| A | B |
|---|
| Energy Efficiency | the % of total energy input that does useful work in an energy conversion system |
| 2 least efficient energy devices | incandescent light bulbs and cars |
| cogeneration | growing in china, using the same fuel source for 2 forms of energy |
| Hybrid Cars | current model gets up to 50 mpg, works better around town not on highway |
| Fuel Cell car | Combines hydrogen and oxygen to produce water, currently battery too large for great distance, negative net energy |
| tankless water heater | generates a nonstop supply of hot water, heats it when you need it. |
| Current large hot water heater | slowly heats water at bottom of tank as you use it. |
| Passive solar heating system | Uses energy efficient windows, brick floors, and walls "thermal mass" to slowly release heat.face house south |
| Negative for passive solar heating system | when sun is not available to heat brick floor or walls, need back up heating system |
| Active solar heating system | collectors mounted on roof, absorb solar energy, pump heated fluid throughout house |
| Advantage for Passive and Active solar heating | energy is free, quick installation, low water and air pollution |
| PVC or Photovoltaic cells (solar) | transparent wafer that moves electrons, solar power tower |
| Advantages of PVC | low operational cost if belong to a grid, low fuel cost, sun is free |
| Disadvantages of PVC | cant store energy well, large batteries if no grid, upfront cost very high, most expensive of all, bad to make: arsenic poisoning |
| Hydroelectric power | leading renewable energy source, 2nd cheapest way to produce energy,7% in US, 20% of World |
| Three Gorges Dam | China |
| Adv. to Hydroelectric | mod to high net energy, high efficiency, provides flood control and irrigation |
| disadvantage to hydroelectric | high construction cost, environmentally misplaces people and animals upstream, decreases silt below dam, fish can't spawn |
| Wind energy | only 1% of energy in US, 6% in world, average growth 22% per year |
| Adv. of wind energy | mod to high net energy, no CO2 , quick construction |
| disadvantage of wind energy | steady winds needed, back up system, high land use, visual pollution, kills birds, inteferes with migration |
| Biomass | plant material and animal waste used as energy source 10 % of world, more in developing (95%), switchgrass, bagesse, sugarcane, corn |
| Biofuels | produced from plant waste,microalgae, ethanol, biodiesel, methanol, biggest producer, Brazil (40% of cars), US, China |
| Advantage of Biomass | large supply of corn, can be grown anywhere,easy to store and transport |
| No net increase in CO2 | If rate of harvesting and conversion of plants to biofuels is equal to the rate of replenishment |
| Disadvantage of Biomass | nonrenewable if harvested unsustainable, large land use, deforestation, soil erosion, water pollution |
| Pure ethanol | also known as E85 (flex fuel) is a mixture of 85% ethanol and 15% gasoline |
| Geothermal Energy | uses a (GHP) system that can heat and cool houses by exploiting the difference b/t the earth’s surface and underground temps. |
| Iceland | gets 95% of electricity form geothermal and hydroelectricity. |
| Adv. of geothermal | very high effiency, low CO2, low land disturbance, |
| disadv. of geothermal | scarcity of suitable sites, depleted if used to rapidly, noise and odor |
