feasibility study for the university of massachusetts lowell solar pv carport project carried out by...

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FEASIBILITY STUDY FOR THE UNIVERSITY OF MASSACHUSETTS LOWELL

SOLAR PV CARPORT PROJECT

CARRIED OUT BY ARKD ENGINEERING

Samir AhmadAndres ReineroPooja Kapadia

VamshiKrishna Domudala

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The Location

Latitude 42.65 Longitude 71.32

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Motivation• UML’s motivation for carrying out this study is to

determine the technical and financial viability of reducing their carbon footprint.

• Promotion of the university’s image as good engineering institution.

• Integration of UML’s electrical vehicle fleet with the EV charging stations powered by in-house generated solar energy.

• Hands on training for engineering students.• Good use of carport space.• And obviously the money!

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Project planning and community issue ( The permitting process)

The permitting process

The conservation commission Local zoning Authority Local town/municipality

National Grid (Impact Study)

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Solar irradiance at the Site

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The elevation difference used in PVsyst

The bleachers are 5ft below datum plane and the height of panels is 10ft above datum plane. Net height difference between 16ft.

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General project layout

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General project layout (with panels)

East –West view

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Carport back structure

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The components Equipment name Name Quantity

Solar panels Yingli 260 Watt (YGE 60 cell) 2160String Inverter SMA Tri power 15KW 9 x (2 MPPT inputs)String Inverter SMA Tri power 25KW 4 x (2 MPPT inputs)

Carport structure Carport structure cooperation 4 x Beam Over Double

Carport structure Carport structure cooperation 1 x Beam Over Single

DC switch gear Bentek ( 8 & 12 Inputs, 15 Amp each)

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Panel board busbar at (Every array)

General (Aluminum bus-bar) 5

Panel bus bar General (Aluminum bus-bar) 1

Digital Acquisition System (DAS) + Meters

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Grounding Transformer - 1

Step up transformer (480V to 13.8KVA)

- 1

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Carport racking structure

Beam over single (Used in Array 1 only)

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Carport racking structure

Beam over double (Used in Array 2,3,4 & 5 only)

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Shading Analysis

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Shading Analysis at 3:15pm

Representation of inter row shading at 3 deg tilt

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Shading Analysis at 3:45pm

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Shading analysis at 7:45AM

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Shading analysis at 9AM

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Main project design specs

Parameter

System size (KW) 561.6

Modules 2160 x Yingli 260 Watt

Modules per string Variable (21 and 18 strings/inverter)

Inverter 21 x SMA Tripower (15KW and 25KW)

Racking Carport Racking (double and single overhang)

Azimuth 10 Deg

Tilt 3 Deg

Total number of strings 108 Strings (two types)

Number Transformer Grounding transformer, Step up transformer

Grid interconnection voltage 13.8 KVA

Total busbars 6

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Single line DC (Array 1)

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DC single line (Array 2)

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DC single line (Array 3,4 & 5)

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Single line diagram (DC side)

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AC single line diagram

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Pvsyst losses assumptions

Soiling Losses 2% monthly

AC Wiring Losses 1.50%

Transformer Losses 0.98%

Albedo - Summer 0.1

Albedo - Winter 0.5 – 0.6

Summer Maximum 45 C

Summer Minimum (ASHRAE) -20 C

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Grid Interconnection (National grid)

13.8 KVA interconnection point available 1000ft far! So we assumed a hypothetical interconnection point near the project

NEC calculationArticle/Table number Description

690.7 Maximum system voltage

690.8690.8(A)690.8(B)

310.15(B)(3)(C)

310.15(B)(2)(a)

Circuit current and circuit sizingMaximum DC circuit currentConductor ampacity Sizing

Ambient temp. adjustment for raceways or cables exposed to sunlight on or above rooftops

Ambient temp. correction factors based on 30 deg C

690.9240.6(A)

Over current protectionTo select standard OCPD’s

Table 8 Voltage drop calculations

280 Surge arrestors

250 Grounding electrode conductor

•690.8(A) Imax = 11.36 Amps•690.8(B)(1) & (2) Ampacity sizing•310.15(B)(17) 18 AWG •Table 8 Voltage drop = 5.77 Volts

= 0.75% of max

•690.9 OCPD = 15A• Article 240.6(A)

•690.7 Vmax= 772Volts

String type 1

PV Output DC Circuit

•690.8(A) Imax = 45.44 Amps•690.8(B)(1) & (2) Ampacity sizing• M1: 56.8 Amps, M2: 69.91•310.15(B)(17) 6 AWG •Table 8 Voltage drop = 1.16 Volts

= 0.15% of max

String type 2

•690.8(A) Imax = 11.36 Amps•690.8(B)(1) & (2) Ampacity sizing•310.15(B)(17) 18 AWG •Table 8 Voltage drop = 5.77 Volts

= 0.75% of max

•690.9 OCPD = 15A• Article 240.6(A)

•690.7 Vmax= 900Volts

PV Output DC Circuit

•690.8(A) Imax = 68.16 Amps•690.8(B)(1) & (2) Ampacity sizing• M1: 85.2 Amps, M2: 104.86•310.15(B)(17) 4 AWG •Table 8 Voltage drop = 0.73 Volts

= 0.08% of max3 AWG= 0.58 Volts= 0.06% of max

AC side NEC Codes

Article 280Article 250

Article 470.19

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PvSyst assumed losses

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Production yield

Specific Yield 1240 Kwh/kw Performance ratio 84.3%

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Environmental benefitsThe annual yield of 696.6 Mwh off 480 metric

tons of CO2 annually.

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Financials

• Project owner – University of Massachusetts• Land owner - University of Massachusetts• Developer – ARKD Engineering ( which is us!)• Financer – Bank of America (Any financial

institution)• National grid is the buyer and transmission

services provider.

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Hard CostComponents Cost $/W

Modules 0.73

Inverters 0.16

Electrical 0.64

Installation Materials

0.1275

Soft CostParameter Cost

Installation 0.2125 $/W

Engineering 0.425 $/W

Permitting & commissioning

0.15 $/W

Installer Overhead & Profit

0.16 $/W

Supply chain cost 0.49 $/W

Tax 0.235 $/W

Interconnection fee $7,500.00

Miscellaneous 0.2 $/W• Carport Structures Corporation charges $0.85 for installation materials, Engineering, and Installation

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6%

12%

4%

2%2%

14%

7%

0%

Installation

Engineering

Permitting and Commissioning

Installer Overhead

Installer profit

Supply chain cost

Tax

Interconnection fee

Soft cost breakup

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6%

12%

4%

2%2%

14%

7%

0%

Installation

Engineering

Permitting and Commissioning

Installer Overhead

Installer profit

Supply chain cost

Tax

Interconnection fee

Soft cost breakup

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Incentives

• Federal 30% Investment Tax Credit (ITC)• SREC – 10 year period SREC Factor 1 Current SREC Value is $274/MWh

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Fixed Input Parameters

• Degradation rate – 0.5%• Maintenance cost – in the range of 15-20 $/kW• Estimated property tax – A*31.75/1000Total annual cost per parking space for commercial property is $384.00A = Total parking spaces*384.00$31.75 per $1000 – property tax rate found on Assessor page of lowellma.gov

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Fixed Input Parameters

• Increase in property tax – 10%Increased Asset Value = Hard cost*31.75/1000Estimated property tax/Increase in asset value• Inverter replacement cost = 0.25 $/W• Income tax rate = 35%

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Variable Input Parameters

Scenarios SREC Value $/MWh

Market Discount Rate

Inflation Rate

Conservative 181.5 1% 1%

Likely 274 2% 1.5%

Optimistic 300 2% 2%

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Simple Payback Period

Conservative Likely Optimistic0.0

5.0

10.0

15.0

20.0

25.0

20.8 20.8 20.8

7.1

5.4 5.0

Simple Payback Period

SPB W/O SREC

SPB with SREC

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NPV Analysis

Conservative Likely Optimistic

-1000000.00

-500000.00

0.00

500000.00

1000000.00

1500000.00

2000000.00

-520780.85-401477.60 -332187.01

644097.01

1267025.52

1494641.23

Net Present Value

NPV w/o SREC ($)

NPV with SREC ($)

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Recommendation to the University• The specific yield of 1240 Kwh/kw represents a healthy

specific yield at 3 deg tilt and 10 azimuth. The project is a technically sound venture.

• The Solar PV carport project will give a good integration to the university EV fleet flans for the future.

• The university can raise capital through Alumni and other endowment sources to further improve the financials.

• This project will be an excellent opportunity for the students in the energy program to engage in hands on training.

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Thank you !!