What is Geothermal Power and is it Renewable

geothermal energy

What is geothermal power

Geothermal power is power produced by geothermal energy. Technologies in use contain binary cycle power stations, flash steam power stations and dry steam power stations. Geothermal electricity production is currently used in 25 countries, while geothermal heating is in use in 72 countries.

As of 2016, global geothermal power capacity amounts to 11.6 gigawatts (GW), of which 26 per cent or 3,547 megawatts (MW) are installed in the United States of America. International markets grew at an average annual rate of 6 per cent over the two years to 2016, and global geothermal power capacity is expected to reach 14.6–17.5 GW by 2020.

Based on present geologic knowledge and technology the GEA publicly reveals, the GEA (Geothermal Energy Association) estimates that only 6.8 per cent of total worldwide potential has been tapped so far, while geothermal power potential to be in the range of 34 GW to 3 TW reported by IPCC. Countries producing more than 16% of their electricity from geothermal sources entail the Philippines, New Zealand, El Salvador, Kenya, Costa Rica, and Iceland.

Why is Geothermal Energy Considered a Renewable Resource

Why is geothermal energy considered a renewable resource? is because the heat extraction is small compared with the Earth’s heat content. More so, the greenhouse gas emissions of geothermal electric stations are on average 44 grams of carbon dioxide per kilowatt-hour of electricity or less than 6% of that of conventional coal-fired plants.

What is geothermal power; As a source of renewable energy for both heating and power, geothermal has the potential to meet 3-6 per cent of global demand by 2040. With economic incentives, it’s estimated that by 2090 it will be feasible to reach 10 per cent of worldwide demand.

Why is Geothermal Energy Renewable

Geothermal energy is renewable simply because the Earth has retained a large amount of the heat energy that was created during the formation of the planet. Additionally, heat is generated continuously by the decay of radioactive elements within the Earth.

However, the amount of heat within the Earth, and the vast amount that’s lost through natural processes (e.g. radiation/conduction to the atmosphere, volcanic activity ), is much more than the amount of heat lost via geothermal energy creation.

However, at any one geothermal field, the fluid levels/fluid pressure in the reservoir or temperature of the geothermal reservoir may reduce over time as fluids are created and energy is extracted.

Produced fluids can be as well re-injected to maintain pressures, though this may further cool down the reservoir if care isn’t taken. Over time, it’s usually necessary to drill additional wells to support energy creation as temperatures and reservoir fluid pressures decline.

How is Geothermal Energy Produced

The steam rotates a turbine that activates a generator, which generates electricity. Most power plants still make use of fossil fuels to boil water for steam. “This geothermal power plant produces electricity for the IVC (Imperial Valley in California).” ~ Warren Gretz

Many power plants need steam to produce electricity. The steam rotates a turbine that actuates a generator, which creates electricity.

What is geothermal power; Most power plants still use this fossil fuels to boil water for steam. However, geothermal power plants use steam produced from reservoirs of hot water found a couple of miles or more beneath the Earth’s surface. Also, there are three types of geothermal power plants such as dry steam, flash steam, and binary cycle.

Dry steam power plants draw from under Earth’s surface resources of steam. However, the steam is piped directly from subterranean wells to the power plant, where it’s directed into a generator/turbine unit. There are two known underground resources of steam in the U.S. – which are, Yellowstone National Park in Wyoming and the Geysers in northern California, where there is a famous geyser known as Old Faithful. Since Yellowstone is protected from development, the only dry steam plants in the nation are at The Geysers.

Flash steam power plants are the most popular. They use geothermal reservoirs of water with temperatures higher than 360°F (182°C). This boiling water flows up via wells in the ground under its pressure.

Moreover, as it flows upward, the pressure reduces, and most of the hot water boils into steam. Then the steam is separated from the water and used to power a generator/turbine. Any condensed steam and leftover water are injected back into the reservoir, however, making this a sustainable resource.

Binary cycle power plants perform on the water at lower temperatures of about 224°-360°F (106°-180°C). These plants utilize the heat from the hot water to boil a working fluid, commonly an organic compound with a low boiling point. Furthermore, the working fluid is vaporized in a heat exchanger and as well used to turn a turbine.

Then the water is injected back into the ground to be reheated. The working fluid and the water are kept separated during the entire process, so there are little or no air emissions.

Small-scale geothermal power plants (under 6 megawatts) have the proficient for widespread application in rural areas, feasibly even as distributed resources of energy.

Distributed resources of energy refer directly to different small modular power-generating technology that can be connected to evolve the operation of the electricity delivery system.

Geothermal Energy Availability

Most of the geothermal reservoirs or geothermal power plants in the United States are located in the western states, and Hawaii. California is the state that produces the most electricity from geothermal energy. At the same time, the Geysers dry steam reservoir in northern California is the highest known dry steam field all over the world.

How Much Does Geothermal Energy Cost

The Economic Stimulus Recovery act of 2008 removed the cap on residential geothermal heat pump systems. House owners can now receive a federal tax incentive equal to 35% the cost of a qualified geothermal heat pump system.

The installation and design of geothermal systems are not DIY (Do It Yourself) projects and therefore require the services of an expert. Additionally, the integration of geothermal exchange systems with other systems in a house requires specialized expertise. More so, geothermal heating system price varies based on the type of loop system, usually either horizontal or vertical.

On average, a typical house of 2600 square feet, with a heating load of 60,500 BTU and a cooling capacity of 60,500 BTU will cost between $22,000 to $26,000 to install. This is around double the cost of a conventional cooling, heating, and hot water system, but geothermal cooling/heating systems can reduce utility bills by 35% to 55%.

The payback for a system can range from 3-10 years, while the lifetime of a system can be 17-22 years, almost double a conventional system. Also, renewable energy systems add value to the equity of your building.

There are United States tax rebates for energy efficacy improvements, including a 35% federal tax credit, and most state and utility companies offer incentives.

Because of the upfront cost for installing this geothermal heat pump systems, it’s widespread to finance these systems. However, monthly payments for financing a geothermal system are much reasonable and can save a house owner money as soon as the system is installed. Two examples of financing are listed below.

Example 1

Project Cost: $25,500

Rebate / Down Payment: $5,500

Amount Financed: $20,500

Interest Rate: 7.89%

Term: 250 Months

Payment: $165.00

Example 2

Project Cost: $15,500

Rebate / Down Payment: $0

Amount Financed: $15,500

Interest Rate: 8.98%

Term: 170 Months

Payment: $141.50

Furthermore, according to Energy Environmental Corporation (EEC), before installing any new cooling and heating system in a home, it’s necessary to re-evaluate and lessen the energy load of the home.

A more energy efficient house will not only decrease the cost of a new system and utility bills, but it’ll highly improve the comfort of your house.

Before going to install and design any systems, you schedule a house energy audit in which an energy auditor will recommend improvements and also make estimates for cost and as well energy savings from these improvements.

Basic improvements usually contain adding air sealing measures and insulation. Energy Environmental Corporation (EEC) works with and can recommend several qualified house Energy Star auditors and installation experts.

Geothermal heat pumps can be integrated with existing systems like traditional forced air or can be installed in a new building or radiant floor heating. Hydronic radiant heating systems will require water-to-water heat pumps while forced air systems will require a water-to-air heat pump.

The size of the ground loop and the size of the geothermal heat pump required depends on the cooling and heating requirements for your house and is critical in ensuring the efficacy and performance of the system. Moreover, the capacity of the geothermal systems is measured in tons.

Typically, a 4-ton setup should enough for the average home, but home size, cooling and needs, local geology and land, and soil availability are all factors which will influence the correct size for your particular home. EEC is experienced in geothermal heat pump installation and can assist you properly size a system.

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