DIFFERENT LOAD MANAGEMENT OPTIONS FOR HOMES, BUSINESSES, PUBLIC CHARGING AND HOUSING COMPANIES

Load management is an issue in almost all charging projects. A few years ago, the issue could have been solved with a massive hub and connection, but this causes very significant costs, both in terms of building the infrastructure and in terms of operating it, for example in the form of power charges.

Load management should always be considered on a site-by-site basis, taking into account not only technical issues and costs, but also the life cycle of the system. It is important to consider the solution in such a way that in the future you do not end up in a situation where you have to make new major investments or replace equipment. Many environments have been built where problems may arise in the future. Not immediately, but within 5-10 years, if a large number of electric cars enter the property. At worst, the problems are such that the equipment has to be replaced in its entirety and the situation has not necessarily been thought out long enough in terms of infrastructure. Many contractors are used to thinking about “correction factors” with the idea that the power will automatically level out for several users. However, in car charging, this idea does not really work in practice. We have already seen sites where electricity consumption has increased 3-4 times, as electric cars have spread rapidly due to positive experiences.

When the choice of contractor and system is often made based on price, there is of course a big temptation for the provider to ignore things that may only cause problems in about 10 years. The know-how and practical experience of the systems is also new, in fact there are few sites where there are very many people charging all-electric cars in relation to, for example, parking spaces. We have experience from a few sites where electric vehicles have spread quickly and almost every site has a charger (most are still all-electric cars). The surprise is the need for peak power, which has indeed increased many times over and the originally considered “practical” maximum power without load management has been greatly exceeded in some places. Load management has therefore become mandatory even for large main connections. However, when prepared for this, it does not cause problems. Spot pricing and optimization further increase charging at the same time and the importance of load management is emphasized. The power fee must also be taken into account here. When charging at the same time, charging becomes very expensive due to power charges. In this case, optimization and load management become even more important and require a versatile system.

As with charging, the best starting point for load management in all locations is an OCPP-based backend system and charging stations that are truly compatible with it at the device level. Ideally, the system as a whole should be such that it will also work in the new 2.01 or 2.1 versions in the future. In addition, it cannot be emphasized enough that by choosing truly OCPP-compatible devices, you will not be in a lock-in situation where you cannot change the device manufacturer/network service. Load management is also broadly defined in the OCPP standard for numerous different options. By choosing charging stations that are directly compatible at the device level (not the manufacturer's API), all options will also be available in the future for network service and load management. This is especially true for larger locations. In smaller systems, you can of course also think about committing to one good device or operator and if new, better services come along, the devices are still electronics that have a lifespan and can be replaced with newer technology. There are also differences in the sites and for certain environments there are devices that are suitable for that site, where the properties, for example in terms of load management, are sufficient or very suitable. Infra is worth considering carefully in all cases.

What load management options are there in practice? The first choice is whether load management is implemented locally at the device level or as a network service. Both have their advantages, the advantages of a network service are its flexibility, not being tied to a single device (OCPP), easy and inexpensive configuration and installation, the possibility of changes in new situations/when installing new devices, and in the future, especially the possibility of various optimization solutions. The advantages of a local service are independence from the internet connection/network service, speed in certain special situations, reliability in particular in cabled solutions, and multi-level support in the latest systems. In practice, a meter/load management device is always connected to the local system, creating a dynamic system that also takes other loads into account in real time. This may be essential, for example, in geothermal sites or other sites where the load varies very strongly or “spikes”.

In many cases, a meter and a local controller can also be connected to a grid-based system, which can enhance the existing grid-based load management. In our opinion, this is often the best solution technically, as it allows the best of both options to be used. The cost is usually slightly higher and requires more from the grid service. Our system is a Woltti SmartMeter, which is based on a local ModBus meter or network analyzer (as well as local systems) and a local controller that separately sends data to the grid service. In the future, P1/HAN measurement and, in small projects, Shelly Pro measurement are also possible. Optimization will be an important part of the charging system in the future, and therefore grid-based load management is also essential if there are plans for, for example, Spot price optimization, solar power or battery systems in the future.

New independent network services have also entered the market, one example of which is Enegic. It is in practice a data transfer component connected to the P1/HAN port, which is connected to the charging device's API interface via the manufacturer's cloud service. Again, there are pros and cons to this. The system is flexible, but always binds to both the Enegic system and the charging device's API service. In smaller projects, the benefits in the form of lower costs can be significant and in small projects it can be quite a good option. The data transfer here is WLAN, which is generally not recommended for housing company/corporate systems. Its failure cases usually always require an on-site visit. If you wish, you can also connect the Enegic load management to the Woltti system.

The data transfer from the charging devices to the backend system is the part that is worth investing in and where most of the faults occur. In practice, experience has shown that the best options are Ethernet cabling or each device's own SIM connection. WLAN/ZigBee/other wireless systems are more susceptible to faults and even if they are implemented with high quality, even in the rare event of a fault, you will most often have to go on site to investigate the matter. This is expensive and also always takes time, so the system does not work as agreed. In addition, building and maintaining networks is reasonably demanding and requires expertise and high-quality equipment.

Hybrid systems have recently gained great popularity because the starting threshold and cost for slow charging are often low. In slow charging, load management always cuts off charging completely and in practice the locations “take turns”. Cars “waking up” after switching is sometimes a problem and therefore in Woltti load management, basic charging (11/22kW) is flexible first. Woltti SmartSchuko can be installed one device at a time, because each device has a SIM card. This makes installation even easier and enables flexibility and reliable operation. The choice of charging devices is also important, as they have big differences, for example in the scope of the OCPP protocol. Plug-And-Play is an important feature that ensures that the installation is quick and the functionality of the devices is as good as possible.

Load management is therefore a large and complex entity. It is worth spending time on its solution so that the solution will work well into the future. There are also significant differences between sites, and therefore it is worth considering the system according to the site.