Studied by 7 people
Nonrenewable resources
exist in a fixed amount and involve energy transformation that cannot be easily replaced
Renewable resources
can be replenished naturally, at or near the rate of consumption and reused
Key to renewable is rate of consumption
Rate of use must be at or below rate of regeneration for renewables
Fossil fuels will run out because they take much longer to generate than the rate that we are using them
The best form of energy to use depends on
the particular purpose for which it is needed
It is possible to determine energy efficiency by
calculating the energy return on energy investment (EROEI)
EROEI equation
Energy obtained from fuel Ă· Energy invested to obtain fuel
The larger the value of EROEI
the more efficient the fuel
EROEI answer
Energy returned on energy invested
The major sources of energy for the world
Oil, coal and peat, and natural gas
Once dominated the US’s energy supply
wood and then coal
Today a mix of three fossil fuels accounts for
the US’s energy use
The recent increase in
natural gas and decrease in oil and coal is quite evident (US)
Electricity accounts for
40% of our energy use
Nearly 30 percent of energy use in the US is for
transportation
Transportation
an area in which efficiency is particularly important
Transportation is achieved primarily through the use of
vehicles fueled by petroleum products
ex. gasoline and diesel
CAFE standards (Corporate Average Fuel Economy)
standards mandate higher fuel efficiency in cars
When was CAFE first enacted
by congress in 1975 (US)
CAFE caused
Fuel efficiencies fell from 22 mpg (1984) to 19 (2004) climbed to 21.1 in 2009
In 2009 Congress mandated that cars must
get 35 mpg by 2020
European and Japanese cars are
twice as efficient as U.S. cars
A generalized version of the Hubbert curve
whether an upper estimate or a lower estimate of total petroleum reserves is used, the date by which petroleum reserves will be depleted does not change substantially
Note
Flashcard