California Continues Drive for Computer and Display Efficiency

Tue, 05/31/2016 - 15:04 -- MrGreen

California got one step closer to adopting a comprehensive energy efficiency standard for computers, monitors, and displays with its recent staff report publication, Revised Analysis of Computers, Computer Monitors, and Signage Displays.

According to the California Energy Commission (CEC), the standards could save 2,500 GWh per year, reducing consumer and business electricity costs by up to $400 million annually. Computers, monitors, and signage displays currently account for up to 4.4% of California's residential sector and 10% of the state's commercial sector electricity consumption.

Computer products covered by the CEC's proposal include desktops, notebooks, thin-clients, small-scale servers, and workstations. Excluded are tablets, smartphones, game consoles, handheld gaming devices, servers other than small-scale units, and industrial computers. The CEC believes that the major opportunity for energy savings in computers is in limiting the unit's energy consumption during non-productive idle, standby, and off modes. The proposed regulation harmonizes with the ENERGY STAR Program Requirements for Computers version 6.1, adopting a Total Energy Consumption (TEC) approach. A computer's TEC is calculated using the following formula:

TEC Calculation (ETEC) for Desktop, Integrated Desktop, Thin Client, & Notebook Computers


Where: POFF = measured power consumption in off mode (W), PSLEEP = measured power consumption in sleep mode (W), PLONG_IDLE = measured power consumption in long idle mode (W), PSHORT_IDLE = measured power consumption in short idle mode (W), and TOFF, TSLEEP, TLONG_IDLE, and TSHORT_IDLE are mode weightings as specified in ENERGY STAR Program Requirements for Computers version 6.1, Table 3.

Energy Consumption Standards for Computers

Computer Type Maximum total energy consumption starting 1/1/18
Desktops and Thin-Clients 50 kWh/yr + applicable adders
Notebook 30 kWh/yr + applicable adders

List of Potentially Applicable Adders (partial list– see standard for complete list)

Function Desktop and Thin-Client Adder (kWh/yr) Notebook Adder (kWh/yr)
Memory (per module) 2.5 2.5
Energy Efficient Ethernet 0.9 0.9
Storage 3.5 inch Drive: 2.6
2.5 inch Drive: 4.5
Solid State Memory: 0.5
Other: 26
Expandability Score For ES < 200: 0
For ES ≥200: (ES-200)/20
Integrated Display 8.76 x 0.35 x (1+EP) x
(4xr + 0.05xA)
8.76 x 0.30 x (1+EP) x
(2xr + 0.02xA)
Notes: "r" is the megapixel resolution of the display, "A" is the viewable screen area in in2, EP = 0 for standard displays, EP = 0.3 for enhanced displays < 27 inches in diagonal length, and EP = 0.75 for enhanced displays ≥ 27 inches in diagonal length

In addition to the above, computers must ship with power management settings that automatically powers down the unit into sleep mode or off mode within 30 minutes of user inactivity and puts connected displays into sleep mode within 15 minutes of user inactivity.

Workstation computers and small scale servers manufactured after January 1, 2018, must comply with the following:

  • Powered using an 80+ Gold internal power supply
  • Incorporate Energy Efficient Ethernet functionality
  • Transition into sleep mode within 30 minutes of user inactivity and power down connected displays within 15 minutes of user inactivity

Displays covered by the CEC proposal include computer monitors with a diagonal screen size of 17 inches or greater and commercial signage displays (excluding electronic billboards and digital picture frames). The modal power consumption metrics used for computer monitors are similar to the ENERGY STAR Program Requirements for Displays, version 6.0. The proposed limits for products manufactured after January 1, 2018 are shown in the following two tables. Monitors with touch screen capability are allowed an additional one watt in on mode power.

Maximum Power Requirements by Mode – Computer Monitors

Diagonal Screen Size in inches (d) On Mode Power (W) (PON_MAX) Sleep Mode Power (W) (PSLEEP_MAX) Off Mode Power (W) (POFF_MAX)
Resolutions ≤ 5.0 MP
17" ≤d <23" (4.2xr) + (0.02xA) +2.2 0.5 0.3
23" ≤d <25" (4.2xr) + (0.04xA) -2.4 0.5 0.3
25" ≤d <61" (4.2xr) + (0.07xA) -10.2 0.5 0.3
Resolutions > 5.0 MP
17" ≤d <23" 21 + (0.02xA) +2.2 0.5 0.3
23" ≤d <25" 21 + (0.04xA) -2.4 0.5 0.3
25" ≤d <61" 21 + (0.07xA) -10.2 0.5 0.3
Note: r = screen resolution (megapixels), A = viewable screen area (in2)

Maximum Power Requirements by Mode – Signage Displays

Screen Size (Area in in2 ) On Mode Power (W) (PON_MAX) Sleep Mode (W) Minimum Power Factor (for P≥ 100 W)
A<1400 (0.12xA) +25 1 0.9
Note: A is a viewable screen area (in2)

In late April, a workshop was held at the CEC's headquarters in Sacramento to provide interested stakeholders an opportunity to comment on the proposed standards. For a copy of the staff report with efficiency requirements, visit the CEC Appliance Efficiency Pre-ruling webpage. For information presented at the April workshop and resulting stakeholder comments, click here.