Video 20: Renewable Energy (APES Unit 6 - Energy Resources and Consumption)

Summary

This video discusses various renewable energy sources, highlighting their benefits and challenges. Biomass, hydroelectric, wind, solar, geothermal, and hydrogen fuel cell energy are explored, along with their environmental impacts. While renewable energies are crucial for reducing reliance on fossil fuels, they come with trade-offs such as deforestation, disruption of ecosystems, and wildlife impact. The video emphasizes the importance of transitioning to renewable infrastructure to combat fossil fuel depletion, despite the higher costs and environmental issues associated with some renewable sources.

Takeaways

• 😀 Renewable energy sources are replenishable and reusable, such as wood used as a biomass fuel in developing countries.
• 😀 Biomass fuels, like wood and charcoal, are low-cost but produce harmful pollutants like carbon monoxide and particulate matter.
• 😀 Ethanol, another biomass fuel, is carbon neutral but has a low energy return on energy investment.
• 😀 Hydroelectric power, the most common renewable energy source after biomass, can be generated through dams or tidal energy systems.
• 😀 Dams can disrupt sediment flow, damage ecosystems, and reduce water availability downstream, affecting both humans and wildlife.
• 😀 Fish migration, especially for species like salmon, is affected by dams, though fish ladders can help mitigate the impact.
• 😀 Wind power is a clean energy source, but wind turbines have issues like bird fatalities and challenges with recycling turbine materials.
• 😀 Solar energy harnesses sunlight through photovoltaic cells, though solar farms can impact desert ecosystems and species like the desert tortoise.
• 😀 Solar towers use mirrors to focus sunlight, but they can be harmful to birds due to the intense heat generated.
• 😀 Geothermal energy, used in regions like Iceland, is a clean energy source but can be expensive and cause hydrogen sulfide leaks in certain conditions.
• 😀 Hydrogen fuel cells produce electricity with only water as a byproduct, but the production of hydrogen still has environmental impacts and is costly.

Q & A

What is biomass fuel, and how is it commonly used?

Biomass fuel is derived from biological sources, such as wood, which can be used to produce energy. It is commonly used in developing countries for cooking, often in the form of firewood and charcoal. Additionally, briquettes and lump charcoal, which are types of biomass fuel, are used for barbecuing.

Why is biomass considered a renewable energy source, and what are its drawbacks?

Biomass is considered renewable because the fuel can be replenished at or near the rate of consumption. However, its drawbacks include the production of carbon monoxide and particulate matter, which can harm respiratory health, especially indoors. Additionally, overharvesting trees for biomass fuel can lead to deforestation.

How does ethanol function as a renewable energy source?

Ethanol, commonly added to gasoline, is a renewable energy source because it is carbon neutral. The carbon released when burning ethanol was originally absorbed by plants during their growth, primarily corn. However, ethanol has a low energy return on energy investment, meaning it takes a lot of energy to produce, and the returns are relatively low.

What are the main environmental concerns associated with hydroelectric power?

Hydroelectric power can disrupt ecosystems in several ways. Dams prevent sediment from flowing downstream, leading to coastal erosion and disrupting river food webs. Additionally, the reduced water flow downstream can harm both ecosystems and human populations. Dams also impact fish populations, especially migratory species like salmon, though fish ladders have been implemented to help mitigate these effects.

What is the principle behind tidal power, and what are its environmental impacts?

Tidal power generates electricity by harnessing the rise and fall of sea levels caused by gravitational forces from the moon and sun. This moving water spins turbines to generate electricity. However, the construction of tidal facilities can disrupt coastal ecosystems, which are home to 90% of marine species.

How does wind power work, and what are its environmental impacts?

Wind power utilizes the kinetic energy of moving air to spin turbines, which then generate electricity. While it is a renewable and clean source of energy, wind power can have negative environmental impacts, such as the killing of migratory birds and bats, as well as the need for non-recyclable materials to construct turbines.

What are the challenges associated with solar power?

Solar power, through photovoltaic cells, uses sunlight to generate electricity. However, solar farms require a lot of space, and placing them in deserts can reduce the range of species like the desert tortoise. The use of solar towers, which focus sunlight to create steam, can also lead to bird fatalities due to intense heat.

How does geothermal energy work, and what are the issues associated with it?

Geothermal energy uses heat from the Earth's interior to generate steam, which spins turbines to produce electricity. While it is a clean source of energy, geothermal energy is expensive to access and is only available in areas with significant geological activity, such as Iceland and parts of the United States. Additionally, it can release toxic hydrogen sulfide gas into the atmosphere.

What is the process behind hydrogen fuel cells, and how do they generate electricity?

Hydrogen fuel cells generate electricity by combining hydrogen and oxygen. Hydrogen is split into protons and electrons, with the electrons creating an electric current. On the oxygen side, the electrons and protons combine with oxygen to form water, which is the only waste product. While hydrogen fuel cells produce no carbon emissions, their production is costly and hydrogen itself can have environmental impacts.

What is the main advantage of renewable energy sources over fossil fuels?

The main advantage of renewable energy sources over fossil fuels is their lower environmental impact. While renewable energy sources have their own environmental issues, such as land use or production costs, they do not release carbon emissions like fossil fuels, which contribute to climate change. Renewables are also sustainable, unlike fossil fuels, which are finite.