A deep dive into our possibilities
How has geothermal energy been used so far? What have the challenges been in utilizing geothermal energy? What possibilities are there? What solutions do we have at hand and who can provide it?
Geothermal energy – and how it has been used so far
Geothermal hot springs have been used by mankind through the centuries for bathing, washing, cooking and baking. The hot springs for these uses were mostly outflows from underlying low temperature reservoirs. The utilization spectrum changed drastically at the beginning of last century when technology to produce electricity from geothermal steam became available and various direct uses of geothermal were developed i.e. for space heating and greenhouse heating, in aquaculture and industry and in snow and ice melting in addition to the balneology uses. The utilization of geothermal increased steadily during the last century and the most rapid development during the last decades has been the dramatic increase in use of geothermal heat pumps for space heating and cooling.
Geothermal energy originates from within the earth’s crust. Most commonly high-temperature geothermal fields are located where the tectonic plates meet. This allows for the earth’s heat to heat ground water forming geothermal fields. Deep wells (1-5 kilometres) are drilled to access these heated fluids which are in turn used to generate electricity before being reinjected back into the ground.
Challenges in utilizing geothermal energy
The utilization of geothermal energy has not been without technical, environmental and political/cultural problems. On the technical side, the most common problems have been related to the chemistry of the geothermal fluids which sometimes contain quite considerable concentrations of minerals and gases, which can cause scaling and corrosion in wells and surface installations which the geothermal fluids flow through. Many of these technical problems have been solved, or minimized at least, by improved well design and well operation, proper material selection and chemical treatment of the geothermal fluids. Utilization of geothermal energy often comes with the obstacle of scaling.
The most common geothermal scales are silica (SiO2) and calcite (CaCO3). Both these scales are white coloured and visually not easy to tell apart. The silica scales often appear grey or black due to small amounts of iron sulphide, a corrosion product found inside all geothermal pipelines.
Silica scales - Silica scales are found to some extent in all high temperature geothermal installations but by maintaining the temperature above the solubility level for amorphous silica (the non-crystalline form of silica), the scaling should not occur and thus this is one of the design criteria for most geothermal plants. In this way the high-pressure separator will not scale, nor the reinjection pipeline, assuming that the so called “hot-injection” method is used. In the high temperature reservoir before the fluid is extracted, the silica concentration is usually in equilibrium with quartz, the crystalline form of silica. Once the water starts to boil and cool down, the silica concentration in the water increases due to the steam loss. The water immediately becomes quartz supersaturated but quartz precipitates are not formed because of the slow growth of quartz crystals.
Up until recently it has only been efficient to generate electricity from medium and high temperature geothermal wells. Limiting where in the world it can be used.
So, inefficiency at low/ medium temperatures and scaling have hindered the true potential of geothermal energy.
Solutions to enable the potential
Today there are solutions available to extract the minerals that cause scaling in geothermal fluids – which further enables electricity generation and sustainable mineral mining.
Scaling and inefficiency in generating electricity on low temperatures have, for many years, stopped electricity generation on wells below 150 degrees Celsius but innovations and technical development has now made it possible.
This enables heat power to be produced in more places in the world, since you can use lower temperatures which are available at more locations than just around the tectonic plates. It also gives the possibility to utilize more energy to create electricity from already existing geothermal heat power plants – illuminating the risk of scaling by removing minerals and extracting more energy from the bottoming cycle of the power plants.
Knowing this, geothermal heat power has the potential to be the largest contributor in reaching Sustainable Development goal #7 – Ensure access to affordable, reliable, sustainable and modern energy for all.
We can provide the solution
Geo40 is a New Zealand based company that has developed a technology to extract silica and other minerals from geothermal brine in geothermal fluids that have already been used for power generation, so that more energy can be utilized without the risk of scaling. The silica in the brine causes scaling in geothermal pipes and wells and limits the heat that can be extracted and utilized for power generation. By extracting and removing the silica and other valuable minerals like lithium and cesium, Geo40's technology reduces operating costs for geothermal power stations, while producing sustainably sourced minerals.
The filtered water from Geo40's application can be utilized in Climeon's Heat Power modules to produce clean electricity and increase power output at geothermal power stations.
Climeon is a Swedish clean-tech vendor, providing a technology that utilizes low temperature (between 70-120 degrees Celsius) geothermal heat and waste heat from industries to generate electricity. The product is protected by patents and offers market-leading performance within its areas of application. Waste heat and geothermal energy jointly comprise a vast energy source that is largely untapped today due to limitations of existing technologies. Climeon's product is one of the heat power systems which is able to utilize this previously unexploited sources of energy to efficiently produce electricity.
Baseload Capital is a Specialized Investment Entity investing in Heat Power. We work globally with the aim to give Heat Power Operators the financial tools to build and operate renewable heat power plants.
In December 2019, we, Climeon, Baseload Capital and GEO40 announced our collaboration. Bringing together the technologies of these three firms opens up a wide range of global opportunities, particularly in recovering waste heat from existing geothermal power plants, so called bottoming cycles.
We believe that we, together, provide business for a better world.