Energy Conversion¶
Power generation with a binary (ORC) plant¶
For power production with a binary cycle (Organic Rankine Cycle or ORC) the efficiency is strongly temperature dependent, somewhere in the range of η≈0.05-0.15 for aquifer temperatures of 80-150°C. The actual efficiency and temperature range which can be effectively be used depend on the ambient temperature and cooling source (Moon and Zarrouk, 2012). The net efficiency for the ORC as function of production temperature used in this study corresponds to:
η (net) = η (Tprod - Ts) / (Tprod + Ts + 2 x 273)
where Tprod is the production temperature in °C and Ts is the ambient (yearly average temperature) in °C.
The generated power is corrected for power consumption by the ESP, resulting in net Power
The following parameters are proposed for the ORC system:
| Parameter | Symbol | Value | Unit |
|---|---|---|---|
| Use ORC | useORC | True | bool |
| Minimum aquifer production temperature | Tminprod | 70 | °C |
| Maximum cooling temperature for reinjection relative to reservoir (ΔT) | ΔTmax | 40-200 | °C |
| Injection (return) temperature | Treturn | 60 | °C |
| base temperature | Ts | 20 | °C |
| Relative Carnot Conversion efficiency | η | in equation | - |
| Parasitic power needs for conversion process (fraction of net power) | epara | na | - |
| Annual load hours | Hload | 8000 | hour |
| Capex Base expense | CAPEXbase | 0 | million€ |
| Capex Variable (including heat exchanger) | CAPEXother,var | 2300 | €/kW |
| base opex | OPEXbase | 10 | k€ |
| annual opex per unit power | OPEXpower | 50 | €/kW |
| Additional opex per unit energy produced | OPEXheat,var | 0 | €/kWh |