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Understanding how much energy we use

In order to make efficiency improvements to our homes and offices, we first need to understand what is using energy.  Follow our energy auditing at the Museum to discover what we learned about our own energy use and what we are doing to improve efficiency and reduce waste.

Electricity use at the Museum<br />Comparing 2005 and 2008 electricity consumption  (lines) vs. hours that the building was open to the public and staffEfficiency payback calculations<br />After measuring energy use around the building, specific calculations were made for payback periods.  This example shows replacing gallery lighting with LEDs.

Electricity accounts for approximately 65% of the Cleveland Museum of Natural History's carbon footprint each year. In 2008, the Museum consumed around 3.5 million kWh, averaging just over 13kWh/sq foot/year. The fuel mix used to supply our electricity results in a blended rate of approximately 1.82 pounds of CO2 per kWh, so our resulting footprint from electricity last year was roughly 6.37 million pounds or 3185 short tons of CO2 (not including transmission losses). We will be completing a more rigorous CO2 accounting from all activities once the final ultility bills from 2008 have arrived.

The Museum faces a number of challenges in reducing its electricity usage. For example, it is open 7 days a week most weeks (averaging around 3300 hours of public occupancy per year), many of the internal lighting and mechanical systems date from original construction of the various wings (some dating to the 1950s), exhibits require careful control of temperature and humidity, and energy use (and waste) is generally out of sight to employees and visitors. As the accompanying chart shows, our electricity use spikes during the summer months for air conditioning (we have 37 air conditioning units), but our 2008 electricity usage (blue line) is significantly below our historical peak consumption (purple line).

Although many of the inefficient energy uses will be eliminated by a LEED-certified addition and renovation of the existing building in the coming years, the Museum is aggressively pursuing ways to increase efficiencies in the near term.

Despite the inherent challenges of working with an existing building, the Museum has reduced electricity consumption from a high of just over 4 million kWh a few years ago by monitoring temperatures and humidity levels and turning off certain HVAC components when the Museum is closed, installing efficient LED exit sign lighting, installing more efficient lighting both as bulbs and fixtures fail and proactively to remove inefficient fixtures, and installing motion sensors in bathrooms, stairwells, certain hallways and other areas that have a number of light fixtures but aren't consistently occupied.

The Museum is also educating employees about efficient use of electricity. Part of the education effort involves understanding exactly how much energy each device in the Museum uses. We also want to prioritize investments in efficiency projects that make sense both from an energy reduction perspective and from a return on investment perspective (especially if certain upgrades may be removed in a renovation). We have started a whole building energy audit, cataloging: each light fixture and bulb type, every device that is plugged into an electrical outlet, and inventorying more than 75 motors than run in exhaust fans, air compressors, and the heating and cooling system. As this spreadsheet is developed, we will publish it here and provide a template for other organizations.

The Museum has one electricity meter, so it can be difficult to determine how much energy individual devices are using - especially in a building as large as the Museum with thousands of light fixtures and devices drawing electricity.

Initially, we planned to emphasize turning off lights and devices when not in use and the elimination of vampire devices or phantom loads (energy consumed by devices that are turned off, but still plugged in). Phantom loads can make up anywhere from 6% to 20% of the annual energy use—by being plugged in and turned off—and nationally, phantom loads consume the equivalent of 7 average size power plants and up to $3 billion in energy costs.

Below is the start of our electricity audit of devices at the Museum.  We will be updating this list as more devices are tested and we will share the results of our action plans to reduce our electricity consumption and carbon footprint. 

Device picture Device name and location

Avg. W/hr

Annual kWh Annual Electricity Cost lbs CO2/year Notes
Coke Machine Coke Machine (Employee lunch room) 417 Watts 3652 kWh $365.29 6,648 lbs CO2 Front lightbulbs have already been removed. Investigating replacing with Energy Star machine and using Vending Miser motion sensor
Pepsi Machine Pepsi Machine (Employee lunch room) 322 Watts 2820 kWh $282.07 5,134 lbs CO2 Machine is smaller than Coke machine. Front lightbulbs have already been removed. Investigating replacing with Energy Star machine and using Vending Miser motion sensor
Vending Machine Vending Machine (Employee lunch room) 21 Watts 184 kWh $18.40 335 lbs CO2 Employee lunch room. Lightbulbs removed.
Refrigerator Refrigerator (4th floor kitchen) 63 Watts 552 kWh $55.20 1,004 lbs CO2 Used 1.11 kWh over 24 hour period.
Refrigerator Refrigerator (Employee lunch room) 79 Watts 692 kWh $69.20 1,260 lbs CO2 2003 Energy Star model.
Water Cooler Water Cooler (Employee lunch room) 83 Watts 727 kWh $72.71 1,323 lbs CO2 Hot and Cold water, measured over 24 hour period.
Coffee Machine Bunn Pour-Omatic Coffee Machine 1 (Employee lunch room) 138 Watts 692 kWh $120.89 2,200 lbs CO2 Consumed 13 kWh over 94 hours (brewing, standby instant hot water)
  Bunn Pour-Omatic Coffee Machine 2 (4th Floor Kitchen) 50 Watts 438 kWh $43.80 797 lbs CO2 Consumed 1.2kW over 24 hours of typical use = 50W/hr. Burner uses 100W when turned on. Used less often than employee lunch room machine
Microwave Microwave (Employee lunch room) 21 Watts 184 kWh $18.40 335 lbs CO2 Used .5kWh over 24 hour period.  Standby power TBD.
D630 Laptop Dell D630 Laptop (GCBL offices) 23 Watts 48 kWh $4.80 87 lbs CO2 Estimated 2080 hours of operation per year. Consumption measured over 8 hours on
GCBL Server Dell PowerEdge 840 Server (GCBL offices) 100 Watts 876 kWh $87.60 1,594 lbs CO2 Server currently runs 24x7 (8760 hours per year). Includes battery backup, external hard drives
Ricoh 2500C Ricoh 2500C Copier (Exec mail room) 61 Watts 534 kWh $53.44 973 lbs CO2 Used 14.3kWh over 233 hours of normal operation.  In energy saver mode, draws 8 Watts.
Postage Meter Postage Meter (Exec mail room) 43 Watts 377 kWh $37.67 686 lbs CO2 26 hour reading, 1.12kWh
Open top refrigerator cooler 1 (Cafe) 630 Watts 5519 kWh $551.88 10,044 lbs CO2 Consumed 56.1kWh over 89 hours = 630W/hr.
Open top refrigerator cooler 2 (Cafe) 630 Watts 5519 kWh $551.88 10,044 lbs CO2 Consumed 56.1kWh over 89 hours = 630W/hr.
Sanyo XtraX Projector - Standby (Conference Room) 7.5 Watts 64.2 kWh $6.42 117 lbs CO2 Consumed 180W in standby mode over 23 hours. Estimated projector is in standby 8560 hours per year.
Sanyo XtraX Projector - In Use(Conference Room) 185 Watts 37 kWh $3.70 67 lbs CO2 Consumes 185W when projector turned on. Estimated that projector is in use 200 hours a year. (200*185W=37kWh)  
Amana Upright Food Freezer Model AU12 (Physical Antropology) 115Watts 1007 kWh $100.74 1,833 lbs CO2 Donation to Museum
Sears Kenmore Freezer Model 20098 (Physical Anthropology) 93 Watts 814 kWh $81.47 1,483 lbs CO2 Donation to Museum
Magic Chef Minifridge 22 Watts 192 kWh $19.27 351 lbs CO2 1.14 kW over 52.5 hours = 22 W/hr avg
GE No Frost Upright Fridge/Freezer Model TBF21DVF (Vertebrate Zoology) 203 Watts 1778 kWh $177.83 3,326 lbs CO2 Donation to Museum
Polycom Voice Station 100 4.6 Watts 40.3 kWh $4.03 73 lbs CO2 Consumed 540W over 117 hours
TOTALS - 22 devices     27,266 kWh $2,726.2 49,625 lbs CO2 (25 short tons)  

We've currently identified 25 tons out of 3,185 yearly CO2 tons of our footprint, but there are some obvious areas for improvement already (vending machines, coolers, coffee machines). The Museum receives a number of donated freezers and refrigerators, many of which are 20+ years old. We are currently evaluating these devices to determine if it makes sense to accept these donations.

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