The Cost of Geothermal Energy

When you’re looking to find how much geothermal heating and cooling costs, it is extremely hard to get an accurate overall price range. These technologies have been around for ages and work by exploiting the constant temperature below the Earth’s surface.

A geothermal heat pump or ground source heat pump has higher efficiency and is used for heating and cooling purposes. It is effective compared to furnaces, electrical heating, or even air source heat pumps.

It is a known fact that this renewable energy source lowers carbon footprint, but how much does geothermal energy cost?

What is the Cost of Geothermal Energy?

At the Geysers, the generated power is sold at about $0.03 to $0.035 per kWh. Some power plants charge more during higher demand periods. Any plant built today would require about $0.05 per kWh.

The cost for your system varies depending on the type of loop system (vertical or horizontal). Installing a heating and cooling load of 60,000 BTU at any typical home of 2,500 sq. ft. will cost somewhere between $20,00 to $25,000.

The lifetime of this system can be anywhere from 18 to 23 years which is double than a conventional system. Moreover, the payback for this system can range from 2 to 10 years. Many states and utility companies even offer incentives. The US tax rebates are available for energy efficiency improvements including 30% federal tax credit.

The Cost of Developing a Geothermal Power Plant

The cost of a geothermal plant is weighted towards early expenses instead of the fuels required to keep them running. First comes well drilling and pipeline construction, it is then followed by resource analysis of drilling information. Next is designing the actual plant.

In general, a power plant construction is completed concurrently with final field development. In the U.S., an initial cost for the power plant and field is about $2500p per installed kW. If it is a small power plant (<1Mwe), then the cost is probably around $3000-$5000/ kWe.

The operating and maintenance cost of these systems range from $0.01-$0.03 per kWh. Most geothermal power plants run at greater than 90% availability but the ones that run at 97% or 98% have increased maintenance costs. Higher-priced electricity accounts for running the plants 98% of the time because it recovers the resulting higher maintenance costs.

However, the geothermal heating and cooling systems can reduce your utility bills by 40% to 60%.

Geothermal Energy Cost depending on the Type of Loop

Indoor Portion Costs

  • Heat Pump Cost Factors

An average geothermal heat pump can cost between $1,500 to $2,500 per ton. Although the actual size of the heat pump is determined by the home’s heating and cooling needs, the standard family with 2,000 sq. ft. the home will require a 5-ton heat pump.

Outdoor Portion Costs

  • Ground Loop Cost Factors

There is an open-loop system that is less common. It circulates water from well or surface water through the system and pumps it back to the ground through a discharge pipe.

Aside from that, the three most common closed-loop systems and the cost associated with each one of them is listed below. This can help you decide which system is best suitable for you.

1. Horizontal System

In this system, layers of coils or straight runs of polyethylene pipe are installed in 6 feet deep trenches. It is one of the cheapest underground options but requires a lot of open space. A house with 2,000 sq. ft. needs 400 ft. of 2 ft. wide trenches.

An average direct cost for this system ranges between $1,000 to $2,000 per ton.

2. Vertical System

This system is used when you have limited space. Holes with 4 inches of diameter are drilled 15 ft. apart and 100 ft. to 400 ft. deep. Two pipes are inserted and connected from the bottom.

An average direct cost for this system ranges between $1,600 to $4,250 per ton

3. Pond/Lake System

This system draws heat from the water instead of the soil. It is the lowest cost option but is applicable only if you have a body of water nearby. A blanket of water cover coils is anchored on racks about 10 ft. deep.

Geothermal Energy: Cost of Drilling Factors

Drilling is more expensive than trenching. While trenching typically costs between $2.50 to $5 per foot, drilling a vertical loop can cost from $5 to $15.50 per foot. In some cases, the vertical loop cost even extends to about $ 30 per foot.

Some factors that impact the cost of drilling:

Equipment A drill rig is a scarce resource and is suitable to be used in one place at a time. It requires major upkeep, labor, and fuel to operate safely.

A 20-year old mud rotary drill rig will cost around $200,000 while a new rotary drill will cost up to $500,000.

Mobilization Fee The most expensive and labor-intensive section of drilling is moving the equipment. It takes almost 1.5 days to fully transport, store, set-up, and fuel the drill suite.

Each piece of this machinery must be well-maintained after use to keep it in good condition.

Geology In case of exceptionally rocky property or a relatively high bedrock, you may need to drill through or around it. Some rocks need to be removed entirely.

But, if the rock is impossible to drill through or remove, you need to drill more than one borehole.

Pipe Death The cost of drilling increases with each foot drilled. The depth required for the ground loop depends on the amount of rock, climate, heating, and cooling needs.

If the loops are not properly sized, the system cannot absorb or reject heat adequately.

Labor Usually, a drilling crew includes a master driller and 1 to 2 helpers.
Materials Vertical ground loop installment requires an assortment of materials such as grout, heat transfer fluid, piping, bore headers, drill bits, bentonite clay, and many more.

Final Words,

The geothermal cost varies according to your needs, system, and home design. Factors such as soil conditions, climate, available land, and local installation costs at the site also play a role in the total cost of geothermal energy.