What is geothermal energy?
Geothermal energy is a renewable energy from the natural source of heat contained within the earth. It can be extracted for beneficial uses including heating, drying and electrical generation.
What are the advantages of geothermal energy sector for Australia?
- Carbon neutral
- Reliable and available 24 hours per day
- Clean energy with low environmental footprint
- Local Job creation
- Dispatchable source of energy
- Small acreage area required for geothermal plant and facilities
- No storage or transportation requirements
- Many beneficial uses for Australian consumers
- Enjoys broad public support
- Application of technology advancements within renewable energy Industry
Does Australia have potential for geothermal energy?
Yes, Australia has a large potential for geothermal energy. Australia is located entirely with the Indo-Australia tectonic plate where is geothermal resource is typically conductive processes rather than convective. Several geothermal ‘hot spots’ exist throughout Australia.
Conductive resources include those in sedimentary formations with largely conductive temperature gradients such as Paris Basin, Germany, and most of the resource in Australia.
Convective resources include high temperature sources of volcanic origin, with naturally flowering geological formations such as Wairakei in New Zealand, Iceland and Turkey
Are there many geothermal power plants?
Yes, there are in excess of 13,270 Megawatts of installed geothermal power plants in 24 countries, worldwide as per the image below.
A 10MW plant as an example may run one Megawatt hour (MWh) of electricity across 6,300 average Australian homes. This depends on many factors such as use and plant details.
WHAT ARE THE BENEFITS OF USING GEOTHERMAL ENERGY?
Answer: Several attributes make it a good source of energy.
First, it’s clean. Energy can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces, and very little if any, of the nitrous oxide or sulfur-bearing gases. Binary plants, which are closed cycle operations, release essentially no emissions.
Geothermal energy is available 24 hours a day, 365 days a year. Geothermal power plants have average availabilities of 90% or higher, compared to about 75% for coal plants.
WHY IS GEOTHERMAL ENERGY A RENEWABLE RESOURCE?
Answer: Because its source is the almost unlimited amount of heat generated by the Earth’s core. Even in geothermal areas dependent on a reservoir of hot water, the volume taken out can be reinjected, making it a sustainable energy source.
WHAT ARE THE ENVIRONMENTAL IMPACTS OF USING GEOTHERMAL ENERGY?
Answer: Geothermal technologies offer many environmental advantages over conventional power generation:
Emissions are low. Only excess steam is emitted by geothermal flash plants. No air emissions or liquids are discharged by binary geothermal plants, which are projected to become the dominant technology in the near future.
Salts and dissolved minerals contained in geothermal fluids are usually reinjected with excess water back into the reservoir at a depth well below groundwater aquifers. This recycles the geothermal water and replenishes the reservoir.
Some geothermal plants do produce some solid materials, or sludges, that require disposal in approved sites. Some of these solids are now being extracted for sale (zinc, silica, and lithium, for example), making the resource even more valuable and environmentally friendly.
WHAT IS THE VISUAL IMPACT OF GEOTHERMAL TECHNOLOGIES?
Answer: District heating systems and geothermal heat pumps are easily integrated into communities with almost no visual impact. Geothermal power plants use relatively small acreages, and don’t require storage, transportation, or combustion of fuels. Either no emissions or just steam are visible. These qualities reduce the overall visual impact of power plants in scenic regions.
IS IT POSSIBLE TO DEPLETE GEOTHERMAL RESERVOIRS?
Answer: The long-term sustainability of geothermal energy production has been demonstrated at the Lardarello field in Italy since 1913, at the Wairakei field in New Zealand since 1958, and at The Geysers field in California since 1960. Pressure and production declines have been experienced at some plants, and operators have begun reinjecting water to maintain reservoir pressure. The City of Santa Rosa, California, pipes its treated wastewater up to The Geysers to be used as reinjection fluid, thereby prolonging the life of the reservoir while recycling the treated wastewater.