Geothermal energy is a promising source of clean, renewable energy. Harnessing the Earth’s natural heat provides data centers with a reliable method of generating electricity and meeting energy needs throughout the year.
In this article, explore the advantages and disadvantages of using geothermal energy in data centers and its potential impact on the energy landscape.
What is geothermal energy?
Geothermal energy is a source of electric power extracted from the heat within the Earth’s crust. Elements within the Earth’s crust and mantle break down through radioactive decay, which releases energy as heat. The Earth’s surface also absorbs heat from solar radiation.
Most geothermal systems connect to underground reservoirs that are kept consistently hot due to the planet’s natural heat generation. The reservoir’s water is converted to steam and pumped through pipes and hydraulic systems to generate electricity through turbines. Many geothermal power plants use this technique, often drilling into reservoirs to establish a connection.
Other geothermal energy generation methods are from human-made underground reservoirs, hot springs and geysers.
Advantages of geothermal energy
Geothermal energy can help data centers build a more diversified energy grid that’s stable, resilient, efficient and sustainable.
High ramp rate
Geothermal energy has a high ramp rate. If energy demand is high on the grid, data centers can instead use geothermal systems to rapidly ramp and supply additional capacity, especially during peak loads.
Geothermal energy can also combine with other energy sources, like solar and wind. For example, if geothermal power plants or systems can’t produce enough energy for baseload power, data centers can connect to other electric systems, including sourcing electricity from other renewables.
Continuous fuel source
Unlike solar and wind energy, geothermal energy can be generated year-round, regardless of the weather or other environmental or climate conditions. The Earth naturally replenishes heat, so geothermal power can be continuously sourced without impacting the stability of the environment.
Low cost
Geothermal power plants also have minimal operating costs. According to research from the Global Geothermal Alliance, operational and maintenance costs are estimated at around 12 cents per megawatt per year. Over the long term, this type of energy production can provide a cost-effective solution to meet the rising energy needs of data centers.
Carbon footprint reduction
Geothermal energy typically does not pollute the surface, air or water; emit smoke; or produce harmful particulates. It has near-zero emissions and produces little to no greenhouse gases.
Geothermal power plants also require minimal land and freshwater use. Unlike wind or solar power plants, which require large areas of land to be cleared, geothermal plants use a much smaller space. They are built underground, which leaves the above environment and ecosystem intact. Geothermal plants also use little water to operate and generate more electricity compared to other energy systems.
A National Renewable Energy Laboratory project examined cold underground thermal energy storage technology to create a cold energy reserve underground with off-peak power. During peak load hours, this reserve could maintain data center temperatures and cool server equipment. Such technology could help make underground data centers even more resilient and self-sufficient.
Geothermal energy potential is largely untapped. New technologies are making it more viable and efficient as they require minimal land use and produce low noise levels compared to other power plants.
Disadvantages of geothermal energy
Geothermal energy use does have disadvantages, especially when searching for the right location to start operations. Much like the importance of picking a data center’s location, admins should consider the environmental impact that building a geothermal plant could have on the surrounding area.
Drilling
The biggest challenge of geothermal energy is finding and accessing a suitable location. While modern monitoring systems with machine learning can help identify and predict potential locations, exploratory drilling is often still necessary to find underground reservoirs. This can be expensive and dangerous, as drilling near a fault line could trigger an earthquake.
It’s worth noting that, while the upfront cost of geothermal energy is high, its efficiency and low operational costs can make up for those costs over the long run.
Heating loss of the surrounding area
Removing heat from the Earth at an unnaturally rapid rate can affect the surrounding area. For example, heat extraction may cool rocks within proximity and reduce the overall temperature of the environment. If not carefully monitored, this would affect the natural ecosystem of plant life and wildlife. Although the environment raises temperatures and adjusts naturally, excessive heat extraction at a continuous rate eventually makes the environment unable to adjust.
Greenhouse gases
Depending on the system, geothermal energy generation can release greenhouse gases, albeit a minimal amount. For example, when first accessing a reservoir, underground gases might release into the atmosphere during drilling or digging. In addition, open-loop systems might release some minimal air emissions, whereas closed-loop systems reinject escaped gases back into the earth.
That said, these emissions are vastly smaller than other sources of energy, especially fossil fuels.
Responsible resource management
Overextraction of heat can negatively affect reservoirs through temperature and fluid loss. As such, extra care must be taken to maintain and protect the reservoirs, which often requires water to be reinjected into the reservoir to stabilize water levels. Freshwater is not necessary for this process, but using “dirty” water could present contamination concerns. Monitoring the area is crucial to prevent contaminants from leaching into the ground.
Jacob Roundy is a freelance writer and editor with more than a decade of experience with specializing in a variety of technology topics, such as data centers, business intelligence, AI/ML, climate change and sustainability. His writing focuses on demystifying tech, tracking trends in the industry, and providing practical guidance to IT leaders and administrators.
