Best Diesel Generator in the UK in 2022
For many people, the words ‘diesel generator’ will conjure the image of the noisy, dirty, and often beaten up, generator they see next to road works or on construction sites. The generators most people see are the ones that are put in the toughest environments, working whatever the weather, taking the knocks, and still generating power.
In fact, diesel generators are incredibly common, but often clean, quiet, and hidden away. They will be ready and waiting, sitting behind the scenes in hospitals, offices, and factories, able to deliver power quickly and reliably when it is needed.
How do Diesel Generators work?
All electricity generation works on the same principle. An alternator generates the current through a process of electromagnetic induction. To create an alternating current, the same as household supplies and the type most generators create, a conductor is held in a rotating magnetic field. It’s what moves this field that makes the difference between different types of generation. Essentially, whether the generator is a massive power station or a small generator, the actual electricity is generated in the same way.
A generator needs fuel for the engine used to create the circular motion in the alternator. The current this generates is then passed through a voltage regulator to ensure a steady output available for the appliances or network attached to the generator.
Consumer electricity generation uses a range of fuels, from renewables like the wind or waves, to fossil fuels and nuclear. But when it comes to generators, diesel has established itself as king.
Renewables are dependent on conditions, gas has storage difficulties, and solid fuels are slow to start. Diesel is readily available and efficient, easy to store and quick to start; it’s the ideal fuel for the situations which need remote power.
But what are the specific advantages of diesel generators?
The Diesel Advantage
Diesel has become the dominant type of generator because it offers efficiency, versatility, and durability. Diesel, as a fuel, has seen its ups and downs, especially with consumer transport. But other technologies have a long way to go to catch up with it when it comes to power generation.
Diesel is one of the most efficient types of fuel. And the efficiency keeps getting better as the technology improves. With advances in features like fuel injection, diesel generators can provide power for lengthy periods off relatively little fuel.
Its fuel efficiency assists its versatility. It means that generators can be easily portable, making them useful for situations where the power may need to be in different locations, for example, providing lighting for open air events, or powering work tools. It also means that the standby diesel generators can operate to provide power for large organisations, often for lengthy periods. Standby diesel generation will be used in situations where power supply is critical, ensuring that, when needed, a reliable supply is always on hand.
And diesel generators are incredibly durable. Diesel does not have spark plugs and runs at a lower temperature than typical petrol engines. Combined with being a relatively simple mechanism, this means that they run a lower risk of developing faults or suffering wear and tear that requires repair. And they are incredibly tough and durable. The reason they are a common sight on worksites is because they can take abuse and keep working.
This combination of factors means that diesel generators have a wide range of applications.
Where are Diesel Generators used?
Diesel generators are everywhere. The factors that make them such a reliable method of power generation lends them to a variety of uses.
In fact, it’s perhaps unhelpful to think of ‘diesel generators’ as a single group. While they may have the fuel and function in common, the range of types of generators makes them very different products.
The main uses, in very broad terms, are for portable generation, standby power and uninterrupted power supply, and standard generation.
Portable generation units are typically smaller, a key factor in their portability. But even then, there can be a considerable range in size. Small generators, sometimes towed, are often used to power tools and equipment that might not be in constant use. While larger units may, while still being portable, be carried by trailer. Their portability, however, does not mean a compromise with performance. The efficiency of diesel means that even small generators can provide power for hours of work. And, of course, the easy availability of diesel fuel means they are easy to keep going.
Standby diesel generators are, perhaps, the most common. Again, these come in many shapes and sizes depending on the function they are fulfilling. Smaller generators can be used to provide power for a few essentials in power cuts. But larger units can fully replace the electric grid for large buildings when needed. These are often installed for essential services, ensuring that power outages will not affect their work. These will often be able to function, serving all the building’s power needs, for days at a time before refuelling. Ensuring the continuity of service.
For many, a standby power supply can be started manually. For example, a standby diesel supply in a home might just be ready for a power cut, and while an inconvenience, the householder can start the generator with a push of a button. This, however, is not an option where the power must be continuous. The impact of even a few seconds loss of power in a hospital, where patients may be relying on life-support systems, or surgeons working in a well-lit, but windowless, theatre, could be fatal. But there are plenty of other uses where continuous power is essential. For example, a server centre will need a constant supply, or a retail centre may have units that have no natural light, and in both cases a power loss could have severe consequences.
For total continuity of service, a standby diesel generator can form part of an uninterrupted power supply, or UPS. These work constantly to ensure that the power supply of a building or facility never cuts off.
In these situations, a UPS can seamlessly fill the power gap. These work by combining a battery with the diesel standby generator. The battery forms part of the power supply, remaining charged while power flows. If there is an outage, this is immediately detected. The battery will continue to supply power while the standby diesel generator starts. Although the battery power will not last long, particularly in environments with high-energy usage, diesel generators start quickly, and will be able to provide power before the battery depletes.
Finally, there are generators that are designed for continuous use. These are intended for ‘island mode’ operation. As the name suggests, this is where the power supply is its own island, separate from the normal grid supply. There are several situations where this might be necessary.
The most obvious use of island-mode generation is in remote situations. Installing and maintaining a connection to the utility grid can be incredibly expensive, especially if there is a significant distance and it is only for a limited use, such as a remote dwelling. In many situations like this, island-mode generation is the most cost-effective solution. In effect, the diesel generator forms its own micro-grid, powering the local area. Rather than expensive, and potentially vulnerable, electrical infrastructure the generator is fuelled by diesel, which can be easily transported and stored.
However, island mode is also sometimes used even in areas where the utility grid is easily accessible. This might be because of security concerns, to ensure reliability, or simply because of a preference for an independent power supply.
What are some typical Standby Generator uses?
The versatility of a standby diesel generator means it’s simply impossible to detail every possible use. However, a few practical examples give an idea of their uses.
The Always-on Generator
Diesel generators can be run around the clock. Making them idea for uses which need a constant power supply. They can also adapt to the power demands made of them. The power generated changes depending on the speed the electromagnetic field in the alternator is turned. Meaning the engine speed will affect the power generated.
One use might be a remote dwelling. Too far from the utility grid for a connection, the diesel generator will constantly be providing power. Those demands will be likely to peak in the evening, when dark falls and people are using devices for entertainment, and drop significantly overnight while people are sleeping, although some appliances will continue to draw power.
In these cases, a generator can adapt the speed of the diesel engine — and the amount of fuel it uses — to ensure that it is not generating excessive power that just goes to waste.
While there are drawbacks to having a generator constantly running, the relative simplicity of a diesel engine means that it is not as prone to failing or suffering wear and tear. And modern generators are designed to run quietly, with the noise further suppressed by good acoustic design.
The uninterrupted supply
Using standby diesel generators as part of a UPS is remarkably common. Indeed, most public buildings and large offices will have them, tucked away and out of sight, to ensure their services can continue or, at the very least, they will have power to help with an orderly shut-down.
One example would be a large office. In these situations, batteries and generator would be stored in a service area, most of the workers will not have seen or even thought about the UPS. In these situations, the office will draw power from the utility grid, but, in the event of failure, the UPS system will immediately start the generator.
Whether users are even aware of this will depend on the system in place and decisions made by the office owners. Some systems, for example, might trigger a warning to computer users to save their work or even shut-down, others might opt for the generator to do its work, so they can continue business as usual.
Once the standby diesel generator is running, it will take on power duties, including charging the batteries, until the main power supply is restored. It might even switch back automatically or wait for a manual intervention to confirm the supply is reliable. A modern UPS provides a smooth transition, any many people may have worked through momentary power outages without even realising that, for a short while, they were effectively working in a power-plant!
The Power Insurance
Another common use of diesel generators is as a traditional insurance measure. This use is common in areas that are connected to the utility grid, but with connections that are sometimes vulnerable. Examples might be where their location is some distance from the generation plant, and reliant on overhead transmission that can be susceptible to adverse weather events. In these cases, the power supply is usually reliable, but when it fails it can mean a lengthy period without power while the problems are fixed.
In situations like this, the standby diesel generator may go years without being used. However, because of their durability, all that they are likely to need during this period will be an occasional check-up and a little light maintenance. If there is a power-outage, they will start quickly and easily. The relative infrequency of use means that there’s little point in investing in a UPS, but the potential length of a failure means having a relatively inexpensive generator is essential.
Finally, there are those that will want power where they go. Diesel generators are popular on boats for several reasons. First is that, obviously, there is no utility grid on the ocean (or even on inland rivers or lakes) meaning that some form of power supply is essential. Second is that, although batteries have improved, they still have a limited capacity. While batteries may be enough for hardened sailors, those that sail for leisure may not just need power for their navigation equipment and lighting, they might also need to power a kitchen and entertainment devices for a whole family.
Small diesel generators are a popular option because of their efficiency, but also because of their safety. Diesel, obviously, should be handled with care, but it is less volatile than other types of fuel, meaning that — with the proper precautions and storage — it can be carried on board safely, ensuring there is enough power for everyone without creating a danger.
Choosing a Diesel Generator
When it comes to choosing a generator, the starting point should be the need it serves. Determining whether you need power for a large building or a small boat will determine the type of generators you should consider. However, even then, think about how it will work.
When the power goes down, what will you do? Do you need a UPS, to ensure there isn’t even a flicker of the lights? Or are you in a situation where, although an inconvenience, having to flick a switch to start your generator isn’t a problem?
What you need to power will also affect the choice you make. Depending on your situation, you might not need a generator that fully replaces your power supply. An office, for example, may only want a UPS to ensure people can save work and shut-down the computers, with the generator only providing enough power for essential purposes: powering the servers, keeping the lights on, and running a few computers for those that must continue working. Similarly, in a home, will you need power as normal (especially as other utilities, like the internet or phone service may have failed too)? Or would you be happy with candle-light, as long as you knew the food in your fridge wasn’t spoiling?
And, on a related note, think about your future needs. Devices and appliances are tending to become more energy efficient, meaning that if nothing changes, a generator that is good today will be probably be good for the future. But are you likely to be purchasing more power-hungry appliances, or even extending your building, needing more lighting and heating? Think ahead to make sure that your generator has the capacity to meet the demands you might make on it in future years.
Finally, think about any special needs you might have from your generator. You might need to be able to manage it remotely, and some will come with independent internet connections that allow you to monitor it, or even start or stop it, from anywhere in the world. Or you might need to think whether the location needs special considerations, a noisy generator in a remote area might not be a problem, but will you have to look at those with acoustic hoods if your generator is in a more built-up area?
Take some time to imagine your generator in use and think about what issues it might cause and what you might want to do with it. Then you can use that information to help you determine the best standby diesel generator for you.