In areas with robust distributed generation (DG) growth, applications to interconnect new solar systems have overwhelmed utility interconnection processes and caused project delays and, in some cases, prohibitive cost increases. To better facilitate interconnection of high penetrations of DG, some utilities are beginning to consider approaches to proactively study distribution circuits in an effort to determine their hosting capacities in advance. Sky discussed a concept paper IREC released this year that discusses proactive planning efforts that are being contemplated or implemented by utilities across the United States.

1. Improving
Interconnec.on:
Integrated
Distribu.on
Planning
Sky
C.
Stanfield
1

2.
What
is
the
Problem?
2

3. Successful
promo.on
of
renewable
resources
increased
na.onwide
interconnec.ons
to
over
90,000
PV
systems
in
2012.
That
number
is
predicted
to
rise
to
150,000
PV
systems
in
2015.
The
number
of
interconnec.on
requests
is
much
higher.
Current
interconnec.on
procedures
are
largely
reac.ve
3

4.
DG
Penetra.on
Compared
to
Es.mated
Hos.ng
Capacity
Es'mated
Hos'ng
Capacity
of
Circuit
Based
on
Customer
Load*
Installed
DG
Capacity
Solar’s
Success
Also
Means
Higher
Penetra.ons
On
U.lity
Distribu.on
Systems
Penetra'on
Level
*
The
two
most
common
es'mates
of
hos'ng
capacity
based
on
customer
load
are
15%
of
peak
load
and
100%
of
minimum
load.
4

5. Over
20%
of
distribu'on
circuits
in
Hawaii
were
over
15%
of
peak
load
in
January
2013.
Pepco
has
closed
a
number
of
its
distribu'on
system
feeders
to
further
DG
development
because
of
high
penetra'ons.
5

6. Some
states
and
u'li'es
are
taking
significant
steps
to
bePer
integrate
high
penetra'ons
of
PV
into
u'lity
distribu'on
systems.
6

7.
A
Possible
Par.al
Solu.on:
Proac.ve,
Integrated
Distribu.on
Planning
7

8. Summary
of
Integrated
Distribu.on
Planning
• IDP
Proac'vely
plans
distribu'on
systems
to
accommodate
DG
before
interconnec'on
screens
are
applied.
• IDP
informs
the
processing
of
subsequent
interconnec.on
requests
by
determining
in
advance
the
level
of
penetra'on
that
can
be
accommodated
without
impacts.
• For
higher
penetra'on
levels,
IDP
gives
a
u.lity
advanced
knowledge
of
the
upgrades
that
may
be
required
to
maintain
safety,
reliability
and
power
quality.
8

9. The
5
Steps
of
IDP
1
Forecast
DG
Growth
on
the
Circuit
2
Establish
the
Hos'ng
Capacity
and
Allowable
Penetra'on
Level
3
Determine
Available
Capacity
on
the
Distribu'on
Circuit
4
Plan
Upgrades
and
Expedite
Interconnec'on
Procedures
Based
on
IDP
5
Publish
the
Results
9

10. 1
Forecast
DG
Growth
on
the
Circuit
U'li'es
can
focus
on
circuits
where
significant
addi'onal
DG
development
is
likely,
i.e.,
establish
a
trigger
point
for
IDP
study
such
as
when
DG
capacity
surpasses
15%
of
peak
load.
A
reasonable
forecast
of
incremental
DG
could
include
the
exis'ng
interconnec'on
queue
plus
a
reasonable
predic'on
of
growth
based
on
market
condi'ons
and
policy
mo'va'ons.
10

11. 2
Establish
the
Hos.ng
Capacity
and
Allowable
Penetra.on
Level
Many
factors
affect
hos.ng
capacity,
including
circuit
characteris'cs
and
the
size,
loca'on
and
type
of
generators.
Need
for
detailed,
accurate
models.
Proac've
circuit
study
can
iden.fy
circuit
characteris.cs
that
may
need
to
be
modified
if
forecasted
levels
of
DG
growth
materialize.
Such
iden'fica'on
will
allow
u'li'es
to
make
an
es.mate
of
hos.ng
capacity,
which
reveals
an
allowable
penetra.on
level,
i.e.,
the
maximum
amount
of
genera'on
of
a
certain
type
and
size
that
can
be
interconnected
in
a
certain
area
with
confidence
that
11
system
impacts
are
unlikely.

12. 3
Determine
Available
Capacity
on
the
Distribu.on
Circuit
Hos'ng
Capacity
is
available
–
and
Capacity
upgrades
are
not
needed
–
when
forecasted
genera.on
is
less
than
infrastructure’s
hos.ng
capacity.
Forecasted
Genera'on
Available
capacity
may
need
to
Exis'ng
be
differen'ated
by
generator
Genera'on
types,
sizes
and
loca'ons.
Available
Capacity
Current
Penetra'on
Level
12

13. 4
Plan
Upgrades
and
Expedite
Interconnec.on
Procedures
Based
on
IDP
Forecasted
Genera'on
When
forecasted
genera.on
exceeds
infrastructure’s
hos.ng
Exis'ng
capacity,
the
u'lity
can
Genera'on
iden'fy
the
technical
factors
limi'ng
DG
development
and
determine
whether
a
minor
or
major
upgrade
is
needed.
Poten'al
Infrastructure
Investments
Hos'ng
Capacity
Current
Penetra'on
Level
13

14. 4
Plan
Upgrades
and
Expedite
Interconnec.on
Procedures
Based
on
IDP
Iden'fying
technical
factors
limi'ng
DG
expansion
can
be
used
two
ways:
1. On
an
aggregate
level,
it
can
give
the
u'lity
the
opportunity
to
iden.fy
and
priori.ze
the
possible
upgrades
to
distribu.on
infrastructure
that
would
be
required
to
accommodate
an'cipated
DG
growth.
2. It
can
be
used
on
a
project-­‐by-­‐project
basis
to
inform
the
interconnec.on
screens
and
procedures
that
are
applied
to
each
facility
individually.
14

15. 5
Publish
the
Results
Ideally,
a
u'lity
will
publish:
• Es'mated
hos'ng
capacity
and
allowable
penetra'on
levels
• The
loca'on
and
'ming
of
any
planned
upgrades
15

16. THANKS to our generous sponsors for the
2013 3iForum and 3iAwards

17. For
more,
see
the
full
paper:
Integrated
Distribu'on
Planning:
A
Proac've
Approach
for
Accommoda'ng
High
Penetra'ons
of
Distributed
Genera'on
Resources,
by
Tim
Lindl
and
Kevin
Fox,
IREC;
Abraham
Ellis
and
Robert
Broderick,
Sandia
Na'onal
Lab
Thanks
to
Tim
Lindl
for
the
generous
use
of
his
presenta.on
slides
Sky Stanfield
Keyes, Fox & Wiedman LLP
(510) 314-8204
sstanfield@kfwlaw.com
17