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Denver International Airport

PV Projects and Energy Management

Presented

to Environmental Regulations

for Airports Conference Sep 27, 2013

Energy Management Program

Evolution

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Major Energy Management Initiatives

at DIA

– Three Photovoltaic Solar Energy Installations – Other Energy Management Projects:

– Less glamorous but usually better “bang for the buck”

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Energy Management Program

– Energy Management Program - Evolving:

– Primary Goal: Reduce Life Cycle Costs, reduce carbon foot print, constraints:

– 24/7 operation

– FAA, TSA and other Regulations

– Unintended consequences

– Currently mostly “Project based”

– Implementing Comprehensive Energy Management Program

– Help from Xcel Energy’s Commercial Efficiency Program

– Systematic Approach to Energy Management

– Upper Management Support necessary

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Data Example

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Major DIA Energy Management Projects

Completed and In Progress

– EcoStart Motor Controllers installed 2007-2009 – Lighting Retrofits – 2008-2012. Nearly 10,000

fixtures so far

– Parking Garage Retrofit in the works – LED Taxiway Lighting Tested

– Turn off Airfield lights on selected runway complexes when slow

– HVAC Control Upgrades

– Hydronic Pump System Optimization – Central Plant Sump Separation

– Central Plant Controls – Renewables - Solar

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EcoStart Motor Controller Example

– November 2006 - Employee Comments

– Talked with Kone Representative (OEM/Operator) – U.S. “Vertical Transportation” Code

– At the time did not allow intermittent operation of escalators/powerwalks – Code changed in 2012 but still requires

variance in Colo.

– Motors sized to operate escalators in “up mode” with 300 lb. per step

– Thus motors are vastly oversized and

usually underloaded…even if can shut off when vacant

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EcoStart Motor Controller Example

–

EcoStart Motor Controllers:

– Manufactured by Power Efficiency Corp of Las Vegas (at the time)

– EcoStart: Kone’s brand name for the product. – Now are coming as a standard option on Kone

escalators. – Also Otis, etc

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EcoStart Motor Controller Example

–

Mechanism:

– Monitor power factor, related to the motor loading, and adjusts voltage accordingly, – reduces core losses

– does not change speed of escalator

–

DIA has 110 escalators and 54 power-walks.

– Escalators 10-20 HP; Powerwalks: 10-30 HP – Significant potential to reduce electrical usage.

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EcoStart Motor Controller Example

–

Overall installed cost $380,000

–

Total Annual Savings = $95,000

–

Average savings was 1.22 kW/unit, 28.5%

–

Average of 10,655 kWh per year per unit

–

$73,000 rebate from Xcel.

–

Simple Payback (avg) = 3.4 yr

–

IRR = 27.5 %

–

Project was very successful

–

Benefit for escalators better than power-walks –

reduced the average.

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More Energy Related Projects

Hydronic Pump Optimization

- Replace tertiary hydronic pumps with control

valve system

- Direct energy saving related to removal of 168

pumps from the system

- Maintenance savings related to decision not to

replace and maintain pumps

- Central utility plant sump separation

- Estimated to reduce energy by more than 1,900

kW and 14 million kWh annually

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Solar PV Basics

– All Photovoltaic (PV) cells produce DC

– Cells -> Modules (Panels one or more modules) – Panels joined in “Strings”; StringsArray

– Then what do you do with the DC power? – Either charge a battery,

– Use DC directly, or

– Use an “Inverter” to convert the DC to AC. – Sometimes a combination of these.

– Most large PV systems convert DC to AC; like all systems at DIA.

– Then you can either use the electrical energy “on-site” or sell it to the electrical grid.

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PV Design Considerations

– How big? - Solar PV is sized in MW DC – “nominal power rating” @ STC = 25 C, 1000 W/m2

– Types of Solar PV Panels:

– Mono-crystalline – Most efficient – most expensive – Poly-crystalline – Less efficient – less expensive

– Non-crystalline (thin film) – Least efficient – least expensive, and more flexible.

– New generation – multijunction; exotic compounds. – Tracking System vs. Fixed Tilt System

– Tracking - follows the sun

– Tracking is more expensive but more efficient – Tracking Systems: Single Axis or Dual Axis. – Also how much does land cost?

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DIA I DIA II DIA III

Existing DIA

Solar

Installations

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DIA PV Installations

– All poly-crystalline panels

– Combined, DIA Solar I, II and II produce approximately 13 million kWh per year;

– This is about 6% of electricity used by DIA in a year – All DIA Solar Arrays are Public-Private Partnerships

– DIA has Ground Lease Agreement and Power Purchase Agreement (PPA) with Owner

– DIA is “site host”:

– Owner Sells Electricity to DIA at agreed prices – DIA use some Electricity on site, and sells excess

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DIA PV Installations

– Owners of the DIA Solar Arrays receive:

– Payments for Electrical Energy from DIA – Federal tax benefits,

– Renewable Energy Certificates (REC) and Rebate Payments from Xcel Energy

– Without Tax Benefits and Xcel Payments, these DIA

Solar Installations would probably not have been built; – would not be financially attractive to Owners

– We all helped to pay for these Solar Arrays: – Through Federal taxes

– Through Xcel Electric Bills

– Colorado Renewable Energy Standard - Increased to 30% by voters in 2010

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DIA I - Pena Blvd PV Facility

–Facility Owner – MMA Renewable Ventures

(now Sun Edison)

–Developer - World Water & Solar Technologies

(now Entech Solar)

–Prime Construction Contractor - Intermountain

Electric (IME)

–Total construction cost approximately $14

million

–Leased Area 8.8 Acres

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DIA I

–

Nominal Rating is 2 MW DC.

–

Annual production is approximately

3.5 million kWh

–

9254 panels at 216 watts each

– Strings of 14 panels.

–

Flat single axis tracking system

– Tracks east-west, but no north/south tilt – Tracking is hydraulically operated

– Trackers required expensive foundation - clay

–

8 Arrays served by 8 Inverters

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DIA II – Fuel Facility

•Serves DIAs Fuel Storage & Distribution

Facility (Fuel Farm)

•Owner - Airport Solar One LLP

•Developer - Oak Leaf Energy Partners

•Contractor – Intermountain Electric

•Leased Area 9.4 Acres

•Commissioned February 2010.

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DIA II

–

Nominal Rating is 1.6 MW DC

–

7392 Panels at 216 watts per panel

– Also Strings of 14 panels

–

Fixed Tilt at 25 degrees South

–

25 degree fixed tilt 17% less efficient per

panel than the flat tracker…but far less

costly to construct

–

Produces 2.5 million kWh per year

–

Cost $4.38 per watt

–

Output matches well to the overall

electrical usage of the Fuel Farm

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DIA III – Lift Station 2

Connects to Sewer pump station far north end of DIA Owner: Denver Airport Solar, LLC (Constellation Energy) Developer: Oakleaf Energy Partners