Energy and its Meanings
Energy, the topic of the 2023 Mary Mulvihill Award, was the subject of discussion at a recent roundtable event, which the Mary Mulvihill Association hosted.
Science communication researcher Brian Trench chaired a highly diverse panel of speakers, reflecting the wide range of meanings and interpretations that can be attached to the term.
For Peter Gallagher, head of astrophysics at the Dublin Institute of Advanced Studies, the concept of energy evokes its formal scientific definition—the ability to do work. “You move things, you heat things, and you light things with energy,” he said. Margie McCarthy, an engineer who is director of research and policy insights at the Sustainable Energy Authority of Ireland, revealed that how we generate and consume energy has become her main preoccupation since taking on her current role. “We’re not going in the right direction,” she said. “Our emissions from energy usage are increasing, not decreasing.”
Niall Moyna, professor of clinical exercise physiology at Dublin City University, views energy as “the currency of life” – it’s what makes human metabolism work. As a feminist, socialist, and LGBTQ+ activist, Ailbhe Smyth has a different lens on the term. Galvanising human energy to bring about social and political change has been a huge part of her work as a campaigner, but she said it’s hard to be analytical about ‘human energy’. “I think about it as vitality,” she said. “We know that human energy is real—we can feel it.” Yet there is “no psychology of human energy”, she said, even if its absence is apparent in individuals experiencing burnout or depression.
Energy is, of course, central to human health. We derive the energy we need to maintain our basal metabolic rate and to fuel our physical activity through the food we consume, but Moyna noted that there is a broad misconception about the relationship between energy, diet, and exercise. Energy metabolism is a highly controlled process and does not vary greatly between individuals, even if the amount of exercise they undertake may vary considerably. He cited research involving the Hadza people in Northern Tanzania, who pursue a hunter-gatherer lifestyle that entails far more physical activity than what we typically experience in western lifestyles. Yet their daily energy expenditure—the total energy they burn every day—is similar to ours, even though they are far more active. “Physical activity has no impact on your total energy expenditure,” he said. Although exercise is hugely important to maintain good physical and mental health, it is very hard to lose weight through exercise—caloric restriction, or consuming less food, is far more significant. Consuming excessive calories, of course, results in weight gain, but it also contributes to underlying chronic conditions, including inflammation. That also features in our energy budget. “That takes an enormous amount of energy,” he said.
Beyond the physical confines of our bodies, our energy use, at individual and societal levels, is hugely problematic in ways that threaten the health of the planet and the ecosystems on which we depend. “It worries me in a way it never worried me before,” Gallagher said. “We don’t need more of it—we need to be more careful with it.” The sun, the ultimate source of the energy that sustains life on this planet, emits enormous amounts of energy through the process of nuclear fusion, in which two hydrogen protons are forced together to form helium isotopes under conditions of ultra-high temperature and gravitational pressure. Mathematically, the phenomenon can be described by Einstein’s famous formula that defines the equivalence of mass and energy: E=MC2 (E=energy; M=mass; and C=the speed of light). “You can take mass and turn it into energy,” said Gallagher. The quantities involved are enormous—just one kilogramme of matter contains about 90 petajoules (90x1015 joules) of energy or 25,020 gigawatt hours (GWh). That’s very close to Ireland’s total consumption of electrical energy, which reached 28,505 GWh in 2021.
Despite sporadic media reports of research ‘breakthroughs’, harnessing nuclear fusion for clean energy generation at scale is not a realistic prospect at present. Recreating the conditions in which it happens within the sun’s core is hugely demanding. “It just can’t be done on earth,” Gallagher quipped. Nuclear fission—the reverse of fusion—is a different matter, of course. Nuclear power now accounts for about 10% of global electricity generation. Ireland never joined the nuclear club, although Waterford-born physicist Ernest Walton played a foundational role in the research that enabled its emergence. Walton and John Cockcroft received the Nobel Prize for Physics in 1951 for their work in splitting the atom, which they achieved by building the world’s first particle accelerator. Some proponents of nuclear power argue that it is a clean and sustainable form of energy, because it does not produce carbon dioxide emissions and does not require large amounts of land, but those arguments overlook its most troubling aspects: the ever-present risk of a catastrophic accident, such as the Chernobyl disaster in Ukraine, in 1986; the problem of safely storing thousands of tonnes of radioactive waste; and the diversion of radioactive materials to produce nuclear weapons. Russia’s veiled threats to use nuclear weapons in its war on Ukraine has reawakened fears of nuclear annihilation. “It appals me that we still haven’t reached a point where that power won’t be used malevolently,” said Smyth.
Even without war, humanity is on a very dangerous trajectory. McCarthy has attended the most recent United Nations Conference on Climate Change (COP) meetings and has encountered representatives of communities from sub-Saharan Africa who are already experiencing the effects of climate change. Some are literally praying for rain, she said. Eliminating carbon dioxide emissions from Ireland’s energy mix by 2050 is a key target. Nationally, she said, we must prioritise technologies that are ready today and will have the greatest cumulative impact on reducing emissions between now and that deadline, instead of waiting for those that may have greater impact but are still not close to deployment. District heating is attractive, she said, because it is agnostic to the source used to generate the power required to heat the water that is distributed to the buildings connected to the pipe network. The energy could come from renewables, from geothermal, biomass or waste heat from data centres, for example. It does not require any substantial changes to the individual buildings either, other than the installation of a heat exchanger, although the installation of pipe networks within a locality will be disruptive. Offshore energy generation also offers possibilities—as well as harvesting wind power, solar power can also be captured, through floating arrays of solar panels that are anchored to but not rigidly fixed to the seabed.
Decarbonising our society over the next several decades will require considerable individual and collective efforts on multiple fronts—and it’s an open question whether we will be able to do enough quickly enough. “I do think we are guilty, as a global society, of short-termism,” Smyth said. “It is important to have an analysis of how our world is structured.” The Anglo-American form of capitalism that we pursue has contributed hugely to unchecked pollution, deforestation, and an ongoing emphasis on car-buying, regardless of the many harms that it brings. Many young people have a sense of helplessness about the state of the world. Taking small steps and setting achievable goals were important in achieving social change, Smyth said. “Think small, think local to start with.” That is not incompatible with operating at scale, to effect large changes, noted Trench in his closing remarks. Smyth’s many decades of work as an activist culminated in the success of the Together for Yes campaign to secure abortion rights for women in Ireland. Although it is hard to define any blueprint for achieving change, working with passion and in solidarity with others is important. “You always have to be prepared to give a bit of yourself,” she said.