7.2A Energy sources, global energy consumption and energy choices Notes

Renewable and Non-Renewable Energy Sources

1. Energy is the backbone of modern society, powering everything from homes to industries.
2. But where does this energy come from?

It can be classified into two main categories: renewable and non-renewable sources.

Renewable Energy Sources

Renewable energy comes from natural processes that are continuously replenished.

These sources are often more sustainable and environmentally friendly.

1. Solar Energy

1. Source: The Sun.
2. How it works: Solar panels (photovoltaic cells) convert sunlight into electricity.
3. Advantages:
   1. Infinite supply: The Sun provides more energy in an hour than the world uses in a year.
   2. Low emissions: No greenhouse gases during operation.
4. Disadvantages:
   1. Intermittent: Depends on sunlight availability.
   2. High initial cost: Panels and installation can be expensive.

2. Wind Energy

1. Source: Wind.
2. How it works: Wind turbines convert kinetic energy from wind into electricity.
3. Advantages:
   1. Clean energy: No emissions during operation.
   2. Scalable: Can be used in small or large installations.
4. Disadvantages:
   1. Intermittent: Requires consistent wind.
   2. Environmental impact: Noise pollution and potential harm to wildlife.

3. Hydropower

1. Source: Flowing water.
2. How it works: Dams or rivers drive turbines to generate electricity.
3. Advantages:
   1. Reliable: Provides a steady energy supply.
   2. Multipurpose: Dams can also support irrigation and flood control.
4. Disadvantages:
   1. Ecological impact: Alters river ecosystems and displaces communities.
   2. High cost: Expensive to build and maintain.

4. Geothermal Energy

1. Source: Heat from the Earth's core.
2. How it works: Steam from underground reservoirs powers turbines.
3. Advantages:
   1. Consistent: Not weather-dependent.
   2. Low emissions: Minimal greenhouse gases.
4. Disadvantages:
   1. Location-specific: Requires volcanic or tectonic activity.
   2. High setup cost: Drilling and infrastructure are expensive.

5. Biomass

1. Source: Organic materials (e.g., wood, crop waste).
2. How it works: Burned directly or converted into biofuels.
3. Advantages:
   1. Renewable: If managed sustainably.
   2. Versatile: Can produce heat, electricity, or fuel.
4. Disadvantages:
   1. Emissions: Releases \$CO_2\$ and other pollutants.
   2. Land use: Competes with food production.

6. Tidal and Wave Energy

1. Source: Ocean movements.
2. How it works: Turbines or generators capture energy from tides or waves.
3. Advantages:
   1. Predictable: Tides are regular and reliable.
   2. High energy potential: Oceans cover 70% of Earth's surface.
4. Disadvantages:
   1. High cost: Expensive to develop and maintain.
   2. Environmental impact: May disrupt marine ecosystems.

Non-Renewable Energy Sources

Non-renewable energy comes from resources that are finite and will eventually deplete.

These sources have powered industrial growth but come with significant environmental costs.

1. Fossil Fuels

1. Types: Coal, oil, and natural gas.
2. How they work: Burned to produce heat, which generates electricity or powers engines.
3. Advantages:
   1. High energy density: Efficient for large-scale energy needs.
   2. Established infrastructure: Widely available and used globally.
4. Disadvantages:
   1. Finite supply: Will eventually run out.
   2. Environmental impact: Major source of greenhouse gases and pollution.

2. Nuclear Energy

1. Source: Uranium or plutonium.
2. How it works: Nuclear fission releases heat, which generates steam to drive turbines.
3. Advantages:
   1. Low emissions: Minimal greenhouse gases during operation.
   2. High energy output: Small amounts of fuel produce large amounts of energy.
4. Disadvantages:
   1. Radioactive waste: Long-term storage is a major challenge.
   2. Safety risks: Accidents like Chernobyl and Fukushima highlight potential dangers.

Why Does This Matter?

1. Environmental Impact: Fossil fuels are the largest contributors to climate change, while renewables offer cleaner alternatives.
2. Energy Security: Countries with diverse energy sources are less vulnerable to supply disruptions.
3. Sustainability: Transitioning to renewables is essential for meeting global energy needs without depleting resources.

Energy Supply and Demand: Addressing the Growing Challenge

1. Global energy consumption is increasing due to rising populations and higher per capita demand.
2. While fossil fuels still dominate global energy supply, the use of renewable energy sources is steadily growing.
3. However, industries like steel, concrete, and synthetic fertilizers still heavily rely on fossil fuels, meaning dependence on them will likely persist for some time.

Changes in Energy Production and Consumption:

Global Changes:

1. Shift to Renewables:
   1. The global push for cleaner energy sources, such as solar, wind, and hydropower, has led to significant investments in renewable energy.
   2. Countries like Germany and China are leading the transition, with increased renewable capacity.
2. Energy Storage Innovations:
   1. Advancements in energy storage, such as battery technologies, are improving the reliability of renewable energy sources, enabling better integration into the grid.