Power System Conference, Clemson, South Carolina, March 8-11, 2005

K E M A T & D C O N S U L T I N G

Power System Conference,

Clemson, South Carolina,

March 8-11, 2005

Principles and Issues Relating to the Principles and Issues Relating to the Interconnection of Wind PowerInterconnection of Wind Power

Zhenyu Fan & Johan Enslin

KEMA T&D CONSULTING

3801 Lake Boone Trail, Suit 200

Raleigh, NC 27607

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Overview:

Study Background Key Issues Objectives & Scope Case Studies Summary

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Source: AWEA’s Global Market Report

1. Germany: 12,001 MW

2. Spain: 4830 MW

3. US: 4275 MW

4. Denmark: 2880 MW

5. India: 1702 MW

Wind Power is growing!

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Table 1: Example of wind systems and installed penetration levels

Region Peak LoadMW

Installed WindMW

Penetration

Denmark 5,000 3,100 62%

Germany 77,000 14,600 19%

Spain 36,000 6,200 17 %

The Netherlands 14,000 1,000 7%

Continental USA 808,000 6,740 0.8%

Texas 63,000 1,288 2%

New Mexico 1,500 265 17%

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Wind Resource in the USAWind Resource in the USA

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Wind Power installed in US

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Wind Power Interconnection Studies

Interconnection procedures are not uniform

In general, interconnection procedures require: to apply for a queue position; system feasibility, system impact, and facilities studies; interconnection and construction agreements; construction of interconnection facilities, and network

upgrades if required.

FERC governs the generation interconnection process

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Interconnected Issues:

Power Flow

Short Circuit

Transient Stability

Electromagnetic Transient

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Protection

Power Leveling and Energy Balancing

Power Quality

Interconnected Issues (Cont.):

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Network Interface Options

• A – Direct link, no compensation• B – SVC, reactive power, voltage• C – STATCOM, added power quality• D – STATCOM with battery, added power balance, trading, UPS,

Black-start, etc.

Wind Farm

SVC

Damper

RCo

Lo

C3

Storage

A)-

B)-C)-

D)-

Q and P

Q

ACAC

ACAC

ACAC

ACAC

ACAC

Offshore grid

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Case Studies:

California ISO System

Dutch Project

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California ISO System:

CA Wind Resources Areas designated "Good" are roughly

equivalent to an estimated mean annual power at 10 meter height of 200 Watts/square meter to 300 W/m2 and "Excellent" to above 300 W/M2.

In the year 2000, wind energy in California produced 3,604 million kilowatt-hours of electricity, about 1.27 percent of the state's total electricity. That's more than enough to light a city the size of San Francisco.

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California ISO System: CA Electricity Market

The CA ISO 2004 Summer peak load is 44,422 MW with a minimum projected planning reserve of 16.4% and a corresponding operating reserve of 2,750 MW. Approximately 32,700 MW are thermal units, 2,600 MW are wind with the remaining 18,700 MW consisting of a mix of hydro, pumped storage and solar.

The 2004 base scenario forecast wind capacity for California during summer peaks is only 235 MW (9.0% of the installed wind capacity).

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Wind Power Operating Reserve and Regulation Impact

Load forecasting error affects operating reserves while short-term fluctuations in load affect regulation

Forecasting errors should be considered in combination

Geographical dispersion of wind resources tend to reduce the amount of incremental load following requirements

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Wind Power Impact on Reliability and System Operation

Hydro-power resources can be used for power balancing wind power plants,

Thermal units on the system would still be used for operating reserves.

System reliability and load following capability will not be affected significantly by the addition of a significant amount of wind generation.

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Wind Power Impact on Generation

The decision to build a wind plant depends on many factors.

Capacity factor of CA ISO is 9% on an annual basis, new wind project are likely to have capacity factors in the 35-40% range.

The addition of large amounts of wind generation to a system would have some economic and physical impact on merchant plants in the medium to long run.

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 Major Dutch HV Network Upgrades for interconnection of a 6,000 MW offshore wind park in the North Sea

Wind Park

ConnectionPoints

Wind Park

ConnectionPoints

Netherlands Project

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Offshore Wind Energy In Netherlands 12% of energy within EU should be provided by

renewables by the year 2010, with a possible installed wind capacity of at least 40 GW

6000 MW by 2020 wind power studies An energy storage system integrated with high

power electronics can mitigate interconnection problems

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Storage Options for 6 GW Wind Farm

Based on Flow-battery technology 6,000 M€, 30 years NPV, 1x1 km size

Not feasible by factor 10 as a single solution

Dimensioning Flow-battery

Surface of Battery Plant for Wind Park (6000 MW):

• 792.000 m2 (e.g 990 x 800 m)

Power

2555 MW

Energy

62004 MWh

Electrolytic

Storage TanksFuel-Cell Stacks

VSC Inverter

and Controller

Transformer

VSC Interface

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Energy Storage

A 2500 MW battery plant will be required Total capacity is 62 GWh Based on the difference between low

and high APX-values, the profits of the reduction of the number of start/stops, and avoiding the investment cost of the stabilization system, and avoiding of the unbalance cost, the project becomes feasible.

In this case, a seven- to eight-year break-even can be achieved,

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Summary

Large-scale wind park requires a different integration approach from those used for smaller wind farms.

Mitigation devices are needed for the interconnection issues with distributed power

Key technologies can minimize the impact on the network

Several functions should be integrated into the functionality of the energy storage system

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Thank You !Thank You !