Importance of standby power-

Designing, specifying, installing and operating power generation systems is a complex, serious business.1 Increasingly, sizing and specifying standby power systems is becoming a business decision driven by factors including economic risk assessment and a growing reliance on a perpetual source of electric power.2 High-horsepower power systems are designed with specific features to meet the life protection, safety, mission-critical, environmental, and independent power generation requirements at airports, data centres, semiconductor manufacturing, government and health care facilities, large commercial buildings, and water and wastewater treatment.3

When designing an enterprise data centre, for example, owners, architects, and engineers have to understand and decide on everything from site to signage. Some of the most critical decisions revolve around the best power distribution infrastructure to suit the facility’s needs. 4While data centre designs, requirements and specifications are as varied as the industries they support, uptime reliability remains the ultimate objective across all industries.5 Fault tolerance is an indicator of reliability, and different industries require varying levels of tolerance. For data centre managers, this concept is often referred to as uptime reliability – an indicator that is the true measure of the data centre’s success and the verification of its operational capacity.6 Designing power systems that achieve high availability performance requires expert attention to system architecture and requisite equipment redundancy, while also avoiding unnecessary duplication that may impede system reliability.7

Downtime means lost revenue

Today, the process of specifying standby power systems must take into account how much a utility outage will cost per hour in terms of lost production, lost products, lost revenue, lost data, or customer dissatisfaction. It also needs to address how much a company is willing to invest in a standby or on-site power system to minimise these risks.8 Against these considerations, almost all facility electrical loads are considered essential because all are necessary for business continuity. Based on research by contingency planning organisations, an electrical outage can cost in excess of $1 million per hour for the average large business. Such losses may go up to $2-3 million per hour or higher for industries such as semiconductor manufacturing, energy production, and telecommunications.

Given these high-stake risks, facility managers in Southeast Asia and across the world need to evaluate new options for providing a continuous supply of power. Major outages like the power blackout across multiple areas in Thailand, which affected nearly 8 million residents and tourists in May,9 and the blackout in Luzon, Philippines, at the start of a sweltering summer this year,10 have focused attention on the devastating business impact that extended power outages can have. In addition, today’s dependence on constantly available electric power demands that every business has some level of standby power.11

Understanding your power needs

As the risk of financial loss due to an outage increases, so does the justification for businesses to have standby power systems that meet more than just the minimum safety or electrical code requirements. This requirement can be divided into four categories:

  • No standby power system required
  • Minimal backup power required for life safety, security, and computer systems
  • Need substantial standby power system to maintain operations during short outages
  • Need near-total standby power to maintain operations for extended time periods.

Finding the right fit for your business

After evaluating the risks and specifying the degree of standby power protection required, an initial sizing estimate of the standby power system can begin by establishing the following project parameters:

  • Minimum generator set load/capacity
  • Maximum allowable frequency and voltage dips
  • Altitude and ambient temperature of the generator set’s location
  • Type of fuel
  • Generator voltage, generator frequency, and number of phases

Identifying loads

A standby generator typically powers a variety of loads with different operating characteristics, such as linear and non-linear loads; with some loads that are extremely sensitive to voltage disturbances; and loads that cycle on and off. The generator must accommodate the highest anticipated starting, peak, and running load expected. In addition to determining the mathematical sum of all the electrical loads, the following factors also affect the sizing of generator sets12:

  • Power factor
  • Single-phase loads and load imbalance
  • Peak power surges caused by loads that cycle on and off
  • Motor loads over 30 kW
  • Non-linear variable frequency drives
  • Non-linear uninterruptible power supply
  • Medical imaging loads
  • Lighting loads
  • Regenerative loads

The case for a multi-generator system

A single, large diesel standby generator may have the capacity to supply all critical loads, but it is often recommended to divide the load among smaller, multiple standby generators to maximise reliability and operational flexibility. Should one standby generator not start when required, the others will kick in and supply the load by drawing on their built-in reserve capacities. Also, with multiple generator systems, one unit can be taken off-line for maintenance without affecting the availability of standby power.13

Another consideration in the general sizing of a standby power system is the amount of physical space available to house the system. Standby systems situated inside buildings should have a dedicated room with sufficient airflow for cooling and sufficient space for maintenance activities. Large standby power systems may even have their own separate building, or be located outdoors in weather-tight and sound-attenuated enclosures or ISO-style containers.

Managing on-site power use

Increasingly, large businesses are opting for on-site power systems which, in addition to serving as standby power, also serve to control overall energy costs. These power systems are set up to run in parallel with the local utility in order to take advantage of utility incentive programmes in place or potential future utility incentive programmes. Utility “uninterruptible” programmes give businesses a credit on their electric bill for allowing the utility to determine when the standby power system should be operated to provide all or part of the business’ load. In this way, the utility benefits from being able to shed part of its load during times of peak demand and reduce strain on its generation and transmission system. In turn, the business benefits from lower electric rates.

Many of these foregoing factors can be determined long before a business owner sits down with a consulting engineer, an electrical contractor, or a generator manufacturer to discuss detailed panning for a standby power system. Before the discussion turns to technical matters and assessment of “how much hardware”, this business-model thinking will have helped companies consider the economic risk associated with a utility outage, and their desired level of response to that risk.14

Choosing the right standby power supplier

While it may be tempting to purchase a cheaper generator set or the first one that meets an immediate need, it is important to consider both the quality of the product and the capability of the supplier, as these will have a considerable impact on the generator’s overall lifespan. Businesses are strongly recommended to approach a supplier that possesses the expertise and has a proven track record in offering power generation products and total solutions, including application expertise, together with full service capability.

Apart from technical expertise, the supplier must be able to provide a high-performance and reliable solution that is tailored to the customer’s specific needs. This involves working with the customer to determine the economic risk associated with a utility outage and the customer’s desired level of response when planning for a standby power system.

Power systems, like any mechanical or electrical infrastructure, are susceptible to eventual failure – it is not a matter of if this will happen, but when. This is precisely why utility planners build redundancy into power systems. But when the equipment does go down, operators must have ready access to reliable service for accurate diagnostics and quick, cost-effective system repairs. A single-sourced system offers operators the advantage of dealing with only one manufacturer’s service technician to troubleshoot the entire system, drastically reducing the number of service calls and overall time spent on site with equipment that is down. Moreover, the technician has the advantage of having innate knowledge of, and complete visibility to, the entire power system.15

Mark James Vanderkolk

Director, Asia Pacific, Power Systems Business, Cummins Power Generation

Mark has been with Cummins since 1988 in various roles across multiple business units. He has experience in power generation markets in Asia-Pac, Europe, Mid East, Africa and Latin America. Mark holds an MBA from the University of Southern Queensland together with an Associate Diploma in Business Administration from Queensland University and is a Certified Master Electrician as well as a certified 6 Sigma Green Belt. Mark has exposure across all parts of Cummins Power Generation business, including gensets, genset controls, paralleling systems and automatic transfer switches.

  • 1Cummins Power Generation: Complete Power Systems – Accountability for Every Aspect of Onsite Power Delivery;
  • 2Cummins Power Generation: White Paper: Economic Risk Assessment Drives Today’s Standby Power System decisions;
  • 3Cummins Power Generation: Complete Power Systems – Accountability for Every Aspect of Onsite Power Delivery;
  • 4Cummins Power Generation: White Paper: Data Center Design Decisions and Their Impact on Power System Infrastructure;
  •  5Achieving Uptime Reliability Through Focused Innovation;
  •  6Cummins Power Generation: White Paper: Top Five Considerations for Specifying a Data Center Power System;
  • 7Achieving Uptime Reliability Through Focused Innovation;
  • 8Cummins Power Generation: White Paper: Economic Risk Assessment Drives Today’s Standby Power System Decisions;
  • 9TMCnet.com: Thailand Suffers Power Outage, Leading Many to Question What Happened to Its Power Protection Plan
  • 10TIME: No End in Sight to the Energy Crisis that Plagues the Philippines;
  • 11Cummins Power Generation: White Paper: Economic Risk Assessment Drives Today’s Sandby Power System Decisions;
  • 12Cummins Power Generation: White Paper: Economic Risk Assessment Drives Today’s Standby Power System Decisions;
  • 13Cummins Power Generation: White Paper: Economic Risk Assessment Drives Today’s Standby Power System Decisions;
  • 14Cummins Power Generation: White Paper: Economic Risk Assessment Drives Today’s Standby Power System Decisions;
  • 15Cummins Power Generation: White Paper: Top Five Considerations for Specifying a Data Center Power System