Renewable Energy

Summary

This video discusses renewable energy sources, emphasizing the need to transition away from fossil fuels due to their finite supply and environmental impact. It explores biomass, hydroelectric power, solar energy, geothermal energy, wind power, and hydrogen fuel cells, while highlighting the importance of sustainability. The video compares renewable and non-renewable energy in terms of potential and energy return on investment. Challenges such as infrastructure, energy storage, and distribution are also addressed, underscoring the need for smart grids to efficiently manage renewable energy resources.

Takeaways

• 🌍 Fossil fuels are non-renewable and pollute the atmosphere, contributing to global warming.
• 🔄 Renewable energy sources need to be sustainable, as overuse of resources like wood can lead to deforestation.
• 💡 Biomass, like wood and charcoal, is one of the most ancient forms of energy, but it can lead to pollution and deforestation.
• 🌊 Hydroelectric power, especially on a small scale, can harness waves and tides, offering a good energy return, but may disrupt ecosystems.
• ☀️ Solar energy, both passive and active, can convert sunlight into electricity, with photovoltaics offering significant potential.
• 🔥 Geothermal energy, as used in places like Iceland, harnesses heat from the Earth and offers high energy returns.
• 💨 Wind power, particularly from offshore turbines, is a promising renewable energy source with a high return on investment.
• ⚡ Hydrogen fuel cells could be a future energy source, but current technology has a low energy return and significant infrastructure challenges.
• 🔋 A major challenge with renewable energy is storing and distributing it efficiently, especially with fluctuating sources like solar and wind.
• 💻 The future of energy management may involve a smart grid, which uses metering and the internet to optimize energy production and distribution.

Q & A

What are some problems associated with relying on fossil fuels?

Fossil fuels are non-renewable, meaning they are finite and will eventually run out. Additionally, they pollute the atmosphere, especially with carbon dioxide, contributing to global warming.

Why is it important to not only focus on renewable energy but also sustainability?

While renewable energy sources can be replenished, they may not always be sustainable. For example, using wood as a renewable energy source can lead to deforestation, and hydroelectric power can disrupt ecosystems by altering river flows.

What is the Energy Returned on Energy Invested (EROI) ratio, and why is it important?

EROI measures the amount of energy gained from an energy source compared to the energy invested in obtaining it. A high EROI means the energy source is economically viable. For instance, coal has a high EROI of 80:1, while corn ethanol has a much lower ratio of 1.3:1.

What are the main types of biomass energy discussed in the video?

The video discusses solid forms of biomass like wood and charcoal, as well as more recent forms like biodiesel (derived from canola or soybean oil) and ethanol (fermented from corn or sugarcane).

What are some challenges of using wood and charcoal as biomass energy sources?

Using wood can lead to pollution and deforestation. Charcoal, while more energy-dense than wood, produces harmful emissions like carbon monoxide and can also contribute to deforestation, as seen in Haiti.

What are the benefits and limitations of small-scale hydroelectric power?

Small-scale hydroelectric power, such as wave and tidal energy, can have an EROI ratio of around 15:1. However, it does not scale as well as large hydroelectric systems, which can have a much greater impact.

What is the difference between passive and active solar energy systems?

Passive solar systems involve simple designs, like positioning windows to maximize sunlight in winter, while active systems involve using solar energy to heat water or generate electricity through photovoltaics. Photovoltaics, which directly convert sunlight into electricity, have an EROI of around 7:1.

How does geothermal energy work, and what is its potential?

Geothermal energy harnesses heat from within the Earth to generate electricity, especially in geologically active regions like Iceland, which has moved to 100% renewable energy, partly through geothermal power.

Why is wind energy considered to have great potential for the future?

Wind energy, particularly from large offshore wind turbines, has a high EROI of 18:1. This makes it one of the most efficient renewable energy sources currently available.

What are the challenges associated with hydrogen fuel cells?

Hydrogen fuel cells have significant potential for the future, but currently, their EROI is less than 1:1, meaning they are not yet economically viable. Future advancements in technology, such as harnessing algae or plants to break apart hydrogen from water, could improve this.

Outlines

00:00

🌍 Introduction to Renewable Energy and its Challenges

Mr. Andersen introduces the topic of renewable energy in contrast to fossil fuels, which are finite and contribute to global warming. He emphasizes the need to transition to renewable sources while ensuring sustainability. Despite being renewable, energy sources like wood and hydroelectric power can cause deforestation and disrupt ecosystems. The video will cover six renewable energy categories, including biomass, hydroelectric, solar, geothermal, wind, and hydrogen, discussing the pros, cons, and challenges related to storage and consistency compared to fossil fuels.

05:01

🌱 The Economics and Sustainability of Biomass

This section delves into biomass, focusing on traditional sources like wood and charcoal, and newer alternatives like biodiesel and ethanol. The concept of energy return on energy invested (EROEI) is discussed, comparing the high efficiency of wood to the lower efficiency of corn ethanol. The environmental impact of biomass, such as pollution and deforestation, is highlighted, using Haiti as an example of severe deforestation due to charcoal use. While biomass has potential, it faces challenges in terms of sustainability and economic viability.

💧 Small-Scale Hydroelectric Power and Its Potential

Here, Mr. Andersen explains small-scale hydroelectric power, including energy from waves and tides. These methods offer a favorable return on investment, with a 15:1 ratio for wave energy. Though not as large-scale as traditional hydroelectric power, small-scale hydro has significant potential in specific environments. He also emphasizes the advantages of using natural water movements to generate renewable energy efficiently.

☀️ Solar Energy: Passive and Active Systems

This section explores different types of solar energy, beginning with passive systems that collect sunlight through strategic window placement. Active systems, such as thermal heating, use water to generate heat. Photovoltaic systems, which directly convert sunlight into electricity, have seen technological advancements and an improved energy return ratio of 7:1. Concentrated solar power plants, which focus sunlight to generate steam for electricity, show even greater promise for the future.

🌋 Geothermal Energy and Heat Pumps

Geothermal energy, particularly in places like Iceland, is presented as a renewable option where heat from beneath the Earth is used to generate electricity. Geothermal systems can be implemented on a smaller scale in homes using heat pumps, which exchange heat with the Earth to maintain comfortable indoor temperatures. This approach is efficient and sustainable, offering potential for both residential and large-scale applications.

💨 Wind Energy and Offshore Wind Turbines

Wind energy, especially from offshore wind turbines, is highlighted as having the greatest current potential. Wind turbines are large and capable of generating a significant amount of energy, with an impressive return on investment ratio of 18:1. The size and scalability of these systems make wind power a major player in the shift towards renewable energy.

🚍 The Future of Hydrogen and Infrastructure Challenges

Mr. Andersen concludes by discussing the future of hydrogen energy, which could revolutionize energy production by splitting water into hydrogen and oxygen. While current hydrogen systems, like fuel cell buses, are inefficient, the technology holds promise. However, major challenges remain in terms of infrastructure for storage and transportation, highlighting the need for innovations like a 'smart grid' to optimize energy distribution across renewable sources.

🔋 Conclusion: Renewable Energy Types and Key Takeaways

In the final section, Mr. Andersen summarizes the renewable energy types discussed, including solid and liquid biomass, small-scale hydroelectric power, passive and active solar, geothermal systems, wind turbines, and hydrogen fuel cells. He reiterates the importance of energy storage and distribution, emphasizing the need for future technological advancements in energy infrastructure to ensure renewable energy sources are effectively harnessed and distributed.

Keywords

💡Renewable Energy

Renewable energy refers to sources of energy that can be replenished naturally and do not run out over time. In the video, renewable energy includes forms like solar, wind, and biomass. The video highlights the importance of transitioning from fossil fuels to renewable sources to mitigate climate change and reduce pollution.

💡Fossil Fuels

Fossil fuels, such as coal, oil, and natural gas, are non-renewable energy sources formed from the remains of ancient organisms. The video emphasizes that fossil fuels are finite and contribute heavily to pollution and global warming, making them unsustainable in the long term.

💡Energy Return on Investment (EROI)

Energy Return on Investment (EROI) is the ratio of energy gained from an energy source to the energy invested in obtaining it. The video discusses how fossil fuels like coal have high EROI (e.g., 80:1 for coal) compared to renewables like ethanol, influencing economic decisions about energy use.

💡Biomass

Biomass is organic material that comes from plants and animals, and it is one of the oldest forms of energy. The video talks about wood and charcoal as solid forms of biomass and biodiesel and ethanol as liquid forms. Though renewable, biomass can cause environmental issues like deforestation and pollution if overused.

💡Solar Energy

Solar energy is the power harnessed from the Sun's rays. The video explains different types of solar energy systems, including passive solar for heating and photovoltaic systems for electricity generation. Solar energy has significant potential but also challenges related to efficiency and consistency.

💡Hydroelectric Power

Hydroelectric power generates electricity by harnessing the energy of flowing water. The video mentions both large-scale dams and small-scale systems like tidal and wave power. Though it has a high energy return, hydroelectric power can disrupt ecosystems by altering natural water flows.

💡Geothermal Energy

Geothermal energy uses heat from within the Earth to generate electricity or heat buildings. In the video, geothermal energy is mentioned as a major renewable energy source in countries like Iceland, offering a high EROI and sustainable long-term potential.

💡Wind Power

Wind power generates energy by converting the kinetic energy of wind into electricity using turbines. The video highlights offshore wind farms as having great potential with high energy returns, making wind one of the most promising renewable energy sources for the future.

💡Hydrogen Fuel Cells

Hydrogen fuel cells generate electricity by combining hydrogen and oxygen, producing only water as a by-product. The video discusses hydrogen as a potential future energy source, though the current EROI is low. Advancements in technology could make hydrogen a more viable option.

💡Sustainability

Sustainability refers to the ability to maintain energy production without depleting resources or causing significant environmental harm. The video stresses that while renewable energy sources are essential, they must also be sustainable, citing examples like deforestation from overusing biomass or ecosystem disruption from hydroelectric power.

Highlights

Fossil fuels are non-renewable and contribute to global warming, prompting the need for renewable energy sources.

Renewable energy sources are not always sustainable, such as wood, which can lead to deforestation if overused.

Biomass energy includes wood and charcoal, but both have environmental downsides like pollution and deforestation.

Hydroelectric power is renewable, but it can disrupt ecosystems by changing the natural flow of rivers.

Biodiesel and ethanol are more recent forms of biomass energy, but their energy return on investment (EROI) is low compared to fossil fuels.

Solar energy offers significant potential, with technologies like passive and active systems, thermal heating, and photovoltaics.

Photovoltaic systems convert sunlight directly into electricity, with an energy return on investment (EROI) of 7:1.

Geothermal energy is used in countries like Iceland, offering a significant return due to its renewable nature and high efficiency.

Wind power, particularly offshore wind turbines, offers a high EROI, with a potential ratio of 18:1.

Hydrogen fuel cells hold future potential, but current technology struggles with low efficiency and a lack of infrastructure.

The main challenge with renewable energy is the inconsistent availability and difficulty in storing and transporting it efficiently.

Energy return over energy invested (EROI) plays a crucial role in determining the viability of energy sources, with coal offering an 80:1 ratio.

The future of energy could involve smart grids that optimize energy production and distribution, improving efficiency.

Ethanol production, particularly from corn, has a low EROI in the U.S., but sugarcane ethanol in Brazil offers a more favorable 8:1 ratio.

Hydroelectric power, while offering high returns, works best at large scales, with smaller projects having lower impact and scalability.

Transcripts

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.