Geothermal handbook: PlanninG and Financing power Generation t e c h n I c a L r e p o r t 2 / 2

F I g u r E 1 . 1 6
Idealized Diagram Showing Multiple Use of Geothermal Energy
Source | ÍSOR (Iceland Geosurvey), 2005, direct communication.
Cooling Water
Electrical Power
Country
 
Utility
Green- 
Houses
Fish Farming
Geothermal Water
Geothermal Water
 
180 l/s
Boiling of shrimps
Drying of wood
Heating 
Fish dryin
g
District
 
Heating
Swimming Pool
 
Snow Melting
 
ENERGY
 
CENTRE
95 l/s
Bathing Lagoon
Lake
Overflow
Fish Farming
To Waste
Binary 
Power Plant
The options for multiple use of energy—as well as the fact that small modular binary units with up 
to 5 MW capacity are readily available and easy to install and operate—make geothermal power 
generation a feasible option for smaller installations in remote and even off-grid locations, especially 
when they replace existing and more costly fossil fuel generation.
In general, the revenue stream from the residual heat use can improve the overall financial viability of 
both small-size or industrial-scale (over 25 MWe) power projects, with additional revenue coming from 
the:
• 
sale of agricultural products grown in greenhouses (e.g., flowers, plants or vegetables), 
• 
extraction of CO
2
from geothermal fluids for industrial purposes (e.g., the soft drink industry),
• 
fish or shellfish or other aquaculture products, 
• 
dehydration (drying) of fruits, nuts and other food products, 
• 
desalination of seawater for drinking water, 

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C h a p t e r 1
• 
use of residual heat for industrial processes (e.g., chemical and biological),
• 
sale of hot water for district heating or cooling purposes, or
• 
extraction of valuable minerals and salts from the geothermal fluids (e.g., silica, manganese,
zinc, and lithium). 
These options are site dependent; some geothermal sites may offer several of these options 
simultaneously while others may offer none. A more comprehensive overview on how geothermal fluids 
and steam can be utilized, depending on their temperature range, is given in Figure 1.17. 
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