Geothermal Energy Facts

The geothermal energy facts reveal that geothermal can clearly provide us with clean renewable energy. What is geothermal energy? In a nutshell, it's energy that's generated by the Earth's own central heating system — its molten core.

Here, we'll take a look at some of the interesting ways this energy can be captured and used for heating and producing electricity.

What Is Geothermal Energy

The magma present in the Earth's subsurface areas heats to temperatures greater than the sun's surface, owed to the tremendous pressure and friction it's subjected to.

Sometimes, the super hot magma works its way through the crust of the Earth in volcanic activity, and it can also manifest its thermal properties in active geysers and fumaroles such as those found in Iceland.

To the non-scientist unfamiliar with the geothermal energy facts, it might appear that this kind of heating source would be unpredictable and difficult to harness, but that's actually not true. Similar to drilling wells for fossil fuels, geothermal well drilling can go deep into the ground to draw up hot water and steam that can be directly used for heating or for spinning the blades of turbines for the generation of clean electrical power.

Actually, the history of geothermal energy systems goes back to antiquity. The ancient Chinese, Greeks, Romans, and Native Americans were well aware of its benefits, and they all made use of hot mineral springs for heating, cooking, and even bathing.

The public baths and radiant, underfloor heating systems built by the Romans in Bath, Somerset, England, in the first century AD, offer one of the first and finest examples of geothermal power used for early commercial purposes.

Let's consider some modern-day geothermal energy facts. Today, there are two commonly used geothermal technologies: heating and cooling, and the generation of electricity.

Geothermal Heat Pumps for Heating and Cooling

Geothermal heating and cooling systems make use of the consistent temperature found near the surface of the Earth's crust. Below 3 meters (10 feet) the ground temperature stays consistently around 12.8°C (55°F), even in northern climates.

A geothermal ground source heat pump (GSHP) operates by running a thermal loop of pipe through this constant ground temperature either by drilling a well vertically or by burying the pipe horizontally in a trench.

Geothermal CoilsWorkers Laying Geothermal Coils
(Source: ©BanksPhotos/

The heat pump's pipe contains refrigerant fluid from which cooling or heating is exchanged as the building's air is passed over it. The process is fully reversible, depending on the season of the year and the desired temperature inside the home or building.

Geothermal cooling is the heat pump's easiest function, as all that's required is to pass the building's warm air over the cooler ground temperature pipes in a heat exchange. This is accomplished using a condenser and coils similar to the way refrigerators operate. Essentially, the building's warm air is pumped into the cooler ground thereby cooling the building, to describe it in its simplest terms.

Geothermal heating is more difficult to accomplish depending on the building's ambient outside temperatures. The heat pump system extracts heat from the ground and pumps it inside to warm the building, but since the ground source temperature is only about 12.8°C (55°F), extreme subzero days will often require supplemental heating to maintain comfortable indoor temperatures. As ambient outside temperatures drop, a geothermal heating/cooling system experiences a corresponding drop in its efficiency.

Geothermal Power Plants for Electricity

Water in hot springs or hot water that pools near the Earth's surface can be pumped from "hot aquifer" wells and its thermal properties used for heating. Such geothermal energy systems are in popular use around the world.

A fine example is the Krafla Power Station pictured below, one of Iceland's largest geothermal power stations in Northeast Iceland next to the Krafla Volcano. It produces approximately 60 MW of electrical power through 33 boreholes drilled into the core of the geothermal system to harness the super-hot fluids which drive the steam turbines.

Krafla Power Station, Geothermal Energy PipesKrafla Power Station, Geothermal Energy Pipes
(Source: ©dmbaker/

If a suitable aquifer isn't available, an artificial one can be created by drilling deep wells into hard rock and injecting water to hydraulically fracture the bedrock. With the help of huge pipes, the resulting heat or steam that's released can be transported and harnessed to generate heat and electrical power. These "enhanced geothermal systems" show greater potential than the harvesting of natural aquifers.

How Geothermal Energy Works

The short video below offers geothermal energy facts and best answers the question of how does geothermal energy work in geothermal energy systems?

Geothermal Energy Advantages

One of the great advantages of geothermal energy is that it has very little effect on the environment. It's believed to be a sustainable and renewable energy source because the Earth is constantly heating. Also, geothermal power plants have significantly low emissions and geothermal heat-pumps are extremely power efficient and are economical to operate. It's a reliable, sustainable, and cost-effective renewable energy source.

Geothermal Energy Disadvantages

One of the disadvantages of geothermal energy is that compared to a steam boiler, the heat gathered by a ground source heat pump is a much lower temperature, so it must be used quickly and efficiently to be useful and cost-effective. Also, the installation costs often run higher than installing conventional heating systems.

The water pumped from geothermal wells in large scale plant installations is corrosive and can contain trace elements of arsenic, mercury, and other toxic chemicals, so care and expense must be taken to ensure it's not disposed of in way that would damage the environment.

Some have voiced concerns that geothermal areas can cool down if the geothermal energy is over harvested. There is only so much heat that can be stored in any single area of the Earth's crust and as thermal energy is extracted from it, the area slowly cools. This begs the question, is thermal energy renewable or not? And if it's not, should we sink much effort and money into researching it?

However, projected commercial heat extraction is very small compared to the Earth's internal heat content, and it's considered a minute fraction of the natural outflow from hot springs and volcanoes. It's also true that thanks to the constant radioactive decay of minerals, geothermal energy does slowly renew and with careful resource planning, a neutralizing effect can be achieved.

The Future of Geothermal Energy Systems

More geothermal energy facts:

Geothermal energy in Iceland provides over 17% of that country's electricity needs. Over 24 countries are currently benefiting from geothermal energy systems, generating almost 70,000 GWh of electricity in 2010. More and more, governments around the world are becoming aware of the cost-saving benefits of this green, renewable energy source.

Most of the current geothermal wells are only about 3 kilometers (2 miles) deep. Apparently, enhanced wells as deep as 10 kilometers (6 miles) will make it possible to take better advantage of the higher geothermal temperatures at deeper levels beneath the Earth's crust. Wells of that depth are now common in the petroleum industry, and expected increases in fossil fuel prices will make deep wells increasingly cost-effective for the geothermal industry in the near future.

Summary of Geothermal Energy Facts

What we're learning through geothermal energy facts is that while geothermal energy systems cannot hope to compete with solar energy's abundance, low cost, and ease in energy harnessing, the advances in geothermal technology will ensure that constant performance geothermal energy systems will provide an increasingly larger share of clean power to the world's homes, offices, and industries.

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