When Do You Need an EMS Controller?

It is a common misconception that steering an energy system in a “smart” way always requires an EMS Controller.
In this article, we explain in which use cases the internal logic of the Autarco inverter is sufficient for the required energy management functionality.

Before you start

All EMS-related features require consumption meter data, either:

• via a smart meter connected to the inverter, or

• via a smart meter connected to the EMS Controller.

 

EMS feature overview

While an EMS can provide many advanced functions, this article focuses on the most common ones:

• Power limitation

• Export limitation

• Peak shaving

• Self-consumption

• Time-of-use optimisation (tariff-based)

• Remote monitoring

• Generator support

• Response to negative export prices (dynamic contracts)

• Smart charging (EPEX / dynamic prices)

• Grid services (imbalance markets)

• EV charge management

• Dynamic load management

• Mixing device brands

 

Feature categories

These features can be divided into three main groups:

2. Cloud EMS

Some features are available via NPR in Helios (on request) or through the EMS Controller.

3. EMS required

Certain advanced features require an EMS to function correctly.
These are listed in the final section of this article.

Feature supported internally in devices

Power limitation

All our latest devices have the capability to limit their power generation.
This power level can be set statically in the inverter or via Digital O&M. This feature does not require a meter or an EMS.

Supported for:

• On-grid inverters

• Hybrid inverters

• PELD

• Cabinet batteries

 

Export limitation

For locations where export is not allowed, the Zero Export feature is the perfect solution.
Our inverters have the capability to limit themselves via the (internal) PELD function.
This makes the device limit production until there is no export.

Does not require EMS
Supported for: On-grid inverters, hybrid inverters, PELD, and cabinet batteries
Requires: External smart meter installation. (for details, take a look here)

 

Peak shaving

This feature allows the user to provide extra power to the load whenever it’s higher than the maximum grid import power.
It is designed for customers dealing with grid congestion or unable to meet consumption demand from the grid.

When setting up this feature, two data points must be defined:

• Max grid import power

• Peak shaving SOC

Max grid import power defines the maximum power the user wants to import from the grid.
Whenever the device detects that the load is higher than the max allowed import power + PV power at that moment, it will start discharging the battery to ensure the consumption demand is met.

Peak shaving SOC defines the state of charge that the battery must reserve for peak shaving.
It should be set based on the expected power and duration of the demand peak.
Like the battery reserve function, the device will always try to charge the battery to the peak shaving SOC as soon as possible.

 

Example:
A peak of 80 kW for 1 hour is expected for the load, with a 3 × 80 A grid connection used together with S2.XLH50000 + BF100.
Assuming the worst-case scenario (no PV, modules covered in snow, etc.) and a max grid import of 50 kW, the battery should supply 30 kW for 1 hour.
This means the peak shaving SOC should be set to at least 30% (30% of the 100 kWh capacity of BF100 when fully charged).

Does not require EMS
Supported for:

• Hybrid inverters (LQH, XLH, and OH series)

• Battery cabinets (smart meter connected to the cabinet required – Acrel ADL400, delivered with the cabinet)

 

Self-consumption

This global feature can be set in parallel with other functions.
It defines the priority of energy supply.
To maximize self-consumption, the inverter will charge the battery whenever consumption demand is met.
Only when the consumption is met and the battery is fully charged will the energy be sent back to the grid.

Does not require EMS
Supported for:

• All Autarco hybrid inverters

• Battery cabinets (smart meter connected to the cabinet required – Acrel ADL400)

 

Grid trading

This global feature sets the opposite priority to self-consumption.
When grid trading is enabled, energy export is prioritized over battery charging once consumption demand is met.

Does not require EMS
Supported for all Autarco hybrid inverters

 

Time schedule 

This feature allows the user to choose multiple charge and discharge time slots.
During these slots, the battery will be forced to charge or discharge until it reaches the set SOC point, the over-discharge SOC, or the slot ends.
It is ideal for systems with stable weekly profiles or markets with low price volatility.

Available hybrid inverters:
MH, MH-MII, LH, LH-MII, LQH, XLH, OH
(4 charge and 4 discharge time slots, with SOC setpoints)

Available cabinets:
DH100F, DH200F, DH200Y
(4 charge and 4 discharge time slots, with separate settings for each day of the week)

 

Remote monitoring

With Autarco communication sticks, remote monitoring is fully supported using the internal device capabilities.

Does not require EMS
Cabinets can be remotely monitored via an external portal.
For cabinet data in MyAutarco, an EMS controller is required.

 

Generator support

Some Autarco hybrid inverter models have a generator port that allows automatic generator start/stop based on the battery’s SOC level.

Does not require EMS
Supported for:

• Hybrid inverters

  • LH-MII series (communication port only)

  • LQH, XLH, and OH series (separate AC generator port)

 

Battery reserve 

This feature is designed for customers who want backup energy during an off-grid state.
It allows setting a battery reserve SOC, which the inverter will always maintain as a minimum charge level.

During normal (on-grid) operation, the battery operates between 100% and the reserve SOC.
The reserved SOC is only used when the inverter detects an off-grid condition, ensuring energy availability during outages.

 

EMS features supported via cloud

Responding to negative export prices with a dynamic contract

The devices we supply do not have insight into dynamic electricity prices.
Therefore, they cannot perform this EMS feature internally.
However, we offer a cloud-based solution where internal export limitation can be switched automatically without the need for a local EMS controller.

Requirements:

• Smart meter installed

• Two-way communication stick

• EMS required when combined with other features

Supported for:

• On-grid inverters

• Hybrid inverters

• PELD (only supported via Cloud NPR)

 

EMS-only features

The following features are only available when using an EMS.

Smart charging based on EPEX / dynamic contract prices

If the energy system must respond to EPEX market or dynamic contract prices, this cannot be done internally by the inverter or battery cabinet.
To enable this feature, an EMS is required to retrieve real-time price data and control the connected devices accordingly.

Requires an EMS

 

Grid services (imbalance markets)

Controlling devices based on grid service signals. For example, to participate in imbalance markets, is only possible via an EMS.
Internal device capabilities do not support this functionality.

Requires an EMS
(or an external party that integrates with the Autarco API)

 

EV charge management

EV charging stations are not directly supported within device-level functionality.
To integrate EV charging with other energy devices, an EMS is required for communication and coordination.

Requires an EMS

 

Dynamic load management

If the system requires specific loads to be enabled or disabled based on grid connection measurements, an EMS is required.
Autarco inverters do not have internal relay or signaling capabilities for this function.

Requires an EMS

 

Combining features

When multiple EMS functions are combined, an EMS is generally required to ensure the features do not interfere with each other.
This ensures correct prioritization and coordination across devices.

Requires an EMS

 

Mixing device brands

Different brands often use proprietary communication protocols and cannot directly interface with one another.
If you want multiple brands of devices to operate together, an EMS is required to coordinate communication and optimize system performance.

Requires an EMS