| Title | Modeling a Complete CO2-EGS Power Generation |
|---|---|
| Authors | Alvin Remoroza, Elham Doroodchi, Behdad Moghtaderi |
| Year | 2011 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | Co2- engineered geothermal system, co2-thermosiphon, power cycle analysis |
| Abstract | A comprehensive analysis of a CO2 EGS power generation was compared against H2O based EGS with Organic Rankine Cycle (ORC). One, two and three- dimensional reservoir simulations were coupled with 1D wellbore flow to examine the effect of different reservoir and injection parameters such as injection pressure, injection temperature, reservoir depth or pressure, injection-production distance, resource temperature, and others. Radial reservoir flow model (2D) compared very well with the 3D results using TOUGH2-ECO2N simulator and can be used for rapid assessment of reservoir and injection/production parameters. Three and higher dimensional reservoir simulation is most appropriately used for detailed analysis of reservoir response to injection/production, i.e. thermal breakthrough and depletion over time. CO2 EGS performance can be optimised (e.g. change injection wellbore diameter) to match or exceed H2O based EGS at a given reservoir condition. CO2 mass circulation is higher than H2O at the same operating and reservoir conditions. CO2 heat extraction rate depends both on reservoir pressure and temperature as compared to H2O that primarily depends on temperature. CO2 heat extraction rate is higher at lower reservoir pressure (shallower reservoir depth) but not necessarily on total exergy and electricity generation potential. Our simulation shows that CO2 EGS thru optimization of injection and reservoir parameters can stably and sustainably generate 10 MW of electricity per 1 km2 of 200 oC geothermal resource. |