Biomasses and biofuels

Photosynthesis

Photosynthesis

Biomass yields

Biomass burning: efficiency and available power

e.g. 2kg municipal waste/person/day

Sugarcane

Ethanol

Ethanol

Biodiesel

Biomass burning: efficiency and available power

Output power = yield × energy density × mass density × burning efficiency Overall biomass efficiency = Power/Insolation Area = Needed power / Output power

Ex: -  wood in Sardinia: yield 10 m3(7 ton)/ha/year, energy density 5 kWh/kg (dry) - sorgo: yield 50ton/ha/year, energy density 5 kWh/kg (dry)

Biomasse - sommario

Energy density 5KWh / kg

Power density = Yield × Energy density = 0.3W /m2

Yield 10− 50 tonha× y

(dry)

Benzina = 10kWh/l (12kWh/kg)

Batterie?

Acqua? (diga di 100m)

= 0.25 – 0.4kWh/kg

= 0.00028kWh/kg

Densità energetica

Idrogeno? = 39kWh/kg