By Claus Koch

Since the major electrical power outage in 2003, many organizations have included continuous power as part of their Business Continuity Planning. As well as the obvious critical services, such as hospitals and municipal water supplies, many high-rise towers, grocery chains and industries with critical processes are all considering back-up power sources essential. If continuous electrical supply is important to your operations, then stand-by power generation may be a worthwhile investment.

Diesel Power:

Continuous back-up power has traditionally been provided with back-up diesel generation. Diesel engines are readily available and economical. Until recently, life saving facilities required that back-up fuel be kept on site. Diesel offers an obvious advantage in this respect since it can be stored easily. However, Diesel’s natural primacy, based on these once valid reasons, is increasingly open to challenge…

Back-up generators normally have a supply of diesel on site that is sufficient to run the generator for several hours. This is satisfactory during most local black-outs. The picture changes, however, when there is an extended, widespread blackout. Diesel delivery trucks are suddenly in short supply. And, when a truck does become available, it is frequently diverted away from your company site towards neighbouring hospitals and life-saving institutions.

Furthermore, although Diesel generators usually offer the lowest capital cost installation, when other variables are factored in, the economics may change… Diesel storage requires land and continuous attention to the storage, which means the Diesel inventory must be turned over and the property must be protected from oil spills. Additionally, periodic test running consumes diesel, which must be replaced. Another cost that must be factored in is that during extended outages diesel becomes difficult to acquire and as demand exceeds supply, it becomes exceedingly expensive.

The Alternative:

The authorities have noted the difficulties involved with acquiring diesel during extended outages. Consequently there have been legislative changes to Life Saving back-up Power, which now mean that life saving generators can be fuelled by off-site supplies. Natural gas is increasingly recognized as the most dependable off-site supply for such purposes. And businesses are quickly catching on to its advantages.

• Extended fuelling is more dependable than on-site diesel. Natural gas is less expensive than diesel. (This is only interesting if the generator is running for extended periods.)
• Fuel storage issues (fuel replacement, real estate, security, land contamination) are eliminated.
• Natural gas generators are more suitable for providing Demand Response

This final point is particularly interesting and opens up the question of Non Emergency Operation of back-up generators. Electric utilities are certainly pursuing short-term capacity additions through Demand Response programs. For lucrative incentives, participants agree to make power available to the utility in times of high prices and power shortages. Aside from reducing lighting and air conditioning loads, emergency power generators are an obvious source of electric power, if allowed to operate for these purposes. Diesel generators are usually excluded from such service for environmental reasons and Certificates of Authorization usually allow a diesel generator to run only for periodic testing and in the event of a power outage. Natural gas generators, however, generally qualify more easily for non-emergency service.

Bi Fuel and converted generators:

Many consumers have existing diesel generators. It is possible that some might be suitable for conversion to natural gas or bi fuel (natural gas and diesel) generators. Bi fuelling is advantageous since it allows the expensive diesel supply to last longer, which can be critical in extended outages. In some cases, the relative environmental benefit of bi fuelling versus diesel only may be the difference that permits generator operation during non-emergency (Demand Response) service.

While on-site power generation may be expensive, many organizations have found the lack of back-up power to be unacceptable and costly in the long-term. It makes sense to find ways to minimize the liabilities and operating costs of such installations and to recover part of the installation cost if it qualifies for Demand Response Programs. Natural gas generators may have a higher initial cost, but they do offer a number of advantages that should be carefully considered before committing to a particular choice.

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