Download Earth’s Changing Environment Lecture 1

Earth’s Changing Environment
Lecture 16
On and Off the Electric Grid
Electric Power Grid
On the Grid - AC Power
Electric Power Plants produce AC –
Alternating Current.
Batteries produce DC – Direct Current
Transmission
Transformers step up
the generator voltage
from 1 kV range to
100 kV range
Why?
Power Substation
Transformers step down to kV range for
neighborhood distribution
House Power
Transformers on
power poles drop
the voltage down to
240 VAC for home
use.
Watt-Hour Meter
Watt-hour meter
measures and records
energy use.
Most house
appliances use AC.
Some household
devices use 240 v
and some use 120 v.
Off the Grid - Distributed Power
DC
Some distributed or off-grid
systems use generators that
produce DC power.
High voltages AC is not
needed because of short
transmission distance
Inverters can generate AC for
AC loads.
Storage or Back-up
Off-Grid Power Systems need
back-up or storage.
Back-up can be gasolinepowered generators or other
forms of energy.
Storage can be battery,
thermal, or mechanical
Battery Storage
Batteries are usually 6.0 volt or
12 volt DC.
Battery storage capacity
expressed in Amp-Hour
values.
A 100 Amp-Hour battery could
deliver 5 Amps for 20 hours.