Choosing a Generator

THE PROBLEM

What is the best backup power for me?

Determining the best solution for you is a decision tree process. Each question you answer helps refine and narrow the path to the best solution.

FIRST QUESTION

Do I want to purchase and own the equipment or would I rather procure backup power as a service and pay for it on a monthly basis?

Just a few years ago, equipment purchase was the only option. But with the advent of Software as a Service and the popularity of outsourcing non-key functions, more and more organizations are choosing Backup Power as a Service.

The first benefit of Backup Power as a Service, is that you don’t need to answer any other questions. Your service provider (in our case, Exergy the Concierge Utility), will provide you with the best solution to meet your organization’s needs and budget. There are of course many additional benefits to Backup Power as a Service. We list a few of the most important below.

  1. No upfront capital cost. You simply pay a monthly service charge and save your capital to build your business rather than investing in an insurance policy.
  2. Reduce risk and eliminate mistakes. Let experts, who understand the equipment, technology and energy markets make the decision for you. Purchase what you want to buy: security that if the grid goes down you have power, rather than equipment that can perform this function but only if it was specified and installed corrected, managed and maintained according to manufacturer specifications.
  3. Save money. Backup generators and batteries, when managed by professionals, can earn money by helping the grid, through programs like demand response. Most organizations lack the experience and access to the energy markets to participate in these programs, which can be quite lucrative. Backup Power as a Service is often substantially less expensive than owning and maintaining the equipment.
  4. People. For most organizations, the operations and maintenance staff is already overloaded and are not equipped to manage and maintain a very foreign piece of equipment that is not core to their or your organization’s everyday functions.
  5. Confidence and peace of mind. Some organizations, especially those in the healthcare and life safety arenas have regulatory and reporting requirements for backup power that can be both onerous and expensive if not managed properly. Let experts who deal with these issues everyday with for many customers take remove this burden from your to-do list.
  6. Continuous improvement and future proofing. Your service provider (Concierge Utility) becomes your partner and an outsource energy department that only has your best interests at heart. A Concierge Utility learns your business and makes sure that systems and services are evolved to meet your changing needs.

I’ve decided to purchase the equipment.

Time to start our journey. There will be multiple questions which might loop back on themselves sometimes.

NEXT QUESTION

Is there anything that can’t go down (dark) at all?

Some equipment can be severely damaged or create life threatening situations if power is abruptly turned off. These systems need to ride through the initial stages of an outage to either perform a controlled shutdown and keep running until power is restored, either from the grid or from backup.

Backup power systems, whether generators or batteries are not instantaneous. They take some time, typically 6 to 30 seconds to come on line. If you have any systems that cannot “go dark” for that period of time, you need an “Uninterruptable Power Supply” (UPS) that works instantaneously.

A UPS is not a battery at least not in the sense that the term is commonly used. UPS equipment is highly specialized and very extensive.

Typically, only a few items, like computer systems, emergency controls and life sustaining equipment require UPS and dedicated UPS systems are installed at point of use for this critical systems. Backup power is they provided upstream from these systems.

NEXT QUESTION

How long do I need to keep running?

This is a much more complicated question than initially appears, since the grid can go down for as little as a few seconds to as long as weeks or even longer.

This question is easy for some organizations. For example, a retail mall store without perishable inventory probably does not require backup power, since the customers are likely to leave anyway, because they can’t continue their shopping unless the entire mall had backup power.

On the other end of the spectrum is a skilled nursing home. Here the entire facility needs backup power for the entire length of the outage.

Your unique operation will determine what is the appropriate duration or durations to be covered. The plural, “durations” is because different operations may require different backup durations. For example, a food processing plant might have two separate duration requirements. A short-term backup of a few hours to shutdown operations and clean the plant and put it into standby and a long duration need for the refrigerators and freezers.

If you are facing an extended outage, what is your operation plan? Can your employees even get to the plant if the outage is caused by weather? How much inventory do you have on hand to keep operating if deliveries are delayed? In any organization there are likely differing duration needs and goal is provide the right backup at the lowest cost.

Batteries are only economical for a couple of hours of duration, while fossil fuel generation (diesel, natural gas and propane) can provide short and long duration power.

NEXT QUESTION

I have decided on long term duration backup power. What is the best generator for me?

Long duration backup power requires a fossil fuel. While there has been much hype regarding hydrogen, there is no hydrogen infrastructure and hydrogen storage is extremely expensive and because the volumetric energy density is so low that long duration power is infeasible with on-site storage. That leaves us with diesel, natural gas or propane.

Which of these fuels depends on a number of factors:

  1. What is available?
  2. Delivery during an emergency.
  3. Alternative use of the generator

In general, if pipeline natural gas is available nearby, this is often the best option. The generators tend to be more expensive but the reduced maintenance surety of fuel delivery and the ability to use the generators for grid support programs, such as demand response, makes them competitive with both diesel and propane with similar emission characteristics.

Many locations lack economical natural gas. Either it is unavailable completely or the pipeline is too distant to be economically viable to tap. In these cases, an on-site stored fuel such as diesel or propane is the only option.

The decision between diesel and propane comes down to 2 factors:

  1. Price difference.
  2. Participation in grid services such as demand response.

There are many areas of the country where propane is less expensive than diesel and on-site storage of propane is simple, and inexpensive. Propane burns much cleaner than diesel and can participate in grid programs without additional emission controls. Participation in grid programs such as demand response and peak demand shaving can substantially reduce the effective cost of a generator.

Diesel emissions are very high and these generators cannot be used for anything other than emergency backup (grid is down) unless they are equipped with significant emission controls which typically doubles the price of the generator. Diesel generators are classed by Tier with Tier s 2,3,and 4 available on the market. Only Tier 4 Final is allowed under law to operate in non-emergency situations.

If your operation is only interested in emergency backup, “grid outage” and the utility does not offer grid programs such as demand response and peak demand reduction, the least cost solution will be a Tier 2 or Tier 3 diesel running with renewable diesel in order to obtain an Investment Tax Credit. You can learn more about Renewable Diesel and the ITC here:

Often a major determinate is the availability of fuel during an emergency. Natural gas, which is delivered via underground pipeline, is impervious to weather conditions and will continue to operate. Diesel and propane require delivery by truck and during an emergency, deliveries maybe impossible. A secondary consideration is alternative fuel use. If damage is wide spread, diesel fuel is often rationed in order to make sure of its availability for emergency vehicles and support crews. Many businesses with diesel backup generators were unable to keep operating because of an inability to obtain refueling service. This is one of the reasons that major brands often require their suppliers to have natural gas backup power rather than diesel.

I have decided on short term duration backup power. What is the best generator for me?

Short term, which we defined as no more than a couple or hours, opens up the opportunity for battery backup in addition to the solutions above for long-term backup. A long term solution can be used for short term, but the reverse is not true. A battery will provide backup only for a couple of hours. So if you are considering battery, you must be absolutely certain you will not want or need backup power past 3 to 4 hours.

The economics and pricing of batteries versus generators can be confusing. Batteries are sold based on the number of kilowatt hours it can provide. Generators are priced by kilowatts since they can run indefinitely if there is fuel available. On average, if you do not care about an outage lasting longer than 4 hours, a battery will be your lowest cost solution. It is important to remember that the lower cost comes with a hard constraint. You will not be able to operate for more than 4 hours.

A four hour battery maybe a perfect fit, if you do not plan to operate for longer than 4 hours during an extended outage (even for days or weeks). Since most outages are of short duration, a battery may be enough to protect you from a lot of outages. We have calculated that a 3 hours battery in Massachusetts will be sufficient to keep you running through 43% of outages.

IN CONCLUSION

The best generator for you is a function of a decision tree that takes into account:

  1. Own the equipment or purchase as a service.
  2. Do you need uninteruptable power?
  3. How long do I need backup power for?
  4. Do I do battery, diesel, natural gas or propane
  5. Do I plan on using the generator for non-emergency (money making) activities.

The decision tree can become quite involved and complex. If you do not feel comfortable traversing the decision tree, we recommend you go with backup power as a service and let the experts provide you with the best solution to your needs.