district cooling systems - aprise 2017resiliencesummit.com/program/pdf/clay.pdf · district cooling...
TRANSCRIPT
Do Electricity Rates Keep You Up at Night?
0
20
40
60
80
100
120
140
$/ Barrel 2010 Dollars
Oil Prices -‐ EIA 2000 AEO vs Actual
LOW Oil Price (EIA 2000 AEO) REF Oil Price (EIA 2000 AEO) HIGH Oil Price (EIA 2000 AEO) Hawaii Fuel Oil
• By 2012, Hawai‘i oil prices rose to 3.8 times the EIA’s forecasted “High” oil price • In hindsight, a Uixed rate contract signed in 2000, even based on a $40 per barrel oil price -‐ consistently above the “High” forecast -‐ would have turned out to be a huge windfall for building owners
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Monte Carlo Analysis: Quantifying Risk
Model Input (Variable) Source
• Monthly weighted average fuel oil prices in Hawai‘i
• DBEDT (Jan 2000 – Jun 2013) & HEI (Jul – Aug 2013)
• GDP Chain-‐type Price Index (for inUlation adjustments)
• U.S. Dept of Commerce: Bureau of Economic Analysis
• “Low”, “Reference”, and “High” oil price forecasts
• Energy Information Administration 2012 Annual Energy Outlook
• Contract speciUics: capacity, energy charge, delivery start date and duration
• Actual HSWAC contract terms
• Monte Carlo Analysis software • Palisade @Risk 6.0 (Microsoft Excel add-‐in)
• Monte Carlo analysis is a method used to quantify risk by simulating thousands of future scenarios such as oil price spikes, recessions, periods of high inUlation, etc.
• A Monte Carlo analysis of Hawai‘i’s electricity rates would run simulations for multiple variables to produce hundreds or thousands of possible outcomes in order to obtain the probabilities of different outcomes occurring
• It allows us to estimate the probabilities of electricity rates increasing 5% or 10% or 15% or etc., or remaining at current levels
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Monte Carlo Analysis: HVAC Inputs
Model Input (Variable) Source
• Electricity Costs • Conventional or ultra efUicient chiller plant annual efUiciency in kW/ton, multiplied annual ton-‐hours, and by HECO $/kWh costs.
• Cooling Tower Water Costs • Cost of water evaporated and discharged into the sewer from the cooling tower operation. Water rates taken from current Board of Water Supply Rates.
• Cooling Tower Sewer Costs • Department of Environmental Services charges for sewage discharged from the cooling tower operation. Sewage rates taken from Department of Environmental Services.
• Costs are calculated based on an assumed peak operating cooling capacity, installed capacity to provide back up for primary equipment, and energy used for cooling measured in ton-‐hours
• Other “Uixed” costs to own and operate a AC system have been estimated based on engineering calculations, engineering reports, and published water and sewer rates for Honolulu, Hawai‘i
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Model Input (Variable) Source
• Water Treatment Chemicals and Refrigerant Costs
• Cost of chemicals used to treat condenser water estimated at $2.00 per 1,000 gallons of water used
• Cost to recharge refrigerant in chillers on an annual basis due to leakage
• Maintenance and Repair Costs • Annual and periodic scheduled maintenance on chiller plant equipment, including unscheduled breakdown repairs over the life of the equipment. Estimated from Electric Power Research Institute (EPRI) Electric Chiller Handbook
• Labor and Administration Costs • Annual on site staff and administration costs to operate equipment 13% of one full-‐time employee’s annual work hours
• System Replacement & Installation Costs • Cost of installation and purchasing replacement chiller equipment at end of life of the existing equipment is estimated at $3,000 per ton installed. Actual costs per ton will depend on speciUic installation requirements
Monte Carlo Analysis: HVAC Inputs (Cont.)
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Typical Chiller Plant Efficiency
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EXCELLENT GOOD FAIR NEEDS IMPROVEMENT
New Technology All-‐Variable Speed
Chiller Plants
High-‐efficiency OpCmized
Chiller Plants
ConvenConal Code-‐Based Chiller Plants
Older Chiller Plants
Chiller Plants with CorrecCble Design or OperaConal Problems
kW/ton C.O.P
0.5 (7.0)
0.6 (5.9)
0.7 (5.0)
0.8 (4.4)
0.9 (3.9)
1.0 (3.5)
1.1 (3.2)
1.2 (2.9)
AVERAGE ANNUAL CHILLER PLANT EFFICIENCY IN KW/TON (C.O.P.) (Input energy includes chillers, condenser pumps and tower fans)
Based on electrically driven centrifugal chiller plants in comfort condi6oning
applica6ons with 42°F (5.6°C) maximum entering condenser water temperature. Local climate adjustment for North American climates is +/-‐ 0.05 kW/ton.
HSWAC Cuts Cost & Reduces Risk for Customers
• Forecasting simulations (Monte Carlo) based on oil price volatility from 2000 to 2013 indicate signiUicant cost savings and risk mitigation provided by HSWAC services
• Buildings operating 5 days per week are expected to save money over on-‐site chilling 85% of the time (85% of possible future oil price scenarios)
• Buildings operating 7 days a week save money more than 95% of the time
Hawaiian Electric Company
One Waterfront Towers
Finance Factors
First Hawaiian Center
Remington College Honolulu
HSWAC Customers
Union Plaza
6
Prince Kuhio Federal Building
HSWAC Cuts Cost & Reduces Risk for Customers
• For 5-‐day a week buildings, oil prices would have to: – Drop below $95 per barrel (oil prices in Hawai‘i are above $130; more than 35% higher), and
– Stay below $95 for 15 years for HSWAC service to be less economical
• For 7-‐day a week buildings, oil prices would have to: – Drop below $70 per barrel (oil prices in Hawai‘i are more than 85% higher), and
– Stay below $70 for 15 years for HSWAC service to be less economical
Hawaiian Electric Company
One Waterfront Towers
Finance Factors
First Hawaiian Center
Remington College Honolulu
HSWAC Customers
Union Plaza
7
Prince Kuhio Federal Building