Energy is a necessity for human survival, and in recent history, we have burned coal and drilled into the Earth’s surface to power our rapidly advancing societies. However, these methods place an enormous strain on the planet we call home. As humans are faced with the alarming ecological impacts of our energy decisions, we can no longer rely on increasingly outdated practices to meet our energy demands.
On February 19, Harvard University Professor Daniel Nocera delivered a lecture at Smith College to discuss the ongoing concern about our energy supply, the increasing demand for renewable alternatives, and what he has done to address this issue.
Nocera began his talk with an introduction to human history. The start of the Holocene period around 10,000 years ago marks the beginning of human civilization. During this period, any activities that humans engaged in did not alter the world’s natural systems. Our current period—the Anthropocene—began with the Industrial Revolution, when human activity disrupted our planet for the first time. Pollution spread globally. Habitats were destroyed. Humans soon became the most powerful creatures on Earth.
In response to the consequences of modern advancements, Nocera outlined an optimistic vision of the future he called the Sustainocene: a period driven by sustainability, environmental consciousness, and renewable energy. Due to our overuse of carbon-based fuel, we have not yet entered this period. To transition into this epoch, we must adopt new methods for energy production and supply, where the move towards carbon neutrality is imperative.
The ever-growing human population puts even more pressure on our current energy practices. According to Nocera, we globally consume 18 TW (terawatts) of energy, or 100 billion 100 W light bulbs, with 81.2% supplied by carbon-based resources. Over the next 30 years, we will need 16 more TW of energy to accommodate the 10.2 billion people on Earth. In addition, energy access is unequal. 1.6 billion people living in developing countries use practically no energy and 1.4 billion have never seen electricity, so accessible energy sources are essential to address this crisis.
Incorporating solar energy into sustainable tools can effectively confront these problems. This carbon-neutral source is limitless, accessible to everyone, and key to achieving a sustainable future.
This is where Nocera’s bionic leaf comes in.
During photosynthesis, plants capture sunlight to convert water and carbon dioxide into glucose. Nocera’s bionic leaf mimics this process with significantly more efficiency. Similar to plants, the artificial leaf uses sunlight to split water molecules (H2O) into hydrogen (H2) and oxygen (O2) in a process called water splitting. This is executed through a system of two water chambers. Each water chamber has its own catalyst, a type of material that speeds up chemical reactions to boost the bionic leaf’s efficiency. Hydrogen will be released and bubble up on one water chamber, while oxygen will follow the same process on the other. These separate “containers” allow scientists to effectively collect both hydrogen and oxygen. The hydrogen is then stored as fuel for energy generation or fertilization. The remaining H2O will be recycled to re-execute water splitting, reducing the chances of overconsuming water supply.
The bionic leaf also offers a solution to a common water processing concern: any machine that uses water is prone to rusting. In most instances, neutral water is used to lower the risk of corrosion. Nocera’s bionic leaf has the advantage of purifying water through forward osmosis, which allows any quality of water to be used.
Near the end of his talk, Nocera shifted gears and discussed fertilizers. Traditional fertilizers require fossil fuels, which consume significant amounts of energy and degrade the environment. Nocera’s biofertilizer, Bionic Leaf-N, works with the bionic leaf as an earth-friendly alternative. The bionic leaf produces both hydrogen and oxygen, where the hydrogen is stored for either energy or fertilization production. To accomplish the latter, the Bionic Leaf N uses ralstonia autropga bacteria, which takes in hydrogen gas and combines it with nitrogen (N2) from the atmosphere to naturally produce ammonia (NH3). This is used to create the biofertilizer. The Nocera Lab’s Bionic Leaf-N has been implemented in 120 field trials around the country, consistently showing promising results.
Both the Bionic Leaf and Bionic Leaf-N show potential for reducing our reliance on high, energy-intensive methods that significantly increase CO2 emissions and environmental pollution. And the best part? The artificial leaf only requires the three most basic resources on Earth: sunlight, air, and water.
Nocera left the audience with a final thought on his research. We naively believe that our planet and its organisms rely on our care, when in reality, it is humanity that is critically threatened by the rapidly evolving climate crisis. The Earth has its own immunological system, and it will be fine in the end—it does not rely on our survival. If we want to protect our own future, we must take immediate action. At this point in human history, the adoption of sustainable energy practices could not be more urgent.
Watch the short YouTube clip by Harvard University on Nocera’s bionic leaf to learn more: https://youtu.be/2KRlRhNbxKg
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