Hakim SAIBI & SAEED September 2014 Geothermal Energy Winner of GRC 2011 photo contest, Reykjanes Geothermal Power Plant, Iceland Hakim SAIBI & SAEED September 2014

Few Keywords Feasibility studies Two phase flow IEA Brine Energy Well Renewable Energy Thermal plants Hybrid systems Efficiency Exergy Reservoir Geofluid Two phase flow Brine Well Drilling Enthalpy Entropy Surface facilities Utilization Scaling Corrosion

Geothermal Reservoir Fed by Rain Water "Geothermal" comes from the Greek words geo (earth) and therme (heat). Thus, geothermal means earth heat. Geothermics can be defined as the study of the temperature distribution in the earth and the phenomena that influence that distribution. The Earth’s heat is continuously radiated from within, and each year rainfall and snowmelt supply new water to geothermal reservoirs. Production from individual geothermal fields can be sustained for decades and perhaps centuries, which explains the renewability of this resource (Geothermal Education Office 2001).

Clay Diablo Fumarole (CA) Hot Springs Geysers Clay Diablo Fumarole (CA) White Island Fumarole New Zealand Fumaroles

Earth Temperature Gradient

Geothermal Regions in the World Geothermal systems are located in regions with a normal or slightly above normal geothermal gradient, creating low-to-medium enthalpy geothermal reservoirs (less than 150°C). The high enthalpy geothermal reservoirs (up to or above 400°C) are especially located in regions around plate margins with high geothermal gradients. The circulation of water in terrestrial geothermal systems can reach depths of approximately 5 km (Pirajno 1992).

Geothermal Electricity in the World Geothermal energy is the most versatile renewable energy and has been used for thousands of years for washing, bathing, cooking and health: the direct utilization of the hot water is long lasting and still growing with different application ranges. The world’s first geothermal district heating system was started in the 14th century at Chaudes-Aigues, France, and the first geothermal well was drilled near Reykjavik, Iceland, in 1755. However, only in the 20th century has geothermal energy been harnessed on a large scale for space heating, electricity production, and industrial use. The first large municipal district heating service was initiated in Iceland in the 1930s and currently provides geothermal heat to approximately 99% of the 200,000 residents of Reykjavik. The first commercial plant to produce electricity became available in 1913 in Larderello, Italy. The use of geothermal energy has increased rapidly since the 1970s. During the period 2000-2010, the globally installed direct use capacity tripled from 15 to 50 GWth, whereas the installed capacity for electricity production increased from 8.0 to 10.7 GWe. At present, geothermal energy is used by 78 countries for heating purposes (called ‘direct-use’) and by 24 countries for electricity production. Figure 1 shows the use of geothermal electricity throughout the world (Bertani 2012).

Historical Trend of Geothermal Installed Capacity The increase in the installed capacity over the last century is clearly visible in Figure 2, with an impressive increase in new plants started in the 1980s, following the energy crisis.

Direct Uses of Geothermal Energy

Geothermal Reservoir Modeling Workflow

Numerical model of synthetic enhanced geothermal system with isosurfaces of temperature after 30 years of heat mining by injection of cold water from the central well and production from two peripheral wells that intersect the stimulated fracture zone.

Japanese Geothermal Power Plants (GRSJ, 2011)

Geothermal Energy in Japan

How you can get involved?! Educational Professional

Topics Borehole geology and alteration mineralogy Chemistry of thermal fluid Drilling (depth of interest!) Energy policy (local and global scale) Environmental aspects Geological explorations Geophysics Geothermal energy utilization Geothermal reservoir Geothermal resources assessment Hydrology and hydrogeology Logging Well testing Extensive field works

Education UNU-GTP (United Nations University-Geothermal Training Program, Iceland) http://www.unugtp.is/ Geothermal diploma course, University of Auckland, New Zealand Smaller contributions from Universities in Japan, USA, Italy, Mexico.

Classification of Geothermal Resources Temperature (ºC)

Japanese Geothermal Resources Classification Enthalpy-Entropy diagram for Water and Steam

Geothermal Utilization High temperature Low temperature

Geothermal Resources Hot dry rock - no water at all, still no commercial utilization Vapor dominated fields - deliver steam ready for the turbine Water dominated fields - water flows into the wells, and boils partly Liquid water - temperature below 100°C (The fluid contains non-condensable gases and dissolved solids)

The cycles Flash (Bjarnarflag (backpressure), Nesjavellir) Double flash (Krafla, Svartsengi) ORC (Svartsengi) Kalina (Husavik)

Direct use applications District heating and snow melting Spas and swimming pools Greenhouses Fish farming (aquaculture) Drying

Before and after geothermal space heating REYKJAVÍK Before and after geothermal space heating 1930 1990 District heating in Reykjavík started in 1930. By 1970 nearly all Houses in Reykjavík were receiving hot water for heating and sales began to nearby municipalities. Today Reykjavík Energy serves about 150.000 people or 99.9% of the population of Reykjavík and five neighboring communities.

ENVIRONMENTAL IMPACT OF GEOTHERMAL UTILIZATION

Environmental Concerns Surface disturbances Physical effects - fluid withdrawal Noise Thermal pollution Chemical pollution Protection Social and economic effects

Surface Disturbances Excavation Construction Roads Landslides Scenery Changes in surface activity Untidiness

Mitigation Drillrigs disappear after Small area of activity, Use Abandoned or unused boreholes can be hidden Small area of activity, mostly underground Source usually exploited near drillsite

Sustainable Development Sustainable development: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs (World Commission on Environment and Development 1987)

Sustainable Production of Energy from an Individual Geothermal System For each geothermal system, and for each mode of production, there exists a certain level of maximum energy production, E0, below which it will be possible to maintain constant energy production for a very long time (100-300 years). If the production rate is greater than E0 it cannot be maintained for this length of time. Geothermal energy production below or equal to E0 is termed sustainable production, while production greater than E0 is termed excessive production (Axelsson et al. 2001)

Geothermal sustainability

Cascade Utilization of Geothermal Energy

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Winter is coming, stay together!