RBCM Energy Accounting to April 2010
June 11, 2010 By: Avalon Mechanical Consultants Ltd. #300 – 1245 Esquimalt Road Victoria, BC V9A 3P2 Phone: (250) 384-4128 Fax: (250) 384-4134 bob@avalonmechanical.com
RBCM
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Energy Accounting
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June 11, 2010
SUMMARY This report presents a detailed review of the energy use at the RBCM. All the metered energy is electrical. There are 2 meters: • The Electric Plus meter, which covers the space and water heating only. Use on this meter is rising. • The regular of “firm” Hydro meter, which covers lights and equipment. This type of consumption has shown a steady decrease over the last couple of years, which provides positive feedback on the RBCM’s technical and behavioural energy and green initiatives. Table 1 Energy Breakdown for 09/10 Fiscal Year End Use End Use Electricity Cost Percent Use ($/yr) (kWh/yr) Heating (E+) 38% 2,225,400 $63,424 Firm E 62% 3,592,800 $207,193 5,818,200
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FINDINGS
2.1
ELECTRIC PLUS HEATING ENERGY
$269,249
Floor Area sq.m
Saving vs 2007 ($6,934) $22,076
19,173
$15,142
The Electric Plus tariff (account 5904680) meters the 600 kW boiler in the basement, which provides space heat and domestic hot water heating. The increase in use is reported as negative savings in the table below: Table 2 E+ “Savings” vs Baseline Year
kWh/yr Degree-days $/yr
2007 base yr 2933 base yr
2008 -106,762 3031 ($3,042.72)
2009 -394,014 3119 ($11,229.40)
An upward consumption trend started in December 2008. Since that time, the average increase in E+ energy (compared to the 2007 baseline) has been as follows: Table 3 E+ Use Increase – 17 Months 2009/10 vs 2007 Baseline Year
23,249 $ 663 278,986 $ 7,951
kWh/mo $/mo kWh/yr $/yr
Avalon Mechanical Consultants Ltd.
RBCM
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Energy Accounting
June 11, 2010
The timing of this upward trend corresponds with the new humidifying/ reheat/dehumidifying system installed for the Temporary Gallery. The increase is more than was anticipated however, which indicates that there may be opportunities to obtain savings from operations and recommissioning of old HVAC systems. The BC Hydro Continuous Optimisation Program may be an option available to RBCM, unless there are firm plans for significant capital projects within the next 2 years. The raw data (unadjusted for a particular year’s weather) is as follows: Graph 1: Raw E+ Consumption by Calendar Year E + CONSUMPTION 3000000 2,541,600 2500000
kWh
2000000
1,818,000
1,920,000
1,927,800
2005
2006
2,079,600
2,208,000
1500000 1000000 500000 0 2004
2007
2008
2009
YEAR
The RBCM established a consumption benchmark in 2007. It was based upon 13 months of consumption - up to and including Nov 07. The E+ consumption and the outdoor temperatures were entered into a linear regression model. Heating degree-days were found to produce a strong correlation with consumption, as indicated in the graph below. Graph 2: Consumption vs Weather Regression – Base Year 2007 10,000 9,000 8,000
Elect (kWh/day)
7,000 6,000 5,000 4,000 3,000 2,000 1,000 0 0
2
4
6
8
10
12
14
16
Heat DD (18C HDD/day)
Avalon Mechanical Consultants Ltd.
RBCM
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Energy Accounting
June 11, 2010
The graph above shows that there was no weather-related consumption, when the outdoor temperature (OAT) was at or above 18C during 2007. In warm weather of this type, the non-weather-sensitive loads (domestic hot water) consumed 2000 kWh/day. As the OAT got colder (moving to the right on the Xaxis of the graph) the consumption went up at a very predictable rate (slope = 526 kWh/HDD). Each month, we enter in the average daily temperatures into the model (from the Environment Canada website), and it compares the PREDICTED CONSUMPTION (based on the above, and the actual weather), with the ACTUAL CONSUMPTION from the bills. A weather-corrected cumulative “savings” graph is produced below to compare weather-corrected performance versus the 2007 baseline. Each month, the actual kWh consumption is subtracted from the consumption predicted by the model (based upon actual OAT) to determine the savings. If the line in the graph goes up, then the actual consumption was higher than the predicted consumption that month – which is the case for every month except during summer ’08, May 09, and March ’10. The downward trend at the end of the graph is an indicator of savings and may be a positive trend going forward. Graph 3: Adjusted E+ CUSUM, December 2007 to 12 March 2010.
Note: There was an extra meter reading in March 2009. Base year to which savings are compared: 2007
Avalon Mechanical Consultants Ltd.
RBCM
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Energy Accounting
2.2
June 11, 2010
FIRM ELECTRICITY – LIGHTS & EQUIPMENT The situation for the firm Hydro usage is better. The daily consumption in 2010 is 11% lower than it was in 2007.
Table 4 Firm Electrical Costs and Consumption
kWh/yr days kWh/day $/day $/yr
2007 3,945,600 364 10,840 $625 $228,164
2008 3,932,400 365 10,774 $621 $226,778
2009 3,666,000 365 10,044 $579 $211,415
2010 1,184,400 123 9,629 $555 $202,688
No occupancy or weather data has been found to have a statistically significant correlation to consumption.
Graph 4: Firm Daily Consumption by Calendar Year Firm Hydro kWh/day 12,000
10,000
8,000
6,000
4,000
2,000
0 2007
2008
2009
2010
Avalon Mechanical Consultants Ltd.
RBCM
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Energy Accounting
June 11, 2010
Graph 5: Firm Monthly Consumption RBCM Firm kWh/mo 400,000 350,000 300,000 250,000 200,000 150,000 100,000
20 10
20 09
20 08
20 07
50,000
Month
Avalon Mechanical Consultants Ltd.