FREQUENTLY ASKED QUESTIONS
Novus Earth FAQs
What is the difference between geoexchange and geothermal?
Geoexchange is a term for low-temperature earth energy used for residential and commercial heating and cooling. The temperatures extracted from shallow wells are between 3.5 C and 15 C close to the earth’s surface. Geothermal is a deep well that extracts medium to high-temperature heat (74 C in Alaska to 500 C in Iceland) intended for power generation or large scale industrial/commercial/residential direct-use heating applications.
How is geothermal energy extracted?
There are 4 basic types of geothermal energy technologies that are used to extract heat from beneath the surface.
Conventional Geothermal Systems: a well is drilled into a heated water reservoir hosted by sedimentary or igneous rock. Certain conditions are required to make it a viable geothermal resource, such as porosity, permeability, temperature, and flow rate.
Enhanced Geothermal Systems: There’s plenty of heat stored down in all that normal, solid, nonporous rock. Geothermal developers make their own reservoir by drilling down into solid rock, injecting water at high pressure to fracture the rock, allowing water to pass through, and then collecting the heated water through another well.
Supercritical Geothermal Systems: “super hot rock” geothermal, taps into extremely deep, extremely hot rock. In order to be considered super hot rock, the water needs to exceed 373 C and 220 bars of pressure. While these geological conditions are hard to come by, the amount of energy produced from these systems is powerful!
Advanced Geothermal Systems: a new generation of closed loop systems, in which no fluids are injected or extracted from the earth. There is no fracking. Instead, fluids circulate in a pressurized self-contained loop underground. The pipes are sealed, picking up heat by conduction and carrying it to the surface. These systems rely on heat being transferred from the surrounding rock and do not require the specific reservoir characteristics such as high permeability and high flow capacity required for conventional geothermal systems. Novus Earth technology uses a closed loop system.
How is geothermal energy generated?
Geothermal energy is generated from the center of the earth which sits at ~6000C and emanates out to the surface of the earth. A portion of the heat of the core comes from friction and gravitational pull, however, the vast majority is generated from the constant radioactive decay of isotopes such as potassium-40 and thorium-232. These are natural isotopes that are abundant in the upper continental crust with half-lives of 1.277 and 14.05 billion years respectively.
Is geothermal energy renewable?
In order for energy to be considered renewable, it has to satisfy the following:
- The source of energy is from nature.
- The energy is easily available in abundance and it eventually does not run out.
- The energy gets replenished by nature after using it.
Geothermal energy is renewable, as it is sourced by the internal heat of the earth which is available in abundance. Geothermal heat gets replenished through sources of heat generated at the crust of the Earth.
How do you produce electricity from geothermal energy?
Electricity generation is produced by bringing high pressure, hot geothermal fluid to the surface. Once at surface, the pressure is dropped, causing the water to vaporize to steam. The steam spins a turbine, which generates electricity. The steam is cooled and condenses back to water to then be injected back into the earth to begin the cycle again. The electricity generation method differs based on the temperature and conditions of the resource:
- 80 – 180C: Binary steam (Organic Rankine or Kalina Cycle)
- 180+C: Flash Steam or Dry Steam – Differs based on whether water is produced that creates the steam, or only steam is produced.
What are the advantages of geothermal energy?
The earth acts as a fully charged battery and is our largest clean energy source. Geothermal has a minimal surface footprint that preserves the land and protects the environment. Geothermal energy is a baseload source of power, available 24/7, 365 days of the year. It complements existing intermittent renewable energies such as wind and solar.
The Novus Earth closed-loop system is scalable and can be used in reservoirs world-wide. The electric and thermal energy is available on demand, making the Novus Earth technology dispatchable. There is zero water use in the power generation process, unique to closed loop geothermal systems.