Lecture 2 Flashcards
What has the rapid use of fossil fuels pumped into the air
Carbon dioxide
Carbon dioxide in the air has led to ___
Temperature rise
Temperature rise is due to the ___
Greenhouse effect
Why is there seasonal variation in carbon dioxide levels
Changes in vegetation in the north and south hemispheres
Why will we likely stop pumping CO2 into the atmosphere
We have likely already reached the peak of oil production
Are fossil fuels renewable
No
Sustainability
The ability of a process to continue indefinitely without depleting any of the material or energy resources required to keep in running
Industries that constantly worry about sustainability
Fishing and forestry
What does sustainable energy require
The production of energy that does not deplete resources
Options for sustainable energy
- hydro
- solar
- wind
- geothermal
- bioenergy
Energy that is an alternative but not sustainable
Nuclear
Hydro
Water power
Water power is indrect ___
Solar power
Water power provides __/6th of the world’s annual electrical output and over ___% of the electricity produced from renewables
1
90%
Hydro power is derived from ____
The hydrological climate cycle
Hydro power is powered by ___
Solar energy
Tidal energy is the result of ___
The interaction of the gravitational pull of the moon (and the sun to some extent) on the seas
What do tidal energy schemes rely on
Twice-daily tides and the flows and ebbs in estuaries and other bodies of water
Problem in feeding power from tidal barrage into the national grid networks
Tidal energy inputs come in short bursts (approx. 12 hour intervals)
Power can be produced for ___ hours during spring tides
5-6
Power can be produced for __ hours during neap tides
3
How long does a tidal cycle last
12.4 hours
___ is the ultimate source of most of our renewable energy
Sun
Types of solar energy
- Solar thermal
- Photovoltaics
Solar thermal
Using the sun to produce heat
Photovoltaic
Using the sun to generate electricity
Forms of low and high temperature solar thermal technology
- Active solar heating
- Solar thermal engines
- Passive solar heating
- Daylighting
Active solar heating
Involves a discrete solar collector usually mounted on a roof
Solar thermal engines
Produce temperatures high enough to drive steam turbines to produce electricity
Passive solar heating
Solar energy used directly in a building to reduce energy required
Daylighting
Uses natural daylight through building design
The net solar power input to the earth is more than ___X humanity’s current rate of fossil and nuclear fuel use
10,000
Photovoltaics cells are typically made of ____
Silicon
Second most abundant element in the earth’s crust
Silicon
Where in the US is solar technology suitable
All states
What are many windmills used for
Water pumping
Can all states use wind turbines to generate electricity
Most can, but some areas are more suited than others
Only form of renewable energy that is independent of the sun
Geothermal
Source of geothermal energy
Within the earth
How to use geothermal energy
One or more boreholes are drilled into the reservoir, and the hot fluid flows or is pumped to the surface. The hot fluid is then used in conventional steam turbines or heating equipment
Is geothermal energy production available throughout the US
No, but heat exchange systems for houses are available in most places (but they do not typically generate electricity)
Renewable energy is __ and __ specific
Location and resource specific
