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Generators as Backup or Primary Electrical Power

Historically, generators have been used by commercial and industrial users where continuity of electricity supply is critical. The decision to purchase a generator is often a “no brainer” for these sectors because the cost of power interruptions is unacceptably high. The decision comes down to which vendor and what make of generator to go with. The same goes for power users, such as contractors, farmers, bush lodge owners, and other remote facility operators that do not have grid supply. They are often obliged to rely on the use of generators to provide power.

With Eskom’s ability to provide power reliably becoming increasingly compromised, more and more South African companies and increasingly, domestic users, are beginning to look at alternative options for ”keeping the lights on”. Generators are one of the first options that most people look at. They are not the only option for providing electrical power though. Where the grid is unreliable or absent, other options are available, so understanding when and why a generator provides the best solution is key to making the right choice. An informed decision prevents costly errors that lead to an unsatisfactory end experience.

The usual, common sense considerations apply when considering a solution for power provision or backup. Buy from a reputable supplier with a proven track record. The cheapest solution is invariably not the best one and usually comes with a raft of compromises that spoil the end experience. The most important consideration is not the initial price but how well the solution will perform and be supported a year, or a few years, after the purchase.

One Size Does Not Fit All

Choice of generator is very much determined by the demand for power at the specific site. The peak demand the unit will need to carry is not the only consideration. Will the generator run on a purely ad hoc basis during grid failure and emergency situations or is it intended to be the only source of electrical power? The demands on a unit that is backed up by a relatively reliable continuous power source, such as grid power from a stable utility, are far less than those on a unit designed to run continuously as the primary power provider. Units intended for running the duration of a power outage and for periodic testing are designed and priced accordingly. They are typically designated as standby generators.
Generators designed to run continuously as primary power providers need to be built for unlimited run time. A primary power rated generator can supply power in situations where there is no grid supply. Applications include rural villages, mines, agricultural plants, and other remote sites where the extension of grid power is cost prohibitive. There are generators that fall somewhere between “standby” and “primary” units, so it is essential to engage with a knowledgeable generator vendor who will be able to provide the most appropriate solution at the best value point.

The Role of Renewable Power Generation?

Solar- and wind-powered power generation are the two power provision solutions most commonly considered as opposed to the installation of a generator. They have a number of attributes that appeal to commercial and industrial entities, as well as the man in the street. The two benefits most commonly cited are that wind and solar power are eco-friendly and the ongoing cost of power generation is relatively low.

There are, however, downsides to these solutions. Wind works best in coastal regions and off shore. Pretoria, for instance, is one of the least windy cities in South Africa. Wind generation is sometimes unpredictable and maintenance costs can be high. Solar generation can also be unpredictable in many regions. The KwaZulu-Natal Midlands, mist belt area, for instance, yields far less solar energy than Gauteng does. Renewable energy needs to be stored for night time use in the case of solar generation. Remote solar installations are difficult to secure and subject to theft and vandalism. Solar systems are also vulnerable to lightning damage. The inconsistency of generation from wind and solar requires the use of batteries for energy storage, which highlights the primary reason why generators remain a popular solution, namely, capital cost.

Although the cost of energy storage has declined consistently in the last decade, large scale energy storage remains an extremely costly exercise. The initial cost of a solar system can be anywhere from five to ten times higher than an equivalent diesel generator. In tough economic times, companies and individuals have limited access to capital and often do not have the wherewithal to cover the significant upfront costs for renewable plants.

Solar and wind installations are complex with site-specific considerations, including the need for sufficient space to house the solar panels or wind turbine masts as the case may be. Wind farms in particular have stringent environmental impact assessment requirements. Generators require far less space comparatively and the installation is generally less onerous than a renewable energy installation. A diesel generator offers far more value on an upfront cost per kilowatt basis than an equivalently sized solar solution.

Generators run at any time required, in any weather and at any time of day. Good quality generators are durable and reliable, and last for many years when properly maintained. They provide a dependable, well-understood source of electrical power that offers solutions in a vast range of sizes, including utility scale generation.

As with most decisions in the power generation arena, the final answer is not a simple “upfront cost” versus “long-term running cost” or “renewable” versus “fossil fuel”.

It Is not as Simple as “Generator or Renewables”.

In many applications, renewable power generation works better when paired with diesel generators. Diesel generators are often paired with solar and wind plants to provide power during extended periods of bad weather (for solar plant) or wind-free spells (wind plant). In off-grid commercial and industrial facilities, a renewable energy plant is almost always accompanied by diesel generators to mitigate the inconsistent nature of renewable system performance even where batteries form part of the system.
The integration of generators with solar and wind generation is a complex undertaking with only a few generator providers having the expertise and experience to optimise the benefits of all of the technologies. The utilization of generators in conjunction with solar plant in industrial and commercial applications, to limit peak demand spikes, requires specialist knowledge and equipment but can create significant financial and technical benefits for the end user.
Consult the Industry Leaders Today

PacB Group has the answers to all of the questions surrounding power generation with regard to both renewable and diesel powered electrical power generation. With a team of internationally qualified experts, PacB provides acclaimed expertise and experience with superior in-house technical support derived from a large portfolio of successful projects. Projects include complex solar/diesel integration and peak demand management.