renewable energy Flashcards
wind turbines- how it works
generator in each turbine
blades directly drive turbine
kinetic - electrical energy
remote areas e.g. coasts and moors
wind turbines pros
renewable
no pollution (except manufacturing)
no permanent damage to landscape
low running costs
wind turbines cons
expensive set up
noisy
eyesore- 1500 to replace coal power stations
can increase power generated to meet demand
solar cells- how they work
electric currents directly from sunlight
used for road signs and satellites in remote areas
lower energy devices eg calculator
solar cells pros
no pulltion (apart from manufacturing)
very reliable in sunny places- still cost effective in cloudy UK
used on small scale e.g. individual homes
no running costs
solar cells cons
high set up costs
expensive and unpractical to set-up to national grid- costs massive compared to value of energy produced
doesn’t work at night
HEP
water stored and allowed through turbines
HEP pros
not much pollution
renewable
can immediately responded to demand surge
reliable- apart from drought (uk no problem)
no running costs
useful for remote areas
HEP cons
flooding- floods habitats and villages
reservoirs unsightly when they dry up
rotting vegetation releases methane and Co2
pumped storage
spare nigh time energy is used to pump water to the higher reservoir- a way of storing energy
extra water can be released during peak times e.g. tea time
wave powered turbines
when waves hit the coast they go up and down, forcing air up in spurts into turbines- which drives generator
wave powered pros
no pollution
useful on small scale eg. islands
no fuel costs or running costs
wave powered cons
hazard to boats
eyesore
unreliable - waves rely on wind
tidal barrages
dams across estury with turbines
tide comes in and fills estury to a height of several meters- drives turbines
then water allowed back out through turbines in controlled amounts
relies on the gravity of the earth and the moon
tidal barrages pros
no pollution good for storing energy for peak times reliable in a sense- tide goes in and out twice a day no fuel or running costs potential to produce lots of energy
tidal barrages cons
tides can be weak- low height so less energy
doesn’t work when water level is the same (happens 4 times a day)
high initial costs
prevent boat access
spoils view
alters habitats
geothermal
in volcanic areas
heat from slow decay of radioactive elements - uranium etc. from deep inside earth heat rocks near the surface
water pumped in and steam rises to surface driving turbines
geothernmal pros
no environmental problems
can be used to directly heat buildings
geothermal cons
high set-up cost compared to energy out
limited locations- volcanic
biofuels
can be solids- straw , nutshells and woodchips
liquids- ethanol
gases- methane- sludge digesters (sewage)
from plant matter- recently dead or alive ]fermentation of sugar cane for ethanol
biggest producers of CO2 fossil fuels
1) coal
2) crude oil
3) natural gas
effe ts of fossil fuels- not obvious
coal mining makes a mess of landscape- open cut
oil spillages
nuclear power- no gases but toxic waste
risk of disaster- nuclear
nuclear cons
expensive to build long start up time nuclear waste decommissioning takes time and money nuclear disasters
biofuel problems
supposedly carbon neutral- gases released were recently taken in by growing plants
only carbon neutral if they grow plants at the rate they burn them
forest areas cleared- loss of habitat and carbon taking in plants
methane from animals anddecaying and burning plants
limited to land available - food prices increase too
