Download Wind Generator Basics - Cape Power Systems Consulting

Wind Generator Basics
Charlie Salamone
Cape Power Systems Consulting
Presented at the Northeast Sustainable Energy Association’s Wind
Project Development Strategies for New England Workshop
3/7/06
Introduction
• Physical interconnection guide
– Typical wind unit and utility characteristics
• Informal utility meeting
– Information to ask about
• Do your homework
– Energy Balance Analysis
Physical Interconnection Guide
Typical transmission voltages
range from 115 kV to 345 kV
Typical distribution
voltages range from
69 kV to 4 kV
Typical supply voltages
range from
480 v to 120 v
Large plants must
interconnect to the
transmission grid
(generally 20 MW
or larger)
Small units (less
than 20 MW) can
connect to the
distribution system
through a step up
transformer or (for
much smaller units)
through a customer
service connection
Physical Interconnection Guide
• Output ranges
– Many units available on the market with outputs ranging from 100 watts
to 3.6 MW
– Output voltages range from 12 volts dc (battery charging units) to 480
volts ac
– Units with output voltages of 240 volts ac are usually best for customer
service connections
• Typical interconnection
components
Informal Utility Meeting
• NOT required but can be helpful
– Conducted before any formal meetings or studies are performed
– Will provide an overview of the process and economics involved
• What to ask:
– Interconnection requirements and procedure description
– Type of supply being provided (I.e. voltage, transformer size,
shared or single customer connection)
– Availability of hourly use data in electronic format
– Electrical facilities in close proximity to facility
– Rates and tariffs applicable to generators (particularly stand-by rate
information)
– Options for utility to purchase excess power
– Options for sale of excess power into market system
Informal Utility Meeting
• What to expect:
– Specific information concerning the process
and your service
– General information concerning timeframes and
interconnection costs
– Very general information concerning near by
facilities and their capacities
Informal Utility Meeting
• What not to expect:
– Don’t expect any information to be binding or
guaranteed
– Don’t expect any specifics concerning viability of an
interconnection point or associated costs
– Don’t expect any advice or recommendations
concerning excess energy sales
– Don’t expect any information that would require studies
or analysis
– Don’t expect any recommendations concerning unit
sizes, designs or construction requirements
Do Your Homework
• Energy use versus energy
output might be a simple
calculation if you lived in
Aruba
– Wind blows between 10 and
15 mph 24 hrs/day almost
all year long
– A 600 kw wind turbine
could expect to produce
3,942 mwh annually
(500x8760x.90) and reduce
demands by at least 500 kw.
• US sited units aren’t quite
so easy
Energy Balance Analysis
• Analysis that estimates energy costs and savings
for a prior year based on actual customer use data
and publicly available wind data – along with a
bunch of assumptions.
• Customer use data
– Use data is usually available from utility on an hourly
basis for an entire year in spreadsheet format
– Some data manipulation is required to format data into
a monthly billing quantity compatible layout
– Billing rates and monthly billing cycle dates are also
needed
Energy Balance Analysis
• Typical customer load profile data:
KW Load
700
600
500
400
300
200
100
KW Load
469
430
391
352
313
274
235
196
157
118
79
40
1
0
Energy Balance Analysis
• Publicly available wind data
– Does not replace the need for site specific
meteorological data
– May be used as a very general proxy for required data
prior to more in-depth analysis
– Public sites where information on wind generation can
be found:
http://seaboard.ndbc.noaa.gov/Maps/northeast_hist.shtml
http://cdo.ncdc.noaa.gov/ulcd/ULCD
http://www.uwig.org/
http://www.awea.org/faq/index.html
http://www.ibew.org/articles/05journal/0509/p14_windmill.htm
Energy Balance Analysis
• Wind power generation calculation is highly
complex but some simplifications can be
made
• Translation of wind data into energy output
will be required (this is the toughest part)
• Once data has been converted it can be
merged with use data to derive an
approximation of:
– Energy use reduction and avoided energy
costs
– Demand reduction and avoided demand
charges
– Excess energy production and sales value
Example Wind Data Results
Intervals
Wind Spd m/s
Output
494
465
436
407
378
349
320
291
262
233
204
175
146
117
88
59
30
45
40
35
30
25
20
15
10
5
0
1
(KW - M/S)
Wind Speed vs Output
100 KW Unit
Energy Balance Analysis
• Results can provide a high level estimate of
economic benefits versus costs of wind unit
installation for your use characteristics
• Will only provide an indication of whether a
more detailed analysis is worth the time and
expense
Results of Analysis
Use=
Export=
Reduced Use=
Savings=
204972
262
185764
19208
kwh
kwh
kwh
kwh
Wind Generator Estimate
1.5 MW Unit
800
KW
600
400
200
0
-200
Customer Load
Wind Output
Net Load/Gen