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When it comes to sustainable spices, ‘single-origin’ isn’t everything

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Monday, September 11, 2023

". . . when shopping, "it's essential to go beyond the label'"

". . . when shopping, "it's essential to go beyond the label'"

". . . when shopping, "it's essential to go beyond the label'"
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Yellen to outline voluntary sustainable investment principles

Treasury Secretary Janet Yellen on Tuesday will outline voluntary standards aimed at promoting sustainable investment and discouraging the practice of misleadingly marketing business activities as environmentally friendly, known as greenwashing. Yellen will make the comments in New York at the Bloomberg Transition Finance Action Forum in New York City, according to excerpts released by the...

Treasury Secretary Janet Yellen on Tuesday will outline voluntary standards aimed at promoting sustainable investment and discouraging the practice of misleadingly marketing business activities as environmentally friendly, known as greenwashing. Yellen will make the comments in New York at the Bloomberg Transition Finance Action Forum in New York City, according to excerpts released by the Treasury Department. The voluntary principles will be accompanied by $340 million in voluntary philanthropic commitments, according to the Treasury Department. The principles outlined by the Treasury Department state that institutions’ commitments should be in line with keeping warming below the international threshold of 1.5 degrees Celsius; and that those institutions should incorporate plans for managed carbon phaseouts in their plans and develop specific metrics and goals as well as specific governance and oversight practices. “There is extensive evidence showing that the changing climate has significant financial impacts. Without considering these factors, financial institutions risk being left behind with stranded assets, outdated business models, and missed opportunities to invest in the growing clean energy economy,” Yellen said in excerpts released by the department. “We are proud to launch the Net-Zero Principles in response. Our goal is to affirm the importance of credible net-zero commitments and to encourage financial institutions that make them to take consistent approaches to implementation. Our work will also help institutions that have not yet made commitments see what doing so might entail.” The department emphasized the voluntary nature of the principles, which come after a period of sharp backlash to the use of environmental and sustainable governance in the finance sector, often accompanied by misleading characterizations of who will be compelled to follow them. The Treasury Department under Yellen, meanwhile, has been criticized by environmentalists for its pace on climate issues, with Joe Thwaites, an international climate finance expert at the Natural Resources Defense Council, telling Bloomberg in 2021 that “the Treasury really hasn’t pulled out all the stops.”

Well behind at halftime: here’s how to get the UN Sustainable Development Goals back on track

Our research shows the world is not on track to achieve any of the Sustainable Development Goals. But with decisive action, we can still achieve a fairer, more sustainable and prosperous future.

United NationsThis week world leaders are gathering at the United Nations (UN) headquarters in New York to review progress against the Sustainable Development Goals. We’re halfway between when the goals were set in 2015 and when they need to be met in 2030.As authors of a global UN report on the goals, we have a message to share. Currently, the world is not on track to achieve any of the 17 goals. There is much at stake. Failing to achieve the goals would mean by the end of the decade, 600 million people will be living in extreme poverty. More than 80 million children and young people will not be in school. Humanity will overshoot the Paris climate agreement’s 1.5℃ “safe” guardrail on average global temperature rise. And, at the current rate, it will take 300 years to attain gender equality.But there is hope. With decisive action, we can shift the dial towards a fairer, more sustainable and prosperous world by 2030. Read more: We modelled 4 scenarios for Australia's future. Economic growth alone can't deliver the goods What does the research say?The set of 17 universal goals agreed in 2015 aim to end poverty, improve health and education, and reduce inequality – while tackling climate change and preserving our oceans and forests. Each of the goals are broken down into targets. Every four years, the UN Secretary-General appoints an independent group of 15 international scientists to assess progress against these goals and recommend how to move forwards. We were among the authors of the latest Global Sustainable Development Report published late last week.To provide a snapshot of progress, we reviewed 36 targets. We found only two were on track (on access to mobile networks and internet usage) and 14 showed fair progress. Twelve showed limited or no progress – including around poverty, safe drinking water and ecosystem conservation. Worryingly, eight targets were assessed as still going backwards. These included reducing greenhouse-gas emissions and fossil fuel subsidies, preventing species extinction and ensuring sustainable fish stocks. Hear from some of the scientists behind the Global Sustainable Development Report 2023. What is holding us back?Recent studies have identified feasible and cost-effective global and national pathways to accelerate progress on the goals. Unfortunately, in many developing countries, insufficient financial resources and weak governance hinder progress. In other cases, existing investments in fossil fuels have generated strong resistance from powerful vested interests. Achieving some goals, such as responsible consumption and production, will also require big, unpopular changes in habits and lifestyles, which are very ingrained.To accelerate progress on the goals, targets must be fully integrated by government and business at all levels into core decision making, budgeting and planning processes. We need to identify and prioritise those areas that lag furthest behind. To be effective, we also need to uncover and address the root causes of inadequate outcomes, which lie in our institutions and governance systems.Accountability also remains weak. The goals are not legally binding and even though countries have expressed their support, this has often failed to translate into policy and investments. In practice, the targets are often “painted on” to existing strategies without redesigning norms and structures to deliver improved outcomes.If the world is to accelerate progress on the goals, governments need to play a more active part, by setting targets, stimulating innovation, shaping markets, and regulating business. We call on policymakers to develop tailored action plans to accelerate progress on the goals in the remaining years to 2030, including measures to improve accountability. Scientists have a major role to play too. As we argued in Nature, scientists can help us redesign institutions, systems and practices. By studying ways to strengthen governance and build momentum for tough but transformative reforms, research can overcome resistance to change, and manage negative side-effects. What does it mean for Australia?Australia tends to perform poorly on the goals when compared to our peers in the OECD (Organisation for Economic Co-operation and Development), ranking 40th in the world in 2023. Our best-performing goals include health and education, while progress lags on environmental goals, economic inequality and cost-of-living pressures. While some environment agencies, businesses and local groups have embraced the goals, Australia’s poor performance is symptomatic of limited traction and commitment at the centre of government. Here, the goals are often seen as an international development issue rather than central to domestic policy efforts. We lack a high-level statement or any strategy or action plan for the goals. There is no lead unit or coordination mechanism in place and no reference to the goals in the federal budget. One promising development, a national Sustainable Development Goal monitoring portal, hasn’t been updated in five years. The best performing countries have taken concrete steps to mainstream the targets and ensure accountability:Denmark requires new government bills to be screened and assessed for their impacts on the goals Finland has taken steps to place sustainable development and people’s wellbeing at the heart of policy and decision making. A sustainable development commission, annual citizens’ panel on sustainable development and national audits provide increased accountability Wales requires public bodies to use sustainable development as a guiding principle reflecting the values and aspirations of the Welsh people.Australia’s first wellbeing framework is an important step forward. The framework of 50 indicators has considerable overlap with the goals, despite notable exceptions such as the lack of a poverty indicator or any specific targets or benchmarks. Read more: Australia's first wellbeing framework is about to measure what matters – but it's harder than counting GDP Start lifting our gameAs we’ve learned through our own research, little will change if such promising initiatives remain box-ticking exercises that fail to reorient our societies and economies towards sustainable development. To achieve real change, indicator frameworks need to be translated into timebound targets that clearly set the agreed direction and level of ambition. These targets must be embedded in the core decision-making processes of government and business.Remember the goals are not a set of technical targets and indicators. They are the outcomes each of us want for our society and the world we live in. While we are behind at halftime, the game is not over. It is up to us to lift our performance and turn the score around. Read more: Climate change threatens the rights of children. The UN just outlined the obligations states have to protect them Cameron Allen receives funding from the Australian Government. Shirin Malekpour receives funding from the Australian Government.

Making aviation fuel from biomass

MIT researchers are converting the plant material lignin into hydrocarbon molecules that could help make jet fuel 100 percent sustainable.

In 2021, nearly a quarter of the world’s carbon dioxide emissions came from the transportation sector, with aviation being a significant contributor. While the growing use of electric vehicles is helping to clean up ground transportation, today’s batteries can’t compete with fossil fuel-derived liquid hydrocarbons in terms of energy delivered per pound of weight — a major concern when it comes to flying. Meanwhile, based on projected growth in travel demand, consumption of jet fuel is projected to double between now and 2050 — the year by which the international aviation industry has pledged to be carbon neutral. Many groups have targeted a 100 percent sustainable hydrocarbon fuel for aircraft, but without much success. Part of the challenge is that aviation fuels are so tightly regulated. “This is a subclass of fuels that has very specific requirements in terms of the chemistry and the physical properties of the fuel, because you can’t risk something going wrong in an airplane engine,” says Yuriy Román-Leshkov, the Robert T. Haslam Professor of Chemical Engineering. “If you’re flying at 30,000 feet, it’s very cold outside, and you don’t want the fuel to thicken or freeze. That’s why the formulation is very specific.” Aviation fuel is a combination of two large classes of chemical compounds. Some 75 to 90 percent of it is made up of “aliphatic” molecules, which consist of long chains of carbon atoms linked together. “This is similar to what we would find in diesel fuels, so it’s a classic hydrocarbon that is out there,” explains Román-Leshkov. The remaining 10 to 25 percent consists of “aromatic” molecules, each of which includes at least one ring made up of six connected carbon atoms. In most transportation fuels, aromatic hydrocarbons are viewed as a source of pollution, so they’re removed as much as possible. However, in aviation fuels, some aromatic molecules must remain because they set the necessary physical and combustion properties of the overall mixture. They also perform one more critical task: They ensure that seals between various components in the aircraft’s fuel system are tight. “The aromatics get absorbed by the plastic seals and make them swell,” explains Román-Leshkov. “If for some reason the fuel changes, so can the seals, and that’s very dangerous.” As a result, aromatics are a necessary component — but they’re also a stumbling block in the move to create sustainable aviation fuels, or SAFs. Companies know how to make the aliphatic fraction from inedible parts of plants and other renewables, but they haven’t yet developed an approved method of generating the aromatic fraction from sustainable sources. As a result, there’s a “blending wall,” explains Román-Leshkov. “Since we need that aromatic content — regardless of its source — there will always be a limit on how much of the sustainable aliphatic hydrocarbons we can use without changing the properties of the mixture.” He notes a similar blending wall with gasoline. “We have a lot of ethanol, but we can’t add more than 10 percent without changing the properties of the gasoline. In fact, current engines can’t handle even 15 percent ethanol without modification.” No shortage of renewable source material — or attempts to convert it For the past five years, understanding and solving the SAF problem has been the goal of research by Román-Leshkov and his MIT team — Michael L. Stone PhD ’21, Matthew S. Webber, and others — as well as their collaborators at Washington State University, the National Renewable Energy Laboratory (NREL), and the Pacific Northwest National Laboratory. Their work has focused on lignin, a tough material that gives plants structural support and protection against microbes and fungi. About 30 percent of the carbon in biomass is in lignin, yet when ethanol is generated from biomass, the lignin is left behind as a waste product. Despite valiant efforts, no one has found an economically viable, scalable way to turn lignin into useful products, including the aromatic molecules needed to make jet fuel 100 percent sustainable. Why not? As Román-Leshkov says, “It’s because of its chemical recalcitrance.” It’s difficult to make it chemically react in useful ways. As a result, every year millions of tons of waste lignin are burned as a low-grade fuel, used as fertilizer, or simply thrown away. Understanding the problem requires understanding what’s happening at the atomic level. A single lignin molecule — the starting point of the challenge — is a big “macromolecule” made up of a network of many aromatic rings connected by oxygen and hydrogen atoms. Put simply, the key to converting lignin into the aromatic fraction of SAF is to break that macromolecule into smaller pieces while in the process getting rid of all of the oxygen atoms. In general, most industrial processes begin with a chemical reaction that prevents the subsequent upgrading of lignin: As the lignin is extracted from the biomass, the aromatic molecules in it react with one another, linking together to form strong networks that won’t react further. As a result, the lignin is no longer useful for making aviation fuels. To avoid that outcome, Román-Leshkov and his team utilize another approach: They use a catalyst to induce a chemical reaction that wouldn’t normally occur during extraction. By reacting the biomass in the presence of a ruthenium-based catalyst, they are able to remove the lignin from the biomass and produce a black liquid called lignin oil. That product is chemically stable, meaning that the aromatic molecules in it will no longer react with one another. So the researchers have now successfully broken the original lignin macromolecule into fragments that contain just one or two aromatic rings each. However, while the isolated fragments don’t chemically react, they still contain oxygen atoms. Therefore, one task remains: finding a way to remove the oxygen atoms. In fact, says Román-Leshkov, getting from the molecules in the lignin oil to the targeted aromatic molecules required them to accomplish three things in a single step: They needed to selectively break the carbon-oxygen bonds to free the oxygen atoms; they needed to avoid incorporating noncarbon atoms into the aromatic rings (for example, atoms from the hydrogen gas that must be present for all of the chemical transformations to occur); and they needed to preserve the carbon backbone of the molecule — that is, the series of linked carbon atoms that connect the aromatic rings that remain. Ultimately, Román-Leshkov and his team found a special ingredient that would do the trick: a molybdenum carbide catalyst. “It’s actually a really amazing catalyst because it can perform those three actions very well,” says Román-Leshkov. “In addition to that, it’s extremely resistant to poisons. Plants can contain a lot of components like proteins, salts, and sulfur, which often poison catalysts so they don’t work anymore. But molybdenum carbide is very robust and isn’t strongly influenced by such impurities.” Trying it out on lignin from poplar trees To test their approach in the lab, the researchers first designed and built a specialized “trickle-bed” reactor, a type of chemical reactor in which both liquids and gases flow downward through a packed bed of catalyst particles. They then obtained biomass from a poplar, a type of tree known as an “energy crop” because it grows quickly and doesn’t require a lot of fertilizer. To begin, they reacted the poplar biomass in the presence of their ruthenium-based catalyst to extract the lignin and produce the lignin oil. They then flowed the oil through their trickle-bed reactor containing the molybdenum carbide catalyst. The mixture that formed contained some of the targeted product but also a lot of others that still contained oxygen atoms. Román-Leshkov notes that in a trickle-bed reactor, the time during which the lignin oil is exposed to the catalyst depends entirely on how quickly it drips down through the packed bed. To increase the exposure time, they tried passing the oil through the same catalyst twice. However, the distribution of products that formed in the second pass wasn’t as they had predicted based on the outcome of the first pass. With further investigation, they figured out why. The first time the lignin oil drips through the reactor, it deposits oxygen onto the catalyst. The deposition of the oxygen changes the behavior of the catalyst such that certain products appear or disappear — with the temperature being critical. “The temperature and oxygen content set the condition of the catalyst in the first pass,” says Román-Leshkov. “Then, on the second pass, the oxygen content in the flow is lower, and the catalyst can fully break the remaining carbon-oxygen bonds.” The process can thus operate continuously: Two separate reactors containing independent catalyst beds would be connected in series, with the first pretreating the lignin oil and the second removing any oxygen that remains. Based on a series of experiments involving lignin oil from poplar biomass, the researchers determined the operating conditions yielding the best outcome: 350 degrees Celsius in the first step and 375 C in the second step. Under those optimized conditions, the mixture that forms is dominated by the targeted aromatic products, with the remainder consisting of small amounts of other jet-fuel aliphatic molecules and some remaining oxygen-containing molecules. The catalyst remains stable while generating more than 87 percent (by weight) of aromatic molecules. “When we do our chemistry with the molybdenum carbide catalyst, our total carbon yields are nearly 85 percent of the theoretical carbon yield,” says Román-Leshkov. “In most lignin-conversion processes, the carbon yields are very low, on the order of 10 percent. That’s why the catalysis community got very excited about our results — because people had not seen carbon yields as high as the ones we generated with this catalyst.” There remains one key question: Does the mixture of components that forms have the properties required for aviation fuel? “When we work with these new substrates to make new fuels, the blend that we create is different from standard jet fuel,” says Román-Leshkov. “Unless it has the exact properties required, it will not qualify for certification as jet fuel.” To check their products, Román-Leshkov and his team send samples to Washington State University, where a team operates a combustion lab devoted to testing fuels. Results from initial testing of the composition and properties of the samples have been encouraging. Based on the composition and published prescreening tools and procedures, the researchers have made initial property predictions for their samples, and they looked good. For example, the freezing point, viscosity, and threshold sooting index are predicted to be lower than the values for conventional aviation aromatics. (In other words, their material should flow more easily and be less likely to freeze than conventional aromatics while also generating less soot in the atmosphere when they burn.) Overall, the predicted properties are near to or more favorable than those of conventional fuel aromatics. Next steps The researchers are continuing to study how their sample blends behave at different temperatures and, in particular, how well they perform that key task: soaking into and swelling the seals inside jet engines. “These molecules are not the typical aromatic molecules that you use in jet fuel,” says Román-Leshkov. “Preliminary tests with sample seals show that there’s no difference in how our lignin-derived aromatics swell the seals, but we need to confirm that. There’s no room for error.” In addition, he and his team are working with their NREL collaborators to scale up their methods. NREL has much larger reactors and other infrastructure needed to produce large quantities of the new sustainable blend. Based on the promising results thus far, the team wants to be prepared for the further testing required for the certification of jet fuels. In addition to testing samples of the fuel, the full certification procedure calls for demonstrating its behavior in an operating engine — “not while flying, but in a lab,” clarifies Román-Leshkov. In addition to requiring large samples, that demonstration is both time-consuming and expensive — which is why it’s the very last step in the strict testing required for a new sustainable aviation fuel to be approved. Román-Leshkov and his colleagues are now exploring the use of their approach with other types of biomass, including pine, switchgrass, and corn stover (the leaves, stalks, and cobs left after corn is harvested). But their results with poplar biomass are promising. If further testing confirms that their aromatic products can replace the aromatics now in jet fuel, “the blending wall could disappear,” says Román-Leshkov. “We’ll have a means of producing all the components in aviation fuel from renewable material, potentially leading to aircraft fuel that’s 100 percent sustainable.” This research was initially funded by the Center for Bioenergy Innovation, a U.S. Department of Energy (DOE) Research Center supported by the Office of Biological and Environmental Research in the DOE Office of Science. More recent funding came from the DOE Bioenergy Technologies Office and from Eni S.p.A. through the MIT Energy Initiative. Michael L. Stone PhD ’21 is now a postdoc in chemical engineering at Stanford University. Matthew S. Webber is a graduate student in the Román-Leshkov group, now on leave for an internship at the National Renewable Energy Laboratory. This article appears in the Spring 2023 issue of Energy Futures, the magazine of the MIT Energy Initiative.

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