Enviromental+Science

__**Enviromental Science**__

//**Fire**// First energy technology -Charcoal found at ancestral sites 1MYA
 * Energy** Capacity to do work
 * Work** Application of force over a distance
 * Power** Rate of the flow of energy, or rate at which work is done

Muscle power from domestic animals dates -Back to at least 10,000 YA

Wind and water power almost as old as muscle power from animals.


 * 19th century** //Steam engine drives switch to coal as major source of energy//

//**20th century**// Oil replaces coal, because of ease of extraction, ease of shiping, ease of storing, and ease of burning as fuel source. As the "easy to get to" supplies of oil begin to be depleted, more remote locations are sought to sustain demand. - operations in the these locations is frequently difficult dangerous. - Environmental, social, and economic costs of relying on them are high.
 * ex** //current gulf oil leak/spill//

//**Currently**// fossil fuels supply~87% of the worlds commercial energy needs


 * Fossil fuel//** Coal, natural gas, petroleum, all derved from the decay of living things from millions of years ago, all are in fixed quantities (not going to get any more of them anytime soon)

Were do we get our energy from? - Just like the rest of the world the USA gets energy from fossil fuels (85% of total) and 43% of that amount is from oil - Due to large coal deposits in North America we rely heavily on it but that trend is changing to cleaner natural gas - Nuclear power is responsible for about 8% of commercial energy (but more like 20% of all electricity)

The largest share of the energy used in the USA is consumed by industry (1/3 of total) -This includes mining milling smelting and forging of primary metals - chemical industry is the second largest industrial user of fossil fuels (but only half of it is used for energy the rest is for raw materials for plastics fertilizers solvents lubricants andorganic chemicals for commercial use)

Energy use - Residential and commercial blds use about 20% of the primary energy consumed in the USA, mostly for space heating ir conditioning lighting and heation water

Energy Efficiency about half of all the energy in primary fuels is lost during conversion to more useful forms -electricity by contrast is almost 100% efficient when used to run an appliance and is converted to useful work and no pollution is given off directly -generation that electricity is not clean - nearly 2/3 of the energy in coal to generate electricity is lost in thermal conversion in the power pland

about 75% of the original energy in crude oil is lost during distillation into liquid fuels transportation of that fuel storage marketing and then combustion in vehicles natural gas is our most efficient fossil fuel only 10% of its energy content is lost in shipping and processing since it moves by pipelines and usually needs very little refining

Because natural gas has more hydrogen per carbon atom than oil or coal it produces about half as much carbon dioxide per unit of energy and therefore is less pollutive than oil or coal

Coal coal is fossilized plant material preserved by burial in sediments and altered by geological forces that compact and condense it into a carbon rich fuel most coal was laid down during the carboniferous period (286 to 360 MYA)

world coal deposits are ten times greater than conventional oil and gas resources combined the total resource is estimated to be 10 trillion metric tons - if all of this could be extracted and if consumption remained at current levels this would last us several thousand years. Coal- Where is all the coal located? -It is not evenly distributed around the world -North America, Europe and Asia contain 90% of the supply -Both China and India plan to greatly increase coal consumption to raise standards of living -If they do so (and they are), Carbon Dioxide emissions will increase and will exacerbate global warming.

Dangers of coal mining: Cave-ins, fires, accidents, and accumulation of poisonous gases (carbon monoxide, carbon dioxide, methane, hydrogen sulfide) EX.-miners trapped in Chile, lucky to be alive, many die every year in similar accidents

Burning Coal -Burning releases uranium, arsenic, lead, cadmium, mercury, rubidium, thallium, and zinc, and others. -Likely to get a higher dose of radiation living next to a coal burning power plant than next to a nuclear power plant (under normal working conditions) -Coal combustion responsible for 25% of atmospheric mercury.

OIL -like coal, it is derived from organic materials created by living organisms millions of years ago and buried in sediment, where high pressures and temps concentrated them and transformed them into energy-rich compounds -Like coal, is basically energy from millions of years ago sunlight -Depending on the age and history, a petroleum deposit will have varying mixtures of oil, gas, and solid tarlike materials. -Some very large deposits of heavy oils and tars are trapped in porous shales, sandstone, and sand deposits in the western areas of North America -Resources are not evenly distributed across the globe -Estimate of the total amount of oil in the world 4 trillion barrels -2006- proven reserves were 1.15 trillion barrels, enough to last only 40 more years (at current consumption rates) -The USA has gone from being the worlds leading exporter in the first half of the 20th century, to being the leading importer at the turn of the 21st century. -Last large untapped resource of oil in the USA is thought to be in the Arctic National Wildlife Reserve in Alaska -Controversial due to environment impact on wildlife and ecosystems. -Environmental impacts of oil are numerous -spills have lasting impacts -BP gulf spill -wildlife may take years to recover, livelihood of gulf coast fishing industry is at stake. -Tourism industry will take hit all slong gulf coast and parts of East Coastline -Carbon emissions from burning various oil products is major source of greenhouse gases.