Office Plug Loads:

Energy Use and Savings

Opportunities

Cathy Higgins, NBI Research Director

April 25, 2013

Answer

1. How much energy

is used by office

equipment?

2. How can energy

use be lowered?

3. How much savings

is possible?

3 Questions:

…based on field research

How much energy is used

• Typical Office Spec:

4-6 watt per square foot (W/sf)

Actual 1990 ~ <1.5 W/sf.

Actual now <1 W/sf

• Computers:

– Originally - 300+ watts

– Early 1990s - 120 watts

– EPA in mid 90s - 75 watts/12 in sleep mode

– Laptops – 15 watts

5 Source: Graph created by Ecova with data from EIA 2008 Annual Energy Outlook

Energy Use Trends

Source: D. Kaneda, IDeAs and Intregal Engineering

Types of Plug Loads

Study Set = Office Equipment

Measured Energy Use Small High Performance Office

Oakland, CA

30%

34%

26%

10%

Plug Loads

Natural Gas

HVAC and NetElectric

Lights

Non-server plug loads ~ 6% of total bldg energy

Desktop

Computers,

Imaging

Equipment and

Monitors

were 95% of the

total energy use of

the studied loads

Percent of the Studied Plug Load Energy Use – Office

Energy Use by Device Category

Off Hour Ratios – too high!

Success

Not

Findings

How to lower energy use and

savings amounts

1. Software optimize energy

saving modes

using power

management

controlled at

equipment or at

the information

technology (IT)

department level

2. Hardware use advanced power

strips and timers to

reduce or eliminate

loads off hours;

procure energy

efficient office

equipment with best

in class when

upgrading or

replacing

14

Idle Mode: ~58W Baseline: 9.6 kWh/week

65% of Desktop Computers Were Often Left Operating in Idle Mode or on Overnight and Weekends

Idle Mode: ~58W Baseline: 9.6 kWh/week

Idle Mode: ~20W Improved Case: 0.43 kWh/week

Energy Reduction = 95%!

Replaced a Desktop Computer by a Mini-Desktop Computer and Enabled Power Management

Printer, Calculator, Speakers Drew Continuous Power Overnight and on Weekends

Baseline: 5.8 kWh/week

Timer Plug Strip to Turn Off the Printer, Calculator and Computer Speakers from 9 p.m. to 6 a.m. on Week Days and all Day on Weekends

Baseline: 5.8 kWh/week Improved Case: 3.26 kWh/week

Energy Reduction = 44%!

Most Computer Monitors Drew High Active Power Compared to High-Efficiency Models Available Today

18

Active Mode: ~40 W Baseline: 0.37 kWh/week

Replaced a Computer Monitor with a Comparable, High-Efficiency Model

19

Active Mode: ~15 W Baseline: 0.37 kWh/week Improved case: 0.24 kWh/week

Energy Reduction

= 35%!

Baseline Monitor & Top Ten

- 43%

3. People Engage occupants and operators: provide simple, easy-to-understand information and reminders (prompts) to encourage users to change personal practices (behaviors) so equipment is not left operating unnecessarily. Utilize green leases, campaigns and competitions

Energy Report to one user

0

50

100

150

200

250

300

350

400

BASELINE CASE IMPROVED CASE - ENERGY REPORT

Small Office

Ann

ual E

nerg

y Co

nsum

ptio

n (k

Wh)

-57%

- 57%

Behavioral Approach % Savings over Base

(avg)

Calendar Reminders 2-31% (6%)

Poster with Remote Control Didn’t use

Feedback Monitors 51%

Energy Report 57%

Tenant Guidelines, Campaigns

Small High Performance Office Oakland, CA

Savings Outcomes

Summary for Low-No Cost Savings

• Software: Equipment Power

Mgmt Software - Turn equipment off when not in use (at device or thru IT)

• Hardware: Plug Strips and Timers to control equipment at the device

• People/Behavior: Prompts, Feedback, Campaigns, Green Policies, Competitions.

Best in Class Equipment

• High Savings (20-90% better)

• Only Cost Effective at procurement

• Replace desktops with laptops

• Monitors

• Imaging Equipment

• Peripherals

Consider reductions in the number of

plug in items.

Ensure all items are

powered down when not in use

Buffalo, NY City Hall - 1,000 Employees Estimated Savings of $71,400 at 12 cents/kWh

Case Study – Real Savings

Source: Sabo, NYSERDA Power Mgmt. Program

Equipment

# of

Units

Low-cost/No-cost Energy

Efficiency Measures

% Saved

With

Extreme

Office

Makeover

Total

Electric

Bill

Savings @

$0.12

PC/Monitors 1000 Shut off & Power Mgmt 69% $55,857

Printers 330 Shut off & Power Mgmt 31% $4,138

Copiers/Doc. Centers 75 Shut off & Power Mgmt 67% $6,815

Faxes/Scanners/MFDs 25 Shut off & Power Mgmt 37% $289

Task Lights 38 Replace w/CFLs 72% $117

Water Coolers 43 Turn off Hot Water Taps 48% $1,522

Refrigerators 22 Replace Old Ineffic. Units 54% $1,718

Coffee Machines (Lg) 17 Turn off at night/timers 25% $597

Vending Machines 2 Replace w/ENERGY STAR 62% $354

Total Equipment Users 1000 62% $71,407

Whole Building

View • Office equipment:

• 6% of the total building

energy use at the study sites

• 6-12% at avg. bldgs

• Savings represented 1-3% at

the study sites.

• Could be double in average

buildings thus 2-6% of total

Market

Connections

Outcomes

Zero Energy Buildings

Source: Pleiss, Hootman, NREL

Plug Load Points

• Plug loads in offices are now many times larger than

efficient lighting loads

• Even in the “best” offices, plug load use in

Unoccupied hours is at least 50% of the Occupied

hours

• NBI measured peak load density of all loads, which

best reflects installed capacity, maxed out at 2.0

W/SF

• You can’t get to savings targets without addressing

plug loads

Office Plug Loads:

Best Practice Guideline

Plug

Guide

to

Office

Equipm

ent

Savings

Summary in Sets of 3 • Energy Use of office equipment plug loads:

– Desktop Computers

– Imaging Equipment and Peripherals

– Computer Monitors

• Approaches to save energy:

– Software

– Hardware

– People: Information and Prompts

• Priority no–low cost strategies and technologies*:

– Aggressive Power Management Settings

– Plug Strips and Timers

– Occupant Reminders and Prompts

*Note: Replacing equipment with low-energy models is a high saving strategy and is low or no cost at the time of planned replacement.

Questions?