HOW THE WORLD WORKS AND YOUR PLACE IN IT Environmental SCIENCE HOW THE WORLD WORKS AND YOUR PLACE IN IT Unit 6 Energy

Oil and Gas Deposits A source rock is a rock that is rich in organic matter. A reservoir rock is a rock that contains many tiny pores with connecting passageways through which the oil and gas can move. A trap, or rock without pores, forms a dam or a lid that keeps the oil and gas from escaping. This lid must be tightly sealed in order for oil and gases to collect in the reservoir.

Secondary Recovery Methods Acid is injected into the well to dissolve channels in the rock. This method involves pumping water, carbon dioxide or other gases into the well to force the oil toward the opening

Simplified Diagram of an Oil Refinery The processing of crude oil begins with distillation. The crude oil is heated to 650°F (340°C). As the oil is heated, the vapors pass through a series of perforated trays in a fractionating tower. The different hydrocarbons condense at different temperatures. The lighter compounds condense near the top of the tower, and the heaviest compounds condense at the bottom of the tower.

Fossil Fuel (Coal) Power Plant The first commercial electric generating station, designed by Thomas Edison, burned coal to heat water and produce steam. The steam turned the turbines, and enough electricity was produced to light 1200 street lamps.

Hydroelectric Power Plant Hydroelectric power is produced when the energy of falling water turns a water turbine.

Nuclear Power Plant The fuel used in nuclear power plants is mainly uranium. When the uranium atoms fission or split apart, they release huge amounts of energy. This energy heats water and creates steam that drives the turbines.

Geothermal Power Plant Geothermal energy is the natural heat or hot water trapped below the earth’s surface. Some of the heat was trapped when the earth was formed. Radioactive substances, chemical reactions, and friction created by moving continents produce additional heat energy. To create electricity, steam or hot water is pumped to the earth’s surface and is used to drive turbines. Geothermal power plants usually create minor environmental impacts compared to those that are fired by fossil fuels. Electric power plants must be located at the geothermal field because too much heat and pressure are lost if the energy is transported more than one mile (1.6 km).

Solar Heating Systems Active Solar Heating Passive Solar Heating Active solar heating requires electricity for pumps or fans that distribute the heat. Often energy is collected in flat plate collectors that are shallow insulated boxes covered with glass and containing a black metal plate. Air or water flowing through the collector is heated and pumped to a storage tank. If the system is designed for space heating, the heat is pumped throughout the building in the same way it is from a conventional furnace. Passive solar heating occurs when the light energy passes through glass and is trapped (the greenhouse effect). Roof overhangs shade the windows from the sun’s rays in the summer, reducing the amount of passive solar heating and the need for air conditioning.

Active Solar Heating Systems

Phosphoric Acid Fuel Cell Phosphoric-acid fuel cells (PAFC) are about the size of a minivan. This type of fuel cell uses phosphoric acid as an electrolyte. Hydrogen gas is ionized at the anode, and the electrons travel through an external circuit to the cathode. At the cathode, the oxygen reacts with the hydrogen ions and the electrons to form water.

Polymer Electrolyte Membrane (PEM)

Basic Electric Generating System Fossil fuel and nuclear power plants produce electricity by heating water to form steam. The force of the steam turns the blades of a large fan-like, or paddle-wheel structure—a turbine. The shaft of the turbine is connected to a generator that consists of a coil of wire in a magnetic field. Rotation of the coil forces the electrons in the wire to move. This flow of electrons is transmitted along wires as electricity.

Aquaculture with Wastewater Aerial view of PP&L’s Aquaculture Project A greenhouse heated by the warm wastewater is being used for hydroponics production of vegetables August through march, and to heat incubators for hatching catfish eggs. Once the small catfish are two inches (5 cm) in length, they are transferred to long concrete pools called raceways. The heat that was absorbed by the water as it passed through the power plant keeps the temperature of the raceways about 80°F (27°C). The optimum temperature for catfish is 84°F (29°C).

Recycling Recycling saves energy and reduces pollution.