Lecture Notes: Fossil Fuels and Biofuels

Fossil Fuels

Types: Coal, petroleum/oil, and natural gas.
Characteristics: Non-renewable energy sources; deplete faster than they form (millions of years to form).

Source of heat energy: Used for transport, electricity production, and heating.
Feedstock for chemical industry: Used in metal production (as reducing agents like coke in iron and steel production), production of plastics, lubricants, waxes, and asphalt.
Natural Gas: Utilized in the Haber process for ammonia production (methane is a key component).

Advantages:
- Abundant and easily extracted/distributed.
- Existing infrastructure for energy production and feedstock use.
- High energy density.
Disadvantages:
- Non-renewable with depleting reserves.
- Combustion releases undesirable products (e.g., CO2, soot, carbon monoxide).
- Contributes to nitrogen/sulfur oxides, leading to smog and acid rain.

Produced from present-day biological processes (biomass), including plant material and animal waste.
Types: Bioethanol and biodiesel.

Bioethanol:
- Produced via fermentation of monosaccharides like glucose.
- Enzymes from yeast facilitate conversion in anaerobic conditions.
- Hydrolysis of complex carbohydrates yields glucose for fermentation.
Biodiesel:
- Derived from natural triglycerides (plant/vegetable oils).
- Produced through transesterification with methanol and a catalyst (e.g., sodium hydroxide).
- Yields biodiesel and byproduct glycerol (used in food/cosmetic industries).

Advantages:
- Less contribution to global warming due to CO2 absorption by crops.
- Renewable and carbon-neutral (offset CO2 emissions during combustion).
Disadvantages:
- Energy-intensive production reliant on fossil fuels.
- Utilization of land for fuel instead of food (food vs. fuel debate).
- Limited infrastructure for production and use.
- Still releases CO2 and nitrogen oxides.

Renewable Energy:
- No direct greenhouse gas emissions from energy production.
- Production and distribution may still rely on fossil fuels.