Coal-Fired Plant Coal is conveyed to boiler In primary water loop, water is boiled into steam Steam is sent through turbine Turbine spins the generator, producing AC electricity Steam is condensed back into water by secondary water loop; secondary water gets hot

Secondary water is sent to cooling pond. Water releases heat to the air Carbon dioxide and other emissions released to air through stack Ash is dumped in landfill: Coal is non-Renewable

Natural Gas-Fired -Natural gas (methane) is burned; products of burning are water vapor and carbon dioxide, which are sent through gas turbine, which spins the generator -In combined-cycle plants, hot gas is then used to boil water into steam, which is sent through steam turbine

-”Cleaner” fuel, although CO 2 is a greenhouse gas -Fuel is cheap and abundant, although non-renewable; obtained from oil wells -Can also be obtained from landfills, and possibly animals -Need pipelines to transport fuel

Hydroelectric Power River is dammed up with a concrete barrier Path through is created (penstock) Turbine is placed in the penstock Water is allowed through the penstock, which turns the turbine Turbine spins the generator, making AC electricity

Can have as many as 10 generators in a single dam Creates large amounts of electricity Renewable No Emissions Large-scale plants limited to few regions of US Not very viable for Wisconsin

Wind Power Wind turns blades Gears take rotation underground to generators Renewable; no emissions Large-scale wind farms could supply the energy needs for much of the nation

Nuclear Power Plant Nuclear reactions convert mass into energy by E = mc 2, releasing tremendous amounts of heat Reaction controlled by control rods, which control rate of reaction. Non-Renewable! Reactor cooled by water in the primary cycle; this water becomes radioactive

Primary cycle and reactor are in containment building, made of reinforced concrete Reactor water pumped to steam generator, which boils secondary water into steam Steam taken out of containment building to turbine, which spins the generator, making AC

Steam is condensed back into water with third (tertiary) loop of water; secondary water is then pumped back to steam generator Tertiary water is sent to cooling towers, which releases its heat to the air

No emission of CO 2 or any other gases; only steam from the cooling towers Radioactive products and water are kept in containment building Problem of radioactive waste products, which must be kept stable for many years, until they are no longer radioactive

Nuclear Plants in Wisconsin: 1 unit in Kewaunee 2 units at Point Beach

Nuclear Waste Disposal As of now there are almost tons of radioactive waste products in the US Currently being stored on the reactor site Not a long-term option Need long-term storage solution ( years)

Waste Disposal (cont.) Must be kept away from water, which could corrode the vessels and cause radioactive waste to enter the water table Must also be in a geologically stable place; not prone to earthquakes, which could crack the vessels open

Yucca Mountain Site

Yucca Mountain Site (cont.) Waste has to be transported from states to site by railroad Potential for terrorist attacks or accidents

Potential for Accidents If any of the pumps fail, reactor could overheat, maybe to the point of meltdown Three Mile Island in Pennsylvania, March 28, 1979

Three Mile Island accident March 28, 1979 Primary coolant pump failed Back-up was not turned on Pressure in reactor increased, creating high- pressure radioactive steam, which opened a relief valve, which stuck open Steam exited into building outside containment building

Three Mile Island (cont.) Steam was released to the outside atmosphere by ventilation system Reactor core above water level suffered partial meltdown Small amount of radiation release No fatalities

Chernobyl accident April 26, 1986 Accident was the result of a failed test of the safety systems Turned off the primary pump on purpose Reaction quickly (less than 1 minute) grew out of control Operator tried to shut it down, but by then superheated steam was created in the bottom of the reactor

Chernobyl accident (cont.) Explosion blew the top off the containment building 8 tons of radioactive material was ejected into the air, as well as other radioactive gases Air entered the reactor, which ignited a graphite fire, which burned for days

Chernobyl accident (cont.) 1 worker died immediately 1 died later that night in hospital within 1 month, 28 more had died die to Acute Radiation Syndrome (ARS) 19 more who had been exposed died, but death could not be attributed to ARS.

Chernobyl 20 yrs later There is a significant increase in childhood thyroid cancer within 50 km of accident

March 11, 2011, Earthquake in Pacific Ocean Japan in Crisis, Discovery.com Video: Nuclear Nightmare, Containing a Disaster, Nuclear meltdownVideo: Nuclear NightmareNuclear meltdown The Fukishima Nuclear Power Plant (Eastern coast of Japan) suffered meltdown of 3 reactors