FIBEROPTICS BY JIM HAYES
Alternative-energy sources vary
from a few kilowatts from residential solar-power systems to megawatts
(MW) from commercial solar stations
and wind farms. Alternative energy
contributions are not trivial. Parts of
the Midwest and Southwest get up to
20 percent of their power from wind.
California is home to the largest geothermal, wind, solar thermal and solar
photovoltaic (PV) power plants in the
world, getting more than 25 percent of
its electrical power from alternative-energy sources. However, such diverse
energy sources create new network
Utilities began using fiber optics for
managing their grid as long as 30 years
ago. Early systems used sensors (some
made with fiber optics) to measure grid
current and voltage, control distribution relays and provide the data needed
to make the grid more efficient. Newer
fiber systems expand the monitoring
and control, some right to the customer’s meter, along with offering new
services such as broadband internet
over fiber to the home.
Alternative energy refers to solar
and wind primarily, although there also
are some geothermal systems. Solar
and wind create a problem for utilities
because their outputs are not easily
dependable. PV systems create electricity when the sun shines; wind farms
create electricity when the wind blows.
Even the amounts of electricity created
vary, depending on to how much the sun
shines, how much the wind blows and
how efficiently the systems are managed.
To maximize efficiency, solar-power
systems often follow the sun; PV panels
move as the sun crosses the sky. Geo-
thermal systems such as the 480-MW
facility at Ivanpah, Calif., have mirrors
that follow the sun to keep it focused
on the generation towers. Ivanpah has
360,000 of these mirrors connected to
13,000 fiber optic cables installed by
workers from IBEW Local No. 357 of
The solar-thermal (steam) generation
systems such as Ivanpah use the sun to
create steam to run turbines, so some
storage of superheated water enables the
period of electrical output to be extended
beyond the peak solar hours.
Wind-power systems are perhaps even
more complicated to manage. They need
to be aimed into the wind, and blades must
be set to maximize output or feathered
when power is not needed. In addition,
the output must be synchronized with the
grid. Basically, every tower is connected
using fiber to provide the controls needed
to efficiently manage its output.
The goal has been to even out the
power produced by solar and wind systems using storage methods that are
reliable and cost-effective. There is certainly no lack of ideas.
The best solution
The reality is that storing energy in batteries seems the best solution. Battery
research and development has been a
big part of the development of electric
vehicles, and pioneers in that market,
such as Tesla, are also focusing on battery storage for solar and wind systems
(see page 38).
Early experiments in battery storage
were problematic. Lead-acid batteries
had short lifetimes when subjected to
the high demands of grid storage. Several early projects ended with fires.
However, the engineering being done
on lithium-ion batteries used in many
consumer electronics devices and electric and hybrid vehicles seem capable of
withstanding the demands of grid storage when properly managed.
In Southern California, several large
battery facilities are coming online right
now. San Diego Gas & Electric is building the largest power-storage facility
in the world in Escondido, Calif. This
facility will have 19,000 battery modules
spread out over 24 trailers with enough
electrical storage to power 20,000
homes for more than four hours.
It’s complicated to manage all these
new storage systems. With more sources
of power—some with timing issues—grid
management becomes difficult. Utilities
are expanding fiber optic communications networks, leasing dark fibers and
using wireless communications of all
types to create complex networks capable of providing the monitoring and
control of their grids.
The focus of grid management is
getting more localized. For better management and higher reliability, utilities
are now looking to microgrids, some not
bigger than a few square blocks, that
can be managed with the complex fiber
optic networks they operate.
A Complex Problem
Fiber optics solve alternative-energy challenges
AS I DISCUSSED LAST MONTH, one of the most complicated problems electrical
utilities face is integrating alternative-energy sources into the traditional grid. In addition to the traditional large electrical generation sources—fossil fuels, hydroelectric
and nuclear—utilities must now deal with large numbers of smaller sources of power.
HAYES is a VDV writer and educator and the president of the Fiber Optic Association. Find
JimHayes.com. S H