BIOGAS

Pros: 

Biogas is a prosperous energy source. It mainly comprises methane, which produces energy, burning up to 55 MJ (megajoules ) per kg. It is made by anaerobic bacteria, which acts upon organic sludge ( made of animal feces, dead flora, fauna, and leftover food), making biogas excellent for using leftover organic matter that would otherwise be wasted and pollute the surrounding environment. 

Cons: 

• it takes an extended amount of time to form
• methane is not a good source of energy in every case
• methane is a highly flammable gas that can be a fire hazard
• biogas also comprises 20-25% co2
• less suitable for dense metropolitan areas

GEOTHERMAL

Pros:

Geothermal energy derives from the very core and mantle of the earth. It heats water, making it useful for heating homes, bathing, and, most importantly, generating electricity.

Cons: 

• extracting energy from it is inefficient
• it is location-specific
• it is unpredictable the source of heat may go dormant without notice
• expensive to set up extraction plants
• harmful gases are often emitted

HYDROGEN

Pros: 

Hydrogen can be easily manufactured by electrolysis, which converts water into oxygen and hydrogen. Hydrogen is a highly energy-dense chemical and produces about 120MJ (megajoules) per kg. Upon burning, it makes water, which has various uses. Oxygen can be used for rocket fuel, hospital supplies, and hydrogen for creating energy. 

Cons:

• Hydrogen is a highly flammable gas that can be a fire hazard
• It is expensive and hard to store and transport hydrogen
• It is costly to produce
• It is dangerous to manufacture