Geothermal and Biomass Energy: Processes and Applications

Geothermal Energy

1. Definition, Components, and Process

Geothermal energy is power derived from the Earth’s internal heat, extracted for direct use as fuel or transformed into electricity.

Components

• Heat source: Extracted from inside the Earth at depths between 100 and 4,500 meters.
• Permeable and porous layer: Capable of retaining water.
• Impermeable rock layer

Process

1. Meltwater penetrates the Earth and accumulates in permeable aquifers.
2. The internal heat source warms the water, forming gases at various pressures that escape the Earth as geysers, volcanic eruptions, or thermal springs.

2. Types of Geothermal Production

• Low and medium energy production: Pressurized water is injected near the heating point and subsequently extracted.
  • Temperature: ~100ºC.
  • Water is used directly or to warm other fluids (heating circuits).
  • Applications: Spas, heating systems, and greenhouses.
• High energy production: Pressurized water is injected near the heating point. The warm water heats a secondary fluid (Freon or ammonia) that evaporates, transporting kinetic energy to a turbine-generator group.
  • Temperature: High-grade heat.
  • Used in geothermal power plants for electricity generation.

Biomass Energy

1. Definition and Process

Biomass is an energy source formed by non-fossil organic material, where the sun drives the development of carbohydrates through photosynthesis. It can be used directly or transformed into other energetic products:

• Physical: Compaction or reduction of volume and drying (e.g., charcoal, firewood).
• Biochemical:
  • Aerobic fermentation (with oxygen): Produces alcohol and ethanol.
  • Anaerobic fermentation (without oxygen): Produces methane.
• Thermochemical:
  • Forest waste direct combustion.
  • Dry distillation: Gas obtention.
  • Gasification (via oxidation or hydrogenation): Hydrocarbon obtention.

2. Steps in Biomass Power Generation

1. Crushing: Cutting fuel into small pieces and separating them by size.
2. Fuel combustion: Heats water in a tank, transporting vapor through pipes.
3. Steam expansion: Water vapor enters the turbine-generator group to produce electricity.
4. Transformer: Raises the voltage for transport through the electrical network.
5. Condenser: Water vapor from the turbine is cooled and returned to the tank.
6. Waste disposal: Purification and filtering of gases before release into the atmosphere.