Small Wind Policies and Technology€¦ · Evance Wind Turbines Ltd. Evance R9000; Conditional Temp...

Small Wind Policies and Technology

Charles Newcomb: Moderator

Improving Distributed Wind’s Bottom Line:

Identifying Best Policies

Alice Orrell

2

Power through Policy

DOE-EERE “Wind and Water Power Program”-funded Project - Power Through Policy: Best Practices for Cost-Effective Distributed Wind

Quantitatively identify distributed wind policy best practices using a pro forma model.

Target audience: state-level decision makers Project team includes private, government, and academic sectors of the industry:

PNNLNRELeFormative OptionsNorth Carolina Solar Center

DeliverablesDistributed Wind Policy Comparison Tool Guidebook

3

Distributed Wind Policy Comparison ToolUser only needs to select two inputs initially:

State Sector

Model is then populated with default values based on these inputs

DSIRE quantitative data feed for policies and incentivesDefault values can be changed by user

Model calculates Cost of Energy (COE)Project Net Present Value (NPV)Project Internal Rate of Return (IRR)Simple Payback

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Distributed Wind Policy Comparison Tool

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Sign up to receive an announcement when the tool goes live online: www.eformativeoptions.com/dwpolicytool.html

http://www.eformativeoptions.com/dwpolicytool.html�

Model Design Challenges

Incentives are Changed FrequentlyWisconsin – complex to opaqueVermont – complex to simpleMaryland – combinedNew Jersey – on holdCalifornia – on hold

Incentive Program Designs are All DifferentCapital Cost Rebates

Capacity-based or Production-based or BothFlat rates or incremental ratesExpected performance or actual performance

Production-Based IncentivesUpfront rebate or given over time

6

Case Studies

Ranking of StatesBased on policies as of April 2011Ranking based on averaging the sectors’ economic results for each state:

Residential: 2.4 kWResidential / Farm: 10 kWNon-Taxed: 50 kW Commercial: 100 kW

Net Metering Example: Massachusetts & Texas

7

State Rankings: Top 10 and Bottom 10

$0.00 $0.05 $0.10 $0.15 $0.20 $0.25 $0.30 $0.35

TennesseeMississippi

IndianaIllinois

West VirginiaSouth Carolina

PennsylvaniaMichigan

FloridaConnecticut

ColoradoCaliforniaMarylandMontana

New JerseyVermont

New YorkMassachusetts

NevadaOregon

COE ($/kWh)

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Net Metering

State policy

Voluntary utility program(s) only

www.dsireusa.org / February 2011

* State policy applies to certain utility types only (e.g., investor-owned utilities)

WA: 100

OR: 25/2,000*

CA: 1,000*

MT: 50*

NV: 1,000*

UT: 25/2,000*

AZ: no limit*

ND: 100*

NM: 80,000*

WY: 25*

HI: 100KIUC: 50

CO: no limitco-ops & munis: 10/25

OK: 100*

MN: 40

LA: 25/300

AR: 25/300

MI: 150*WI: 20*

MO: 100

IA: 500*

IN: 10*IL: 40*

FL: 2,000*

KY: 30*

OH: no limit*

GA: 10/100WV: 25/50/500/2,000

NC: 1,000*

VT: 20/250/2,200

VA: 20/500*

NH: 100MA: 60/1,000/2,000/10,000*

RI: 1,650/2,250/3,500*

CT: 2,000*NY: 10/25/500/2,000*PA: 50/3,000/5,000*NJ: no limit*

DE: 25/100/2,000co-ops & munis: 25/100/500

MD: 2,000

DC: 1,000

Note: Numbers indicate individual system capacity limit in kW. Some limits vary by customer type, technology and/or application. Other limits might also apply. This map generally does not address statutory changes until administrative rules have been adopted to implement such changes.

NE: 25

KS: 25/200*

ME: 660co-ops & munis: 100

PR: 25/1,000

AK: 25*

43 states + DC & PR have adopted a net

metering policy

DC

DSIRE Net Metering Map as of February 2011

State-wide net metering

Net Metering – Massachusetts &Texas

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A state is considered to have state-wide net metering in model if IOUs, electric cooperatives, and municipalities ALL allow net metering

16 states without asterisks on the previous mapOnly IOUs in MA are obligated to provide net meteringOnly voluntary net metering programs in TX

Sector Texas Massachusetts

Net Present Value (NPV)

Without net metering

With net metering

Without net metering

With net metering

Residential ($11,913) ($7,389) $698 $5,038

Residential / Farm ($37,814) ($24,132) ($12,808) $57

Non-Taxed ($260,184) ($105,224) ($93,840) $82,608

Commercial ($222,438) ($38,706) ($177,161) $23,706

Texas: Modest improvementAssume net metering is at retail cost of electricity

Commercial / Non-Taxed Entities: $0.1075/kWhResidential: $0.1304/kWh

Massachusetts: Great improvementAssume net metering is at retail cost of electricity

Commercial / Non-Taxed Entities: $0.158/kWhResidential: $0.1768/kWh

Great for areas that already have net metering, but…There are no electric co-ops in MA, so a state-wide net metering policy would only affect municipal utilities.Are there sufficient wind resources in urban municipalities?

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Net Metering – Massachusetts &Texas

Summary

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Tool can be used by policy makers and incentive managers to

Play “what if” game by adjusting default inputs and current incentivesDetermine what incentives really improve the bottom line

Going ForwardDSIRE data feed is keeping up with incentive changesTool and Guidebook will be published June 2011

Alice Orrell509-372-4632

[email protected]

13

Growing the Small Wind Market Through Testing and Certification

Brent Summerville, Technical DirectorSmall Wind Certification Council

TM

SWCC: Small Wind Certification Council

New independent, third-party certification body to serve North America

Certify that small wind turbines (SWTs) meet the requirements of the new AWEA Small Wind Turbine Performance and Safety Standard

Used as incentive eligibility

TM

Problem

Small turbine performance specifications are not standardized

Agencies and utilities providing financial assistance are asking for performance assurance to increase support for incentives

Consumers need greater certainty of function, performance, and durability

Less than half of turbine models on the market have been tested

TM

Growth

www.awea.org

TMwww.greentechmedia.com

California

Inaccurate performance ratings (Power) Suspension of $3/watt rebate in March,

stakeholder meeting in April

http://www.greentechmedia.com/�

TM

New Jersey

REIP, Renewable Energy Incentive Program (rebate based on expected kWh)

Field failures = suspend program in March and call a stakeholder meeting in April

www.njcleanenergy.com

http://www.njcleanenergy.com/�

TM

Why Certification?

Allow consumer comparison of products

Funding agencies will gain greater confidence that small turbines installed with public assistance have been tested for safety, function, performance and durability and meet requirements of consensus standards

Consumer protection and industry credibility

TM

Trend: Require certification for incentives

Energy Trust of Oregon Focus on Energy (Wisconsin) New York State Energy Research and

Development Authority (NYSERDA) Massachusetts Clean Energy Center

(MassCEC) California Energy Commission (CEC) Colorado, Iowa, Maine, Maryland,

Minnesota, Nevada, Vermont New Jersey?

TM

UK/MCS leading the way

8 turbines now on the MCS list

www.microgenerationcertification.org

http://www.microgenerationcertification.org/�

TM

SWCC Certification Pending ApplicantsAmerican Zephyr Corporation Airdolphin GTO Under TestBergey Windpower Co. Bergey 5kW Under ContractBergey Windpower Co. Bergey Excel-S Under TestBRI Energy Solutions, Ltd Vbine 10-05 Under ContractEndurance Wind Power Inc. Endurance S-343 Under ContractEnertech, Inc. Enertech E13 Under ContractEvance Wind Turbines Ltd. Evance R9000 Conditional Temp CertEveready Diversified Products Kestrel e400i 3kW 250V & 48Vdc Under ContractEvoco Energy Evoco 10kW Conditional Temp CertGaia Wind Ltd. GW 133-11kW Certified Under MCSPolaris America LLC P15-50 & P10-20 Under ContractPotencia Industrial S.A. 10kW Hummingbird Under ContractRenewegy, LLC Renewegy VP-20 Under ContractSeaforth Energy AOC 15-50 Under ContractSouthwest Windpower Skystream 3.7 Conditional Temp CertTaisei Techno Co. TTK-10kW Under ContractTalk, Inc. Suelflow 100 Under ContractUrban Green Energy UGE-1k and UGE-4k Under ContractUrWind UrWind O2 Under TestVentera Energy Corporation Ventera VT10 Under TestWindspire Energy Windspire – 800040 Under ContractXzeres Wind Corporation Xzeres-442SR Certified Under MCS

TM

Trend: Status reporting

SWCC Status reporting Previous Application Pending Conditional Temporary Certification Certified

New Under Contract Under Test Reports Submitted Limited Power Performance Certification Conditional Temporary Certification Certified

Trend: Consumer Labeling

Example: AWEA Standard

Coming soon…International Labeling

TM

Product Development Scenarios

1. “The Short Circuit”

2. Certification

Dream up a wind turbine

design

Build one, see if it works

Sell to customers

Revise design based on customer problems


design

Build one, see if it works;

thorough shakedown

testing

Test and Certify to Standards

Sell to Customers

TM

Trend: “Cash flow hybrid”


design

Build one, see if it works;

thorough shakedown

testing

Test and Certify to Standards

Sell to Customers

TM

Certification based on…

an evaluation of:

Field testing

Wind turbine design

TM

Trend: Understanding VAWTs

TM

Trend: Reciprocity

TM

Certification to AWEA vs.MCS Certification in the UK

MCS Certification to BWEA

Required Limited Design Evaluation Power Performance Safety and Function Duration Acoustic Noise (reporting

differs) Factory Production Control

SWCC Certification to AWEA

Required Limited Design Evaluation Power Performance Safety and Function Duration Acoustic Noise (reporting

differs)

TM

Trend: Reciprocity

UK and North America Harmonization of BWEA/AWEA Standards Example: Acoustics

Testing performed per IEC 61400-11 with some modifications Analyzed for

AWEA Standard

Analyzed for BWEA

Standard

TM

Trend: Installer Certification

North American Board of Certified Energy Practitioners (NABCEP) has certified 1st round of installerswww.nabcep.org

http://www.nabcep.org/�

SWCC certifies Mechanical Strength, Durability, Function & Performance of turbine systemto the AWEA standard

NRTLs certify Electrical Safety of Turbine &Controller (new UL Standards in development)

PE certifies Tower & Foundation

NABCEP certifies the Installer

NRTLs certify Inverterto IEEE 1547/UL 1741

Wired per National Electrical Code (NEC) (new in 2011)

Grid-t

ie S

mal

l W

ind T

urb

ine

in t

he

US

Thank youBrent SummervilleTechnical Director, [email protected]

mailto:[email protected]�

Advanced Controls that Optimize Variable Speed Stall Regulated TurbinesJim StoverVice President, Product ManagementWindpower 2011

©2009. Northern Power Systems. All Rights Reserved. Not to be used or shared without permission. Proprietary and Confidential.

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Community Wind Technology Needs

Improved Efficiency in Low Winds

Low Maintenance

Utility Friendly:

• High Power Quality• Net Metering Ready

Simplified Installation

Low Noise

Aesthetic Fit with Surroundings


DOE Support for Permanent Magnet Direct Drive (PMDD) Development

DOE and NREL support for advanced drivetrain development

• Permanent magnet generators

• Full active power converters

• Digital signal processing (DSP) based platform simultaneously controls both turbine operation and power converter

WindPact and LWST: NPS 2.3 in MichiganMidsize Program: NPS 450 Under Development

McKay Photo

DWT Program: NPS 100 at McGlynn Elementary

http://www.energy.gov/index.htm�


Geared Drivetrain

Generator GearboxBearing & CouplingPower

Converter

Bearing & Coupling

1/3 moving parts = lower up-front cost, high reliability and lower O&M

No gearbox replacements (20 yrs = 4,000,000 miles on a transmission)

Variable speed torque control of “digital drivetrain” captures max power

Low noise and better power quality for utility interconnect

GeneratorPower

Converter

Direct Drive

Variable Speed, Stall Control Permanent Magnet Direct Drive: Efficiency, Simplicity and Max AEP

Pitch Bearings & Motors

Fixed Pitch


DOE Distributed Wind Turbine (DWT) Program Results…

100kW rated power

• 30 or 37m tower, 21m rotor

• Fixed pitch, variable speed

Meets Customer needs

• Low maintenance (1 visit per year)

• 24/7 SCADA monitoring

• Low noise for permitting

• Easy utility interconnection

• Simplified installation logistics

Design certification

• Certified to CE, UL, CSA safety and performance standards

• Power curve and noise validated by DNV to IEC standards

Community Wind: typically local power; “inside the meter”;

competes with retail-level economics


Wind Power Basics: Extracting Energy…

Betz Limit• Maximum portion of the power in a wind

stream that can be extracted• Cp max = 59.26%

Blade dynamics• Incoming wind speed (V)

combined with bladerotational speed determines aerodynamics and sum to driving force of rotor (Fd)

• Tip Speed Ratio (TSR) = blade rotational speed over wind speed

• To optimize angle of attack along the blade it must twist from root to tip

• Stall occurs as angle of attack increases and TSR decreases at high V


Wind Turbine Design Challenge: Maximize Efficiency While Maintaining High Wind Control

Power in Wind: P = 0.5ρACpV3

• P = Power• ρ = mass density of air• A = area swept by the rotor blades• Cp = power coefficient• V = wind speed

Ptarget = 0.5ρACp target (R/TSRtarget)3ω3

• R = rotor radius measured at the blade tip• TSR = Tip Speed Ratio = ωR/V • ω = rotational speed of the blade

Optimizing power• As wind speed changes, rotor speed should

adjust to maintain optimum TSR and Cp, until maximum tip speed (65-75 m/s) is reached

• BUT, wind speed is not a good control parameter - it is erratic and there are measurement delays

Ref.: Control Strategy for Variable-Speed, Stall-Regulated Wind Turbines, NREL/CP-500-24311 - UC Category: 1211, E. Muljadi, K. Pierce, P. Migliore


“Digital Drivetrain” Enables Fast Response and Maximum Power Tracking

From above, Ptarget is a function of RPM

Permanent magnet generator and full active power converter• Extract electrical torque (current)

to control RPM • Sized to contain wind gusts at

rated power

Advanced DSP controls provide superior torque control• Fast response to wind fluctuations • Sets RPM to track Max Cp over

low and medium wind speeds• Actively manages stall in high

winds

Generator & Converter limit RPM, increasing blade angle of attack

and creating stall


Overview Of Variable Speed Turbine Control

Blade profilematching powerand speed data

TurbinePerformanceCompensationAlgorithm

Speed-loop closedloop controller

MeasuredPower

Measuredspeed

SpeedCmd1 SpeedCmd2

Torque/current

command

Powercmd

Speed Loop Controller: hosted on DSP and samples > 10,000 times per second to calculate optimum torque command for instantaneous conditions

Turbine Performance Compensation Algorithm: compensates for blade performance, air density and other site conditions


0

2

4

6

8

10

12

14

16

18

0

20

40

60

80

100

120

25 45 65 85 105 125

Win

d S

pee

d (

m/s

)

Po

wer

(kW

), R

oto

r S

pee

d (

RP

M)

Sample time

Real Time Controller Performance

Power Converter extracts current from the generator per optimum torque calculation

Fast response delivers maximum power tracking and optimal performance

Efficiency of a pitch regulated turbine without the added cost, complexity or ongoing maintenance of a pitch subsystem

More current is drawn to slow the

rotor in gustsLess is drawn to

maintain rotor speed when winds are falling


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Additional Benefits Include Improved Grid Power Quality and Active Tower Damping

Tower Damping: Advanced active tower damping reduces fatigue

Power Quality: Smooth power transfer to the grid

Site Optimization: Line voltage correction

Site Optimization: Air Density Compensation


Tower damping reduces mechanical resonance by controlling rotor torque

Control algorithm can also provide damping to any minor blade imbalances

Active Tower Resonance Damping Reduces Fatigue and Enables Use of a Lighter, More Cost-Effective Tower

Without Tower Damping

Active Tower Damping

Up to 10 x reduction in tower motion


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Design Objectives of Taller “Soft” Tower: Greater Energy Capture and Lower Installation Costs

Less weight = lower cost; greater height = more energy capture

Three section nested design simplifies shipping: single 40’ flatbed truck

Installation with a common 60-ton truck crane

“Stiff” Tower “Soft” Tower % Change

Tower Height 30m 37m +23%

Tower Weight 13,800kg 13,100kg -5%

Fundamental Frequency

1.2 Hz 0.8 Hz


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Power Quality Comparison of a Converter-Connected Turbine vs. and Induction Turbine

Reactive power (Northern Power 100 provides +/- 45kVAR with or without wind) can be used to support grid voltage

No inrush current on turbine startup – avoids voltage dip on local grid

Better behavior on weaker and distributed grids

0%

50%

100%

150%

200%

10 15 20 25 30 35 40 45 50

Time (Seconds)

App

aren

t Pow

er (k

VA

)

Asynchronous generator

Northern Power 100


-50

-40

-30

-20

-10

0

10

20

30

40

50

98.0%

99.0%

100.0%

101.0%

102.0%

103.0%

104.0%

105.0%

106.0%

107.0%

0 11 21 31 41 51 61 71 81 91 101 111 121

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Site Optimization: Site Utility Voltage SupportExample of using Reactive Power +/- 42kVAR in raising or lowering site Voltage by up to 2.5% to improve site conditions (example only)

Demonstration below performed at Barre, Vermont - performance is highly site specific and can be tuned on a case-by-case basis

Grid Voltage

Reactive Power

Time (seconds)

1. Reactive Power command of -42 kVAR

drives grid voltage down by 2.5%

2. Similar increase in Reactive Power

command of +42 kVARbrings grid voltage up


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0

20

40

60

80

100

120

Site Optimization: Air Density Compensation

Auto-tuning of rotor speed to maintain control and maximize power in colder temperatures: -3C, winds varying 9-15m/s over 4.5 hours

Power (kW)

Rotor RPM

Wind Speed (scaled)

2. As wind peaks, rotor speed limits to maintain control

3. Rotor returns to full RPM to maximize power as wind

dies down

1. At full RPM, power converter extracts more

Current as wind rises


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SmartView SCADA: Access to All Real-Time Data for Performance Enhancement and Optimization


Distributed Applications Demand Sophisticated Performance from a Reliable Machine

Customer Need Pitch StallPMDD Variable Speed

Stall Benefit

Low Up-Front CostBetter ROI / More green energy

Energy CaptureBetter ROI / More green energy

Low O&MReliable, Low Cost Performance

Utility FriendlyBetter Power Quality and Easier Interconnect

NoiseLower RPM, Lower Noise, Easier Permitting

Efficiency of a pitch regulated turbine without the added cost, complexity, or ongoing maintenance of pitch subsystem


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Thank You

Jim StoverVice President Product ManagementNorthern Power Systems29 Pitman RdBarre, VT [email protected]

Please visit: www.northernpower.com

mailto:[email protected]�

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