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What you should know by the end of this lesson:
What you should know by the end of this lesson:
What are the sources of Hydrogen
How is energy produced from these sources
Hydrogen Energy
Hydrogen Energy
The hydrogen economy is a system of delivering energy using hydrogen. The term was first used by John Bockris, a Nobel winning scientist and professor of electrochemistry, during a presentation in 1970 at General Motors. The hydrogen economy is based on the idea of using hydrogen gas to replace fossil fuels as a source of energy for heating and powering vehicles. Hydrogen is attractive because whether it is burned to produce heat or reacted with oxygen in a fuel cell to produce electricity, the only by-product is water.
The video Hydrogen 101 contains pretty much everything you need to know for this section.
Sources of Hydrogen
Sources of Hydrogen
Hydrogen is not found in its purest form on Earth and it is typically locked up in other compounds, including hydrocarbons and water (H2O). To reduce these compounds back into simpler components, which includes gaseous hydrogen, takes a lot of energy. At present a number of strategies can be used to produce hydrogen:
Digital Workbook Task and Paper Jotter Task:
Take a quad note in your jotter of the methods of producing hydrogen (see attached)
Make sure you have the name of each process
Give a brief explanation of how the process works to produce hydrogen
Steam Reforming
Process:
From natural gas (methane). This is the most common method of producing hydrogen and involves passing steam at high pressure and high temperatures (between 700 and 1,100°C) over a catalyst such as platinum or nickel. This reaction also produces carbon monoxide, which in turn can be reacted with more steam to produce more hydrogen gas.
Pros/Cons:
This process can be up to 80% efficient and greenhouse gas emissions are lower than in a typical combustion engine. However, large amounts of energy are required and the platinum catalysts are very expensive.
Coal Gasification
Process:
This involves pulverising coal and heating at very high temperatures (up to 1,800°C) with oxygen, producing syngas (a mixture of hydrogen gas, carbon monoxide and carbon dioxide). This is mixed with steam to help remove the carbon monoxide and the carbon dioxide can then be removed leaving the hydrogen gas for use as a fuel.
Pros/Cons:
Similar to steam reforming this requires large energy inputs and it also produces CO2 which needs to be sequestered (stored), although emissions are lower than a traditional thermal power plant. However, coal, although a fossil fuel, is an abundant energy source.
Electrolysis
Process:
This involves directing an electrical current
through an electrolyte, usually water or an alkali
solution which produces both hydrogen and
oxygen.
Pros/Cons:
This requires a large amount of
energy although such technology could be
integrated within a wind farm or hydro-electric
power station.
Pyrolysis
Process:
Organic matter is heated in the absence of
oxygen, which breaks down the molecules this
releases hydrogen gas and carbon monoxide.
Pros/Cons:
This is much easier to do at a smaller scale, we
do the first part of the process while cooking. On a
large scale, it produces a lot of unwanted
products during production. It is not viable purely
for the purposed of generating hydrogen.
Producing Hydrogen Power
Unlike traditional fossil fuels which require a combustion process to work, there is no burning of fuel in a hydrogen fuel cell.
Digital Workbook Task and Paper Jotter Task:
Create your own copy of Diagram 1: Hydrogen Fuel Cell
Copy out the explanation of what is going on inside the fuel cell to generate electricity.
Diagram 1: Hydrogen Fuel Cell
What is going on inside:
A hydrogen fuel cell is an electrochemical device that combines hydrogen and oxygen to produce electricity, with water and heat as its by-products. In its simplest form, a single fuel cell consists of two electrodes, an anode (negatively charged) and a cathode (positively charged), with an electrolyte between them. The electrical current powers the vehicle.
Fuel cells are similar to batteries (which power electric cars) in that both convert the energy produced by a chemical reaction into usable electricity. However as long as hydrogen is supplied into the fuel cell, it will never lose its charge.
Lesson Complete
Lesson Complete
Now return to your Teams assignment and complete the quiz to test how well you have understood this lesson
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