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Natural gas vs. alternatives and renewables as sources of electric power moving into the future
natural gas increase, add up all alternatives to match up natural gas and renewables (solar, hydro, and wind added up (NOT INCLUDING OTHER) = 953 billion kwh
Renewable energy sources all derive from
the sun’s energy
Geothermal energy
sun heats Earth’s surface and geothermal systems harvest this energy
Low-density near-surface geothermal
solar energy stored by soil and rock near the surface
low-density near-surface geothermal qualities
widespread and easily obtained, renewed by the sun
how solar energy helps other fuels
helps hydropower (dams) produce energy and is used as an energy source for biomass (algae)
Drawbacks of solar energy
solar energy is site-specific
detailed observation of potential site = necessary to evaluate daily/seasonal variability of its solar energy potential
renewable energy production trend over 2015-2022
huge increase
renewable energy production methods of electricity generation from largest to smallest
hydropower, wind, solar, other
renewable energy production growing fastest in electricity production
solar, other, wind, hydro
types of energy use growing fastest
wind/solar, biofuel, hydro/geo, nuclear
methods of energy use for oil, gas
oil 0.3%, gas 0.9%
natural gas, coal, biomass energy use trends respectively
increase, decrease, increase (0.1%)
dark, windless days/winters =
intermittent supply
first option for battery development trends/converting electricity into transportable energy?
store electricity in batteries and use electrical vehicles
second option for battery development trends/converting electricity into transportable energy?
transfer energy in electricity to a gaseous or liquid fuel
hydrogen
simplest gaseous fuel energy in electricity can be transferred to
why are battery development trends/converting electricity into transportable energy vital for non-hydropower renewables?
solar and wind are still variable sources that produce changing amounts of energy. batteries can store electricity to still work
active solar energy systems
mechanical power (mechanical pumps) circulates air/fluids from solar collectors to heat storage location. heat is then pumped to where energy is used
passive solar energy designs
avoid direct solar energy in hot weather, retain heat in cold
examples of passive solar energy
overhangs block summer sun, allow winter sun
deciduous trees as landscaping
walls in buildings absorb heat in day, release at night
PV doping
process of intentionally adding small amounts of impurity atoms (dopants) to semiconductors
n-type
electron rich
p-type
hole-rich (missing electrons)
how is current generated in PV?
2 layers of p and n-semiconductors, electrons move b/w them
band energy
amount of energy required to make electron “jump”
what is happening to the cost of solar PV and the use of PV for generating electrical power?
costs down 150x, cumulative installations up 115,000x
concentrated solar/solar thermal generators
focus sunlight onto water-holding containers via mirrors. resulting steam turns turbines
concentrated solar projections
2050, PV and CS = 37% global electricity
87% growth b/w 2017 and 2023
challenges of concentrated solar
making it cost-competitive w natural gas or fuel
large variety of metals, glass, plastics, fluids used in manufacture and use of solar equipment (some substances may cause environmental problems through production/accidental release of toxic materials)
hydropower (freshwater): why are we not likely to see an increase in large hydropower facilities?
large hydropower facilities flood large tracts of land that could’ve had other uses, greatly alter habitats, and public outcry against turning wild rivers into many lakes
advantages of hydropower
clean, efficient, reliable
efficiency of water power
no fuel burning, does not pollute atmosphere, produces no radioactive/other waste
disadvantage of hydropower in relation to sediments
dams trap sediment that would otherwise reach the sea and eventually replenish sand on the beach
disadvantage of hydropower in relation to land use
large dams and reservoirs flood large tracts of land that could’ve had other uses (towns, agriculture)
advantage of hydropower in relation to potential energy
may help reduce high cost of importing energy
How does harnessing tidal energy work?
dam built across bay or estuary entrance, water held in/out of bay until significant difference in level forces water in/out = runs turbines
environmental impacts of tidal power
changes hydrology of bay, restricts passage of fish, changes habitats
