1. Electricity and Hydrogen
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Energy Carriers
Electricity and Hydrogen
Gateway – Energy and the Environment
© 2011 Project Lead The Way, Inc.

2. Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Energy Carriers
Energy carriers move energy in a usable form from one place to another.
Electricity  Most well-known energy carrier
Hydrogen  Not yet widely used, but has great potential for the future

3. Where Does Electricity Come From?
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Where Does Electricity Come From?
Magnets
Electromagnetism is magnetism created by a current of electricity
A magnetic field can move electrons
Batteries
Produce moving electrons through a chemical reaction
If students have already completed the Magic of Electrons™ unit, remind them of the motor and generator that they made in that unit. You might also remind students of the Electromagnet they used in the Automation and Robotics™ unit.
If not, you may want to spend more time on electromagnetism – see the Magic of Electrons™ unit.
Magnetism and electricity are related. Magnets can create electricity and electricity can produce magnetic fields.
Every time a magnetic field changes, an electric field is created. Every time an electric field changes, a magnetic
field is created. Magnetism and electricity are always linked together; you can’t have one without the other.

4. Electricity from Turbines
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Electricity from Turbines
Power plants use huge turbine generators to make electricity
Fuels to spin turbines include
Wind
Burning coal, oil, or natural gas to make steam
Split uranium atoms can heat water into steam
Power of rushing water from a dam

5. Electricity from Batteries
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Electricity from Batteries
A battery has a + terminal and a – terminal.
Electrons collect on the negative terminal.
Connect a load, like a light or motor, with wires to the battery.
A chemical reaction in the battery forces the electrons to flow from the battery into the wire.
off on

6. Is Electricity Exhaustible or Inexhaustible?
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Is Electricity Exhaustible or Inexhaustible?
Neither; electricity is a secondary source of energy.
Electricity is produced by burning coal, oil, or natural gas – all exhaustible resources.
Electricity is also produced with hydro, wind, and solar power – all inexhaustible resources.

7. Transporting Electricity
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Transporting Electricity
Power plant generates electricity
Transformer steps up voltage for transmission
Transmission line carries electricity long distances.
Transformer on pole steps down voltage before entering house
Distribution line carries electricity to house
Neighborhood transformer steps down voltage

8. Transporting Electricity
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Transporting Electricity
Electricity moves through a complex transmission system. Transformers are located in substations near the electric generating plant. In much the same way that a pump builds up the pressure of water in a hose, transformers step up the electricity voltage to levels ranging from 69,000 to 765,000 volts. The voltage levels depend on the distance the electricity must travel and the amount desired. From the transformers, electricity enters the transmission system. Large lines on towers carry electricity in much the same way that long hoses carry water under great pressure. The transmission lines, which consist of heavy cables strung between tall towers, carry power to the point where it is needed. Electricity travels at nearly the speed of light, arriving at a destination at almost the same moment it is produced.
Step-down transformers located in distribution substations reduce the voltage of the electricity to lower levels so it can be carried on smaller cables or distribution lines. Smaller transformers on poles or underground further reduce the voltage so that it can be used by residential customers. Homes and farms require 120 or 240 volt service. Industrial customers using large amounts of power ordinarily require higher service voltages.

9. The Future of Electricity
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
The Future of Electricity
Electricity cannot easily be stored. It must be generated and delivered at the precise moment it is needed.
Electricity travels down whatever paths are made available, but cannot be directed to a certain location.
Electricity can be made from inexhaustible and renewable energy sources.
Engineering researchers are searching for ways to efficiently store electricity and deliver it when and where it is needed.

10. Another Option – Hydrogen
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Another Option – Hydrogen
Hydrogen is the most abundant gas in the universe, but it does not exist naturally on Earth.
How is hydrogen made?
Steam reforming separates hydrogen atoms from carbon atoms in methane (CH4)
Advantage – least expensive
Disadvantage – methane is a fossil fuel, so greenhouse gases are emitted
Electrolysis splits hydrogen from water
Advantage – no emissions
Disadvantage – very expensive
Hydrogen gas is lighter than air and, as a result, it rises in the atmosphere. This is why hydrogen as a gas (H2) is not found by itself on earth. It is found only in compound form with other elements. Hydrogen combined with oxygen is water (H2 O). Hydrogen combined with carbon forms different compounds such as methane (C H4), coal, and petroleum. Hydrogen is also found in all growing things—biomass. It is an abundant element in the earth's crust. Since hydrogen doesn't exist on earth as a gas, we must separate it from other elements. We can separate hydrogen atoms from water, biomass, or natural gas molecules. Hydrogen can be produced at large central facilities or at small plants for local use. Every region of the country (and the world) has some resource that can be used to make hydrogen. Its flexibility is one of its main advantages.

11. Hydrogen Uses of Hydrogen
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Hydrogen
Uses of Hydrogen
Industry  refining metals and processing food
NASA  energy fuel
Hydrogen batteries power electrical systems; the only by-product is pure water, which the crew drinks
Fuel Cells
Emergency power for hospitals
Longer power for laptops and cell phones
Military
Vehicles

12. Why Hydrogen?
Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Hydrogen is everywhere. It is the most abundant element in the universe.
Hydrogen can be made from renewable resources.
Hydrogen fuel cells produce no emissions.
Hydrogen is efficient, emits little pollution, and can be used for transportation, heating, and power generation.
Because of the high cost to build fuel cells, large hydrogen power plants won't be built for a while. Today, there are an estimated 500 hydrogen-fueled vehicles in the U.S., mostly in California. Most of these vehicles are buses and automobiles powered by electric motors. They store hydrogen gas or liquid on board and convert the hydrogen into electricity for the motor using a fuel cell. Only a few of these vehicles burn the hydrogen directly (producing almost no pollution). The present cost of fuel cell vehicles greatly exceeds that of conventional vehicles in large part due to the expense of producing fuel cells.

13. Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Future of Hydrogen
Great potential as an environmentally clean energy fuel
Great potential to reduce our reliance on imported energy sources
BUT . . .
Facilities to make, store, and move hydrogen must be built
Fuel cells must become more affordable
Consumers need technology and education to safely use hydrogen

14. Energy Carriers
PLTW Gateway
Unit 3 – Lesson 3.2 – Solving the Energy Crisis
Image Resources
Microsoft, Inc. (2009). Clip art. Retrieved April 10, 2009, from
National Energy Education Development Project (NEED). (2009). Retrieved April 10, 2009, from
Minnesota Power. (2009). Retrieved April 10, 2009, from