4 FAQs about DC Coupling in Utility-Scale Energy Storage

The installation of DC Coupled solutions in utility-scale energy storage, pioneered by Dynapower in 2018, has grown quickly in popularity. However, there are still some common misconceptions about this topology and its applications that I’d like to address. In short, DC coupled solutions are less expensive, simpler, lower maintenance, and revenue-positive solution for most PV installations…so let’s clear up some of the confusion surrounding this groundbreaking technology.

Is DC Coupling only suitable for small-scale applications?

• No, while this technology is sometimes associated with residential or small-scale systems, it is also highly applicable to utility-scale energy storage projects. It delivers significant benefits, such as higher efficiency, simplified system design, and enhanced flexibility, regardless of the scale of the installation. In fact, the streamlined design and reduced equipment costs associated with DC coupling make it an attractive option for utility-scale energy storage projects.

Isn’t Reverse DC Coupled technology too complicated for utility-scale applications?

• No. Reverse DC coupled solutions, also known as DC-optimized AC coupling, are often misunderstood as a complication for utility-scale energy storage projects. However, it actually offers unique advantages in terms of system compatibility, optimal battery charging, and grid independence. It enables the integration of existing AC-coupled storage systems with newly installed PV systems, allowing for upgrades without major system overhauls. Moreover, by utilizing the maximum power point tracking (MPPT) capabilities of PV inverters, reverse DC coupling ensures optimal battery charging, maximizing the energy harvest from solar panels. Lastly, reverse DC coupled technology can provide partial or complete grid independence during power outages, making it a valuable configuration for utility-scale applications.

Will using DC Coupled or Reverse DC Coupled technology increase overall system costs?

• Just the opposite: these configurations can actually reduce overall system costs in several ways:
  • By eliminating the need for separate PV and energy storage inverters, DC coupling simplifies the system design and reduces equipment costs.
  • The streamlined installation process and reduced maintenance requirements further contribute to cost savings.
  • Similarly, reverse DC coupling allows for the integration of existing AC-coupled storage systems with new PV systems, minimizing the need for costly system replacements.
  • Additionally, the efficiency gains achieved through these coupling methods can lead to long-term cost savings by maximizing energy yield.

What are the revenue opportunities for DC Coupling and Reverse DC Coupling?

• DC coupling and reverse DC coupling open additional revenue streams including:
  • Through participation in demand response programs, DC-coupled or reverse DC-coupled systems can provide grid stabilization services during peak demand periods, earning revenue.
  • The bidirectional energy flow and advanced control systems in these configurations also enable participation in utility programs or grid operator contracts for grid services such as frequency regulation and voltage support.
  • The ability to optimize energy consumption based on time-of-use tariffs can result in cost savings and revenue optimization. Revenue opportunities for DC and Reverse DC Coupling include:

• Clipping recapture*
• Curtailment recapture*
• Low voltage harvesting*
• Capacity firming**
• Energy time shifting**
• Ramp rate control**

*Only available with DC Coupled solutions

**Available with AC and DC Coupled solutions

Still have questions? Send us an email and one of our Clean Energy experts will get back to you with more information.

For more information on DC-coupled systems, read my previous blog post providing an overview of the technology, or visit our technologies page here.