Overcoming the Pitfalls of PLCs: How Software and Algorithms Deliver Superior Microgrid Performance

In recent years, microgrids have become an increasingly popular method to deliver cost-effective energy, reduce emissions, and strengthen energy infrastructure resilience. These benefits have made microgrids particularly attractive for Commercial and Industrial (C&) operations that rely on critical power sources in the face of energy price volatility and escalating risks of outages.
The choice of control and optimization can ultimately be a major differentiator as more complex microgrid use cases become the norm. EPCs must have more sophisticated tools to handle modern microgrids that use a solar PV system, battery storage, and larger loads for electric vehicle (EV) charging.

The Disadvantages of PLCs

PLCs are well-established standard bearers for industrial automation processes. Due to the widespread familiarity with these systems, PLCs were also applied to the first microgrid iterations as control systems. Although PLCs can provide some level of control for basic systems (i.e., standby generators controlled with generator controls and PLCs to form a microgrid), they were not explicitly designed for the complexity and demands of the modern microgrid.
Many of those proficient with PLCs will probably already be well-acquainted with some of the common problems these systems present in normal industrial usage, like:

  1. Module failure of the Input/Output (I/O) system,
  2. Electrical noise interference,
  3. Corrupted memory,
  4. Power problems.

But when applied to the modern microgrid, additional issues arise since PLCs lack the communication capabilities, flexibility, and scalability necessary to control and optimize these complex systems effectively.
Insufficient Communication Capabilities
Many PLCs cannot communicate with devices outside the microgrid or access real-time data from other sources. This can be an issue for grid-connected microgrids since the PLC cannot access data from the larger power grid — data that could benefit operations and assist with energy arbitrage.

Inflexible Design
Although PLCs can be tweaked or adapted for various operations, they do not have the flexibility to handle dynamic systems where EPCs must consider many interdependent variables for optimal performance and function. This lack of flexibility will significantly limit the full range of functionality necessary to control the modern microgrid and ensure peak system performance.

Inefficient Scalability
PLCs are also limited in their scalability – something that microgrids require. As microgrids increase in size and complexity, their control systems must also be able to scale accordingly. However, PLCs are restricted by their centralized hardware and software capabilities and cannot efficiently adapt to a microgrid’s changing needs. This lack of scalability can cause problems if an EPC needs to expand the microgrid or add new assets. The PLC may be unable to support the increased load without re-engineering the entire control system at significant time and cost.

As microgrids become more complex, it is imperative that EPC firms use a reliable solution to ensure the performance, efficiency, and safety of the system. While PLCs have served their purpose in the early stages of microgrids and may continue playing a role in simpler fossil-fuel-based microgrids, they do not offer a compelling solution for managing and monitoring the modern microgrid.

The Alternatives to PLCs

A platform using algorithms and software offers a more flexible, powerful, and scalable strategy to control and optimize the modern microgrid.
Enhanced Communication Capabilities
For starters, algorithms and software are better equipped to handle the complexity of microgrids. A modern microgrid combines numerous Distributed Energy Resources (DERs), such as solar panels, generators, loads, storage, and energy management systems — none of which were designed or manufactured to communicate with each other. But algorithms and software use a decentralized architecture that can more easily integrate, manage, and communicate each component compared to the centralized approach of PLCs. This also allows algorithms and software to easily integrate with other systems, such as communications networks and computer systems.

Improved Flexibility
Algorithms and software offer greater flexibility than PLCs since they can be easily modified and updated to respond to changing conditions. In contrast, PLCs are more rigid and require more effort to change. Since software and algorithms are designed to analyze data and make decisions quickly and accurately, they can immediately detect environmental changes and make the necessary adjustments to ensure efficient and safe microgrid operation.

In addition, EPCs can tune and adjust software and algorithms to better meet specific customer optimization goals. For example, algorithms and software can be used to:

  1. Optimize the operation of the microgrid to minimize power losses
  2. Improve power efficiency
  3. Maximize the use of renewable energy sources

Or implement more sophisticated control techniques such as:

  1. Optimal power flow
  2. Economic dispatch
  3. Advanced strategies for distributed generation systems

These advanced control techniques are impossible with traditional PLCs, which are limited to fixed processes like basic on/off control of power flows.
Rapid Scalability
The robust communication capabilities and flexibility of algorithms and software make them simpler and faster to scale. EPCs can adapt them to different types of assets to add and integrate components and resources with existing systems while maintaining functionality and control.

These advantages also make software and algorithms much more cost-effective than PLCs. They require less hardware, are easier to install, and can be updated and adjusted more quickly than PLCs, making them a smart option for controlling, optimizing, and scaling C&I microgrids.

The Superior Performance of Modern Microgrids

Despite the limitations of PLCs in controlling and optimizing the modern microgrid, the advantages of software and algorithms have not been fully realized because of the relative newness of the microgrid market and its rapid rate of innovation.
For EPCs seeking to maximize the benefits of the microgrids they deploy, algorithms and software offer the flexibility, advanced control techniques, and cost-effectiveness to deliver project success based on customers’ goals, priorities, and objectives.
To overcome the disadvantages of traditional PLCs, Heila Technologies developed the Heila EDGE microgrid control platform. The Heila EDGE uses sophisticated yet user-intuitive software and advanced algorithms embedded in each device to build self-sustaining microgrids from the ground up. By writing our own software and algorithms to achieve a superior-performing microgrid for more complex use cases, Heila Technologies delivers the differentiator that EPCs need to propel their microgrid offerings and provide project success.
Regardless if it’s a full-wrap or a partial-wrap contract, Heila iQ provides the critical energy data, reporting, and recommendations to help EPCs standardize and simplify onsite DER deployments for C&I facilities.
Could you benefit from some guidance on making a business case for microgrids? This eBook may be of help.
Sparked any further questions? Let us know here — we’d be happy to hear from you.