Which set-up is the best for your battery project?
Thinking about batteries in your everyday life, there are many different options. With the common AA-batteries you can power many things from your remote for your TV, to your polaroid camera or the clock on your wall. There are rechargeable batteries and batteries, which you use until they are empty and throw away. You and I know both which one is the more sustainable option of the two. But in your life, you will find that these are not the only batteries you use daily. Rechargeable batteries, also called accumulators, are installed in your mobile phone, the electric bike you love to cycle on in your free time and in a bigger fashion in your electric car you use to go to work. So, you can see that batteries are versatile in their function and how they are used, but what about industrial mobile batteries and their set-up options?
While this past blog post about mobile batteries in general also mentions the different application areas of mobile batteries, this time you will learn more about technical set-ups and their differences. Depending on the situation of a project, the most suitable set-up option will be chosen. All of the options have their distinct advantages and disadvantages. At the end of this blog post you will be familiar with the different terms used to describe the set-ups and can make an informed guess about which set-up is the most suitable for your own project. To ensure an optimal choice and a set-up based on data, you can always contact experts to help you.
Make an informed choice
Before choosing your set-up, you also need to be aware of some key data to make an informed choice. So, we encourage you to think about these aspects before you make a choice to end up with the right solution.
You need to know about:
- The already available power sources (for instance in Amperes or kilowatts (kW) or kVA or amps): This could be a grid connection or solar panels or any other form of power source available on site. And if there are no power sources at the location, be sure to mention this as well.
- The rated power of your application (for instance in kW, kVA or ampere): What do you expect the power consumption to be? Here you can include all the equipment or any energy consumers, such as heating, the tower crane on the construction site, the lightshow for your festival or what else needs the electricity provided by the mobile battery. Try to list the current rating of the required electricity connections (in Ampere), and the power rating (in kW) if available. The more you know about your application, the better the set-up can be matched with your project.
- What differences are there for the energy demand (e.g. day/night or season)?: In some cases, you might only need power during the day and the battery can charge at night. In other case the heating you have installed will run only minimally in the summer but have a much higher power demand in the winter. Be sure to include all predictable fluctuations.
- Expected lead time: Your project might only last a few days or several months to a year. This can change the set-up as well since the investment in a long-term solution can range higher than for a one-day event.
Be sure to keep these aspects in mind when choosing your set-up and when talking to experts about the possible options for your project. The set-up options presented in this blog post can be used as a guideline, but each project is different and needs to be assessed first by an expert before making a choice.
Island – The battery alone
Most people when they think of batteries, they expect a full discharge as with an AA battery. This is exactly the case for an island set-up. Here the battery is the sole power source and will provide all energy until fully discharged. In theory, there is an option to replace the battery with a new one. However, this is generally not advised since the replacement of the battery is connected to not only transport costs, but also the related transport emissions. These emissions may be higher than the combination of the battery with for instance another power source, such as a small grid connection or diesel generator.
This set-up is the most suitable when a low amount of energy is necessary, or the battery is only used for a short period of time. Since mobile batteries are powerful, they can provide high amounts of power for a short period until fully discharged. As an advantage, no additional power sources are needed, and the set-up is therefore more flexible. The disadvantage on the other hand is that the battery can run empty, and no more electricity is available. To prevent this, the energy consumption must be calculated precisely before the beginning of the project to ensure that the consumption is below the amount of power the battery can supply. This set-up scenario is the only one out of all scenarios presented in this blog post, where the battery can be fully discharged at the end of the project, since no power sources are connected.
Disclaimer: All the following set-ups are based on the possibilities Greener Power Solutions provides with their mobile batteries. The set-ups provided can differ with different companies and other types of batteries. This is an overview of possibilities to give you, the reader, more insights into what you can do when including a mobile battery, but there may be more possibilities provided by others. Keep that in mind when reading and always discuss all set-up options in detail with your battery expert to ensure the right fit.
Peak shaving – Boosting a power source to provide power peaks
Often, there might be a power source available on location or a diesel generator can be used to provide power. For a grid connection, it could be a 3×80-ampere grid connection. While this grid connection itself is not able to supply the necessary power to charge for instance a tower crane, it can be combined with a battery for this purpose. While the grid connection charges the battery and delivers all the energy, the battery is used as a buffer for this energy to provide the power peaks needed by the tower crane.
The same goes for a diesel generator. Normally, the problem of a generator can be that you need to choose the generator, which can supply the maximum power that you need for the power peaks of your equipment. This can lead to a powerful diesel generator running on a very low and therefore inefficient load for long periods of time, since most of its power is not necessary for normal operations but only the power peaks. This inefficiency does not only waste resources, such as the diesel fuel, but also produces high amounts of emissions together with noise and unpleasant smells. By combining the diesel generator with a mobile battery, the diesel generator will only be turned on by the battery to charge the battery.
Example case:
This graph shows the data from a tower crane. This is an example of a case where peak shaving is a great option, since there are power peaks of up to 140 Ampere. Furthermore, this tower crane can in theory have power peaks of up to 220 Ampere.
In a normal case a 250 kVA diesel generator would be used for this kind of project to be able to supply enough energy for the power peaks of the tower cranes. However, since the average load is only at around 13.9 Ampere, most of the time the generator would run for a much lower and not optimal load, which leads to high inefficiency and energy waste. With a peak shaving set-up this inefficiency can be prevented.
Peak shaving has four advantages:
- It means that the running hours of the generator are reduced
- When running it runs at optimal load, which is efficient
- Through higher efficiency the resources are used optimally
- And through reduced running hours, there are less emissions, there is less noise and less unpleasant smells.
While combining a battery with a diesel generator might not be the first solution, which comes in mind, the higher efficiency results in a more sustainable solution. The diesel generator as a flexible power source can be an option for many cases, which should be considered. Read more about the sustainability of mobile batteries and how the combination of battery and diesel generator compared to using only a generator in this blog post about the lifecycle assessment done by our former intern.
Peak shaving can therefore be an easy solution when the bigger grid connection cannot be delivered on time and to optimize efficiency. By using the mobile battery to set up a smart grid, optimal use of the available electricity is ensured.
Cycle – Reducing running hours of diesel generators
When a mobile battery is connected to a diesel generator, this diesel generator will not necessarily have to run the full day and night as normally would be the case. Instead, the battery will be charged by the diesel generator until a maximum capacity and afterwards the diesel generator can be turned off until the battery needs to be charged again. This interplay of charging and the discharging of the battery until a certain threshold means that the diesel generator’s running hours can be greatly reduced, and the load is optimized. Since the running hours of the diesel generators correspond to the charging cycles of the battery, the term cycling is used in this case.
As explained in the previous part about peak shaving, the reduced running hours have additional benefits, such as higher efficiency, reduced emissions, reduced noise, and smell. In general, the running hours can be reduced by 80-90% with this set-up, diesel fuel is reduced by 30% to 60%, which in turn also reduces CO2, nitrogen, and particulate matter emissions by the same percentage. Additionally, the diesel generator for the project can be reduced in size and power in most cases since the battery will act as a buffer. While direct emissions are still produced, in some cases this will be the most cost-efficient method, especially for off-grid projects without other available energy sources. So, you should keep it in mind when thinking about a possible energy supply set-up for your next project.
Load share – Distribution of the load to multiple power sources
We have talked about the possibilities when there is either a grid connection or a diesel generator on location – but what if there are both? Or what if the grid connection or one diesel generator alone is not enough to supply the necessary power? In this situation, a load sharing set-up can be a fitting solution. Taking the example of one grid connection and one diesel generator, the battery will make sure that the grid connection is used optimally. Only when the power supplied by the grid connection is not sufficient, then the diesel generator will be added into the mix to supply energy grid synchronous and with an optimal load. By using the combination of grid and generator, sufficient energy can be supplied without the necessity of larger grid connection. This is also possible with two diesel generators, which will then run alternately to prevent overstraining one generator. Similarly, to the combination of a grid and a generator, both of the generators will only run simultaneously when necessary.
This combination of energy sources can be advantageous when a back-up diesel generator is necessary to secure the energy supply or when the power provided by one energy source is not enough for the whole duration of the project.
Renewables – Making use of renewable energy for a sustainable solution
When searching for sustainable solutions, renewable energies are the way to go. And they are also perfect for a combination with mobile batteries. Since wind and solar energy are prone to fluctuations in the generation of power, the mobile battery can store any excess power not directly needed. Additionally, the battery can be used to create a smart grid, where the battery controls the supply of the available electricity.
Mobile batteries cannot only be used with solar panels or wind turbines, there has also been a project with kitepower to store the electricity generated by a kite for further use. Read more about this specific project here. There are a variety of possibilities and new renewable power sources can be connected to mobile batteries. To ensure a smooth process and communication between the different elements of the available smart grid, the right software is necessary. This software can be developed specifically for certain set-ups and tested beforehand to provide a flawless process once the project is up and running.
Due to the fluctuations renewable energy sources often have, one of the disadvantages is that most of the time there needs to be a back-up option. This can be for instance a grid connection or a diesel generator. However, when the set-up works, the energy provided is 100% sustainable.
Parallel – The combination of multiple batteries for maximum power
A parallel set-up basically means that there will be more than one battery involved. For instance, two batteries can be combined with a grid connection to then supply a higher power together than on their own. The capacity of two batteries is higher than one and this kind of set-up can be combined with different energy sources. Additionally, the discharging and charging of the different batteries can be managed by software to ensure a seamless process.
The costs of renting two mobile batteries or maybe even more are obviously higher than for renting just one. Additionally, the batteries take up more space together. These aspects must be considered when choosing this set-up. However, combining two or more batteries does lead to a higher capacity and additional security regarding the power supply.
The role of software
All of the set-up options explained after the island-mode in this blog post are possible because of the software of the battery provided by Greener Power Solutions in this case. With the different control options and programs available in the energy management system (EMS) many different combinations of power sources and power consumers are possible. Additionally, specific software can be written for your special case to ensure that all elements work together seamlessly. The software furthermore ensures that there are clear insights available into the energy consumption, power peaks and the state of charge of the battery. This means that any problems can be detected quickly, and measures can be taken to solve them swiftly.
Plenty of choices for your next project
While a mobile battery is definitely different in application and set-up than your usual AA-batteries at home, similarly they offer a wide array of options to you. From one to multiple power sources, from diesel to grid to renewable or combining multiple batteries to get the energy supply you need – everything is possible. We hope to have given you widespread overview of your options and an idea of what the energy supply set-up for your next project is going to look like.