ENSP101 Chapter 19 Conventional Energy 19 1 Energy Resources and Uses Unit of measure o Work the application of force through a distance requires energy input o Joules a unit of energy 1 joule is the energy expended in 1 second by a current of 1 amp flowing through a resistance of 1 ohm o Energy the capacity to do work o Power the rate of energy delivery measured in horsepower or watts o Watt the force exerted by 1 joule or the equivalent of a current of 1 amp per second flowing through a resistance of 1 ohm Worldwide commercial energy consumption o Oil 37 o Coal 26 o Natural gas 24 o Nuclear 6 Hydropower 6 Wind etc 1 By 2025 energy experts expect that emerging economies such as China and India will be consuming nearly as much energy as Europe and North America o India s oil consumption has doubled sine 1992 o China went from near self sufficiency in the mid 1990s to the world s 2nd largest importer in 2004 Oil prices have fluctuated rapidly over the past 40 years On average each person in the US or Canada uses more than 300 gigajoules per year o By contrast in the poorest countries of the world such as Bangladesh each person on average consumes less than one gigajoule per year Current US energy consumption o Imported oil 31 o Coal 22 o Gas 20 o Domestic oil 12 o Nuclear 8 o Renewables 6 Energy use sectors o Industrial 33 7 o Transportation 27 7 o Residential 20 6 o Commercial 18 Fossil fuels supply 85 of the energy used in the US and oil 3 4 of it imported makes up half that amount Canada is now the largest oil supplier for the US and industry is the largest energy use sector o Transportation however uses the vast bulk of all oil About of all the energy in primary fuels is lost during conversion to more useful forms while it is being shipped to the site of end use or during its use Natural gas is our most efficient fossil fuel o Only 10 of its energy content is lost in shipping and processing since it moves by pipelines and usually needs very little refining 19 2 Coal Fossilized plant material preserved by burial in sediments and altered by geological forces that compact and condense it into a carbon rich fuel o Essentially a non renewable resource World coal deposits are 10x greater than conventional oil and gas resources combined Total resource is estimated to be 10 trillion metric tons Known reserves have been identified but not thoroughly mapped Proven reserves have been mapped measured and shown to be economically recoverable Ultimate reserves include unknown as well as known resources Underground mines are subject to cave ins fires accidents and accumulation of poisonous or explosive gases carbon monoxide carbon dioxide methane hydrogen sulfide Proven in place coal reserves by region o Europe and Eurasia 36 o Asia Pacific 30 o North America 26 o Africa and Middle East 6 o South and Central America 2 Black lung disease inflammation and fibrosis caused by accumulation of coal dust in the lungs or airways Strip mining or surface mining is cheaper and safer than underground mining but often makes the land unfit for any other use o Also contributes to water pollution o Sulfur and other water soluble minerals make mine drainage and runoff from coal piles and mine tailings acidic and highly toxic o Another type of strip mining is mountaintop removal where the tops of mountain ridges are scraped off and dumped into valleys below to get at coal seams Coal burning releases radioactivity and many toxic metals o You are likely to get a higher dose of radiation living next door to a coal burning power plant than a nuclear plant under normal non accident conditions o Coal combustion is responsible for about 25 of all atmospheric mercury pollution in the US o Coal burning power plants create huge amounts of ash most of which is pumped as a slurry into open storage ponds o Coal burning is the largest single source of greenhouse gases and acid rain in many areas Sulfur can be removed from coal before it is burned or sulfur compounds can be removed from the flue gas after combustion o Formation of nitrogen oxides during combustion also can be minimized The ultimate limit to our use of coal in conventional boilers is CO2 emissions Carbon sequestration storing carbon in geological formations or at the bottom of the ocean The UN estimates that at least the CO2 we release every year could be pumped into deep geologic formations o This can enhance gas and oil recovery Alternatively CO2 can be stored in depleted oil or gas wells forced into tight sandstone formations injected into deep briny aquifers or compressed and pumped to the bottom of the ocean Some utilities are burning coal together with biomass crops in their power plants o This produces less CO2 than coal alone and also improves the combustion characteristics of biomass alone o Another proposal is to convert coal to either liquid or gas 19 3 Oil Petroleum is derived from organic molecules created by living organisms millions of years ago and buried in sediments where high pressures and temperatures concentrated and transformed them into energy rich compounds o Depending on its age and history a petroleum deposit will have varying mixtures of oil gas and solid tarlike materials Oil and gas deposits often accumulate under layers of shale or other impermeable sediments especially where folding and deformation of systems create pockets that will trap upward moving hydrocarbons An oil pool is not usually a reservoir of liquid in an open cavern but rather individual droplets or a thin film of liquid permeating spaces in a porous sandstone or limestone Pumping oil out of a reservoir is much like sucking liquid out of a sponge o The first fraction comes out easily but removing subsequent fractions o Methods for squeezing more oil from a reservoir are called secondary requires increasing effort recovery techniques The total amount of oil in a world is estimated to be about 4 trillion barrels 600 billion metric tons half of which is thought to be ultimately recoverable o Some 465 billion barrels of oil already have been consumed Many geologists expect that within a decade or so world oil production will peak and then begin to decline By far the largest supply of proven in place oil is in Saudi Arabia which claims 262 7 billion barrels almost of the total proven world reserve Refining oil releases high levels of air pollution Like other fossil fuels burning petroleum produces CO2 emissions and contributes to global climate change o n many