ENERGY-AGRO-FOOD INTENSIVE SCHOOL

ENERGY_AGRO-FOOD Energy_Agro-food Synergies in

Africa: New Models for African Universities

Bioenergy Production and Management

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Eng. Prof. Ayub N. Gitau University of Nairobi

Renewable Energy – comes from resources which are naturally replenished

Examples : Solar (PV and Thermal) energy, Wind energy, Hydro power, Geothermal, Tidal & Biogas.

Renewable Energy Technologies - which helps in harnessing energy from sources which are capable of replenishing themselves.

Solar photovoltaic panel

There are three primary technologies to harness solar energy;

Solar photovoltaic (PV) panels - directly convert light to electricity

Uses heat from the sun (thermal energy) to drive utility-scale, electric turbines

Collect thermal energy to provide hot water and air conditioning

Wind turbines are used to harness wind energy

Heat energy stored in the ground

Bioenergy – Renewable energy derived from biomass either for heating, power generation or transport purposes

Biomass - Biological material derived from living, or recently living organisms. It most often refers to plants or plant-based materials.

Biomass sources include; Short rotation forestry Energy crops e.g. oil crops, rape seed,

sunflower Wood wastes i.e. forest residues, wood

processing waste, construction residues Agricultural residues & waste i.e. straw &

animal manure Sewage sludge Industrial residues e.g. from food

industry e.g. sugar industry

Types of bioenergy include; Biogas Liquid biofuels Wood energy

Grouped into two major categories; i. Thermochemical & ii. Biochemical (aerobic).

Commonly used -Biochemical process (fermentation)

Three main types of technologies; Floating drum, Fixed dome & Tubular reactors

Tubular Reactor

Floating Drum

Renewable Energy Technology

Merits Demerits

Solar Energy • Clean and renewable energy source

• Once installed, can be produced free of charge

• Low maintenance costs • No pollution

• High investment cost • Weather dependent • Uses a lot of space

Wind Energy • Clean • Sustainable • Cost effective • Great resource to generate energy

in remote locations

• Turbines may cause noise and aesthetic pollution

• Possibilities of accidents from turbine blades

• Unreliable • High investment cost

Hydropower • Clean fuel source • Available as needed

• Impacts on water quality & flow

• Can be impacted by drought • Limits movement of aquatic

life

Renewable Energy Technology

Merits Demerits

Geothermal Energy • Non-polluting & environmental friendly

• No wastage or generation of by-products

• Can be used direct • Low maintenance costs • Not dependent on weather

• Only few sites have the potential of Geothermal Energy

• Danger of volcano eruption • High investment cost • May release some harmful &

poisonous gas Bioenergy • Emits little or no net greenhouse gas

emissions • Useful way of managing waste

disposal • Has well-established technology

that’s able to deliver reliable energy • Is plentiful wherever there are

agricultural crops and forestry • can help to stabilize soils, improve

soil fertility and reduce erosion • Can generate both heat and electricity

in a cogeneration power plant

• More expensive energy

Thank you!

Asante.

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