How Does Geothermal Energy Fit into Decarbonization Efforts?

 In the global pursuit of a sustainable, low-carbon future, renewable energy technologies are vital. While solar and wind often dominate the clean energy conversation, geothermal energy is a powerful, underutilized resource that holds tremendous potential in the decarbonization of the energy sector.

Decarbonization refers to reducing carbon dioxide (CO₂) and other greenhouse gas (GHG) emissions, especially from energy production. Geothermal energy, which harnesses heat from beneath the Earth's surface, offers a clean, reliable, and constant energy source, making it a valuable ally in the fight against climate change.

This article explores the role of geothermal energy in global decarbonization efforts, including its benefits, applications, challenges, and future prospects.

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What Is Geothermal Energy?

Geothermal energy comes from the natural heat stored within the Earth’s crust. This heat is primarily generated from:

• The original formation of the planet,

• Radioactive decay of minerals,

• Residual heat from volcanic activity.

This energy can be accessed by drilling wells to reach underground reservoirs of hot water and steam, which can then be used to:

• Generate electricity in geothermal power plants.

• Provide direct heating for buildings, greenhouses, and industries.

• Supply energy to district heating systems.

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The Importance of Decarbonization

Decarbonization is central to combating global warming and its destructive impacts—rising sea levels, extreme weather, food insecurity, and biodiversity loss. According to the Intergovernmental Panel on Climate Change (IPCC), the world must reach net-zero emissions by 2050 to limit global warming to 1.5°C.

Since the energy sector contributes about 73% of global greenhouse gas emissions, transitioning away from fossil fuels to clean alternatives like geothermal energy is critical.

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How Geothermal Energy Supports Decarbonization

1. Low Greenhouse Gas Emissions

Geothermal energy systems have very low lifecycle emissions. Most geothermal power plants emit only 15–50 grams of CO₂ per kilowatt-hour (gCO₂/kWh)—a fraction compared to:

• Coal (820 gCO₂/kWh),

• Natural gas (450 gCO₂/kWh).

In many cases, especially closed-loop or binary cycle plants, emissions can be nearly zero, making geothermal one of the cleanest forms of baseload energy.

2. 24/7 Renewable Energy Source

Unlike wind and solar, which are intermittent and weather-dependent, geothermal provides constant, dispatchable energy. This makes it ideal for replacing coal or gas in base-load power generation, reducing the need for fossil fuel backup systems and ensuring energy security.

3. Supports Electrification of Heat

A large portion of global emissions comes from heating buildings and industrial processes. Geothermal energy can directly provide low-carbon heat, helping decarbonize:

• Space heating (homes, offices, campuses),

• Industrial heat (food processing, drying, textile, chemical industries),

• District heating networks.

This direct-use application bypasses the need for electricity and is one of the most efficient forms of geothermal use.

4. Reduces Fossil Fuel Dependence

By replacing coal, oil, or gas in both electricity and heating, geothermal energy helps reduce reliance on fossil fuels. In areas with significant geothermal resources (like Iceland or Kenya), it has allowed countries to:

• Cut emissions drastically,

• Lower energy import bills,

• Improve air quality and public health.

5. Low Land Footprint

Geothermal power plants have a much smaller land footprint than wind or solar farms per unit of energy generated. This makes them especially attractive in densely populated or ecologically sensitive regions.

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Applications in Decarbonization

A. Geothermal Electricity Generation

Used mainly in high-temperature geothermal fields, electricity is generated using:

• Dry steam plants: Use steam directly from geothermal reservoirs.

• Flash steam plants: Convert high-pressure hot water into steam.

• Binary cycle plants: Use moderate-temperature water to heat another fluid that drives a turbine.

Example:

• Iceland generates over 25% of its electricity from geothermal.

• Kenya generates over 40% of its power from geothermal, making it Africa’s leader.

B. Direct Use and District Heating

Direct use involves tapping geothermal heat for applications without converting it into electricity. This includes:

• Residential and commercial heating,

• Spa and wellness centers,

• Snow melting on roads and sidewalks,

• Greenhouse heating and fish farming.

District heating systems, particularly in Europe and China, use geothermal energy to heat entire neighborhoods and cities, drastically reducing emissions from heating oil and natural gas.

C. Geothermal Heat Pumps

Also known as ground-source heat pumps, these systems extract heat from shallow ground for space heating in the winter and cooling in the summer. They are suitable for residential and commercial buildings, even in areas without volcanic activity.

They are highly energy-efficient, reducing electricity usage by up to 70% compared to conventional heating/cooling systems.

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Global Potential and Adoption

Despite being underutilized, geothermal energy has vast potential. According to the International Renewable Energy Agency (IRENA):

• Global installed geothermal electricity capacity was about 15 GW in 2023.

• Potential exists for hundreds of gigawatts, especially with enhanced geothermal systems (EGS) and deep drilling technologies.

Countries with significant geothermal capacity:

• United States – World leader in installed capacity.

• Indonesia – Fast-growing market with high potential.

• Philippines, Turkey, Iceland, Kenya, New Zealand – Strong producers.

Emerging interest is growing in regions such as Latin America, East Africa, Central Asia, and Europe.

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Geothermal’s Role in a Clean Energy Mix

Geothermal energy complements other renewables in several ways:

• Provides baseload power to balance intermittent sources like wind and solar.

• Helps stabilize the grid, reducing reliance on fossil fuel backup.

• Offers hybrid solutions, such as combining geothermal with solar or biomass to improve efficiency and output.

In countries with diverse energy mixes, geothermal can help decarbonize the electricity sector faster, especially when coupled with modern grid technologies and storage systems.

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Economic Benefits

• Job Creation: Geothermal projects require skilled labor in geology, engineering, construction, and maintenance.

• Local Energy Security: Reduces fuel imports and stabilizes energy prices.

• Revenue Streams: Heat can be sold for industrial processes or heating, and electricity sold into national grids.

• Rural Development: Geothermal projects often stimulate economic activity in underdeveloped regions.

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Challenges and Limitations

1. High Initial Costs

Geothermal projects require significant upfront investment, particularly for exploration and drilling, which can account for up to 50% of total project cost. If resources are not found or viable, costs are sunk.

2. Geographic Limitations

Geothermal electricity generation is primarily feasible in tectonically active regions—areas near fault lines, volcanoes, or hot springs. However, geothermal heating and heat pumps can work in nearly all locations.

3. Environmental Concerns

• Water use and potential contamination,

• Induced seismicity (minor earthquakes from drilling),

• Surface subsidence if fluid extraction is not managed carefully.

Modern technologies and regulation have greatly mitigated most of these risks.

4. Long Development Timelines

Project timelines can be lengthy due to permitting, drilling, and testing. This can delay returns on investment and make financing difficult, especially in developing countries.

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Technological Innovations Boosting Geothermal’s Role

A. Enhanced Geothermal Systems (EGS)

EGS involves creating artificial geothermal reservoirs by fracturing dry, hot rocks and injecting water to produce steam. This can unlock geothermal potential in previously non-viable regions.

Countries like the U.S., Australia, and Germany are leading in EGS pilot projects.

B. Closed-Loop Systems

These systems circulate a working fluid through a sealed pipe underground, without interacting with natural geothermal fluids. This reduces environmental impact and allows deployment in more locations.

C. Geothermal-Lithium Extraction

In some geothermal brines, valuable minerals like lithium can be extracted. This can generate additional revenue and support battery industries, boosting the financial viability of geothermal projects.

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Policy and Investment Needs

To scale geothermal energy and support decarbonization, countries must:

• Streamline permitting and exploration incentives,

• Provide financial support through tax credits, grants, and low-interest loans,

• Invest in R&D for EGS and heat pump technology,

• Integrate geothermal into national climate and energy strategies,

• Build local expertise and supply chains.

Organizations like the World Bank, IRENA, and Geothermal Development Facility are working to de-risk investment and expand geothermal access in developing countries.

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Geothermal in the Context of Net-Zero

To reach global net-zero goals by 2050:

• Geothermal electricity generation must expand from 15 GW to over 200 GW, according to IRENA.

• Direct use of geothermal heat must also grow substantially to replace fossil fuels in buildings and industry.

• Innovations like EGS will be essential for unlocking geothermal potential in new regions.

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Conclusion

Geothermal energy is a powerful and dependable solution in the global effort to decarbonize the energy system. With nearly zero emissions, constant output, and direct heating applications, geothermal can play a transformative role in reducing our reliance on fossil fuels.

While it faces challenges in cost and geography, emerging technologies and policy support are paving the way for wider adoption. As the world shifts to a low-carbon economy, geothermal energy must rise from the shadows to take its rightful place at the heart of climate action and sustainable development.