Geothermal Energy Technology IE 4395/IE 5390/MFG 5390 Green Energy Manufacturing Final Project Report

Transcription

1 2013 Geothermal Energy Technology IE 4395/IE 5390/MFG 5390 Green Energy Manufacturing Final Project Report Homero Jesus Gomez, Luis Hidrogo, Luis Quinones, Pablo Loya, David Moreno Geothermal energy technology 10/02/2013

2 Table of Contents Introduction... 4 Issues with Geothermal Energy... 6 USA and ETHIOPIA... 7 Technical development since last Two decades / Geothermal energy policies and future prospects Environmental impact of geothermal energy Summary of the Project and key findings List of Figures List of Tables

3 References

4 INTRODUCTION Sustainable energy is the critical theme of today's society. The enormous geothermal energy is supposed as renewable resource such as wind, solar and biomass. Our planet holds gigantic, untapped and inexhaustible heat resources. More significantly, because of its lower emissions of greenhouse gas (CO 2 ), geothermal energy is effective on reducing the catastrophic environmental deterioration. The period between the sixteenth and seventeenth century, when the first mines were excavated to a few hundred metres below ground level, that man deduced, from simple physical sensations that the Earth's temperature increased with depth. The first measurements by thermometer were probably performed in 1740 by De Gensanne, in a mine near Belfort, in France (Buffon, 1778). By 1870, modern scientific methods were being used to study the thermal regime of the Earth (Bullard, 1965), but it was not until the twentieth century, that we could fully comprehend such phenomena as heat balance and the Earth's thermal history. All modern thermal models of the Earth, in fact, must take into account the heat continually generated by the decay of the long-lived radioactive isotopes of uranium (U 238, U 235 ), thorium (Th 232 ) and potassium (K 40 ), which are present in the Earth (Lubimova, 1968). Realistic theories on these models were not available until the 1980s, when it was demonstrated that there was no equilibrium between the radiogenic heat generated in the Earth's interior and the heat dissipated into space from the Earth, and that our planet is slowly cooling down. The thermal energy of the Earth is therefore immense, but only a fraction could be utilized by men. So far our utilization of this energy has been limited to areas in which geological conditions permit a carrier transfer the heat from deep hot zones to or near the surface, thus giving rise to geothermal resources; innovative techniques in the near future, however, may offer new perspectives in this sector. A chemical industry was set up in Italy (in the zone now known as Larderello), to extract boric acid from the boric hot waters emerging naturally or from specially drilled shallow boreholes. The boric acid was obtained by evaporating the boric waters in iron boilers, using the wood from nearby forests as fuel. In 1827 Francesco Larderel, founder of this industry, developed a system for utilising the heat of the boric fluids in the evaporation process, rather than burning wood from the rapidly depleting forests (Figure 1). Figure 1. The covered lagoon used in the first half of the 19th century in the Larderello area, Italy, to collect the hot boric waters and extract the boric acid 4

5 The geothermal steam was used to raise liquids in primitive gas lifts and later in reciprocating and centrifugal pumps and winches, all of which were used in drilling or the local boric acid industry. Between 1850 and 1875 the factory at Larderello held the monopoly in Europe for boric acid production. Between 1910 and 1940 the low-pressure steam in this part of Tuscany was brought into use to heat the industrial and residential buildings and greenhouses. In 1892 the first geothermal district heating system began operations in Boise, Idaho (USA). In 1928 Iceland, another pioneer in the utilization of geothermal energy, also began exploiting its geothermal fluids (mainly hot waters) for domestic heating purposes. By 1904 the first attempt was being made at generating electricity from geothermal steam; again, it was to take place at Larderello (Figure 3). Figure 2. The engine used at Larderello in 1904 in the first experiment in generating electric energy from geothermal steam, along with its inventor, Prince Piero Ginori Conti Electricity generation at Larderello was a commercial success. By 1942 the installed geothermoelectric capacity had reached 127,650 kw. Several countries were soon to follow the example set by Italy. In 1919 the first geothermal wells in Japan were drilled at Beppu, followed in 1921 by wells drilled at The Geysers, California, USA. In 1958 a small geothermal power plant began operating in New Zealand, in 1959 another began in Mexico, in 1960 in the USA, followed by many other countries in the years to come. After the Second World War many countries were attracted by geothermal energy, considering it to be economically competitive with other forms of energy In the United States, most geothermal reservoirs of hot water are located in the western states, Alaska, and Hawaii. Wells can be drilled into underground reservoirs for the generation of electricity. Some geothermal power plants use the steam from a reservoir to power a turbine/generator, while others use the hot water to boil a working fluid that vaporizes and then turns a turbine. 5

6 Figure 3. Geothermal Energy Uses ISSUES WITH GEOTHERMAL ENERGY Although geothermal energy has proven to arguably be the most benign and abundant energy resource, there are some concerns focusing on possible environmental issues. Geothermal energy is abundant, a hole can be drilled almost anywhere to get access to high temperature geothermal energy, unfortunately it is extremely expensive. Yet, there are specific locations that enable economical use of 6

7 geothermal energy resources such as geological faults that blend deep earth heat with underground water to produce either hot water or steam. As every other energy source geothermal energy has its own issues, such as environmental friendliness, reliability, cost, availability, aesthetics, and sustainability. Environmental Friendliness. Even though geothermal energy use entails some environmental impact, the costs are clearly over weighted by the environmental benefits. Most geothermal facilities operate without emissions, some even avoid natural sulfur emissions just by placing a tap over the sites used to obtain geothermal energy. The geothermal energy generation process does produce pollutant gases such as silica and carbon dioxide, which in fact are almost completely removed from the vapors and then recycled. The removal of dangerous gases from vapor leads to the point were almost 100% of the visible gases coming out from the generation of geothermal energy, is just water vapor. Geothermal energy generation does not require a lot of space, which also reduces the impact on a major portion of land. Geothermal energy proves to be a clean and safe power generation source. Energy Reliability. Once in operation, geothermal plants are arguably the most reliable energy generation methods. The geothermal power generation process is so simple that almost anything can go wrong. There is no need to transport fuel or dispose of anything. So a geothermal power generation plant can easily last for a long period of time. Energy Cost. The cost of generating power via geothermal technology can compete with any other conventional method of power generation. Although high costs come fast at first when the plant has to be built, and holes have to be built, geothermal power generation pays back also very fast. The reason for this, is that there is no need to spend money on any kind of fuel. Finding the best producing hydrothermal wells is the key to economically exploit geothermal power generation. Energy Availability. Geothermal energy is available any place where hot magma is able to reach areas close to the surface, heating up water to temperatures above 212F. To be cost effective, a site has to have enough volume of water or steam in the purest way possible, a water source to cool down the equipment used, and close to power transmission lines. The key to the availability of geothermal energy, is the development of drilling technology, as this technology gets better, drilling costs will decrease and geothermal technology will become available in more places. Energy Aesthetics. Geothermal power plants actually don t have big issues related to aesthetics. Since they don t require a huge amount of space they have the least visual impact of any power generation technology. Energy Sustainability. Geothermal resources can last a long time. Actually there is more geothermal energy resources below the ground than oil, gas, coal or any other mineable nuclear fuels combines. USA AND ETHIOPIA Many different factors are leading some countries in Africa to explore the better way of developing the geothermal resources. First of all, Africa has the smallest amount of energy use of any populated continent in the world. Only the 25% approximately of Africa s population has access to electricity, more than half of which is traditional biomass which aggravate the deforestation and health problems in there. The demand increasing of electricity also adds rush the 7

8 need to increase the access of electricity in Africa. At the same time, increasing demand of electricity aggravate all the problems currently associated with Africa s electricity sector. For example, the dependence on imported oil-products for thermal power generation make African countries vulnerable to the changing price of fossil fuels. Furthermore, due to climactic oscillations, the reliability of hydropower as a primary source of electricity for many African countries has been put in doubt. Africa s geothermal resources are concentrated in the East African Rift System (EARS includes Congo, Ethiopia, Kenya, Madagascar, Mozambique, Rwanda, Tanzania, Uganda, and Zambia) and remain largely undeveloped. Nowadays, only 217 MW approximately of geothermal resources have been developed in Kenya and Ethiopia for electricity production. The estimated potential of geothermal resources in EARS is more than 15,000 MW. TECHNICAL DEVELOPMENT SINCE LAST TWO DECADES Archeological evidence show that geothermal resources in North America were used for the first time more than 10,000 years ago when Paleo-Indians settled a hot springs. Since then geothermal technology has evolved to what we have today. A timeline obtained from the Geothermal Technologies Office of the last two decades of USA s geothermal power generation history is shown next The Bonneville Power Administration selects three sites in the Pacific Northwest for geothermal demonstration projects Electrical generation begins at the 25-MW geothermal plant in the Puna field of Hawaii A 23-MW binary power plant is completed at Steamboat Springs, Nevada DOE creates two industry/government collaborative efforts to promote the use of geothermal energy which consequently will help to reduce greenhouse gas emissions. One is related to the development of geothermal resources for electric power generation and the other is aimed toward the accelerated use of geothermal heat pumps A DOE low-temperature resource assessment of 10 western states identifies nearly 9000 thermal wells and springs and 271 communities collocated with a geothermal resource greater than 50ºC. 8

9 2000 DOE initiates its GeoPowering the West program to encourage development of geothermal resources in the western U. S Secretary of the Interior Gail Norton convened a renewable energy summit with officials from DOI, DOE, and other agencies to identify actions required to support renewable energy development. Recommendations specific to geothermal emerged from the meeting Organized by GeoPowering the West, geothermal development working groups are active in five states Nevada, Idaho, New Mexico, Oregon, and Washington The Utah Geothermal Working Group is formed According to the U.S. Department of Interior's Bureau of Land Management, geothermal energy generated over 14,800 GWh of electricity in 2005, enough power to supply the annual needs of 1.3 million homes The Energy Independence and Security Act of 2007 which includes the Advanced Geothermal Research and Development Act of 2007 provided authorization and direction for DOE's geothermal research activities Through the American Recovery and Reinvestment Act (ARRA) of 2009, the Geothermal Technologies Office awarded $368.2 million to 149 geothermal projects in 38 states and the District of Columbia In FY 2010, the DOE Geothermal Technologies Office contributed $786,000 to the Small Business Innovation Research (SBIR) Program and $94,000 to the Small Business Technology Transfer (STTR) program for geothermal projects. 2011/2012 According to the Geothermal Energy Association (GEA) Annual U.S. Geothermal Power Production and Development Report, geothermal companies increased installed capacity from 3102 MW to 3187 MW over this time frame. 9

10 2012 The Enhanced Geothermal Systems (EGS) field demonstration project achieves a steam production equivalent of five megawatts at an abandoned part of the Geysers Field in Northern California, encouraging expectations that this vast energy source (100+ GW) can be further developed and scaled up for nationwide deployment in the long-term. The table shows next compares the installed geothermal electric capacity in the top geothermal power generating countries in the world. Table 1Geothermal Electric Capacity. Installed geothermal electric capacity Country Capacity (MW) Capacity (MW) Percentage of national electricity production US Phillipines Indonesia Mexico Italy New Zeland Iceland Japan Iran El Salvador Kenya GEOTHERMAL ENERGY POLICIES AND FUTURE PROSPECTS Geothermal energy production and use are governed by numerous federal, state, and local laws ranging from environmental protection statutes to zoning regulations. Unique laws at the federal and state level govern the leasing and permitting of geothermal resources on federal and state land. Federal geothermal leasing is governed by the John Rishel Geothermal Leasing Amendments passed as part of the 2005 energy bill. The most important laws are the renewable portfolio standards (RPS) that require utility companies to have a growing percentage of renewable power generation in their mix. About 43 states today have some form of RPS requirement. In addition to this, states offer a wide range of additional rules, policies and incentives for renewable generation. California has a unique grant fund to promote the development of new or existing geothermal resources and technologies known as the Geothermal Resources Development Account. Funded from geothermal royalty revenues 10

11 Queensland Parliament passed legislation in August 2010 introducing a geothermal framework designed to encourage and facilitate the safe production of virtually CO2 emission-free geothermal energy. The Geothermal Energy Act 2010 (the Act) enables the licensing of a proponent to explore for, or produce, geothermal energy. In 2004, Queensland introduced legislation that enabled the commencement of exploration for geothermal energy. The Geothermal Exploration Act 2004 was introduced as interim legislation to allow exploration to commence whilst legislation to facilitate production was developed. The Act incorporates an exploration framework which will allow proponents to explore for geothermal energy under a geothermal exploration permit. Importantly, where the holder of a geothermal exploration permit has discovered a geothermal resource, the Act permits the holder to apply for a geothermal production lease. When granted, it permits the holder to commence large scale production of geothermal energy. The Act also recognises existing resource tenures (under the Mineral Resources Act 1989, Petroleum Act 1923, the Petroleum and Gas (Production and Safety) Act 2004 and the Greenhouse Gas and Storage Act 2009) and provides a mechanism to ensure efficient use of the State's resources by allowing overlapping authorities for exploration or production. On 2 March 2012, the exploration and production provisions commenced, under the Act and the Geothermal Energy Regulation At this time, the Geothermal Exploration Act 2004 and the Geothermal Exploration Regulation 2005 were repealed. Figure 4. Future Energy From its beginning in the LarderelloField in Italy in 1904, nearly 10,000 MWe of capacity worldwide today, additional capacity with direct use and geothermal heat pumps (e.g>150,000 MWt 11

12 worldwide), and also, current costs from 7 10 /kwh. For this reason, there is attractive technology for dispatchable base load power for both developed and developing countries Figure 5. Average Surface Geothermal Gradient ENVIRONMENTAL IMPACT OF GEOTHERMAL ENERGY Geothermal power generation, even when is less harmful to the environment tan fossil fuels power generation plants is still a considerable impact on the environment. One of the principal impacts to the environment is the quality and consumption of the water. For example water is used to create steam in the thermoelectric power plant to move the turbines in order to create electricity. The thermoelectric plants use the water in different ways: Once-trough, wet recirculating, and dry-cool. Water is also used by geothermal plants for cooling and re-injection. All U.S. geothermal power facilities use wet-recirculating technology with cooling towers. Depending on the cooling technology used, geothermal plants can require between 1,700 and 4,000 gallons of water per megawatt-hour. However, most geothermal plants can use either geothermal fluid or freshwater for cooling; the use of geothermal fluids rather than freshwater clearly reduces the plants overall water impact. Once-trough system is the one that impact the environment more directly. This system consumes water directly from rivers, lakes, aquifers or the ocean. This system uses the water one time only all the water remaining from the process is disposed or loosed in the form of steam. This system was used because its simplicity in the past years now because of the impact it has on the water withdrawals is harder to use it 12

13 because water supply is harder to obtain. A total of 43 percent of thermoelectric power generation stations uses once-trough. Wet-recirculating or closed loops systems still consume water even when it uses the most of it. Thermoelectric plants expose water to ambient air temperature to cool it down with this some water is loss as steam and the remaining is re-injected to the condensers. Air emissions another big issue for geothermal power generation. With two different systems for gas emission handling geothermal power generation contributes to the air pollution. The first system used is the open loop system. This system releases to the environment the steam produced during the cool down process. The second process, closed-loop system, still release some steam in less percentage. This system re-injects the steam or gasses emitted during the process directly into the ground. All this steam or gas released into the environment contains harmful amounts of mercury hydrogen sulfide, arsenic among others. All this emissions can cause health problems like respiratory and hearth disease. Once in the atmosphere, hydrogen sulfide changes into sulfur dioxide (SO2). This contributes to the formation of small acidic particulates that can be absorbed by the bloodstream and cause heart and lung disease. These plants require a wide territory, and are commonly installed in places with delicate ecosystems. Hydrothermal plants are sited on geological hot spots," which tend to have higher levels of earthquake risk. There is evidence that hydrothermal plants can lead to an even greater earthquake frequency. SUMMARY OF THE FINDINGS PROJECT AND KEY Right now some of the biggest concerns about geothermal energy is the cost, lack of knowledge and safety issues. The lack of knowledge about geothermal energy is a big factor on the development of this new clean energy. In the other hand is the environment impact it has over earth; these systems are well known to produce small earthquakes. Because of this and because this geothermal places are located on sensitive areas a deep study is required with lots of regulations in order to be able to install a geothermal energy production facility. For the moment, cost is also a primary barrier to widespread adoption. USGS s William says traditional geothermal electricity is the ballpark in terms of cost with other electricity sources. A 2009 report by the investment bank Credit S Suisse quoted a conventional geothermal cost of 3.6U.S. Cents per kilowatt hour, below the 5.5 cents for coal Until EGS is developed on a wide scale, initially it will probably wouldn t be competitive, William says. Right now we re looking at sort of slow but steady development. 13

14 LIST OF FIGURES Figure 1. The covered lagoon used in the first half of the 19th century in the Larderello area, Italy, to collect the hot boric waters and extract the boric acid... 4 Figure 2. The engine used at Larderello in 1904 in the first experiment in generating electric energy from geothermal steam, along with its inventor, Prince Piero Ginori Conti... 5 Figure 3. Geothermal Energy Uses... 6 Figure 7. Future Energy Figure 8. Average Surface Geothermal Gradient LIST OF TABLES Table 1Geothermal Electric Capacity

15 REFERENCES 1. ""Geothermal Energy." National Geographic. N.p., n.d. Web. 01 Oct "Pros and Cons of Geothermal Energy." Pros and Cons of Geothermal Energy. N.p., n.d. Web. 01 Oct "Wikipedia." Receiver (radio) 17 April urnal/ Small power plants are defined as having an electric generating capacity less than 300 MW. Dougherty, B., Page, T., & Bernow, S Comments on the EPA s Proposed Regulations on Cooling Water Intake Structures for New Facilities. Boston, MA: Tellus Institute. 5. National Research Council (NRC) Hidden costs of energy: Unpriced consequences of energy production and use. Washington, DC: National Academies Press. Online at National Renewable Energy Laboratory (NREL) Renewable Electricity Futures Study Geothermal energies promise and problems 15