Secondary Fuels Flashcards
Secondary fuel
An energy source that is produced by the conversion of a primary fuel.
Most common secondary fuel
electricity
Why produce a secondary energy?
May be applicable to more uses, may be easier to store and transport, useful in peak shaving
Electricity
a secondary energy source produced by converting a primary energy source such as a fossil fuel, renewable source or nuclear.
Other secondary fuels
Hydrogen, refuse derived fuel, charcoal
Electricity is a secondary fuel and can be generated from
combustion of fossil fuels, nuclear fission, PV solar cells, wind turbines, fuel cells
Generation of electricity from hydrogen fuel cells
Hydrogen and oxygen is used in a fuel cell, Hydrogen reacts with oxygen to produce water and electricity. Hydrogen ions pass through the electrolyte membrane, free electrons follow a pathway and produce an electric current.
Advantages of electricity
no pollution during use, can be easily converted to other energy forms (light, heat sound etc), transportation is easy via cables
Disadvantages of electricity
Converting primary fuels to secondary fuels is not efficient, storing electricity is difficult, production of some electricity is highly polluting e.g. combustion of fossil fuels.
Transport of electricity
use of cables and a larger interconnected national grid system
Production of hydrogen
hydrogen can be produced from the electrolysis of water often because there is a surplus of electricity generated and electricity is hard to store
Using hydrogen
Hydrogen gas can be used in the natural gas network, used to produce electricity in hydrogen fuel cells, to produce electricity in power stations, used as a vehicle fuel
Four ways of storing hydrogen
compressed gas - reduced the gas volume up to 700 times, liquified under high pressure and low temperatures, as metal hydrides, as ammonia (NH3)
The hydrogen economy
a term for the roles hydrogen can play alongside low-carbon electricity to reduce emissions of greenhouse gases.
How can hydrogen solve the intermittency of renewables?
at times of surplus renewable energy production, for example when it is very windy at night time or on very sunny days, excess electricity is used for the electrolysis of water to produce hydrogen. Hydrogen can be stored and used later for combustion or used in hydrogen fuel cells. This solves the problem of energy shortages during times of intermittence which is characteristic of many renewable energy sources.
