Transcript Energy Efficiency

Fossil fuels currently supply roughly 86% of worldwide
commercial energy. These fuels are easy and convenient to
use, but they have environmental, political, and social costs.
 To reduce or even eliminate
dependence on fossil fuels or
nuclear energy, these sources have
to be used more efficiently and new
technology for renewable sources
needs to be relied upon.
Hybrid coal-solar plant
 None of the renewable sources
mentioned here are likely to
completely replace fossil fuels,
however, it is possible to use them
in combination to make a
significant difference in our energy
needs.
 Solar energy is a vast and
significant resource. Solar energy is  Transportation is one of the
responsible for other types of
biggest areas of energy use today,
renewable resources such as wind but it is also the area that shows
power, hydropower, and tidal energy.the most promise for conservation
and new technology.
Incandescent
The best way to conserve energy is to
improve energy efficiency.
Energy Efficiency is the measure of
how much work we can get from
each unit of energy we use.
CFLs: Compact
Fluorescent Light Bulbs
84% of all of the
commercial energy
used in the US is
wasted. 43% of this
energy is wasted
unavoidably because
of what the second
law of
thermodynamics has
taught us.
This 43% is
wasted
unnecessarily,
mostly due to the
inefficiency of
incandescent
lights, furnaces,
industrial motors,
coal and nuclear
power plants, and
motor vehicles.
Motor
Incandescent
Furnace
• Energy is transferred in natural processes. The study of
these transfers is known as thermodynamics. While there
are three laws, the only two that we’ll be using are the first
and the second. Here is a summary:
The First Law:
Energy is neither created
nor destroyed as it moves
through natural systems.
The Second Law:
Energy is constantly
degraded to lower forms as
it is used. Entropy, a state
of disorder, increases in
natural systems.
• The ability to do work
Potential: Energy that is stored
Lake Mead is behind the Hoover dam, and
represents a huge amount of potential
mechanical energy
The energy stored inside coal, oil and
natural gas (before it is burned) is potential
chemical energy, just as the burger on your
plate is…before you eat it.
In a perfect world, all the energy in that
hamburger would be converted to
something useful. Energy in=Energy out.
This is, of course, not what happens. (2nd
Law of thermodynamics)
Kinetic Energy: Energy in motion
Kinetic energy is based on an object’s
mass and speed or velocity. We can
use these “moving objects” to generate
electrical energy.
On the American side of the
border, the Robert Moses
Niagara Power Plant and the
Lewiston Pump Generating
Plant, together generate more
than 2.4 million kilowatts of
electricity, enough to power 24
million 100-watt light bulbs.
Kinetic energy and electricity production is accomplished with the help
of a technological breakthrough called a turbine. A turbine is a rotary
engine that extracts energy from a fluid flowing and converting it into
useful work, with the exception of photovoltaic cells, it is this
technology that we employ to generate nearly ALL of our electricity.
So since energy in, rarely if ever is equal to energy out, we have to set a
definition for efficiency.
Energy many times gets lost to the ecosystem in the form of thermal
energy. (heat)
Energy efficiency is basically
a measure of the usefulness
of energy…using as much as
you can without losing any!
The closer you can get to
energy in= energy out, the
more efficient the system is.
%E=work out/work in · 100%
Your jobs as adults will be to find ways to efficiently use
the energy Earth has available.
Another reason for energy inefficiency is that so many of
us live and work in leaky and poorly insulated buildings.
This thermal image
shows the poorly
insulated home
losing heat energy.
The US and Canada, as well as most developing countries
are extremely wasteful of energy resources. Only 5% of us
rely on mass transit.
Japan, Germany and France, however, are two to three
times more energy efficient than the US is.
Widely Used, and Largely Wasteful…
• Incandescent light bulbs:
Use only 5-10% of the
electricity they draw to
produce light. The rest is
wasted as heat energy.
• Motor Vehicles with
internal combustion engines
waste about 94% of the
energy available in fuel.
• Nuclear power plants producing electricity wastes about
83% of the energy in its nuclear fuel and probably 92% when
we add in the additional cost of mining and processing the
uranium, and storing the waste for thousands of years.
Resistance heating occurs when the passage of an electrical current through a
conductor releases heat.
• Coal-fired power plants waste 66% of the energy released
by burning coal to produce electricity and probably 75-80%
if we include the energy needed to mine, and transport it to
the plant.
How efficient are green plants at absorbing the sun’s
energy? How much of the sun’s energy that strikes the
Earth’s surface gets converted into carbohydrates by plants
to feed consumers?
Would you be
surprised to learn
that less than 1% of
the energy of the
sun actually goes
into manufacturing
carbohydrates!
Even plants are
inefficient!
By contrast, with
passive solar heating,
only about 10% of the
incoming solar energy is
wasted.
Passive Solar Energy
homes are successful
at dramatically
cutting heating
energy costs while
providing a healthy
environment to live
in.
Active solar technologies are employed
to convert solar energy into usable light,
heat, cause air-movement for ventilation
or cooling, or store heat for future use.
Active solar uses electrical or
mechanical equipment, such as pumps
and fans, to increase the usable heat in
a system.
• Biodiesel reduces emissions of CO, and CO2
• Higher net energy yield
• Reduced hydrocarbon emissions
• Better gas mileage (40% better)
• Potentially renewable
How could biodiesel possibly be non-renewable?
Biodiesel is produced from vegetable oil extracted from
soybeans, rapeseeds, sunflowers, oil palms, and jatropha
shrubs. We can also use animal fats to produce biodiesel.
We can even use waste oils
and fats from restaurants
to make biodiesel.
Algae grow naturally all over the world. Under optimal
conditions, it can be grown in massive, almost limitless,
amounts. Half of algae's composition, by weight, is oil.
Scientists have been studying this oil for decades to
convert it into algae biodiesel -- a fuel that burns cleaner
and more efficiently than petroleum.
Algae biodiesel manufacturers
are building biodiesel plants
close to energy manufacturing
plants that produce lots of
carbon dioxide, because the
algae use CO2 to
photosynthesize. Recycling
carbon dioxide reduces
pollution.