois Institute of Technology to a 12-megawatt islanded microgrid, which is saving the university millions of dollars annually. Building similar microgrids throughout Chicago would create a “smart city” that would enhance the sustainability, reliability, resilience, security, and economics of the electric power system, he said.
Another advantage of renewable energy sources and microgrids is that not as much transmission is needed, because very large generating plants in the past had to be placed far from residential areas with a large transmission system to bring power back to where people live. But smaller power generation units can be closer to where people live and reduce the need for massive transmission systems. This is especially an advantage in developing countries, where the costs of building addi-
tional transmission system densities are prohibitive. Many energy development projects in low-income countries, particularly on the African continent, are already net zero and can remain that way as the energy infrastructure is expanded. “These underdeveloped and developing countries will get to be ahead of the United States at some point when we think about net zero.”
Microgrids come in different sizes and shapes. With microgrids in Africa, for example, local resources might include hydro, solar, biomass, or other available energy sources. “That’s the beauty of microgrids, because we can localize a solution depending on what’s locally available and then use that,” said Shahidehpour. The microgrid at his university uses about 8 megawatts of natural gas and about 1 megawatt of renewable energy, and more renewable energy is being brought on board.
“The future of our communities belongs to these distributed power control systems where we can promote renewable energy and storage and control the load,” Shahidehpour concluded. He reminded listeners that such systems are not only technical but social, economic, and political. “We as engineers have largely overlooked issues like policies and who’s going to pay for all this and how our individual customers can participate in getting all of this done. This is something that I hope the National Academy can participate in and come up with solutions to problems.”
