The Energy Conversion of Hydrogen Fuel Cells

Articles in discussion:

• Geothermal energy for sustainable development: A review for sustainability impacts and assessment frameworks

• Environmental and social aspects of geothermal energy in Italy

When you think about the amount of energy you can harness from the sun, you may get excited about how it's almost inexhaustible when comparing our minute terrestrial lifespan to that of our planet. It provides us with sunlight to harness through photovoltaic panels, pressure and temperature differentials that create wind caused by uneven surface heating, and biomass formation, which is directly related to the harnessing of the energy by organic material through the energy the Earth receives from beyond the clouds. These famous and major forms of renewable power have one thing in common: the sun, and it delivers the ultimate effect to allow them to generate power. But the reality is that there is also immense power right beneath our feet, in the Earth’s core.

*Energy can't be created or destroyed - the first law of thermodynamics. This means that energy doesn't 'disappear,' it just becomes scarcer. I advise you to read more about entropy to understand this.

Our Earth is marvelous in the way it maintains a perfect balance for sustaining life (except for human-made climate change), forming itself over billions of years to reach that point to allow us to open our eyes every day (and all other species, too). Its internal energy is a result of primordial heat leftover from its formation and the ongoing decay of radioactive isotopes within its mantle and crust. This, to us, looks like inexhaustible energy, and we can effectively harness this by capturing the heat created by the core and using it to turn water into steam. This is known as geothermal energy, the most creative way we've managed to capture the energy being created right under our feet. For some context, geothermal power plants generate electricity by running pipes several kilometers deep underground, where the operating temperatures range from 150°C to over 350°C. This superheated water vapor is used to spin turbines that, in effect, create the electricity that gets delivered to the power grid and our homes.

So, geothermal is perfect; we use the ground without depending on the weather, it uses minimal water compared to fossil fuels, and it is clean, right? Well, the reality is that geothermal energy generation, like all its counterparts, both renewable and non-renewable, has its flaws. The general market overview for geothermal energy is still small, representing about 0.1% of the global primary energy supply. Even so, it is predicted to reach 3% of global electricity demand and 5% global heating demand by 2050. It is important to note that it is a highly reliable source of energy, as shifts in the Earth's core movements oscillate in 70-year periods and reversals of the magnetic poles have a crazy range of occurrence every 10,000-580 million years. Now, a cool perspective, if we can effectively harness all the geothermal energy located within 5,000 meters under the surface, we can generate 370,000 terawatt hours per year (TWh/yr). Assuming an average consumption rate of 3,600 kilowatt hours per person per year (kWh/person-year), we can deliver electricity to up to 103 billion people. Reaching 8,000 meters under the surface, this increases to 5.3 million terawatt hours per year. Do the math, and it gets crazy.

This might make you think: "Hell, why not just make everything geothermal?" Well, like Confucius once said, "Better a diamond with a flaw than a pebble without," geothermal has its flaws,  and we will explore these flaws and the effects of geothermal energy production on society and health.

What are the pros of geothermal energy? The following fields are positively affected by it:

1. Poverty: geothermal energy is cheaper in the long run, improving access to marginalized groups to energy, drinking water (less affected than from fossil fuel deep-well tapping), and improved living conditions.

2. Health: An efficient energy source improves healthcare delivery, sanitation, and individual nutrition.

3. Atmosphere: less greenhouse gas emissions, duh.

4. Land: better land use and improvement of local ecosystems.

5. Water: freshwater is less affected when compared to non-renewable sources of energy.

What are the cons of geothermal energy? The following fields are negatively affected by it:

1. Poverty: access to land can be more restricted and raise prices, while further displacing communities to build plants on sources of geothermal energy.

2. Health: Geothermal is stinky due to the sulfur that seeps from the Earth's surface. Geothermal plants are also loud, creating further inconveniences for nearby communities.

3. Atmosphere: Geothermal energy can still produce a small degree of greenhouse gas emissions (without considering the carbon waste created by the manufacturing of its components), mainly carbon dioxide.

4. Land: In addition to the effects of land outlined in poverty, soil compaction takes place that can affect nearby ecosystems, and the application of geothermal energy is limited to zones that are 'hot.'

5. Water: Soil compaction can still affect nearby freshwater sources, causing seepage of certain toxins from underground to underground water reservoirs.

When considering these effects, although geothermal energy is considerably friendlier than fossil fuels, environmental risks still exist in the implementation of our current geothermal capturing methods and systems. Additionally, there doesn't exist a financial incentive in the geothermal energy market for energy producers to invest in it when compared to its more famous counterparts, like solar or wind. Energy equity, access, and affordability are not assured if these plants are developed and introduced to the market. The financial incentives lie mainly in the fact that the sources of geothermal energy are limited in terms of land. Geothermal energy is mostly present in seismically active areas, where they are either uninhabited, remote, or located in underdeveloped regions. This hinders access for private companies or public institutions to develop these power plants without incurring high infrastructure development, startup capital, and operating costs.

Let's take a case study, the Italian Republic (of which I'm a proud citizen), where we (yes, that might be a stretch, but I couldn't care less about your opinion) pride ourselves on being a top producer of geothermal energy in Europe and among the top ten in the world.  Their source of geothermal energy is aided by the tectonic and volcanic activity in the region, and they supply about 2% of the world's total renewable heat consumption. Their systems operate in what is known as direct cycle technology, and to avoid boring you to tears, both the leftover steam and leftover water are reused to improve the system's efficiency by being reinjected into the pipe runs and turbine. Additionally, more systems are being developed, such as a biomass-geothermal hybrid, but that's for another day. With that being said, these systems come with the aforementioned risks of toxic gas remnants leaking into freshwater sources deep underground and into the Earth's atmosphere. Specifically, the harmful gases are CO2, H2S (the stinky one), H2, and CH4, and the release of these is further compounded by the slightly flawed reinjection method that can allow these to 'leak' from the complicated steps it takes. Nevertheless, Italian politicians have surprisingly been effective (pun intended) in ensuring regulations towards geothermal power plants have strict emission limits, partial reinjection and abatement systems that are adopted to reduce the environmental risk, and proper drilling and maintenance procedures are in place.

In conclusion, geothermal energy is a fascinating reminder that the ground beneath our feet is not just stable earth but a living engine of heat, motion, and decay that can be tapped to power our world. It is not perfect; it comes with tradeoffs in land, water, and social impact, and the technology is still small compared to solar or wind. Yet, its potential is staggering, and its reliability in seismically active zones makes it more than just a scientific curiosity; it is a real solution waiting to scale. Whether the market and policymakers are willing to take the long-term investment risk remains to be seen, but the science is already there. If we can refine reinjection methods, reduce emissions, and integrate geothermal into a broader renewable portfolio, then it will not just be Italy’s pride; it can become one of the cornerstones of how we power the future. The question is not whether the Earth has enough energy; it always will. The real question is whether we are smart enough to use it responsibly.

Disclaimer: The reflections shared here are my own technical and analytical perspectives. They are not definitive statements of fact or policy positions. I welcome thoughtful discussion; feel free to contact me if you’d like to explore these ideas further.