Green Energy: Fuel Cell? Solar? Wind? Our Future?

Dr. Hayden SoDepartment of Electrical and Electronic

Engineering3 Oct, 2008

What do we have today?

Global Warming

Carbon Dioxide

… and running out of resources…

GeoThermal

Finding Alternative Energy Sources

Clean(Does notpollute)

Renewable(Naturally Replenished)

Wind

Biodiesel

Nuclear

HydrogenFuel Cell

Ethanol

Solar

Fossil

Hydrogen Fuel Cell

Hydrogen flows in Air/Oxygen flows in other side

Catalyst forces H2 to split into electrons and positive ions Polymer Electrolyte

Membrane (PEM) only allows positive ions to

flow through

Negative charges flow externally to

form electric current

H-RACER DEMO

Fuel Cell in Real World

Honda FCX Clarity

AC Transit (near Berkeley)

BMW Hydrogen 7

Getting Hydrogen

HondaHome Energy Station IV

Problems with Hydrogen Fuel Cell Cars

Bulky• Large amount of hydrogen needed for long range

Energy efficiency of producing hydrogen• Not all sources of hydrogen is renewable• May use more energy to generate hydrogen that

overcome its benefit PEM depreciate fast Not work at temp < 0 or > 100 degree C Lack of infrastructure

• No existing infrastructure to deliver hydrogen economically

A Hybrid Solution

Hybrid Technology

Conventional combustion + Electric Engine

Gas: PowerElectric: save gas

Combustion engine turns off automatically when not needed

Electric motor powered by on-board battery

Battery charged during brake/deceleration

Hybrid Vehicles Sale

19901991

19921993

19941995

19961997

19981999

20002001

20022003

20042005

20062007

01,0002,0003,0004,0005,0006,0007,0008,0009,000

10,000

Pessenger Car Sales 1990-2007

(in 1

000

units

)

Hybrid Vehicle Sales

Solar Energy

Convert radiation from the Sun into electricity by photovoltaics and other means.

Pros: always available (during day time), renewable, free Cons: doesn’t work at night, cloudy day, large area Increase in efficiency recent years:

• 17% in 1980s, around 40% in 2007

Helios

Biofuel: Biodiesel and Ethanol

Generate electricity through Biomass• Sugar cane, core, animal

manure, etc… Make biodiesel/ethanol

to use in car Pros: Net carbon

neutral (hopefully) Cons: Food for

electricity? Pest?

Just Yesterday

Honda unveils new version of Insight• The first commercially

available hybrid vehicle

Original Honda Insight, 1999

Summary

We NEED to find alternative Earth-friendly energy sources, NOW

Global warming + high oil price has motivated many innovations in the past 2-3 years

More innovations needed Huge engineering effort Do you best to save the world:

Take care of Planet Earth.View of the Earth as seen by

the Apollo 17