High-Efficiency UPS Equipment for a Data Center

Summary

High-Efficiency UPS Equipment for a Data Center

Data Center UPS Equipment: High Efficiency vs. Standard

Installing new, more efficient UPS units as a direct replacement to reduce losses and save energy.

Synopsis:

Uninterruptable Power Supplies (UPS) deliver instant power to data centers and/or end use equipment during power supply interruptions. UPS equipment is designed to temporarily provide power to operate data center equipment until emergency power generation comes online or the equipment can be properly shut down. UPS are a necessity in data centers unless servers have their own backup batteries, but conventional UPS are not very energy efficient. While the energy efficiency of UPS technology has increased and continues to improve, designers and operators of data centers may not be aware of these advances and could be wasting energy.

When designing a new data center or when existing UPS equipment fails or is scheduled for an end-of-life replacement, new high-efficiency UPS equipment should be specified. If an existing UPS is older than 10 years, it may be cost-effective to replace it immediately (U.S. DOE, 2008). Specifications for high-efficiency UPS equipment can include the following factors: size of data center and reliability requirements as well as the type and part-load performance.

Through the selection of high-efficiency UPS equipment, data centers can reduce energy waste while maintaining reliability. Improved efficiency of UPS equipment is due in part to improvements in switching technology (insulated-gate bipolar transistor replacing silicon controlled rectifier) and controls (digital signal processing replacing analog control). The efficiency improvement resulting from installing high-efficiency UPS equipment ranges from 0.5% to 7% (LBNL, 2005). Additional benefits of high-efficiency UPS also include reduced facility cooling needs and smaller UPS equipment footprint.

Energy Savings: 3%

Energy Savings Rating: Limited Assessment What's this?

Level	Status	Description
1	Concept not validated	Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.
2	Concept validated:	An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.
3	Limited assessment	An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline.
4	Extensive assessment	Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions.
5	Comprehensive analysis	Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.
6	Approved measure	Protocols for technology application are established and approved.

TAG Technical Score: 3.0

Details

High-Efficiency UPS Equipment for a Data Center

Data Center UPS Equipment: High Efficiency vs. Standard

Installing new, more efficient UPS units as a direct replacement to reduce losses and save energy.

Item ID: 488

Sector: Commercial, Industrial

Energy System: Power Systems--Backup Power

Technical Advisory Group: 2013 Information Technology TAG (#8)
Average TAG Rating: 3.85 out of 5
TAG Ranking Date: 10/25/2013
TAG Rating Commentary:

Good idea - but not emerging - well known. Challenge is encouraging replacement of working UPS based only on marginal increase in efficiency.
UPS replacements are typically costly and disruptive enough that they're only replaced at end of life. Efficiency gains of high efficiency units tend not to be cost effective as an efficiency only upgrade.
Easy, available, cost-effective.
Also one that has an effective bypass mode to eliminate conversion loss.
But not new/emerging.
Not an ET.
I think the savings potential is higher than this description indicates.
Nearly all datacenters simply must have a UPS solution.

Synopsis:

Baseline Example:

Baseline Description: Conventional 70 kVA UPS
Baseline Energy Use: 218794 kWh per year per unit

Comments:

Based on a conventional 70 kVA UPS:
- 38% load
- 85.2% load point efficiency
- 80% Power Factor
- 24-7 operation (8,760 hours/year)
(LBNL, 2005, page 36)

Manufacturer's Energy Savings Claims:

"Typical" Savings: 2%
Savings Range: From 1% to 8%

Comments:

(APC, 2013-10-11)

Best Estimate of Energy Savings:

"Typical" Savings: 3%
Low and High Energy Savings: 1% to 7%
Energy Savings Reliability: 3 - Limited Assessment

Comments:

Baseline Energy Use:

Based on a 70 kVA UPS:
- 38% load, 85.2% (typical efficiency) and 86.6% (high efficiency) load point efficiencies, 80% Power Factor
- 24-7 operation (8,760 hours/year)
- Annual Energy Consumption is 218,794 kWh/yr (typical efficiency) and 215,257 kWh/yr (high efficiency)
- Annual Energy Savings = (218,794 - 215,257) / (218,794) = 1.6%

The range of energy savings is dependent on the size of the UPS.
- For a 10 kVA UPS:
  - 38% load, 83.6% (typical efficiency) and 84.2% (high efficiency) load point efficiencies, 80% Power Factor
  - 24-7 operation (8,760 hours/year)
  - Annual Energy Consumption is 31,855 kWh/yr (typical efficiency) and 31,628 kWh/yr (high efficiency)
  - Annual Energy Savings = (31,855- 31,628) / (31,855) = 0.7%
- For a 200 kVA UPS:
  - 38% load, 85.2% (typical efficiency) and 93.0% (high efficiency) load point efficiencies, 80% Power Factor
  - 24-7 operation (8,760 hours/year)
  - Annual Energy Consumption is 625,127 kWh/yr (typical efficiency) and 572,697 kWh/yr (high efficiency)
  - Annual Energy Savings = (625,127- 572,697) / (625,127) = 8.4%
Source: (LBNL, 2005, pages 36-37)

Energy Use of Emerging Technology:

212,230.2 kWh per unit per year What's this?

Energy Use of an Emerging Technology is based upon the following algorithm.

Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))

Comments:

According to the Green Grid, UPS equipment has a lifetime of up to 20 years. (Garnier, 2012) Equipment life may be impacted by the lifespan of individual components within the UPS equipment.

Technical Potential:
Units: unit
Currently no data available.

First Cost:

Installed first cost per: unit

Comments:

Prices based on cost data from: http://www.cdw.com/shop/products/APC-Symmetra-PX-70kW-Scalable-to-100kW-power-array-70-kW-70000-VA/2917939.aspx
UPS unit costs vary depending on the size of equipment. The $/kW output for UPS are as follows:
- 10 kW: $775/kW
- 70 kW: $815/kW
- 200 kW: $675/kW
Installation costs are estimated to be approximately 20% of the equipment cost.

Unfortunately, we do not have good cost data for energy efficient versus standard efficiency UPS equipment. Equipment replacement costs are very high and retrofits based on energy savings will likely make sense only at the end-of-life of the baseline unit.

Cost Effectiveness:

Simple payback, new construction (years): N/A

Simple payback, retrofit (years): N/A

What's this?

Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.

Detailed Description:

High-efficiency UPS equipment offers a more efficient power delivery with battery backup than conventional UPS equipment. Efficiency improvements are due in part to improvements in switching technology (insulated-gate bipolar transistor replacing silicon controlled rectifier) and controls (digital signal processing replacing analog control), reducing the energy losses in power electronics of the UPS.

Product Information:
APC, Symmetra PX 70 kW

Standard Practice:

Standard practice is to install UPS equipment that satisfies the power delivery and reliability requirements within a data center for a good price.

Development Status:

UPS systems are commercially available and are likely to inherently be more efficient than legacy units, especially if they are older than 10 years. Manufacturers include: Dell, IBM, APC, Emerson Network Power, GE

Non-Energy Benefits:

Newer UPS equipment that is more efficient will have less heat rejected into the datacenter. Additional benefits may include increased reliability of having a new unit installed versus having a legacy unit in operations.

End User Drawbacks:

Higher first cost and installation. Since some UPS equipment feeds power to an entire datacenter, the installation may require planned downtime, which may be a problem for datacenter facilities with 24-7 operation.

Operations and Maintenance Costs:

Comments:

Operations and maintenance costs for datacenter UPS systems will vary depending on the size, however preventive maintenance is key in preserving reliability and energy efficiency. (Mulligan, 2013)

Effective Life:

Anticipated Lifespan of Emerging Technology: 20 years

Comments:

According to the Green Grid, UPS equipment has a lifetime of up to 20 years. (Garnier, 2012) Equipment life may be impacted by the lifespan of individual components within the UPS equipment.

Competing Technologies:

There may be variations of UPS equipment such as Modular UPS with VMMS control which may offer better performance and reliability as well as energy savings. Alternative technologies to UPS battery backup might include flywheels and ultracapacitors. Non-financial factors that should be used in a comparison include: typical runtime (duration), history in the marketplace, operating conditions, environmental impact, safety, power range, reliability, maintenance requirements, recharge time and number of deep charge/discharge cycles. (McCluer, 2011)

Reference and Citations:

LBNL, 01/01/2005. High Performance Buildings: Data Centers Uninterruptible Power Supplies (UPS)
Lawrence Berkeley National Lab
Special Notes: pages 36-39

U.S. DOE, 06/11/2008. Data Center Assessment Tool Suite
U.S. Department of Energy Save Energy Now
Special Notes: page 131

Public Interest Energy Research Program, 09/01/2008. Uninterruptible Power Supplies: A Data Center Efficiency Opportunity
State of California Energy Commission

APC, 10/11/2013. Making Large UPS Systems More Efficient
Schneider Electric
Special Notes: pages 5-8

Art Mulligan, 11/05/2013. UPS Service Plans: How to Maximize Your Returns
Eaton Corporation

Christophe Garnier, 01/01/2012. Data Centre Life Cycle Assessment Guidelines
The Green Grid , White Paper #45, v2

Stephen McCluer, 01/01/2011. Comparing Data Center Batteries, Flywheels and Ultracapacitors
White Paper #65 , Revision 2
Special Notes: page 14

Rank & Scores

High-Efficiency UPS Equipment for a Data Center

2013 Information Technology TAG (#8)

Technical Advisory Group: 2013 Information Technology TAG (#8)
TAG Ranking: 4 out of 57
Average TAG Rating: 3.85 out of 5
TAG Ranking Date: 10/25/2013
TAG Rating Commentary:

Good idea - but not emerging - well known. Challenge is encouraging replacement of working UPS based only on marginal increase in efficiency.
UPS replacements are typically costly and disruptive enough that they're only replaced at end of life. Efficiency gains of high efficiency units tend not to be cost effective as an efficiency only upgrade.
Easy, available, cost-effective.
Also one that has an effective bypass mode to eliminate conversion loss.
But not new/emerging.
Not an ET.
I think the savings potential is higher than this description indicates.
Nearly all datacenters simply must have a UPS solution.

Technical Score Details

TAG Technical Score: 3.0 out of 5

How significant and reliable are the energy savings?
Energy Savings Score: 2.7 Comments:

More effective for larger and higher tier DC's
Ranked low because energy savings are relatively low and payback is very long.
Particularly line interactive firmware upgrades UPS systems on low loaded UPS
Savings seem to be relatively low. On the order of 10%. Looks like design and size selection are important factors in energy savings.
0.7% PNW technical potential, according to NEEA study
Energy savings tend to be improvements in the range of 4% - 7%. Savings are less reliable in UPS units that operate at higher efficiency as an operator selected Eco-mode or Energy saver System. UPS units tend to serve stable, continuous loads (8,760 hrs), so smaller efficiency improvements can still result in significant energy savings
Very reliable, but not a huge piece of the pie

How great are the non-energy advantages for adopting this technology?
Non-Energy Benefits Score: 2.5
Comments:

Replacing or eliminating old batteries would be a benefit to the end user
Sometimes a newer UPS system comes with more robust or advanced control and monitoring abilities.
Better designed systems could result in better reliability.
There are no other benefits other than energy efficiency.
Newer UPS units typically include better monitoring and metering capability
Can eliminate unneeded equipment

How ready are product and provider to scale up for widespread use in the Pacific Northwest?
Technology Readiness Score: 4.2
Comments:

Efficient UPS systems are readily available
Seem to be quite a few major vendors in this space.
We are seeing more widespread interest and actual deployments of higher efficiency UPS units in our utility service area. UPS units are typically replaced at the end of their useful life and not solely for an efficiency gain. It's typically too expensive to justify a new UPS purchase based on energy savings. There is very good uptake from data center operators choosing UPS units that operate at 95% - 98% efficiency compared to a less efficient (90% - 91%) UPS system that they typically consider when replacing an end of life UPS.

How easy is it to change to the proposed technology?
Ease of Adoption Score: 2.9
Comments:

Would require a major shut down for most data centers.
Very disruptive and expensive to implement.
Seems to be moderate difficulty for new construction. Out of the question for retrofit. Operators seem to be reluctant to run units in eco-mode.
Good but only when the old equipment reaches end of life
Existing UPS equipment has a long life span and is rarely replaced before end of life. This measure will have by far the most applicability to new installations.
There are good reliable choices for data center operators to choose more efficient UPS systems. Some operators are reluctant to use energy saver or eco mode UPS systems that may not provide the same performance as their current less efficient "double conversion" UPS units. There are double conversion UPS units on the market now that are almost as efficient (94% - 97%) as the units operating in energy saver or eco mode that bypass the UPS unit unless there is a power
Pretty quick swap out that IT managers wouldn't be nervous about - wouldn't disrupt anything else

Considering all costs and all benefits, how good a purchase is this technology for the owner?
Value Score: 2.7
Comments:

Small savings, lots of industry resistance, just seems OK.
Value of choosing a more efficient UPS is very good when considered on an incremental cost basis. The site is going to purchase a new UPS. The decision is to choose a lower cost, less efficient model or higher cost higher, efficiency model. When the costs are analyzed on this basis payback for the higher efficiency UPS is typically 5 yrs or less, and can be less than 2 yrs. with a utility incentive.

Completed:
12/4/2013 3:57:05 PM
Last Edited:
12/4/2013 3:57:05 PM