Energy conservation
a decrease in energy used based primarily on reducing unnecessary waste of energy
Energy efficiency
the measure of how much work we can get from each unit of energy we use
4 widely used devices that waste large amounts of energy unnecessarily
- incandescent lightbulb
- a motor vehicle with an internal combustion engine
- a nuclear power plant
- a coal-fired power plant
cogeneration, or combined heat and power (CHP)
2 forms of energy (like steam and electricity) are produced from the same fuel source. ex: the steam used could heat the plant or other nearby buildings
How we can save energy and money
using cogeneration, or CHP systems; replace energy-wasting electric motors; recycle materials; switch from low-efficiency incandescent lighting to higher-efficiency fluorescent and LED lighting.
passive solar heating system
absorbs and stores heat from the sun directly within a well-insulated structure without the need for pumps of fans to distribute the heat
active solar heating system
absorbs energy from the sun by pumping a heat-absorbing fluid (like water or antifreeze solution) through special collectors usually mounted on a roof or on special racks to face the sun. some of the collected heatcan be used directly. The rest can be sto
Photovoltaic (PV) cells or solar cells
convert solar energy into electrical energy. most solar cells are thin wafers of purified silicon with trace amounts of metals that allow them to function as semiconductors to produce electricity. a typical solar cell has a thickness ranging from less tha
geothermal energy
heat stored in soil, underground rocks, and fluids in the earth's matle. we can tap into this stored energy to heat and cool buildings and to produce electricy.
super efficient and ultralight cars
cars that could eventually get 34-128 kpl; or 80-300 mgp
hybrid car
energy efficient, gasoline-electric. invented by Feridand Porsche in 1900. it has a small traditional gasoline-powered motor and an electric motor used to provide the energy needed for acceleration and hill climbing.
plug-in hybrid electric vehicle
a hybrid with a second and more powerful battery that can be plugged into a standard outlet and recharded.
energy-efficient diesel car
accounts for 45% of new passenger car sales in Europe
fuel cell
are at least twice as efficient as internal combustion engines, have no mobing parts, require little maintenance, and use hydrogen gas as fuel to produce electricity without emitting CO2 and other air pollutants.
green architecture
based on energy-efficient and money-saving designs, makes use of natural lighting, passive solar heating, geothermal heat pumps for heating and cooling, cogeneration, solar hot water heaters, solar cells, fuel cells, natural ventilation, recycled building
Ways to retrofit buildings to save energy
insulate and plug leaks, use energy-efficient windows, stop other heating and cooling losses, heat houses more efficiently, heat water more efficiently, use energy-efficient appliances, use energy-efficient lighting
rebound effect
some people might start using more energy if they save money by improving energy efficieny.
solar thermal sysems
concentrate and transform energy from the sun into high-temperature thermal energy, which can then be used directly or to heat water and produce steam to generate electricity.
heliostats
huge arrays of computer controlled mirrors that track the sun and focus sunlight on this central heat collection tower
Hydropower
Water flowing from higher to lower elevations in rivers and can be controlled by dams and reservoirs and used to produce electricity. It is an indirect form of solar energy because it is based on the evaporation of water, which is deposited at higher elev
Micro-hydropower generators
May become an increasingly important way to produce electricity. It uses the power of flowing water water to turn a rotor with blades that feed up and he's got have generators to produce electric current.
biofuels
biomass consists of plant materials and animals wastes that can be burned directly as a solid fuel or converted into gaseous or liquid biofuels.
Biomass
consists of plant materials and animals wastes that can be burned directly as a solid fuel or converted into gaseous or liquid biofuels. It is an indirect form of solar energy because it consists of combustible organic compounds prudced by photosynthesis.
district heating systems
supply nearly hald of the heat for residential and commercial buildings in Sweden.
biodiesel
is prodiced from vegetable oil extracted from soybeans, rapeseeds, sunflowers, oilpalms, and jatropha shrubs, and fats such as used vegetable oils from restaurants.
ethanol
can be made through the fermentation and distillation of sugars in plants such as sugarcane, corn, and switchgrass, and from agricultural, forestry, and municipal wastes. This process involves converting starch in plant material to simple sugars that are
gasohol
gasoline miixed with 10-23% pure ethanol, which can be burned in conventional gasoline engines.
bagasse
a residue produced when sugarcane is crushed
geothermal heat pump system
can heat and cool a house by ecploiting the temperature differences between the earth's surface and underground, almost anywhere in the world at a depth of 3-6 meters. in winter, a closed loop of buried pipes circulates a fluid, which extracts heat from t
hydrothermal reservoirs
wells are drilled into these reservoirs to extract their dry steam, wet steam, or hot water, which are used to heat buildings, provide awuaclture ponds, and spin turbines to produce electricity. cool water left over can be pumped back into the reservoirs
supply-side of hard-path approach
fossil fuel and nuclear power interests generally favor this. it is built around scouring a country tp find more nonrenewable oil, natural gas, and coal, and building more energy-wasting coal-burning and nuclear power plants.
demand-side or soft-path approach
many environmental scientists and economists favor this. this emphasizes reducing energy waste and depending more on a mix of renewable resources such as solar, wind, geothermal, and biomass. proponents see this energy path as more sustainable than relyin