TerraCOH Frequently Asked Questions (FAQ) & Glossary

Scroll down after the FAQ to explore Energy Industry Terms and Definitions


Question #1- How can geothermal compete with conventional power sources given its energy conversion efficiency tends to be less than 15% at most?

Answer: Existing baseload power sources – coal, natural gas, and nuclear – operate at very high temperatures, generally in excess of 350 °C. Assuming a conservative heat rejection temperature of 30 °C, these high cycle temperatures result in Carnot efficiencies in excess of 51% and thermal efficiencies generally over 40%.

Geothermal systems, which utilize much lower maximum temperatures, cannot compete – and don’t care to try to compete – with legacy baseload power sources in terms of thermal efficiency. Instead, they achieve operational and cost benefits over other power sources via relatively low levelized capital costs, minimal operational costs, and no fuel costs. Moreover, they provide power with no or minimal emissions, thereby reducing environmental impacts and associated regulatory and societal costs.

Question #2 - What does Baseload mean?

Answer: Baseload power plants provide reliable power to maintain a large-scale electrical grid and generally shut down only for scheduled maintenance or emergency repairs. Typically, they require large upfront capital investments but provide reasonably low-cost electricity. In contrast, peak-load power plants generally run only when demand for electricity is high, such as during summer afternoons when air conditioning loads are high. In short, Baseload Capacity is the power output of a power plant that can be continuously produced 24/7.

Question #3 – What does Dispatchable mean?

Answer: The ability schedule and control the generation and delivery of electric power as needed.

Question #4 – What proprietary technologies does TerraCOH have?

Answer: TerraCOH has 2-core proprietary technologies. Carbon Dioxide Plume Geothermal (CPG) ™ and the Earth Battery™ comprise TerraCOH Power Systems (TPS).

Carbon Dioxide (CO2) Plume Geothermal – (CPG)™ technology is the next generation of geothermal, lowering both the capital and operating cost for electricity production and exponentially increasing the geographic extent. This simultaneously allows power generators to lower their costs while meeting their customers’ and regulators’ dispatchable demands for 24/7, emission free power.

Earth Battery™ technology permanently, safely, and profitably stores vast quantities of CO2 in the earth to harvest geothermal energy, store energy from electric grids and thermal energy from low-carbon above-ground sources, such as solar thermal farms and decarbonized fossil energy power plants. Our system is recharged when supply exceeds demand and discharged when demand exceeds supply. Our technology minimizes water usage associated with power generation, while generating water by removing it to assure safe underground pressures.

Question #5 - Why CO2 Power Systems over legacy Power Systems?

Answer: A CO2 system has several advantages over conventional low-temperature (i.e., below 150 deg C) geothermal power systems. For instance, with CO2, we can achieve higher thermal energy to electricity conversion efficiencies, at these low temperatures, than are typically possible with conventional, organic rankine cycle (ORC) power systems. This improvement is possible because, in full CPG™ deployments, CO2 is sent directly from the subsurface through the power system, avoiding the need for conventional heat exchangers, which inherently decrease efficiency. In addition, by directly using CO2, we completely or partially avoid the need for pumps to produce fluid from the subsurface. The thermophysical properties of CO2 will result in CO2 siphoning itself through the subsurface, something which can happen with water but only at far higher temperatures (in excess of 350 deg C). By comparison, pumping dense brine can result in upwards of 50% parasitic losses in conventional ORC operations.

CO2 power systems are also far more compact than steam or ORC power systems, allowing them to be assembled offsite and delivered by truck to field locations, where they will be largely ready to be put in service upon arrival. This compact, modular design optimizes costs, space and overall power generation performance.

Question #6 - Does TerraCOH get involved in fracking wells?

Answer: NO! We do not do any fracking of wells, like is done in the oil industry.

Question #7 – Where do you get the CO2?

Answer: There are several sources for CO2. In the simplest case, we will deploy at sites that already have CO2 below-ground, such as existing geologic CO2 sequestration sites, natural CO2 sources and enhanced oil recovery (EOR) fields. Thereafter, we will secure CO2 from largescale emitters. We are working with entities that are planning commercial-scale CO2 capture operations and need an entity, such as TerraCOH, that can use and consume millions of tonnes of CO2 per year.

Question #8 – Doesn’t the CO2 corrode your power system?

Answer: The potential for corrosion is something that every geothermal power project must consider, and conventional geothermal technologies must be more concerned with corrosion than TerraCOH. Water dissolves and carries far more contaminants than does CO2, hence corrosion is a major issue with conventional geothermal systems. Nonetheless, our power systems are built from high grade stainless steel, to further limit the potential for corrosion or degradation over time.

Question #9 – Are your “Power Systems” really able to just “Bolt-On”? Isn’t it more complex than that?

Answer: Each and every site will require an in-depth study of its unique parameters in order that our TerraCOH Power System (TPS) work most efficiently. This includes defining geologic conditions, analysis of subsurface fluid composition, defining optimal TPS configuration and design, etc…. Our term, “Bolt On”, refers to how our TPS, once properly designed for a given site, can be incorporated into existing geologic fluid production operations with minimal impact on said operations. Tapping into an existing working site has its challenges, one we are prepared to meet. Our goal is never to disrupt service, as our TPS is a self-contained, mobile, all-in-one unit, and we are careful in choosing site locations to limit possible obstacles.

Question #10 – Has your technology been verified in any way?

Answer: Yes! All key aspects of CPG™ technology and additional critical elements of CPG™ deployment have been numerically analyzed by Lawrence Livermore National Lab, University of Minnesota, ETH (Zurich, Switzerland), and The Ohio State University. Importantly, the power system we will use has been commercially operated in non-geothermal operations. Geologic CO2 injection and production systems have been existed in the CO2 sequestration space and EOR industry for decades. Thus, we can deploy existing (off the shelf) technologies and expertise in a new way to create our commercial CPG™ deployments.

Question #11 - Are you going to disrupt well site operations?

Answer: No. Our power system is designed to operate in parallel with any existing operations, in those cases where we generate geothermal power in regions with hydrocarbon production facilities. Should our power systems require maintenance or have any other operational disruptions, they will be bypasses to ensure we do not interrupt existing operations. When our power systems are installed onsite, alongside an existing hydrocarbon operation, some modifications to the existing production pipelines will be required, such as adding bypass valves. However, these minimal additions can largely be timed to coincide with planned downtime for maintenance.

Question #12 - What is the expected life at an on-site power system?

Answer: With proper, occasional maintenance, power systems in our applications will have lifespans of 25+ years. Multifluid geologic plumes that are used for pure geothermal power generation are general expected to have lifespans of 25-40 years, after which they may need to recharge for a similar amount of time before being used for heat extraction again. Formations that are used for energy storage will generally have an unlimited lifespan.

Question #13 - What is the typical life expectancy at a producing well site?

Answer: A pure CPG™ energy production site will have an expected lifespan of 25-40 years, after which the geothermal heat will need to recharge for a similar period of time before being harvested again. An Earth Battery™ energy storage field will generally have an unlimited lifespan, depending on how it is operated. Once CO2 is placed in the ground, it is expected to stay in the subsurface indefinitely. We can design a given operation to utilize a fixed volume of CO2 (on the order of a few million tonnes), or a site can grow continuously with time, increasing the amount of CO2 that is sequestered as well as the amount of geothermal energy that can be generated and/or the energy that can be stored.

Question #14 - Can your technology be implemented at horizontal wells or just vertical wells?

Answer: Optimal deployments of our technology will use both vertical and horizontal wells.



45Q Tax Credit
The value of the tax credit depends upon the type of CO2 storage. CO2 used for saline storage would receive $50 per tonne of CO2 stored while utilization in products, including EOR, would receive only $35 per tonne of CO2
•Saline storage earns a higher $/tonne CO2 storage credit than utilization because saline operations do not generate a marketable product, and therefore require a higher incentive level to be economic.
•The credits last for up to 12 years for projects started within the specified time period. After that period, the credits end.

Baseload Capacity
The power output of a power plant that can be continuously produced.

Baseload Demand
The minimum demand experienced by a power plant.

Baseload Power Plant
A power plant that is normally operated to generate a base load, and that usually operates at a constant load; examples include coal fired and nuclear fueled power plants.

Brayton Cycle
A thermodynamic cycle using constant pressure, heat addition and rejection, representing the idealized behavior of the working fluid in a gas turbine type heat engine.

British Thermal Unit (Btu)
The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit; equal to 252 calories.

Carbon Capture and Storage (CCS)
Also referred to as Carbon Capture, and Sequestration is a technology that can capture up to 90% of the carbon dioxide (CO2) emissions produced from the use of fossil fuels in electricity generation and industrial processes, preventing the carbon dioxide from entering the atmosphere by securely storing the CO2 in a contained geologic formation.

Carbon Capture Utilization and Storage (CCUS)
Carbon Capture, Utilization and Storage (CCUS); also referred to as Carbon Capture, Utilization and Sequestration, is a process that captures carbon dioxide (CO2) emissions from sources like coal-fired power plants and either reuses or stores it so it will not enter the atmosphere. Carbon dioxide storage in geologic formations includes oil and gas reserviors, unminable coal seams and deep saline reserviors - structures that have stored crude oil, natural gas, brine and carbon dioxide over millions of years which may be drawn on to inable the sequestered CO2 to be used as an asset rather than a waste product.

Carbon Dioxide (CO2)
A colorless, odorless noncombustible gas with the formula CO2 that is present in the atmosphere. It is formed by the combustion of carbon and carbon compounds (such as fossil fuels and biomass), by respiration, which is a slow combustion in animals and plants, and by the gradual oxidation of organic matter in the soil.

Carbon Dioxide (CO2) Plume Geothermal (CPG)™
TerraCOH's proprietary process of using CO2 as the working fluid in a shallow depth, closed loop, geothermal power generation.

Carbon Credit
A tradable credit granted to a country, company, etc.; for reducing emissions of carbon dioxide or other greenhouse gases by one metric tonne below a specified quota. Once each member's emissions are converted into tradable credits, the exchange works like any financial market.

Carnot Cycle
An ideal heat engine (conceived by Sadi Carnot) in which the sequence of operations forming the working cycle consists of isothermal expansion, adiabatic expansion, isothermal compression, and adiabatic compression back to its initial state.

Clean Power Generator
A company or other organizational unit that produces electricity from sources that are thought to be environmentally cleaner than traditional sources. Clean, or green, power is usually defined as power from renewable energy that comes from wind, solar, biomass energy, etc. There are various definitions of clean resources. Some definitions include power produced from waste-to-energy and wood-fired plants that may still produce significant air emissions. Some states have defined certain local resources as clean that other states would not consider clean. For example, the state of Texas has defined power from efficient natural gas-fired power plants as clean. Some northwest states include power from large hydropower projects as clean although these projects damage fish populations. Various states have disclosure and labeling requirement for generation source and air emissions that assist customers in comparing electricity characteristics other than price. This allows customers to decide for themselves what they consider to be "clean." The federal government is also exploring this issue.

Closed Cycle
A system in which a working fluid is used over and over without introduction of new fluid.

Closed-Loop Geothermal
Closed-loop (also known as "indirect") systems circulate a solution of water, CO2, or other working fluid through a series of sealed loops of piping. Once the heat has been transferred into or out of the solution, the solution is recirculated. The loops can be installed in the ground horizontally or vertically.

The rate at which electricity is delivered to or by a system, part of a system, or piece of equipment expressed in kilowatts, kilovolt amperes, or other suitable unit, at a given instant or averaged over a specified period of time.

Demand Charge
A charge for the maximum rate at which energy is used during peak hours of a billing period. That part of a power provider service charged for on the basis of the possible demand as distinguished from the energy actually consumed.

Demand(ed) Factor
The ratio of the maximum demand on an electricity generating and distribution system to the total connected load on the system; usually expressed as a percentage.

Demand Power
see Peak-Load.

Dependable Capacity
The load-carrying ability of an electric power plant during a specific time interval and period when related to the characteristics of the load to be/being supplied; determined by capability, operating power factor, and the portion of the load the station is to supply. Direct Access The ability of an electric power consumer to purchase electricity from a supplier of their choice without being physically inhibited by the owner of the electric distribution and transmission system to which the consumer is connected to. (See also Open Access.)

To schedule and control the generation and delivery of electric power.

The ability to dispatch power.

Distributed Generation
A term used by the power industry to describe localized or on-site power generation.

Earth Battery™
TerraCOH's proprietary energy storage process.

Electric Energy
The amount of work accomplished by electrical power, usually measured in kilowatt-hours (kWh). One kWh is 1,000 Watts and is equal to 3,413 Btu.

Electricity Grid
A common term referring to an electricity transmission and distribution system.

Electric Rate
The unit price and quantity to which it applies as specified in a rate schedule or contract.

Electric Rate Schedule
A statement of the electric rate(s), terms, and conditions for electricity sale or supply.

Electric System
The physically connected generation, transmission, and distribution facilities and components operated as a unit.

Electric System Loss(es)
The total amount of electric energy loss in an electric system between the generation source and points of delivery.

Electric Power Plant
A facility or piece of equipment that produces electricity. Electric Power Sector Those privately or publicly owned establishments that generate, transmit, distribute, or sell electricity.

Electric Utility
A corporation, person, agency, authority or other legal entity that owns and/or operates facilities for the generation, transmission, distribution or sale of electricity primarily for use by the public. Also known as a power provider.

Pollution (including gas, noise, heat, and radiation) discharged into the atmosphere by residential, commercial, and industrial facilities, ie. Carbon Dioxide (CO2)

The elimination of the pollution (including gas, noise, heat, and radiation) discharged into the atmosphere by residential, commercial, and industrial facilities, ie. Carbon Dioxide (CO2)

The capability of doing work; different forms of energy can be converted to other forms, but the total amount of energy remains the same.

Enhanced oil recovery (EOR)
The implementation of various techniques for increasing the amount of crude oil that can be extracted from an oil field. Enhanced oil recovery is also called improved oil recovery or tertiary recovery (as opposed to primary and secondary recovery).

Geothermal Energy
Energy produced by the internal heat of the earth; geothermal heat sources include: hydrothermal convective systems; pressurized water reservoirs; hot dry rocks; manual gradients; and magma. Geothermal energy can be used directly for heating or to produce electric power.

Geothermal Power Station
An electricity generating facility that uses geothermal energy.

Gigawatt (GW)
A unit of power equal to 1 billion Watts; 1 million kilowatts, or 1,000 megawatts.

Greenhouse Gases (GHG)
Those gases, such as water vapor, carbon dioxide, tropospheric ozone, methane, and low level ozone that are transparent to solar radiation, but opaque to long wave radiation, and which contribute to the greenhouse effect.

Green Power
A popular term for energy produced from clean, renewable energy resources.

Green Pricing
A practice engaged in by some regulated utilities (i.e. power providers) where electricity produced from clean, renewable resources is sold at a higher cost than that produced from fossil or nuclear power plants, supposedly because some buyers are willing to pay a premium for clean power. Grid A common term referring to an electricity transmission and distribution system.

Grid-Connected System
Independent power systems that are connected to an electricity transmission and distribution system (referred to as the electricity grid) such that the systems can draw on the grid's reserve capacity in times of need, and feed electricity back into the grid during times of excess production.

Heat Exchanger
A device used to transfer heat from a fluid (liquid or gas) to another fluid where the two fluids are physically separated.

Heat Transfer Fluid
See Working Fluid.

Hot Dry Rock
A geothermal energy resource that consists of high temperature rocks above 300 °F (150 °C) that may be fractured and have little or no water. To extract the heat, the rock must first be fractured, then water is injected into the rock and pumped out to extract the heat. In the western United States, as much as 95,000 square miles (246,050 square km) have hot dry rock potential.

Hydrothermal fluids
These fluids can be either water or steam trapped in fractured or porous rocks; they are found from several hundred feet to several miles below the Earth's surface. The temperatures vary from about 90 °F to 680 °F (32 °C to 360 °C) but roughly 2/3 range in temperature from 150 °F to 250 °F (65.5 °C to 121.1 °C). The latter are the easiest to access and, therefore, the only forms being used commercially.

A metric unit of energy or work; the energy produced by a force of one Newton operating through a distance of one meter; 1 Joule per second equals 1 Watt or 0.737 foot-pounds; 1 Btu equals 1,055 Joules. Joule's Law The rate of heat production by a steady current in any part of an electrical circuit that is proportional to the resistance and to the square of the current, or, the internal energy of an ideal gas depends only on its temperature.

Kilowatt (kW)
A standard unit of electrical power equal to one thousand watts, or to the energy consumption at a rate of 1000 Joules per second.

Kilowatt-hour (kWh)
A unit or measure of electricity supply or consumption of 1,000 Watts over the period of one hour; equivalent to 3,412 Btu.

Process of, relating to, or being a previous or outdated way of doing things.

Levelized Cost of Electricity (LCOE)
The levelized cost of electricity (LCOE) is a measure of a power source which attempts to compare different methods of electricity generation on a comparable basis.

Molten or partially molten rock at temperatures ranging from 1,260 F to 2,880 F (700 °C to 1600 °C). Some magma bodies are believed to exist at drillable depths within the Earth's crust, although practical technologies for harnessing magma energy have not been developed. If ever utilized, magma represents a potentially enormous resource.

Megawatt (MW)
One thousand kilowatts, or 1 million watts; standard measure of electric power plant generating capacity.

Megawatt-hour (MWh)
One thousand kilowatt-hours or 1 million watt-hours. Name Plate A metal tag attached to a machine or appliance that contains information such as brand name, serial number, voltage, power ratings under specified conditions, and other manufacturer supplied data.

On-Peak Energy
Energy supplied during periods of relatively high system demands as specified by the supplier.

On-Site Generation
Generation of energy at the location where all or most of it will be used.

On-Peak Energy
Energy supplied during periods of relatively high system demands as specified by the supplier.

Power generated that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.

Peak Shifting
The process of moving existing loads to off-peak periods.

Porous Media
A solid that contains pores; normally, it refers to interconnected pores that can transmit the flow of fluids. (The term refers to the aquifer geology when discussing sites for CAES.)

Energy that is capable or available for doing work; the time rate at which work is performed, measured in horsepower, Watts, or Btu per hour. Electric power is the product of electric current and electromotive force.

Power Factor (PF)
The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source, expressed in volt-amperes or kilovolt-amperes.

Power Generation Mix
The proportion of electricity distributed by a power provider that is generated from available sources such as coal, natural gas, petroleum, nuclear, hydropower, wind, or geothermal.

Power Provider
A company or other organizational unit that sells and distributes electrical power (e.g., private or public electrical utility), either to other distribution and wholesale businesses or to end-users. Sometimes power providers also generate the power they sell.

Stand-Alone Generator
A power source/generator that operates independently of or is not connected to an electric transmission and distribution network; used to meet a load(s) physically close to the generator.

Stand-Alone Inverter
An inverter that operates independent of or is not connected to an electric transmission and distribution network.

Stand-Alone System
An system that operates independent of or is not connected to an electric transmission and distribution network.

A unit of heat containing 100,000 British thermal units (Btu).

Thermal Capacitance
The ability of a material to absorb and store heat for use later.

Thermal Efficiency
A measure of the efficiency of converting a fuel to energy and useful work; useful work and energy output divided by higher heating value of input fuel times 100 (for percent).

Thermal Energy
The energy developed through the use of heat energy.

Thermal Energy Storage (TES)
The storage of heat energy during power provider off-peak times at night, for use during the next day without incurring daytime peak electric rates.

Thermal Mass
Materials that store heat.

Thermodynamic Cycle
An idealized process in which a working fluid (water, air, CO2 etc) successively changes its state (from a liquid to a gas and back to a liquid) for the purpose of producing useful work or energy, or transferring energy.

The natural, convective movement of air or water due to differences in temperature. In solar passive design a thermosyphon collector can be constructed and attached to a house to deliver heat to the home by the continuous pattern of the convective loop (or thermosyphon).

Terawatt (TW)
A unit of power equal to one trillion (1012) watts.

Watt (W)
The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or one joule per second. It is the product of Voltage and Current (amperage).

(Wh) A unit of electricity consumption of one Watt over the period of one hour.

Working Fluid
A working fluid is a pressurized gas (ie. CO2) or liquid that actuates a machine. Examples include steam in a steam engine, air in a hot air engine and hydraulic fluid in a hydraulic motor or hydraulic cylinder. More generally, in a thermodynamic system, the working fluid is a liquid or gas that absorbs or transmits energy.



The next generation of Geothermal Energy


Working together with all power producers



Creative solutions, Game-changing results