Geothermal Power

In News

• The state-run explorer Oil and Natural Gas Corporation (ONGC) will generate electricity on a utility scale by tapping steam gushing from the earth’s bowels at Puga, Ladakh.

About

• This will be India’s first geothermal energy project, and also the world’s highest. 
• ONGC started drilling its first well for the project recently and encountered high-pressure steam at 100 degrees Celsius with a discharge rate of 100 tonne geothermal energy per hour.
• Phases:
  • In the first phase, the company will drill 1,000-metre-deep wells to run a one-megawatt power plant as a pilot. 
  • The third phase envisages a deeper exploration of the geothermal reservoir and a higher capacity demonstration plant. 
  • A commercial size plant will be set up in the third phase.
• Promising Prospects:
  • Puga and Chumathang area in general, are deemed as the most promising geothermal prospects. 
  • Puga is a remote valley located at an altitude of over 14,000 feet, near the de-facto border with China.
  • These areas were discovered in the 1970s and initial exploratory efforts were made in the 1980s by the Geological Survey of India (GSI). 
• Global Leaders:
  • The US, Indonesia, Philippines, Turkey and New Zealand have gigawatt-size geothermal capacities. 
  • Mexico and Italy have 900 megawatt-plus capacity, while Kenya has over 800 mw, followed by Iceland, Japan and others.

Significance of Project

• It will boost Ladakh’s potential to emerge as one of the country’s clean energy bowls by expanding the area’s horizon beyond solar/wind power.
• A bigger plant will provide 24×7 supply for the far-flung settlements and the large defence establishment in the eastern sector, reducing their dependence on diesel for running generators. 
• The plant can also play a vital role as a stabiliser for the 15 GW solar/wind project being planned in the nearby morey plains in the south-west.
• The geothermal foray is part of a strategy adopted by the ONGC, India’s largest oil and gas producer, to offset its carbon footprint.
• The pilot plant provides power and heating needs of the nearby settlements of Tibetan pastoralist refugee settlements at Sumdo and nearby areas. 
• The hot water from the spring could be used for space-heating and establishing hot swimming pools to attract tourists, which will give a boost to tourism in Ladakh.

Geothermal Energy

• About:
  • The word geothermal comes from the Greek words geo (earth) and therme (heat).
  • It refers to the heat stored beneath the earth’s surface that is carried to the surface by water and/or steam.
• Sources:
  • This thermal energy is contained in the rock and fluids beneath Earth’s crust. 
  • It can be found from the shallow ground to several miles below the surface, and even farther down to the extremely hot molten rock called magma.
  • Rocks and water absorb heat from magma deep underground.
  • The slow decay of radioactive particles in the earth’s core produces geothermal energy.
• Usage:
  • It is carbon-free and provides a perpetual supply of heat.
  • It can be directly used or converted into electricity.
  • Geothermal water can be used directly to heat homes and offices or grow plants in greenhouses. 

Image Courtesy: greenesa.com

Advantages

• This energy is clean, sustainable, carbon-free, continuous, uninterrupted and environment-friendly.
• It can be extracted without burning fossil fuels like coal, gas, or oil.
• Geothermal fields produce only about 1/6th of the carbon dioxide (CO2) that a relatively clean natural-gas-fueled power plant produces. 
• Unlike solar and wind energy, geothermal energy is always available throughout the year.
• It’s also relatively inexpensive and savings from direct use can be as much as 80 percent over fossil fuels.

Disadvantages

• High Initial Cost: Though the energy provides free heat production, the initial capital costs tend to be higher.
• Toxic Metals: Sometimes the reservoirs are detected with toxic heavy metals, including mercury, arsenic, and boron.
• Unpleasant Gases: The process of extraction releases hydrogen sulfide, a gas that smells like a rotten egg at low concentrations.
• Disposal Issue: Another issue is the disposal of some geothermal fluids, which may carry low levels of toxic materials.
• Diminishing Steam: Geothermal sites are capable of providing heat for many decades; however, specific locations may cool down eventually.

Conclusion

• Geothermal energy is considered a cheap, never-ending resource and a base-load generator.
• These resources can be exploited from naturally occurring heat, rock, and water or through enhanced geothermal systems.

Source: TOI