American scientists have announced what they have called a major breakthrough in a long-elusive goal of creating energy from nuclear fusion.

The U.S. Department of Energy said on Dec. 13, 2022, that for the first time – and after several decades of trying – scientists have managed to get more energy out of the process than they had to put in.

But just how significant is the development? And how far off is the long-sought dream of fusion providing abundant, clean energy? Carolyn Kuranz, an associate professor of nuclear engineering at the University of Michigan who has worked at the facility that just broke the fusion record, helps explain this new result.

What happened in the fusion chamber?

Fusion is a nuclear reaction that combines two atoms to create one or more new atoms with slightly less total mass. The difference in mass is released as energy, as described by Einstein’s famous equation, E = mc² , where energy equals mass times the speed of light squared. Since the speed of light is enormous, converting just a tiny amount of mass into energy – like what happens in fusion – produces a similarly enormous amount of energy.

Researchers at the U.S. Government’s National Ignition Facility in California have demonstrated, for the first time, what is known as “fusion ignition.” Ignition is when a fusion reaction produces more energy than is being put into the reaction from an outside source and becomes self-sustaining.

The technique used at the National Ignition Facility involved shooting 192 lasers at a 0.04 inch (1 mm) pellet of fuel made of deuterium and tritium – two versions of the element hydrogen with extra neutrons – placed in a gold canister. When the lasers hit the canister, they produce X-rays that heat and compress the fuel pellet to about 20 times the density of lead and to more than 5 million degrees Fahrenheit (3 million Celsius) – about 100 times hotter than the surface of the Sun. If you can maintain these conditions for a long enough time, the fuel will fuse and release energy.

The fuel and canister get vaporized within a few billionths of a second during the experiment. Researchers then hope their equipment survived the heat and accurately measured the energy released by the fusion reaction.

So what did they accomplish?

To assess the success of a fusion experiment, physicists look at the ratio between the energy released from the process of fusion and the amount of energy within the lasers. This ratio is called gain.

Anything above a gain of 1 means that the fusion process released more energy than the lasers delivered.

On Dec. 5, 2022, the National Ignition Facility shot a pellet of fuel with 2 million joules of laser energy – about the amount of power it takes to run a hair dryer for 15 minutes – all contained within a few billionths of a second. This triggered a fusion reaction that released 3 million joules. That is a gain of about 1.5, smashing the previous record of a gain of 0.7 achieved by the facility in August 2021.

How big a deal is this result?

Fusion energy has been the “holy grail” of energy production for nearly half a century. While a gain of 1.5 is, I believe, a truly historic scientific breakthrough, there is still a long way to go before fusion is a viable energy source.

While the laser energy of 2 million joules was less than the fusion yield of 3 million joules, it took the facility nearly 300 million joules to produce the lasers used in this experiment. This result has shown that fusion ignition is possible, but it will take a lot of work to improve the efficiency to the point where fusion can provide a net positive energy return when taking into consideration the entire end-to-end system, not just a single interaction between the lasers and the fuel.

What needs to be improved?

There are a number of pieces of the fusion puzzle that scientists have been steadily improving for decades to produce this result, and further work can make this process more efficient.

First, lasers were only invented in 1960. When the U.S. government completed construction of the National Ignition Facility in 2009, it was the most powerful laser facility in the world, able to deliver 1 million joules of energy to a target. The 2 million joules it produces today is 50 times more energetic than the next most powerful laser on Earth. More powerful lasers and less energy-intensive ways to produce those powerful lasers could greatly improve the overall efficiency of the system.

Fusion conditions are very challenging to sustain, and any small imperfection in the capsule or fuel can increase the energy requirement and decrease efficiency. Scientists have made a lot of progress to more efficiently transfer energy from the laser to the canister and the X-ray radiation from the canister to the fuel capsule, but currently only about 10% to 30% of the total laser energy is transferred to the canister to the fuel.

Finally, while one part of the fuel, deuterium, is naturally abundant in sea water, tritium is much rarer. Fusion itself actually produces tritium, so researchers are hoping to develop ways of harvesting this tritium directly. In the meantime, there are other methods available to produce the needed fuel.

These and other scientific, technological and engineering hurdles will need to be overcome before fusion will produce electricity for your home. Work will also need to be done to bring the cost of a fusion power plant well down from the US$3.5 billion of the National Ignition Facility. These steps will require significant investment from both the federal government and private industry.

It’s worth noting that there is a global race around fusion, with many other labs around the world pursuing different techniques. But with the new result from the National Ignition Facility, the world has, for the first time, seen evidence that the dream of fusion is achievable.

Carolyn Kuranz, Associate Professor of Nuclear Engineering, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.

You saw it at Thanksgiving, and you’ll likely see it at your next holiday feast: piles of unwanted food – unfinished second helpings, underwhelming kitchen experiments and the like – all dressed up with no place to go, except the back of the refrigerator. With luck, hungry relatives will discover some of it before the inevitable green mold renders it inedible.

U.S. consumers waste a lot of food year-round – about one-third of all purchased food. That’s equivalent to 1,250 calories per person per day, or US$1,500 worth of groceries for a four-person household each year, an estimate that doesn’t include recent food price inflation. And when food goes bad, the land, labor, water, chemicals and energy that went into producing, processing, transporting, storing and preparing it are wasted too.

Where does all that unwanted food go? Mainly underground. Food waste occupies almost 25% of landfill space nationwide. Once buried, it breaks down, generating methane, a potent greenhouse gas that contributes to climate change. Recognizing those impacts, the U.S. government has set a goal of cutting food waste in half by 2030.

Reducing wasted food could protect natural resources, save consumers money, reduce hunger and slow climate change. But as an agricultural economist and director of the Ohio State Food Waste Collaborative, I know all too well that there’s no ready elegant solution. Developing meaningful interventions requires burrowing into the systems that make reducing food waste such a challenge for consumers, and understanding how both physical and human factors drive this problem.

Consumers and the squander sequence

To avoid being wasted, food must avert a gauntlet of possible missteps as it moves from soil to stomach. Baruch College marketing expert Lauren Block and her colleagues call this pathway the squander sequence.

It’s an example of what economists call an O-ring technology, harking back to the rubber seals whose catastrophic failure caused the Space Shuttle Challenger disaster in 1986. As in that event, failure of even a small component in the multistage sequence of transforming raw materials into human nutrition leads to failure of the entire task.

MIT economist Michael Kremer has shown that when corporations of many types are confronted with such sequential tasks, they put their highest-skilled staff at the final stages of production. Otherwise the companies risk losing all the value they have added to their raw materials through the production sequence.

Who performs the final stages of production in today’s modern food system? That would be us: frenzied, multitasking, money- and time-constrained consumers. At the end of a typical day, we’re often juggling myriad demands as we try to produce a nutritious, delicious meal for our households.

Unfortunately, sprawling modern food systems are not managed like a single integrated firm that’s focused on maximizing profits. And consumers are not the highly skilled heavy hitters that Kremer envisioned to manage the final stage of the complex food system. It’s not surprising that failure – here, wasting food – often is the result.

Indeed, out of everyone employed across the fragmented U.S. food system, consumers may have the least professional training in handling and preparing food. Adding to the mayhem, firms may not always want to help consumers get the most out of food purchases. That could reduce their sales – and if food that’s been stored longer degrades and becomes less appetizing or safe, producers’ reputations could suffer.

Three paths to squash the squandering

What options exist for reducing food waste in the kitchen? Here are several approaches.

• Build consumer skills.

This could start with students, perhaps through reinvesting in family and consumer science courses – the modern, expanded realm of old-school home economics classes. Or schools could insert food-related modules into existing classes. Biology students could learn why mold forms, and math students could calculate how to expand or reduce recipes.

Outside of school, there are expanding self-education opportunities available online or via clever gamified experiences like Hellman’s Fridge Night Mission, an app that challenges and coaches users to get one more meal a week out of their fridges, freezers and pantries. Yes, it may involve adding some mayo.

Recent studies have found that when people had the opportunity to brush up on their kitchen management skills early in the COVID-19 pandemic, food waste declined. However, as consumers returned to busy pre-COVID schedules and routines such as eating out, wastage rebounded.

• Make home meal preparation easier.

Enter the meal kit, which provides the exact quantity of ingredients needed. One recent study showed that compared to traditional home-cooked meals, wasted food declined by 38% for meals prepared from kits.

Meal kits generate increased packaging waste, but this additional impact may be offset by reduced food waste. Net environmental benefits may be case specific, and warrant more study.

• Heighten the consequences for wasting food.

South Korea has begun implementing taxes on food wasted in homes by requiring people to dispose of it in special costly bags or, for apartment dwellers, through pay-as-you-go kiosks.

A recent analysis suggests that a small tax of 6 cents per kilogram – which, translated for a typical U.S. household, would total about $12 yearly – yielded a nearly 20% reduction in waste among the affected households. The tax also spurred households to spend 5% more time, or about an hour more per week, preparing meals, but the changes that people made reduced their yearly grocery bills by about $170.

No silver bullets

Each of these paths is promising, but there is no single solution to this problem. Not all consumers will seek out or encounter opportunities to improve their food-handling skills. Meal kits introduce logistical issues of their own and could be too expensive for some households. And few U.S. cities may be willing or able to develop systems for tracking and taxing wasted food.

As the National Academies of Science, Engineering and Medicine concluded in a 2020 report, there’s a need for many solutions to address food waste’s large contribution to global climate change and worldwide nutritional shortfalls. Both the United Nations and the U.S. National Science Foundation are funding efforts to track and measure food waste. I expect that this work will help us understand waste patterns more clearly and find effective ways to squelch the squander sequence.

Brian E. Roe, Professor of Agricultural, Environmental, and Development Economics, The Ohio State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.