Electricity tends to flow south in North America
Dec. 12, 2011 - eia.gov
|Source: U.S. Energy Information Administration, based on Federal Energy Regulatory Commission (FERC) Form 714 data.
The map above shows that electricity tends to flow
south in North America. The numbers on the map reflect
average net power flows—metered hourly—between
electric systems aggregated by regions for the year
2010. Most electric power demand is served by local
generators. Net interregional trade accounted for
less than 1% of delivered power in 2010. However,
excess, low-cost power—primarily from hydroelectric
generators in the Pacific Northwest, Manitoba, and
Quebec—supplied higher-cost markets to the
In the map above, the numbers next to the arrows
represent annual net flows of electricity between
regions measured in millions of megawatt-hours. FERC's
714 collects from all U.S. balancing
authorities (electric systems) the annual sum of actual hourly
interchange (flows) received from and delivered to
other directly-connected balancing authorities. The
numbers shown in the figure represent the net balance
of flows between pairs of regions created from balancing
authority level data.
Electricity tends to flow south in North America.
Electricity flows south from the Northwest to California
and the Southwest. It flows south from Manitoba to
the Midwest and from there to the Central region
Power Pool) and the Tennessee Valley
Authority (TVA). Electricity also flows south from
TVA to the Southern region (Southern Company) and
from the Southern region into Florida. It flows south
from eastern Canada into New England, New York, and
There is also a circular flow pattern from the Midwest
region through the Central, Gulf, TVA, Southern and
Carolinas regions into the Mid-Atlantic region (PJM
Interconnection) and on to New York (New York ISO).
Surprisingly, the data show that, on net, power flows
from the Mid-Atlantic region to the Midwest. The
flow of low-cost, coal-fired power from the Midwest
to the east during on-peak hours may be offset by
the flow of nuclear generation from Exelon's Commonwealth
Edison service area in and around Chicago (part of
the Mid-Atlantic region) to the surrounding Midwest
region during off-peak hours.
California is the largest net importer of electricity,
consuming power produced in the Northwest and Southwest.
These two regions provide about 25% of California's
While the map shows annual data, some flows are distinctly
seasonal. For instance, the hydro capacity in the
Pacific Northwest generates large amounts of electricity
in excess of the region's need (and, therefore, large
transfers to other regions) when river flows are
typically highest in spring and early summer.
The map does not show sometimes significant intraregional
flows, with one exception. The far western part (in
northern Illinois) of the Mid-Atlantic region (PJM
Interconnection) is separated from the rest of PJM.
Substantial, low-cost electricity generated with
nuclear and coal-fired capacity from the Commonwealth
Edison service area flows over transmission lines
through the Midwest region (Midwest ISO) and back
into the eastern portion of PJM (see red arrow).
This intraregional flow amounted to about 100 million
MWhs in 2010, or 14% of delivered power in PJM.