Hi. It’s Mr. Andersen and this AP environmental sciences video 23. It is on energy consumption.
I think about the amount of energy that my body requires in one day, it is really not
that much. A little over 2000 kilocalories of energy. And I could get most of that in
one large pepperoni pizza. But I use more energy than that. Right now I am using a computer.
I am using the internet. I am using lights. I am heating my house. If I go somewhere I
am probably going to drive. And if we were to put that in pizzas the average person in
the US requires over 300 large pepperoni pizzas of energy everyday. And most of that energy
is coming from fossil fuels. As we talked about in the last video energy is the ability
to do work or transfer heat. And if we look at human consumption of energy over time,
we can learn lessons from the past as we plan towards the future. And where did our energy
come from to begin with? Just like that pizza it came from our food. But it did not take
long before humans discovered fire and we could unlock the power found within wood.
We domesticated animals, and we could leverage some of their power. We used wind power very
early, grinding up grains and moving water around. And our society started to grow. But
as the population increased we underwent our first energy crisis. An energy crisis occurs
when you have a lack of supply or an increase in the price of the source of that energy.
In this case deforestation was leading to a decrease in the amount of wood and charcoal
that we had. We could not support our population. Thankfully we discovered coal. Coal has a
much larger return on investment, way more energy. It is wood, but wood that was deposited
way underneath the earth thousands of years ago. And we could get energy from that. It
led us into the industrial revolution. We then discovered oil and gas. But with each
of these, since they are nonrenewable energy sources, we have seen and will continue to
see a number of energy crisis as well. And so as we plan towards the future it is important
that we come up with an economic solution for our energy. And so we should look at the
energy’s return on investment. As we start to see a decrease in oil things like wind
and solar are going to be more feasible or more viable over time. And we also have to
consider the externalities. These are fossil fuels that we are using and with that we are
increasing pollution. We are increasing global warming. And so as we plan for the future
we want to shift towards renewable sources of energy. And more importantly sustainable
so that over time we have a consistent amount of energy and we eliminate the energy crisis
over time. And so if we look at our energy sources over time, this is from 1776 until
today, you can see a huge increase in the amount of wood that we were using. But over
time that was replaced by coal. You see an exponential growth in coal. We then see an
exponential growth in oil, in gas. We see an increase in nuclear. Right now we are seeing
an increase in renewable resources as well. And so over time we will get a decrease in
the supplies of these energy sources. And an energy crisis occurs if we have a decrease
in supply and also an increase in price. And so if we look at price for a second, this
is the price of oil in the US since it was essentially discovered. You can see it is
variable to begin with. The lower line here is the price and the upper line is putting
it in the modern day 2008 dollars. You can see that oil prices were fairly consistent
for a long period of time. You can see a big jump right here. Why is that? We had the 1973
oil crisis or energy crisis. What caused that? It was foreign policy. The US was involved
in the Yom Kippur War. We were funding Israel. OPEC, a number of Arab countries put an embargo
on the oil, so we could not get cheap oil from the Middle East. And as a result the
price went from $3.00 a barrel up to $12.00 a barrel. And as a result we had lines at
the pump. There was not enough gas. We saw another oil crisis in the 1970s as well with
the Iranian Revolution. There was this decrease in supply at this point, increase in price.
Again we had huge lines at the pump. And there were government policies put forward to start
to increase mileage of cars for example and ways that we could conserve our oil. We saw
the same thing in 2003. This is a multifactorial cause. A lot of it has to do with global requirements
for energy. We see a huge increase in oil prices as well. Now the oil prices are dropping
off. But over time, since it is a nonrenewable resource, we are going to have decreases in
the amount of oil that we can find, increases in the price over time. And if we look at
where is our energy coming from today, it is oil, coal and natural gas. That is where
most of our energy is coming from right now in the world. Now the renewable sources are
a growing segment. But if we look at that there is still traditional biomass. So this
is going to be wood that makes up 9 percent of the energy that we are getting from our
environment. And so overtime what we have to move towards is away from nonrenewable
and towards renewable sources of energy. Now we will not just due that on our own. As the
model we have talked about before, the earth supports society and everything is driven
by the economy. We have to have economic drivers that are going to move us towards these renewable
sources of energy. And a good way to look at that is the energy return on investment.
Basically what you do is you look at a ratio of how much energy it requires to get the
energy source, and how much we get out of it. So it is a ratio of energy acquired versus
energy consumed to get that energy. And so if we look at something like hydropower, for
everyone $1 invested we get $100 of energy back. Or coal is going to be an 80 to 1 ratio.
Now things that you may have heard put forward as a solution, if we look at ethanol coming
from corn, it is going to be around 1.3 to 1. And so we have to put a huge amount of
energy to grow the corn. We use fossil fuels to harvest it to get energy out. And so it
is not economically viable at this point to use some of these renewable resources. But
these are going to change over time. So if we look at oil imports in the 1990s that ratio
was 40 to 1. But if we look at oil imports in 2007 you can see that has dropped way down,
closer to around 12 to 1. And now if we look at things like wind, it has a higher ratio.
And so there is going to be a movement away from fossil fuels towards renewable resources.
And the reason why is that they are going to become cheaper. The technology is going
to improve. And the one thing that we are not even considering yet are all the externalities
of these fossil fuels. We really do not put a true value on the fossil fuels. Because
as we use them we are polluting our environment and one of the big ones is that we are increasing
the amount of carbon dioxide in the atmosphere which is leading to global change in temperature.
And so these externalities, these external costs of these fossil fuels are things we
are going to have to consider as well. So where do we move in the future? We want to
move towards renewable forms of energy. Energy that keeps coming back so we can eliminate
the energy crisis. We want them to be sustainable, be it solar or wind or sustainable biomass.
And so did you learn the following. Could you pause the video at this point and fill
in the blanks? If not, let me do it for you. So energy consumption over time was food then
we used wood. Animals. Wind. We then used coal, oil, gas. And with each of these we
have energy crisis associate with it. As we decrease supply, increase the price. And then
the last one is we really have to start considering not only the return on investment, but the
externalities. What cost do we have to society by using fossil fuels or nonrenewables.
Well, I hope you learned all of that and I hope that was helpful.