Major Energy Resources • Non Renewable Resources Fossil Fuels – Coal, Petroleum, Natural gas, Biofuels, Biogas, wood • Renewable Resource • Nuclear • Solar • Hydropower • Wind Power • Tidal and Ocean Thermal • Geothermal
Observations of Climate Change – Global Warming Temperature, Evaporation & rainfall are increasing; More of the rainfall is occurring in downpours Corals are bleaching Glaciers are retreating Sea ice is shrinking Sea level is rising Wildfires are increasing Hurricane, storm and flood damages are much larger
Nuclear Power Fission of 1 kilogram of uranium releases more energy than does burning 3 million kg of coal.
Geothermal Features associated with groundwater • Hot springs • Water is 6-9oC warmer than the mean annual air temperature of the locality • The water for most hot springs is heated by cooling of igneous rock
Features associated with groundwater • Geysers • Intermittent hot springs • Water erupts with great force • Occur where extensive underground chambers exist within hot igneous rock • Groundwater heats, expands, changes to steam, and erupts
Evolution of a geyser eruption
Yellowstone Geyser erupting – geothermal energy for a ‘Supervolcano’
Geothermal Energy is energy stored in the form of heat beneath the surface of the solid earthGeothermal Energy can be spectacular! Geysers and volcanoes show the earth’s heat Photos of US Geological Survey
What is geothermal energy?Geothermal energy is heat from Earth’s interior. Geothermal heat originates from Earth's fiery formation more than four billion years ago. At Earth's core— 7900 km (4,000) miles deep - temperatures may reach over 6000 degrees Centigrade, 9,000 degrees Fahrenheit
Direct Sources function by sending water down a well to be heated by the Earth’s warmth. • Then a heat pump is used to take the heat from the underground water to the substance that heats the house. • Then after the water it is cooled is injected back into the Earth. • Ground Heat Collectors This system uses horizontal loops filled with circulating water at a depth of 80 to 160 cm underground.
Borehole Heat Exchange This type uses one or two underground vertical loops that extend 150 meters below the surface
‘Ring of Fire’ Hawaii Pacific Ocean High-Enthalpy Geothermal Energy world-wide Graph from Geothermal Education Office, California
Sources of Earth’s Internal Energy • About 70% comes from the decay of radioactive nuclei with long half lives that are embedded within the rocks in lithosphere and mantle • Some energy is from residual heat left over from Earth’s formation. Temperature increases with depth in Lithosphere
Geothermal Energy is energy stored in the form of heat beneath the surface of the solid earth. Geothermal gradient • Normally 20 to 30º C / km, 1300-1400º C at base of lithosphere, 3000-6000º C + in core Lithosphere Mantle Outer Core Inner Core Graph from Geothermal Education Office, California
Geothermal Power: Natural steam is extracted from wells to power the turbine generator. The left-over cool water is pumped down to sustain production.
Hawaii Geothermal Area The Hawaii geothermal area includes the Puna Geothermal Venture, which is located about 38 km (21 miles) south of Hilo on the Big Island of Hawaii. The facility is situated along the Lower East Rift Zone of the Kilauea Volcano. At the Puna Geothermal Venture, geothermal fluid is brought to the surface through production wells, which tap into the resource at a depth of almost a mile. The steam, along with its non-condensable gases, is routed to the power plant and used to produce electricity for the Big Island of Hawaii.
Benefits of Volcanoes: Geothermal Energy - One of the benefits of volcanism is geothermal power. The geothermal power plant on Kilauea's east rift zone is shown here. Pu'u O'o is up-rift from this plant. (This photo was taken on December 29, 1989.) The drilling has encountered some of the hottest underground fluids yet found. At a depth of 1,969 m the hole has a temperature of 350 degrees C. Increased development of Hawaii's geothermal resources is under consideration
Hawaii Geothermal Inter-island Submarine Cable Project Proposed Route (Fesmire and Richardson, 1990).
Map of the major islands of Hawaii showing the location of the 20 Potential Geothermal Resource Areas (PGRAs)
HAWAII AND GEOTHERMAL WHAT HAS BEEN HAPPENING? There is still resistance to using geothermal energy by some members of he local population even though the above issues have been and will continue to be addressed by the government and the developers. However there are well organized groups and various community organizations that will continue to express concern in various ways about the ability of the government and developers to provide socially and environmentally sound geothermal power. Further, the level of support given by the state’s political establishment to expansion of geothermal capacity–
The 30 megawatt (MW) PGV plant uses air-cooled condensers and noise reduction enclosures. It’s a low-profile plant, 8 meter, 24 feet high, and has near zero emissions. Geothermal fluid and gas is reinjected into the deep earth. Puna Geothermal Venture geothermal power plant provides about 20% of electricity demand on the Big Island of Hawaii.
Global Warming and the Fossil Fuels: There are approximately 1700 kWh of electricity in a barrel of fuel oil, however, power plants are, on average, 31% efficient and an additional 5% of that energy is lost in transmission from source to user. Thus, 1700*0.31*0.95 = 501 net kWh per barrel. Burning of a barrel of crude oil 0.43 tons of carbon dioxide are released into the environment. A barrel has 42 gallons, one gallon produces 0.011 tons.
Steam Engine Internal Combustion Engine Piston
Effect on Coastal AreasLava from Kupaianaha pond enters the ocean near Kalapana and extends the coastline (December 27, 1989). Intermittent littoral (sea shore) explosions added spatter to a large littoral cone on top of the sea cliff. Lava flows temporarily destroy land. However, when these same flows reach the sea, new land is added to the total area of the island.
Different Geothermal Energy Sources • Hot Water Reservoirs: As the name implies these are reservoirs of hot underground water. There is a large amount of them in the US, but they are more suited for space heating than for electricity production. • Natural Steam Reservoirs: In this case a hole dug into the ground can cause steam to come to the surface. This type of resource is rare in the US. • Geopressured Reservoirs: In this type of reserve, brine completely saturated with natural gas in stored under pressure from the weight of overlying rock. This type of resource can be used for both heat and for natural gas.
Normal Geothermal Gradient: At any place on the planet, there is a normal temperature gradient of +300C per km dug into the earth. Therefore, if one digs 20,000 feet the temperature will be about 1900C above the surface temperature. This difference will be enough to produce electricity. However, no useful and economical technology has been developed to extracted this large source of energy. • Hot Dry Rock: This type of condition exists in 5% of the US. It is similar to Normal Geothermal Gradient, but the gradient is 400C/km dug underground. • Molten Magma: No technology exists to tap into the heat reserves stored in magma. The best sources for this in the US are in Alaska and Hawaii.
World Geothermal Provinces Indian Plate
A short glimpse at geothermal power First experiment to produce geo-thermal power, done in Italy in 1904 by prince Ginori Conti Photo courtesy of ENEL/ERGA, Italy Photos: Lund Modern geothermal power plants in Larderello, Italy
A short glimpse at geothermal power Principle of EGS system for geothermal power production Drilling rig at the European R&D site Soultz-sous-Forêts (F)
Deep Geothermal Energy Geothermal heating plant Neustadt-Glewe photo O. Joswig doublet system, used since the late 1970s in France and since 1984 in (Eastern) Germany
Present world-wide geothermal energy resources are constrained to areas where hot springs, geysers, and volcanic activity produce sufficient heat energy near the Earth’s surface for electric power generation. These areas follow plate tectonic boundaries around the world. Vast areas of the Earth lie sufficiently far from these boundaries that they are generally untapped for geothermal electric power production. • A clean, renewable and environmentally benign energy source based on the heat in the earth • Used in 58 countries of the world. Known in over 80 • Electricity generation 53 TWh/a in 22 countries • Direct heating use 53 TWh/a in 55 countries • Geothermal is number three of the renewable energy sources in world electrictity production after hydro and biomass. It is followed by wind and solar energy
Iceland 200 Russia 23 Italy 762 USA 2002 Turkey 20 Japan 549 Azores 16 Mexico 858 Guatemala 33 El Salvador 161 Nicaragua 70 Costa Rica 143 China 29 Thailand 0.3 Guadeloupe 4 Philippines 1931 Ethiopia 9 Kenya 58 Indonesia 787 Australia 0.2 New Zealand 437 Geothermal electricity Installed capacity MWe 2001
United States Geothermal Electric Power Generation Potential(GeoPowering The West - DOE, 2000)Top 3 States: Nevada, California, UtahOther High Potential States: Idaho, Hawaii, New Mexico, Oregon, South Dakota,Texas, andWyoming
The basic requirements for an exploitable DPSGE geothermal region are similar to those for oil and gas exploration: 1) a sufficiently high geothermal gradient; 2) A significantly large, porous and permeable reservoir to receive and heat injection fluids; 3) A seal to contain the system.
Water temperature (optimum range) 230o to 380o F (110o to 193o C) Construction costs ~ $1500 per kW including exploration and drilling. 10 Mw plant $15,000,000 (National Renewable Energy Laboratory, 1999)
Geothermal Delivery Systems Existing Plant Designs Dry Steam Power Plants – use steam directly. Flash Steam Power Plants – hot water under pressure (most common). Binary Cycle Power Plants – hot water through heat exchanger. Feedstock Systems – incremental heat in elevated water temperatures. New Plant Designs Power Tube – iso-pentane & iso-butane into subsurface.