Science – Society – Technology
From: Sustainable operation of geothermal power plants: why economics matters
Parameter | Symbol | Case 1 | Case 2 | Unit | Source/section |
---|---|---|---|---|---|
Thermal capacity of reservoir rock | \({c}_{\text{r}}\) | 800 | 1000 | (J kg−1 K−1) | Proske (undated: 7) Stober and Bucher (2014: 10) |
Density of reservoir rock | \({\rho }_{\text{r}}\) | 2600 | 2700 | (kg m−3) | Proske (undated: 7) |
Specific thermal capacity of fluid | \({c}_{\text{f}}\) | 4120 | 4120 | (J kg−1 K−1) | – |
Density of heat carrying fluid | \({\rho }_{\text{f}}\) | 1000 | 1000 | (kg m−3) | – |
Porosity | \(\Phi\) | 20 | 1 | (%) | Björnsson and Bodvarsson (1990: 19) Moeck (2014: 878) |
Reservoir volume | \(V\) | 4.5 ⋅ 109 | 3 ⋅ 109 | (m3) | – Bine.info (2009) |
Reservoir temperature | TR | 270 | 180 | (°C) | Björnsson and Bodvarsson (1990: 19) Gerard and Kappelmeyer (1987: 399) |
Surface temperature | TS | 14 | 14 | (°C) | Walter (2016: 7) |
Measured drilling depth | MD | 1500 | 4000 | (m) | Bignall et al. (2010: 6) Moeck (2014: 875) |
Recovery factor | R | 20 | 5 | (%) | cf. “Recovery factor” |
Temperature of produced fluid | \({T}_{\text{prod}}\) | 260 | 175 | (°C) | |
Temperature of reinjected fluid | \({T}_{\text{rein j}}\) | 65 | 65 | (°C) | cf. “Reinjection” Bine.info (2009) |
Heat from radioactive decay | \({H}_{\text{R}}\) | 2.7 ⋅ 10–6 | 3 ⋅ 10–6 | (W m−3) | Hasterok and Webb (2017: 925) Rybach (1976) |
Heat flow from earth’s interior | \({H}_{\text{F}}\) | 13.3 | 0.105c | (W m−2) | O'Sullivan et al. (2010: 315) |
Reservoir surface area | \(A\) | 3∙107 | 3 ⋅ 106 | (m2) | O'Sullivan et al. (2010: 315) Bine.info (2009) |
Net conversion efficiency | \(\eta\) | 14 | 8 | (%) | cf. “Conversion efficiency” |
Average productivity per well | \(\bar{w}\) | 5 | 1.5 | (MWe) | cf. “Well productivity” |
Electricity price/feed-in tariff | \(p\) | 50 | 240d | (€ MWh−1) | EEX (2019) BDEW (2017: 36) |
Discount rate | \(i\) | 5 | 5 | (%) | – |
Reference initial production decline rate | \({D}_{\text{i}}\) | 5 | 5 | (%) | cf. “Production decline” |
Reference initial capacitya | \({W}_{\text{i}}\) | 100 | 25 | (MWe) | cf. “Production decline” |
Well reserve factor | \(r\) | 10 | 0 | (%) | cf. “Production decline” |
Tax rate | \(\text{tax}\) | 20b | –e | (%) | – |
Surrounding thermal compensation | \(\beta\) | 1 | 6 | (%) | cf. “Recovery factor” |
Plant type | Flash | Binary | O'Sullivan et al. (2010: 315) Bine.info (2009) | ||
Capacity factor | cap | 0.95 | 0.95 | (%) | cf. “Capacity factor” |
Start for make-up well drilling | 1 | 1 | (a) | cf. “Costs (Number of wells required)” |