See the fifth lesson of our comprehensive eMobility training on OICP!

Having a chance to work with well-established startups from the e-mobility sector, Bartek gained invaluable knowledge on the industry requirements. On his path, he was given the opportunity to work on numerous EMSP applications and CPO platforms. Bartek is also our Head of Delivery.

Bartłomiej Łazarczyk

 is happy to introduce you to the Open Standards course led by our e-mobility expert - Bartlomiej. Throughout the following lessons, we will uncover the technicalities and functionalities of the OICP - a protocol developed by 

 - as well as business aspects for e-Mobility Service Providers and Charge Point Operators.

Such a knowledge-pack should serve everyone operating in the e-mobility industry as it unfolds the most crucial aspects of navigating through Open Standards utilization and many more!


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eRoamingAuthorization + eRoamingReservation

Open InterCharge Protocol Training - Lesson 5

From a CPO perspective this service is probably the most important one in the whole OICP protocol besides authorization service it allows CPO to push static data regarding his charging infrastructure to the Hubject platform in order to allow other EMPs to use it. This service contains only one operation: eRoaming push EVSE data. Of course implementation is mandatory by every CPO partner. Hubject will first check if there is a valid contract between him and CPO. This time Hubject platform is a subscriber to CPO not the specific EMP. Operations like ‘update’ or ‘delete’ are also handled by the same operation; it can be specified in the action type field in the request which we'll see just in a moment.

Hubject has a policy to keep history and version receive the data sets for most of the data that is pushed to their platform. Every push and every update creates a new version of data. Only the latest version of data will be used, but due to keeping history, it is possible to revert some changes on demand. History of all EVSE data records pushed by CPO is stored and versioned by Hubject. Because of that, Hubject can reconstruct static EVSE data for any point in the past. As I've told you before in eRoamingPushEVSEData request you can specify which kind of operation you would like to perform. Action type field defines whether you would like to perform a full load, insert ,update or delete operation. Also, in this request you must provide a list of EVSE data records assigned to a specific operator. EVSE data record is huge and complicated. Nonetheless, it's crucial to at least briefly know what is the structure, what are the fields and what do they represent.

Starting with accessibility, it specifies how the charging station can be accessed. Accessibility location tells us where it could be accessed. Additional info, as the name suggests, is an optional field that specifies additional information regarding charging station. Address is an object that represents a full charging station address - it contains information like country, city, postal code, street name, house number or even parking spot or floor. Authentication modes specify which kind of authentication methods are supported in a given charging station. Calibration law data availability tells us how a charging station provides metering law data. Charging facilities is a list of supported facilities it can specify whether it's AC/DC, what kind of voltage, amperage and power is supported. Charging pool ID and charging station ID are IDs related to the European charging infrastructure model. We will come back to this topic later.

Charging station names, charging station image and charging station location reference are other additional information regarding charging station. It's often presented to the end-user by EMPs. Dynamic info available specifies whether CPO is able to provide dynamic EVSE status. EVSE ID is quite obvious - it's an idea of EVSE. Energy source is a list of sources that are used to provide electric energy. Environmental impact specifies the impact that is being produced by those sources. Geocharge point entrants are geo coordinates of charge point facility entrance, it can be expressed in google, decimal degree or minute/seconds degree format. Hotline phone number and hub operator ID are self-explanatory. IsHubjectCompatible specifies whether eRoaming via intercharge network is possible. Max capacity field is in case EVSE has limited capacity, i.e. has built-in battery, values are expressed in kilowatt hours. Opening times field should be visible only when the charging station is not 24h available. Payment options, as the name suggests, is a list of payment options that are supported: it can be no payment in case of free charging, direct in case of paying by card or cash, or contract in case of for example subscription. Blocks is a list of supported plug types, i.e. type 2. Renewable energy tells us whether a charging station uses this kind of energy. Sub operator name is self-explanatory. Value added services is a list of additional services offered by a charging station: it can be for example reservation, dynamic pricing, parking sensor, maximum power charging, charging plans, roof provided and few others. DeltaType field is mostly valid for pull operations. It is strictly connected with the last call parameter, which can be provided in pull operations query. In general, it says what kind of operation was performed in the middle time compared to the last call. It can be ‘insert’, ‘update’ or ‘delete’. If you provide the last full parameter inquiry and no operation was performed in the middle time, then the given record should not be returned in response. Finally, we have the last update field which tells us when the last time record was updated.

Another EVSE related service important from CPO perspective is eRoaming EVSE status. In contrast to eRoaming EVSE data, it focuses only on dynamic EVSE data, especially status information. It's also very simple - it has only one operation. This operation is eRoaming push EVSE status. Of course, it allows us to push dynamic EVSE data to the Hubject platform. Implementation is mandatory by every CPO partner. When it comes to validation, it behaves the same as for eRoaming push EVSE data. Also, it's possible to specify the action type for a given operation. Similar as for EVSE data records, the history of all EVSE status records is stored and versioned by Hubject.

When it comes to the request of this operation, it's very simple. You need to provide a combination of EVSE ID with evs status in EVSE status records list.

eRoaming Hubs explained

Get our comprehensive PDF packed with knowledge on eRoaming, hubs and protocols!

Being an eMobility leader in various projects across multiple startups, Piotr was responsible for OCPI and OCPP integration as well as EMP and CPO platforms development. With extensive expertise in the open standards field and eMobility tech solutions, he is leading teams of experienced developers and contributing with invaluable knowledge and experience.

Piotr Majcher

Certainly, roaming is something known to everyone at this point. However, what that has to do with eMobility?

Being a broad term for services allowing for connection outside of the usual network, roaming turns out to be an on-point solution for EV charging. With many players in the eMobility game (i.e. Charging Point Operators, eMobility Service Providers), some type of a connector is a must. Here’s exactly where eRoaming comes into play allowing for multi-dimensional connection between operators and EV drivers.

In short, eRoaming can be established via the use of hubs and protocols. A hub here can be an open platform which, after subscribing, can be used by many operators, who operate on common terms. This all happens in such a way that a certain charging pool introduced to a common hub can then be easily used by clients (EV drivers) of different providers. Such a solution allows electric vehicle users to charge their car across cities/countries with limited hussle.

In order to facilitate such a solution, the hubs developed their own open protocols, which are essentially responsible for the connection. They also define the functionalities of each eRoaming platform.

Amongst the existing hubs, we can differentiate three major ones. They all come with their own open standards and unify hundreds of CPOs and EMPs as well as millions of EV drivers.

The three biggest hubs and their protocols are:

(eMobility Inter-Operation Protocol - eMIP)

Apart from the proprietary protocols coming from hubs, it’s worth mentioning that there's also an independent one - 

Open Charge Point Interface Protocol (OCPI)

. It allows for eRoaming between the hubs as well as peer-to-peer connection.

To learn more about eRoaming, hubs & protocols, their importance and functionality as well as the future of eMobility - take a look at our exclusive paper covering all that needs to be covered on the topic!

Download our comprehensive PDF and learn about the pricing structures in e-mobility

Although it would seem rather straightforward, the pricing system within the EV charging environment extends further than just to the payments made by electric vehicles right after they charge their car.

Being such an interconnected network of mutual dependencies between numerous involved parties, e-mobility charging services require various levels of settlements.


It must be noted that it takes a few units to build up and manage a charging network. From 

, which manufacture the hardware side of required components (connectors, chargers, cables, etc), through 

, which are responsible for the backend management, all the way to 

, which determine the final user (here: EV driver) experience, there is a whole network of reliabilities.

Put simply and briefly, CPO’s are to establish billing connections with both EVSE and eMSP’s, in order to put the entire charging formation in place, while ensuring all parties receive transparent information and clear instructions.

To facilitate it, there are multiple types of pricings and contracts, some of which allow for complex, dynamic price models. Such undertaking is required so that eMSP’s can shape their end-users pricing often based on certain conditions, leaving the rates flexible.


Interoperability - the core of proper functioning

It should go without saying, that managing a pool of charging stations - oftentimes distributed across entire countries/regions - is not an easy task to handle and can only be achieved via advanced levels of interoperability and clear, unified procedures.

Open Standards are the chief example of how this can be achieved and maintained. Through the utilization of API’s like OICP the flow of information can be sustained in a transparent manner. This allows for a seamless communication and can facilitate the management of a vast majority of proceedings remotely, which comes in handy while developing a state-wide network, especially when there are numerous parties involved.


Knowing the behind-the-scenes nuances and arrangements, we prepared a comprehensive paper portraying the pricing structure within the e-mobility industry. Those who are willing to learn more about tariffs within charging services, should definitely find it useful.

Download our free paper and broaden your horizons with some great knowledge!

E-mobility tariffs. How is the pricing structured within the industry?

Open standards can be a game changer for both eMSP's and CPO's. Here is why.

The initial stages of technologies lead to various types of solutions addressing the same problem. Each company develops a different approach. At the beginning of the XXth century, when commercial electricity had come to the mainstream, multiple energy producers offered power supply with miscellaneous frequencies and voltages. As time passed, governments began to impose certain standards on suppliers. This standard-setting led to the joint effort to create the first power grid.

From the first power plant to the moment when all energy providers linked to the same network, decades passed. This was only possible because they took a mutual direction.

 - literally and figuratively. With global warming, exhaustion of solid fuel resources, and lifestyle changes, companies face the challenge of how to provide accessible new charging forms of green power.

Now, as the e-mobility era is here, we are on the same page, like we were at the very beginning of the XXth century. We already have plenty of providers: eMobility Service Providers (eMSP) and Charge Point Operators (CPO) - two substantial sides of the e-Mobility world. One of the main challenges ahead of this market is to deliver the best user experience, at possible minimum resources use. As usual, user experience is a matter of well-designed apps, customer support, and simplicity itself. But there is an additional fact. End-users need to be able to charge cars at any charging station without being concerned about accessibility. The issue is - having the contract signed with the Charge Point Operators recharging point service. How to achieve this? Partners must take the same course, and this is where the standards start to play a major role. There are two possibilities: Open Charge Point Interfaces or Open Intercharge Protocols. What are the benefits?

The main goal of the Open Charge Point Interface (OCPI) is to allow electric vehicle drivers to charge their cars at any station. OCPI defines a set of modules that cover most cases the driver may need. There are two technical modules that are used to establish connectivity between two platforms using OCPI: Credentials module and Versions module. Other modules are strongly related to real-life use cases. These would be:

Locations - module responsible for sharing information about the Charge Points, like address, geolocation, real-time data about the current status, electrical parameters.

Sessions & Commands - module allows the end-user to start the charging session and be informed about the current status of the charging session.

OCPI is an open standard, and what may be very important for the adopters - it’s very flexible. For instance, CPOs (Charge Point Operators) may implement only the Locations module (apart from two technical mandatory modules) when only sharing Point Of Interest data. With no necessary exposing the eRoaming functionality. But the ultimate goal for many CPOs is to allow end-users to charge their car. In that case, many more modules need to be implemented (Sessions, Commands, CDRs). Some others are optional, even for the eRoaming (Tokens, Tariffs), and that depends on the agreement between certain allies. It’s in terms of how financial flow and security is modeled.

The biggest advantage of having OCPI implemented is that it’s almost a one-time investment. The initial effort is significant, as it might be challenging to transfer internal models and processes to the OCPI. But once it’s done for a partner, it opens the company for quick and cost-effective integration with a lot of other associates.

A bit different concept is proposed by the Berlin-based innovative company - Hubject. Hubject developed its own API (OICP) covering almost the same cases as OCPI. There is one extra. Hubject also acts as a hub. It connects CPOs and eMSPs. Once a company is connected to the Hubject platform, it becomes open for integration with any other comrade being already assigned. That’s a huge advantage because the integration is done once, with one platform, and of course it becomes profitable when it comes to an alliance with multiple partners.

Yet another advantage of the Open Intercharge Protocol is that it’s quite easy to implement. Like with most protocols, the main challenge is to synchronize our internal models with the standard one. What is comforting with OICP - there is not too much to implement. It depends on the level of integration we want to achieve, but it’s enough to implement about 5 HTTP calls to expose eRoaming through the Hubject platform.

Having in mind multiple historical examples, it may be difficult to be a part of a developed market without following widely adopted standards. Initially, it may need some additional effort. But when the standard is implemented, our platform becomes open for the whole market 

. Without it, we would need to spend weeks or months doing the integration with each partner separately.

Open InterCharge Protocole Training. Lesson 5

17 MARCH 2022 • 7 MIN READ