PDF Publication Title:
Text from PDF Page: 010
Geothermal Energy Chapter 4 For hydrothermal submarine vents, an estimate of >100 GWe (>2.8 EJ/ yr) offshore technical potential has been made (Hiriart et al., 2010). This is based on the 3,900 km of ocean ridges confirmed as having hydro- thermal vents,4 with the assumption that only 1% could be developed for electricity production using a recovery factor of 4%. This assumption is based on capturing part of the heat from the flowing submarine vent without any drilling, but considering offshore drilling, a technical poten- tial of 1,000 GWe (28.4 EJ/yr) from hydrothermal vents may be possible. However, the technical potential of these resources is still highly uncer- tain, and is therefore not included in Figure 4.2. For geothermal direct uses, Stefansson (2005) estimated 4,400 GWth from hydrothermal systems as the world geothermal technical potential from resources <130°C, with a minimum of 1,000 GWth and a maxi- mum, considering hidden resources, of 22,000 to 44,000 GWth. Taking a worldwide average CF for direct uses of 30%, the geothermal technical potential for heat can be estimated to be 41.6 EJ/yr with a lower value of 9.5 EJ/yr and an upper value of 312.2 EJ/yr (equivalent to 33,000 GWth of installed capacity) (Figure 4.2). Krewitt et al. (2009) used the same values estimated by Stefansson (2005) in GWth, but a CF of 100% was assumed when converted into EJ/r, leading to an average upper limit of 33,000 GWth, or 1,040 EJ/yr. In comparison, the IPCC Fourth Assessment Report (AR4) estimated an available energy resource for geothermal (including potential reserves) of 5,000 EJ/yr (Sims et al., 2007; see their Table 4.2). This amount cannot be properly considered as technical potential and looks overestimated compared with the geothermal technical potentials presented in Figure 4.2. It is important to note, however, that technical potentials tend to increase as technology progresses and overcomes some of the technical constraints of accessing theoretically available resources. 4.2.2 Regional technical potential The assessed geothermal technical potentials included in Table 4.2 and Figure 4.2 are presented on a regional basis in Table 4.3. The regional breakdown in Table 4.3 is based on the methodology applied by EPRI (1978) to estimate theoretical geothermal potentials for each country, and then countries were grouped into the IEA regions. Thus, the present disaggregation of the global technical potentials is based on factors accounting for regional variations in the average geothermal gradient and the presence of either a diffuse geothermal anomaly or a high-temperature region, associated with volcanism or plate boundaries as estimated by EPRI (1978). Applying these factors to the global technical potentials listed in Table 4.2 gives the values stated in Table 4.3. The separation into electric and thermal (direct uses) technical potentials is somewhat arbitrary in that most higher- temperature resources could be used for either or both in combined 4 Some discharge thermal energy of up to 60 MWth (Lupton, 1995) but there are other submarine vents, such as the one known as ‘Rainbow’, with an estimated output of 1 to 5 GWth (German et al., 1996). heat and power applications depending on local market conditions and the distance between geothermal facilities and the consuming centres. Technical potentials for direct uses include only identified and hidden hydrothermal systems as estimated by Stefansson (2005), and are presented independently from depth since direct uses of geo- thermal energy usually do not require developments over 3 km in depth. 4.2.3 Possible impact of climate change on resource potential Geothermal resources are not dependent on climate conditions and climate change is not expected to have a significant impact on the geo- thermal resource potential. The operation of geothermal heat pumps will not be affected significantly by a gradual change in ambient tem- perature associated with climate change, but in some power plants it may affect the ability to reject heat efficiently and perhaps adversely impact power generation (Hiriart, 2007). On a local basis, the effect of climate change on rainfall distribution may have a long-term effect on the recharge to specific groundwater aquifers, which in turn may affect discharges from some hot springs, and could have an effect on water levels in shallow geothermally heated aquifers. Also, the avail- ability of cooling water from surface water supplies could be affected by changes in rainfall patterns, and this may require air-cooled power plant condensers (Saadat et al., 2010). However, each of these effects, if they occur, can be remedied by adjustments to the technology, generally for an incremental cost. Regarding future EGS projects, water manage- ment may impact the development of EGS particularly in water-deficient regions, where availability is an issue. 4.3 Technology and applications For the last 100 years, geothermal energy has provided safe, reli- able, environmentally benign energy used in a sustainable manner to generate electric power and provide direct heating services from hydrothermal-type resources, using mature technologies. Geothermal typically provides base-load generation, but it has also been used for meeting peak demand. Today’s technologies for using hydrothermal resources have demonstrated high average CFs (up to 90% in newer plants, see DiPippo (2008)) in electric generation with low GHG emis- sions. However, technologies for EGS-type geothermal resources are still in demonstration (see Section 4.3.4). Geothermal energy is currently extracted using wells or other means that produce hot fluids from: (a) hydrothermal reservoirs with naturally high permeability; or (b) EGS-type reservoirs with artificial fluid pathways. Production wells discharge hot water and/or steam. In high-temperature hydrothermal reservoirs, as pressure drops a fraction of the liquid water component ‘flashes’ to steam. Separated steam is piped to a turbine to generate electricity and the remaining hot water may be flashed again at lower pressures (and temperatures) to obtain more steam. The 410PDF Image | Geothermal Energy 4
PDF Search Title:
Geothermal Energy 4Original File Name Searched:
Chapter_4_Geothermal_Energy_.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)