Nuclear Energy
True or False: Nuclear is a renewable energy source
False: Nuclear requires breaking down of radioactive elements.
What is passive solar?
Absorbing or blocking heat from the sun, w/out use of mechanical/electrical equip.
What is the name of the dog that Mr. Jauch watches?
Benito
What sport does Mr. Jauch coach at the school?
Cheerleading
What is the main use for hydrogen fuel cells?
Electric Cars
What is Biomass?
Organic matter (wood/charcoal, dried animal waste, dead leaves/brush) burned to release heat - primarily for heating homes/cooking.
What makes hydroelectricity a renewable resource?
Water is not depleted, it is constantly replenished naturally through the water cycle.
What are the three main fossil fuels we discussed in class?
Oil
Coal
Natural Gas
Name a con of burning coal.
Habitat destruction to clear land for mining
Produces pollutants & releases CO2 (GHG → global warming)
Releases more CO2 than any other FF when burned for electricity gen.
Releases PM (soot, ash) which can irritate respiratory tracts of humans/animals
Produces toxic ash contaminated with lead, mercury, and arsenic
Taken to landfills or stored in ash ponds; both can leak into ground/surface waters, or into soil
Releases SOx & NOx (sulfur and nitrogen oxides) which irritate resp. systems, and contribute to smog and acid precipitation
How does Nuclear create energy?
Heat →Water into Steam → Steam turns a turbine → Turbine powers generator → Generator produces electricity
What is active solar energy?
Use of mechanical/electrical equip. to capture sun’s heat (solar water heaters or CST - concentrated solar thermal), or convert light rays directly into electricity (PV cells)
What makes geothermal a renewable energy source?
Heat is generated through the Earth's core. It is renewable since heat from earth’s core won’t run out; but only renewable if groundwater is returned after use.
Name a good location to build a wind turbine.
Open Fields, Offshore on coasts of large bodies of water, tops of mountains.
What is the by product created by a hydrogen fuel cell?
Water
Where in the world is biomass most commonly used as a fuel source?
Utilized primarily in developing countries. (Heating homes/Cooking)
How does hydroelectric energy work?
Kinetic energy of moving water → spins a turbine (mechanical energy) → turbine powers generator
What makes fossil fuels nonrenewable?
Exist in fixed amounts on earth & can’t easily be replaced or regenerated
Fossil Fuels Fossilized remains of ancient biomass that take millions of years to form
Coal, Oil, Nat. Gas
Which is more efficient for generating electricity? Coal or Natural Gas?
Natural Gas
Name 2 cons to nuclear energy
Spent Fuel Rods: used fuel rods remain radioactive for millions of years & need to be stored in lead containers on site @ Nuclear PPs
Mine tailings: leftover rock & soil from mining may have radioactive elements that can contaminate water or soil nearby
Water use: nuclear PPs require lots of water and can deplete local surface or groundwater sources
Thermal Pollution: hot water from PP released back into surface waters can cause thermal shock (decreased O2 & suffocation)
Name 2 pros of using solar energy.
No air pollutants, No CO2, released, Renewable, No mining of fossil fuels required for electricity production.
How does geothermal energy work?
Naturally heated water reservoirs underground are drilled into & piped up to the surface (or water can be piped down into naturally heated rock layers)
The heat from magma turns the water into steam, which is forced through pipes to spin a turbine. Water is cooled in cooling tower & returned to the ground to start the process over.
How is energy generated from wind turbines.
Kinetic energy of moving air (wind) spins a turbine; generator converts mechanical energy of turbine into electricity
Why may hydrogen fuel cells not be considered an entirely clean energy source?
Since 95% of H2 production requires methane (CH4), H fuel cells are based on a non-renewable & CO2 releasing energy source
Why does burning biomass releases CO2, but not increase atmospheric CO2 levels like FF burning does.
Burning biomass releases modern carbon (CO2 that was recently sequestered, or taken out of the atmosphere) whereas FF burning releases fossil carbon that had been stored for millions of years.
Name 2 drawbacks of hydroelectric dams.
Floods habitats behind the dam.
Prevents upstream migration of fish.
Sediment changes upstream and downstream:
upstream becomes warmer (less O2) and rocky stream bed habitats covered in sediment
Downstream loses sediment (important nutrient source), decreased water level, loses stream bed habitat.
Sediment builds up behind the dam.
Nutrients in sediment don't reach wetlands downstream.
Fossil Fuel combustion during dam construction, increased evap. due to larger surface area of reservoir, and methane release due to anaerobic decomp. of organic matter in reservoir.
Human homes & businesses must be relocated due to reservoir flooding, Initial construction is very expensive (does create long-term jobs though), sediment buildup must be dredged (removed by crane) eventually
How does coal form?
Pressure from overlying rock & sediment layers compacts peat into coal over time
Heat produced from electricity generation is used to provide heat to a building. This process is called?
Cogeneration
Name an environmental consequence of a nuclear meltdown.
Contaminated soil: radiation can remain in soil and harm plants and animals in the future (genetic mutations)
Radiation spread: radiation can be carried by the wind over long distances, affecting ecosystems far from the meltdown site.
Name 2 cons of solar energy.
Semiconductor metals (silicon) still need to be mined to produce PV cells (solar panels) this can disrupt habitats & pollute water with mine tailings, and air with particle matter.
Silicon is a limited resource.
Solar panel farms can displace habitats.
Name 2 pros to geothermal energy.
Potentially renewable, only if water is piped back into the ground for reuse.
Much less CO2 emission than FF electricity.
No release of (PM/SOx/NOx/CO) as is case with FFs
Non-depletable (isn’t decreased by its use) - even better than renewable!
No GHG emissions or air pollutants released when generating electricity
No CO2 (climate change) or NOx/SOx/PM as with burning FFs
Can share land uses (don’t destroy habitat or cause soil/water contamination as FFs do)
What makes hydrogen more beneficial than energy sources such as solar, geothermal, and hydroelectric?
H2 gas can be stored in pressurized tanks, it can be transported for use creating electricity later, in a different location.
Which crop(s) is utilized to make the biofuel Ethanol?
Corn grain or sugar cane are broken down & yeast ferments sugars. This process creates ethanol.
Name 2 benefits of hydroelectric dams.
No green house gas emissions:
- Reservoirs and dams can be tourist attractions
- Jobs are created to maintain the dam
- Reliable electricity source generated for surrounding area
- No air pollutants released during electricity generation.
Allows for control of downstream seasonal flooding.
The process of extracting natural gas is known as...
Fracking
What are tar sands?
Combination of clay, sand, water, and bitumen. Bitumen is a thick, sticky, semi-solid form of petroleum (not liquid)
Name 2 famous nuclear meltdowns.
Three Mile Island (US), Fukushima (Japan), Chernobyl (Ukraine)
Explain how solar panels work.
Photons (particles carrying energy from sun) cause separation of charges between two semiconductor layers (n & p); electrons separate from protons & flow through circuit to load, delivering energy (as electricity).
Not everywhere on earth has access to geothermal energy reaching close enough to surface to access it.
Hydrogen sulfide can be released, which is toxic and can be lethal to humans & animals.
Cost of drilling that deep in the earth can be very high initially
Sometimes so high that it’s not even worth it
Name 2 cons of wind energy?
Intermittency (isn’t always available) can’t replace base-load power (sources that are always available like FFs, nuclear or Geothermal)
Can’t replace base-load power (sources that are always available like FFs, nuclear or Geothermal)
Can kill birds and bats (especially larger, migratory birds)
Can be considered an eyesore or source of noise pollution by some
Explain how a hydrogen fuel cell battery works.
H2 gas enters fuel cell where it’s split into protons (H+) and electrons (e-) by an electrolyte membrane that only lets protons pass through
Electrons take an alternative route (circuit) around the membrane, which generates an electrical current
O2 molecules enter fuel cell break apart into individual O atoms and combine with two hydrogens (H+) to form H2O as a by product (only emissions from F fuel cells)
Deforestation, Greenhouse gas emissions, Significant land use, water requirement, not a very efficient fuel source.
Name a method of helping migratory fish such as Salmon to cross hydroelectric dams.
Fish ladders or Salmon Cannon
Which of the three main fossil fuels is cleanest?
Coal
Oil
Natural Gas
Natural Gas
Name 1 of the top 5 countries for oil reserves.
2. Saudi Arabia
3. Iran
4. Canada
5. Iraq