Hi it's Mr. Andersen and this is AP environmental sciences video 28. It's on renewable energy.
we really live in a society that's driven and governed by fossil fuels.
The whole infrastructure is built on fossil fuels, but they have problems.
They're non-renewable, so they're finite, will run out, and they're polluting the atmosphere,
especially with carbon dioxide that's leading to global warming. And so we have to
reduce the amount of energy that we're using,
but we also have to move towards more renewable forms of energy.
And so in this video, we'll talk about the six following categories.
But just because it's renewable doesn't mean it's sustainable.
So wood, for example, is a wonderful form of renewable biomass energy,
but if you use too much of it, it leads to deforestation.
Or hydroelectric power is great,
but can change the natural flow of a river, can change that whole ecosystem.
And so we have to make sure that our energy sources are not only renewable, but sustainable.
So we'll start by talking about biomass, one of the most ancient forms.
We'll talk aabout solid forms, wood and charcoal.
And then we'll talk about more recent forms biodiesel and ethanol.
We’ll then talk about small-scale hydroelectric power in the form of waves and tides.
We’ll then talk about all the different types of solar systems, both passive and active.
And then thermal heating systems and photovoltaics, those that actually convert the energy of the Sun into,
directly into electricity. We’ll then talk about geothermal electricity, generating forms of energy,
and then heat pumps that can be used residentially.
We’ll then talk about wind power and wind turbines.
We’ll then talk about hydrogen in the future. As a way we could harness that power in fuel cells.
But the big problem is going to be the infrastructure itself. In other words, how do we store this energy,
and how do we move it where it needs to go.
Because if we're looking at fossil fuels, we can get consistent energy.
but the solar energy and the wind energy is not always going to be consistent.
So let's look at the size difference between renewable and non-renewable.
if this sphere represents the amount of energy
that we consume on our planet every year, 16 terawatts of energy,
then each of these spheres represents the potential energy that
we can find in both non-renewable and renewable resources.
The one that dwarfs everything else is going to be the Sun.
So the potential energy found within the Sun is huge,
but we have a lot of it in coal uranium oil and natural gas.
The problem with all of these on the right side is that they're non-renewable. We will run out of these.
Now if we look at how much are we using the global energy consumption, as I mentioned earlier is,
almost on all non renewables. And so it seems puzzling that we have a lot more energy potential on the left side,
but we're using energy reserves that are eventually going to run away. Well, it all comes down to
economics or energy returned over, energy invested. And this is a term that I'll keep coming back to.
So if we look at a one to one ratio, that would mean we're investing $1.00 in this form of energy,
and we're getting $1 back. So we could call that the break-even.
And we don't even look at energy sources until they become around a 3:1 ratio.
If we're investing $1 we're getting $3 back. What do you think coal is?
Well if we look at coal, it's about eighty to one. It's a very small amount of money
that's invested in coal mining and coal production, compared to the amount of energy
that we get back. Now if we look at something in the U.S. like corn ethanol, it's a one-point three to one.
So you can see, there's no economic incentive for us to start using ethanol
until this ratio becomes more compatible with that of the nonrenewables.
So let's start with biomass. Wood is one of the most ancient forms of biomass.
And so we use it in Montana. We use it all across the northern latitudes.
Cut down some old trees, put them in a wood-burning stove. And you can heat your house.
Now if we look at the energy returned over energy invested, it's a 25 to 1 ratio.
This is going to be the highest ratio that we'll show you of any the renewables.
And so why isn't this the perfect form? Well, it leads to other problems.
It leads to pollution and can lead to deforestation.
So if you're using this cooking, you're going to get a huge amount of soot that's coming off of it.
And that's not usually how it's used, especially in developing countries.
They'll make that wood into charcoal. So you cover it up, and then you heat it up.
And aerobically you get charcoal, which has a lot more potential energy, but also a lot more problem.
And so as you use charcoal, we can have increases in carbon monoxide.
It's going to be dirty, and also can lead to deforestation.
So in Haiti, so this is Haiti, on the left side, they have a huge amount of deforestation.
It used to be, I think 60% of Haiti was trees. And now something like 2%.
And they're sneaking into the adjacent Dominican Republic to take charcoal back to where they are.
And so there are huge problems again, not sustainable. If we look at biomass, two big areas is biodiesel.
So we're taking things like canola and canola oil or soybean oil and we're refining it to make a diesel.
And if we look at the energy return to energy invested, it's a very small number.
If we're looking at ethanol, so corn ethanol, we're fermenting the sugars inside it to make ethanol.
It's like drinking alcohol, but we can eventually combust it.
If we're looking at corn again, it's a one point three to one ratio.
If we were to go to sugarcane, in the U.S., it's going to be a three to one ratio.
But in Brazil, it's going to be up to an eight to one ratio. So it depends on what our energy source is.
And where it's actually being grown can change the amount of energy we get back.
I talked about hydroelectric power on a large scale in a separate video. I'll put a link to that here.
But hydroelectric power can have a huge return on investment. For looking at small scale
hydroelectric, waves over time, as the, as the wind blows over the surface of the water,
we generate these waves. We can harness some of that. We can have a 15 to one ratio.
If we're looking at tidal energy, as the tide comes in and out,
we can harness that energy with a similar, similar kind of a ratio.
Again, it doesn't scale as large as large-scale hydroelectric.
If we're looking at solar energy, we've got passive energy.
That’s when we’re just letting light in, especially during the winter, and we're collecting it,
So this would be an example of a passive heating system,
where we have all of the windows on the south-facing side of the house,
and then a huge amount of insulation to hold that thermal heat on the inside.
If we're talking about more active systems, so this would be a thermal heating system,
where we're heating up water and we're using it to heat our house.
It's got a really low efficiency or low return on investment. If we're looking at photovoltaics,
converting the energy right into electricity, there's been huge growth in this technology.
The ratio is closer to seven to one.
And if we're looking at these giant concentrating power plants, where we condense
all of that energy on one point to heat up, heat up water, and then generate electricity through steam,
we can get a high ratio. There's a huge amount of potential for solar energy in the future.
If we're looking at geothermal, this is energy from within the earth.
So in Iceland, for example, they've gone a hundred percent renewables.
A lot of that's hydroelectric, but they're also using geothermal power. As you heat up that material underneath the earth,
it's generating electricity as it flows through turbines, get a huge ratio on that.
And then we can use a heat pump in your own house, where we're pumping fluids or air down into the earth,
where it's being heated during the winter. And it returns some of that energy to us.
And even during the summer, it can pump back some of the cool air underneath the earth.
And then we can use wind. Wind has probably the greatest potential at this point right now,
especially these offshore wind turbines. And so they're, they're massive. If we look at the size of this person here,
compared to the turbine and the generator. We can get a huge amount of return, eighteen to one ratio.
And then as we look to the future, a lot of people say the future is in hydrogen.
So if we can separate water into hydrogen and oxygen,
and then we have them on either side of an electrolyte,
we can generate electricity, as they flow together generating just water, as a by-product.
And so this is a bus that's running just on hydrogen fuel. The ratio is incredibly small now.
It's less than that break-even point. But it could be in the future that we can get some way to
harness the power of algae, or harness the power of plants
to do the breaking of the hydrogen and oxygen apart for us.
It could be something that we look at in the future, but again the major constraints are at this point is that
we have the the whole infrastructure built on fossil fuels,
the movement, the storage of the material.
And so what we have to do is move towards an area of, maybe a smart grid,
where we're figuring out, where's energy being produced, how do we move it to where it needs to go.
It's not only power lines. but it's also harnessing the power of metering and the internet
to figure out where the energy is and where it has to go.
And so again did you learn the following? could you pause the video at this point and fill in all the blanks?
If you can, I'll try to do it for you. So renewable energy, we've got solid and liquid.
This would be like biodiesel and ethanol. Hydroelectric small scale could be the winds and the tides.
We've got passive solar, and then we have active solar heating water systems. And then the photovoltaics.
We got geothermal heat pumps and then we've got hydrogen in fuel cells,
wind and turbines, a huge way that we can generate energy.
But it all comes down to storage of that energy, and then moving it, where it needs to go.
And I hope that was helpful.
