The advantages of using DC electricity
We make electricity in two forms: alternating current (AC) and direct current (DC).
Each form has its disadvantages and advantages in the way it is made and how it can be used. The important advantage of AC electricity is that it is easier to transport over long distances. Mains electricity is AC because it comes to us over long distances from the large centralised generating stations spread throughout Australia. For independent power plants this advantage is not important because the electricity doesn’t move very far to get to where it is used; for independent power plants the advantages of DC electricity are more important.
The biggest advantage of DC electricity is that it is easier to store than AC electricity, especially on a small scale.
Storing electricity when it is made, for use later when it is needed, is a critical concept for a hybrid independent power plant. When electricity is stored we can use it when we need it, and storing it increases its density, so we can take as much power as we want to operate high-powered equipment. When we store electricity we can turn the generator set off most of the time which saves fuel, and we can use electricity when our renewable sources such as solar cells are not providing electricity.
The best way to store electrical energy for relatively small-scale applications is to use rechargeable storage batteries. We can retrieve electricity from a storage battery bank silently, efficiently, and immediately when we need it.
Storage batteries require DC electricity, so to get the advantages of storing electricity in a storage battery bank, we must generate DC electricity.
Providing AC mains electricity
In practice, we ultimately need to provide mains-style AC electricity because most of the equipment that we want to use is designed to run on mains-style electricity.
An important advantage of using DC electricity for an independent power plant is that AC mains electricity can be generated twice as efficiently by using a diesel DC generator, and converting the DC electricity to mains-style AC electricity, than by generating mains style AC electricity directly using a petrol AC synchronous generator.
Variable engine speed
An AC synchronous generator must turn at a single, specific, speed to control the characteristics of the mains-style electricity that it generates; if more power is needed, the engine cannot be sped up; if only a little power is needed the engine cannot be slowed down. For a DC generator, the characteristics of the mains-style electricity are determined by the DC to AC conversion process, so the turning speed of a DC generator doesn’t matter, and the driving engine can turn at a range of speeds. This means that if a lot of power is needed the maximum potential of the engine can be used by running it at its maximum speed; if only a little power is needed the engine can be slowed down, saving fuel and wear, and making less noise.
Providing the alternator’s magnetic field
Because the turning speed of an AC synchronous generator can’t be changed to match a changing electrical load, the generator’s output must be controlled by changing the strength of the magnetic field in its alternator. To make the magnetic field controllable it must be produced using an electromagnet, called a field winding, which uses some of the electricity made by the generator. Because a DC generator can be controlled by varying its speed, its alternator can use permanent magnets to create its magnetic field, and so doesn’t lose any of the electricity that it makes to the field winding.
Variable speed and no field winding make a DC generator much more efficient than a synchronous AC generator.
Because PowerMaker is a DC generator, it receives all of the advantages of DC electricity.
Independent power plants
- Independent energy solutions overview
- Generator sets for independent power plants
- Hybrid independent power plants
- Sizing your independent plant
- Independent energy system components
- Using a conventional generator set
Independent energy system components
- Control system
- Solar panel
- Solar controller
- Storage battery bank
- Battery charger
Independent energy system concepts
AC Diesel Generators
At Eniquest we provide Australian built AC Diesel Generators built tough for all applications. Eniquest AC generators are engineered using Australian military technology to ensure you have the best generator for the job.
DC Diesel Generators
At Eniquest we provide Australian built DC Diesel Generators suited built tough for all applications. Click here to find you Australian manufactured DC Diesel Generator.
Eniquest has Australian Manufactured AC and DC generators built specifically for telecommunications. With Eniquest you can ensure you have reliable power 24/7 no matter where you are. Click here to find you Australian manufactured Diesel Generator.
At Eniquest we provide Diesel Generators and In-Service Spares to the Military for all power production applications. We understand the need for reliable, accessible military spec equipment and parts that you can depend on.