Sources of Energy, Mineral Exploration and THERMAL STRUCTURE OF THE EARTH Lecture Notes 2010

May 18, 2010 Geo 702 Lecture 3 ENERGY ability to do work -potential energy -energy in motion (kinetic) 1st law of thermodynamics energy is neither created or destroyed -it can be conserved 2nd law of thermodynamicsenergy can be reduced from a higher form into a lower form -potential to lower the quality as change from 1 form to another -passive solar energy (the Romans) heating systems, solar baths, transparent windows -oil stores have been declining – other energy sources have emerged Sources of Energy -demand for energy -developed countries use most energy (have about 20% of energy but use 4/5 of worlds energy) -developing countries have most energy reserves but use much less Mineral Exploration -feasibility studies studying/surveying to see if processes are economically recoverable - methods of mining- capital intensive and require technological innovations -i.e. surface mining, robotics, automated equipment (for underground mining) -benefits of underground mining= less surface destruction, can create tunnels for many km under the earth, don’t have to destroy vegetation, less expensive, less risks for humans -open pit mining Impact of Mining- -surface mining has caused destruction of many landscapes -surface water contamination -air pollution Open-Pit Mining/Strip Mining/ Surface -create spoil paths -china coal mines (~61% of coal ), Saskatchewan coal mines -significant problems for miners Underground mining Operation -shafts are used to drop and pick up coal -in short term cause less environmental damage- in long term – any instability can cause mines to collapse = destruction of property and deaths Socio-economic impacts of mining operations Insecuriy of employment – due to mine shut down or permanent closure - As soon as a mine opens it begins to close -finite in supply and soon run out Violent Explosions-methane gas- potential to catch fire- has killed many people -ie. China coal mines Subsidence of underground mines i.e. Crandall Canyon mine in Utah, USA -as tunnels collapse -rehabilitate/restore mining site- Regulations in place oil Crises -life way of major industrial countries -strategic resource -1974- worst crises -1991 Gulf war in which allied forces able to root out Iraqi republican -implications for civilians -oil and gas transportation via pipelines good for transportation but said to be posing a lot of environmental problems i.e. accidental leakage- ruin soil and water resources -must clear huge hector of land to create these Reclamation/restoration/rehabilitation Quality of Ecological restoration- require consistent effort (simultaneous mining ), water contamination, no compliance to rehabilitation, Safety Outcome Aesthetic Outcome- a lot of aesthetic outcomes (eye sore – can effect economic value of property or rent) Air Quality Outcome Restoration Work- -regarding of soil piles - FOSSIL FUELS RUNNING OUT (oil, gas, coal) WHY ARE WE STILL DEPENDENT ON THEM? EVEN THOUGH THEY HAVE CHALLENGES/ ENVIRONMENTAL PROBLEMS -most companies still making money (multi million dollar investments so don’t see the need to switch over) -coal/oil/natural gas very high energy components- provides a lot of energy -easily combustible -a lot of technology that is able to produce i.e. gas from coal - technology available to work with those types of energy -consumption level of those fuels very high (i.e. automobiles in the world rely on gasoline and oil) -so many gas stations around the world – huge numbers of people are employed in this sector -iif you shut the fossil fuels down- this employees lose their jobs -can we break away? Not until exhausted resources ATMOSPHERE IS A MIXTURE OF GASES -nitrogen fixation (look up what it is) -nitrogen constituent of the air ins 78% and oxygen ins 21% -too much N in biomass (or from agriculture fields) into water systems= cultural eutrophicationtoo much nitrogen or phosphorous released -agar bloom dies and sucks oxygen from water body (depleted of oxygen= cultural eutrophication)= human induced -Oxygen 2nd largest consequence of atmosphere (many processes by which can gain or lose oxygen) -combustion processes -forest fires- removes oxygen from atmosphere -gain oxygen in atmosphere through photosynthesis by absorbing CO2 and releasing oxygen -Carbon Dioxide- 0.033% of earths atmosphere but is major contributor to global warming -important heat-absorbing gas that plays a major role in the earth’s green house effect -too much can be detrimental- need a balance -gain carbon via combusion processes (automobiles, coal burning etc.) -natural balance has been tempered with so its offset water vapor= green house gas (small concentration is good but too much detrimental) -water vapor is a minute liquid-and-solid masses of various compositions -green house gases trap gases from escaping= green house effects effects 2 ways: reflect or scatter sun rays trap sun and don’t let heat escape= detrimental -nitrogen oxide (form automobiles) reacts with sunlight -ozone depletion THERMAL STRUCTURE OF THE EARTH -the troposphere is warm at the bottom next to the Earth’s surface and cools upward at a rate of -6.4 degrees per 1000 meters -the mixing motion is essential for the Earth’s weather -above the Troposphere lies the stratosphere where the temp trend reverses i.e. it warms with altitude -at an altitude of 50 km the warming stops and reverses again as we wenter the mesosphere -above the mesosphere is the thermosphere which is exceedingly light -Tropopause= zone between stratosphere and troposphere -pressure gradient- dif between low and high pressure -temperature reduces with altitude Greenhouse Effect and Global Warming - create a blanket of gases that trap heat which creates the warming condition of global warming carbon dioxide, methane, nitrous oxide, CFC-12, HCFC-22, perfluromethane, sulphur hexa-fluroide -Acid rain has caused hydrolysis of tomb stones = pollution, erosion, -CO2 speculated that it will continue to rise- Evidence of Contemporary Warming -changes in habitats and ecosystems -i.e. polar bears are drowning - ice melting= increased water levels -potential that Greenland ice melts= flooded cities Diseases causing scare -too much exposure to sunlight can cause cataract -global warming creates moisture and creates moisture depletion from soil at same time -CORAL REEFS -agar bloom around most coral reefs International Initiatives to combat Global warming and climate change -this has not been achieved- still being debated -KYOTO PROTOCOL -transferable emissions reduce credits -debate- cutting down emissions but still contributing to green house gas RENEWABLE ENERGY SOURCES - Nuclear Fission- used to create steam, generation of electricity -fusion process can generate about 4 times amount of energy -non reusable for other supplies required (ie. Uranium= debate if its renewable) -highly sophisticated so requires huge capital investment (disadvantage) -can pose safety risks -moral questions -Biomass- -energy produced very low compared to conventional sources -degradation of environment -trees cut -Hydroelectric Power -typical hydroelectric dam -hydro is a cleaner option- continuous supply of energy -no emissions -water source is renewable (continuous generating) - main problem =power failure once exceeding capacity to produce (cascading effect- too much demand for electricity) -dam construction distrupts migratory path of fisheries, -high concentration of sedement - dams are very risky in cases of natural disasters -changing habitats/ecosystems -Wind Energy - cost effective over the years -cost of wind turbines have been reducing -wind farms -disadvantage of wind turbines- not used on large scale because creates lots of interference in neighbourhood, inconvenient, has to be placed in an area where there is a windstream of air so cant be placed anywhere (need constant wind of at least 15 miles per hour) -rotating plates can cause injury or death to birds -wind farm is a huge hector of land used - challenge -Solar Energy -still in elementary stage of development -3 examples 1) passive- design buildings to allow radiation in from sun, prevent radiation from escaping- doesn’t require any mechanical components- just orientation of buildings and incoming solar radiation 2)Active Solar Energy- 3) photovoltaic -direct solar energy directly into electricity -latitudinal location further away from equator less solar radiation they get (Especially in winter months) -other factors: Day and night effects how much solar radiation you receive -cheaper in terms of constant energy supply from the sun (perpetual) -clean technology (environmentally friendly) -disadvantage- availability of sunlight (winter ) QUESTIONS Among renewable energy which is the “best” and why? Solar- many ways can use the energy in our every day life Make sure of all of them- depending on circumstances, time of year, what you are looking to power, costs, Last Renewable Resource -GEOTHERMAL -ring of fire