The Whos and Watts of the Gen Set Market
Expert Ingersoll Rand Product Marketing Manager Todd Howe Discusses Generators
- Todd, give us a rundown of the major categories of generators on the market today. How are these power units grouped in the industry – by size, wattage, features?
With commercial generators available from as small as 1,000 watts to more than 2 megawatts, generators are an extremely broad product category and there are several different ways to segment those categories. Common methods include segmentation by power rating, type of fuel, stationary or mobile design, emergency standby or prime power duty or by product application.
- What are the differences between a homeowner-grade generator and a contractor-grade generator?
Generally speaking, a homeowner-grade generator will be designed for occasional use, such as during a power failure or for recreational use, whereas a contractor-grade generator needs to be designed for continuous use in jobsite environments. In addition, contractor grade generators may include additional features, such as mobility kits and auto idle control to suit the needs of construction applications.
- What is the best way for a professional to match applications and wattage requirements to buying a new generator?
 To properly size a generator, you need to understand the electrical requirements of each device that needs to be powered by the generator. At a minimum, the voltage and amperage need to be known for each device. That information is usually available on the data plate on the equipment or can come from the manual. If the actual data is not readily available, there are tables to assist in estimating the power requirements for various types of equipment. Voltage multiplied by the amperage will give the power -- the wattage -- requirement for the device.
As a simple example, suppose a contractor has an electric heater that is rated for 120 volts and 30 amps per the heater’s data plate. The power requirement of the heater is 120 × 30 = 3,600 watts. Therefore, the contractor needs a generator that produces at least 3,600 watts of output to power the heater.
Sizing gets somewhat more complex for certain devices. Electric motors, for example, require a certain amount of power to run, but require an extra amount of power briefly during startup. This extra amount of power can vary as much as five times over the amount of power required for the motor to run. Additional calculations are required to determine this startup “in-rush” and that calculation needs to be compared to the generator’s capabilities to ensure adequate sizing. Equipment that requires three phase voltage also requires slightly different calculations and must be sized to a generator that is capable of producing three phase voltage.
Although the sizing procedure can appear somewhat intimidating, generator suppliers are there to assist customers to accurately size generators for their application, especially for large or complex projects.
- How can a pro ensure he or she doesn’t overload their new generator?
Once the sizing requirements are determined, I typically recommend customers choose a generator that will operate at 75 to 85 percent of its rating. This ensures a margin of extra capacity is available to account for unexpected additional loads and will allow the generator to operate at its optimum efficiency.
- What are the common features available to new buyers?
Features and options vary considerably depending upon the type of generator. For portable generators, one of the most common options is a mobility kit. With larger, diesel powered generators, manufacturers have a large range of options available that allow the customer to customize the machine to suit the requirements of the application. Some of the most common options are digital control panels, cold weather start kits, auto start stop capability and external fuel tank connections. The decision to specify certain options typically depends on the expected use of the generator and specific needs dictated by the application.
- What’s the price range for most generator sets?
Pricing for generators varies greatly, from a few hundred dollars for a homeowner-grade, 5,000-watt portable to in excess of $350,000 for a containerized 1.5-megawatt unit.
- How big is the generator market today? Is it a growing industry?
The generator market has been growing steadily over the past several years with a lot of the growth attributed to heightened public awareness of the importance of emergency backup, rental and portable generators to restore power in the wake of weather related outages and other emergency situations. It’s difficult to gauge the number of generators sold annually, due to the broadness of the product categories available. Of the categories that we target, we look at the portable generator [less than 10,000-watt] market as being in excess of a $500 million market and the mobile generator market [10kW to 500kW] as being about a $240 million market. Our expectations are that the market will still be strong for 2007 albeit with slower growth than the record growth experienced in 2005 and 2006.
- How can a new buyer judge the quality of a gen set when it comes to features like portability, the engine, fuel tank and maintenance?
The key concern most buyers have about generators is that they must be reliable. These units are required because utility power isn’t available, so a failure with the generator can have significant consequences. A buyer should judge the quality of the components, such as the engine and also judge the assembly quality of the unit. Wire routing and robustness of wiring terminations in the control panel can often be indicators of quality assembly. Generators, especially portable units, experience a lot of vibration, so failures can occur from loose connections or inadequate tightening of components.
 In addition to quality, the buyer needs to ensure he has selected a generator that includes the features needed for the application. Large fuel tanks, for example, may be considered essential by a contractor who will run the generator for 10 hours a day, whereas a recreational user may not mind refueling the generator more frequently and could accept a smaller fuel tank. The old adage “you get what you pay for” most definitely applies to generators. Pricing will vary significantly for units with the same output rating depending upon the level of features included and the expected life cycle of the unit.
- What is “start-up” or “surge” wattage?
Start-up or surge wattage is a commonly listed rating in portable generator specifications. This is an overload rating to allow for the starting in-rush associated with the startup of electric motors. When sizing a generator, it is important that all the devices connected to the generator do not exceed the continuous rating of the generator, in order to prevent shutdown or damage due to overload. Because the starting in-rush for electric motors is a momentary event, the generator is designed to safely support that demand up to the limit of the surge rating, but only for a short period of time. Extended operation of the generator at the surge rating will potentially damage the generator or result in reduced service life.
- What types of safety requirements are imperative for safe and secure generator use?
 Generators have several areas that require safety concern. Of course they produce electricity, so care must be taken to prevent contact with live electrical parts and to prevent shock. Additionally, generators have rotating components and hot parts that, although guarded, an operator must be aware of and use caution when working around. Another far too common mistake is to use a generator in a confined space, such as a garage, which can result in the buildup of carbon monoxide from the engine exhaust and cause sickness or even death from prolonged exposure.
The generator’s instruction manual is an excellent source of valuable safety information and should be read thoroughly by anyone who may have to operate the unit. Also, the generator dealer can provide operator and safety training with respect to the use of the product. Lastly, a licensed electrician should be consulted to ensure proper connection and compliance with local and national electric codes, particularly on generator sets that are not equipped with receptacle outlets and require hardwire connection.
- What maintenance tips can you share to help our readership maintain their portable power plants?
Proper maintenance is a key requirement to ensuring your generator’s reliability, so that it’s ready when it’s needed. Again, the instruction manual and the generator dealer can provide recommendations to keep the unit serviced and operating at peak performance. Change the engine oil and filters as recommended in the manual. For units that get occasional use, one of the biggest issues is keeping the fuel system free of contaminants. For units that will be stored for long periods of time, a fuel stabilizing additive should be used to prevent fuel degradation that can lead to starting problems and expensive repairs to the fuel system. In addition, units that have starting batteries should be connected to a battery charger to ensure the battery is fully charged to start the unit when needed.
- If well maintained, how long should a generator and a generator’s engine last?
If a generator is well maintained and properly applied, the unit should provide many years of service. Useful life of a contractor grade portable generator is typically in excess of 2,000 hours and useful life of a mobile diesel unit is in excess of 10,000 hours, though there are many examples of units that greatly exceed these estimates due to conscientious maintenance and operation practices.
- Who are the major customers of professional generators?
Both mobile and portable generators are very common equipment used by contractors for various kinds of work. Power to run tools, pumps, compressors, job trailers, lighting and heating/AC is essential for jobsites that are off the utility grid or have yet to be connected to the grid. Another key professional user is the events contractor, providing remote power at sporting events, carnivals, concerts and racetracks. The size of the generator is determined by the size of the job and by calculation of the power requirements of the application. Generators are extremely popular items for rental. Two thirds of all mobile generators are sold to rental applications and portable generators are also popular rental items.
- What market trends do you see today in the professional generator market?
Some of the key market trends for generators are environmental related. The engine emissions on both gas and diesel powered units are getting cleaner thanks to advances in engine and control system technology. In addition, generator customers are requesting quieter units as jobsite noise becomes more of an issue in urban areas and for nighttime construction. Also, a growing number of jobsites are requiring environmental containment on mobile generators. This design feature seals the package and keeps the full volume of fuel, oil and coolant from spilling from the machine in the event of a failure.
- When considering the upcoming storm season, what generator tips can you offer both homeowners and professional contractors?
The biggest recommendation I can make to both homeowners and contractors who have the potential to be affected by weather related outages or natural disasters is to be prepared well in advance. You don’t want to wait for an outage before you decide to rent or purchase a generator, as they will be typically be in short supply during these times. If you already have a generator, it’s a good idea to ensure the unit is maintained, fueled and in good operating condition so you know it’s ready to work when the power goes off. Be sure to plan ahead and have extra fuel available and perhaps even spare maintenance parts, so you’re covered if the outage should last for an extended period of time.
Keith Gribbins is managing editor of Compact Equipment.
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