Fossil & bio fuels

Define ‘fossil fuels’ and provide examples.

Natural energy sources formed from remains of acient plants and animals that lived millions of years ago

How are they formed: buried under layers of sediment subjected to intense heat and pressure

Fossil fuels are rich in hydrocarbons = highly efficient sources of energy when burned

e.g

1. Coal: solid fossil fuel that forms from the remains of ancient plant material → uses: electricity generation and steel production

2. Oil: Petroleum, a liquid fossil fuel formed from the remains of marine microorganisms →, refined into various products like gasoline, diesel and jet fuel

3. Natural gas: is a gaseous fossil fuel composed of methne →Uses: heating, electricity generation and fuel for vehicles

Crude oil refining steps:

1. separation: crude oil is heated in a furnace then sent to distillation tower

   • Lighter fractions like gasoline and liquefied refinery gases rise to the top while heavier fractions like diesel and heavy oils settle at the bottom

2. Conversion breaks hydrocarbons into smaller ones

   • Heavier fractions are converted into valuable products through process like cracking breaks down large hydrocarbons into smaller ones

3. Treatment: Treating the fractions removing impurities (sulfur, nitrogen and metals) ensures products meet quality standards and environmental regulations

Advantages of Fossil fuels

• Reliability

• High energy: large amounts of energy per unit of volume

• Economic benefits: creates numerous jobs and contributes to economy

• Established infrastructure: technology and infrastructure is widespread

• Affordability - cheaper than alternative energy sources

Disadvantages of fossil fuels

Enviromental - releases green house gases contributing to air pollution

Finite resource - Non renewable and eventually deplete

Health risk air pollution from fossil fuel combustion can cause respiratory and cardiovascular diseases

Elecolgical damage: mining and drilling cause significant environment degradtion and habitat destruction

Define ‘biofuels’ and provide examples.

Biofuels are renewable energy sources derived from organic materials such as plants and animal waste

• can be produced quickly through

Examples:

Bioethanol - alcohol based biofuel typically made from fermenting sugars found in crops like corn, sugarcane, and wheat

• Ethanol is blended with gasoline to create E10 (10% ethanol, 90% gasoline) or higher blends like E85 (85 ethanol, 15% gasoline)

Biodisel produced through transesterification of vegetable oils anima fats or recycled cooking oil

• Blended with petroleum diesel in various proportions such as B20 (20% biodiesel, 80% petroleum diesel)

Advantages of biofuels

Renewable - made from renewable resources e.g plants and animals wastes which can be replenshed over short period

Reduced greenhouse gas emissions

Energy security biofuels can be produced locally reducing dependence

Biodegradeable Generally less toxic and more biodegradeable

Economic benefits - create jobs in agriculture, manufacturing and distribution, boosting local economies

Disadvantages

Land use change large scale biofuel production can lead to deforestation and conversion of natural habitats into agricultural

Food production competition - growing biofuel crops compete with food crops for land and resources → potentially driving up food prices leading to food shortages

Water consumption - requires large amounts of water which ca strain local water resources (specially in arid regions)

Economic impacts - production ad processing can be costly

Energy balance energy required to produce biofuels

Compare fossil fuels and biofuels in terms of energy output and suitability for purpose.