The world’s first power grid was designed and built in the US over 100 years ago, and it’s showing its age. However, complete infrastructure replacement would be prohibitively expensive, so today’s challenge is incorporating 21st century technology into the existing 19th century framework. It has become clear that distributed energy resources (DERs) are an integral part of that engineering puzzle. It is increasingly important for DERs to be able to connect to the grid or operate on their own as microgrids, which strengthens reliability, lowers power generation costs and optimizes overall system efficiency.
As engineers continue down this grid optimization path, DERs must communicate with each other in real-time to optimize their value and effectively coordinate the flow of energy. You want “technology that enables pristine power conversion and energy storage devices to work seamlessly together, as well as allowing separate microgrid systems to work together as part of a larger system,” said Keith Klarer, Director of VectorStat Data Architecture for Rhombus Energy Solutions.
An excellent example of this is Minnesota’s University of St. Thomas research microgrid, which is led by Professor Greg Mowry. “Professor Mowry needs a mechanism by which these geographically separate microgrids can communicate,” said Klarer. “If a failure occurs anywhere in the system he needs to know what happened and have the system recover automatically. Other parts can take up the slack of the failing unit,” Klarer added.
This dynamic communication and resilience is made possible by the VectorStat® software stack, which Klarer helped to build. VectorStat is the brains behind the intelligent inverters that Rhombus Energy supplies to the University’s microgrid. “Vector” references how the software connects and communicates with any hardware in a unique peer-to-peer application, like a microgrid. And the word “Stat” means “immediately,” which refers to the real-time access that users have to their energy hardware.
VectorStat utilizes applets to create the rules and control the microgrid. The applets can be written in a multitude of programming languages. These applets are similar to what revolutionized the cell phone industry by allowing a large number of developers to create a wide range of applications. Many different functions like peak shaving on-grid and critical load optimization when off-grid can be easily implemented and rules distributed to each unit by VectorStat. “The key to success in this industry is to allow anyone to develop energy control applications, which opens the door to new concepts and advances in controls like never before seen,” says Joseph Gottlieb, CTO of Rhombus.
Professor Mowry’s microgrid will have two inverters — one for a solar photovoltaic (PV) array and one for a battery storage system. “The attractor is that my research is involved with advanced inverter technology and distributed intelligence control systems,” Mowry said. “Based on 10 actually deployed microgrids around the world, I believe it’s better to use distributed intelligence control methods rather than centralized control methods for managing microgrids because central control is a single point of failure that can bring the whole system down.”
Reducing Power Generation Costs
In addition to greater resilience, the software provides system visibility that can help reduce the cost of generating power. “It also provides operational insights that haven’t been available before,” said Klarer. “End users can see how all the systems are operating and it provides analytics that show how energy costs fluctuate throughout the day in greater detail than in the past. That information helps improve the business models of power systems,” he explained.
As demand for power changes, VectorStat can meet the demand in a cost-effective manner by having different energy sources pick up various parts of the load. For example, if your solar array can handle the entire load at a given time, you don’t need to simultaneously run a diesel genset. Centralized control systems can do this as well, but VectorStat can talk to various generation components and tell them how much each piece should contribute and how much each piece can handle.
Rules used in an operation between power generation sources connected to a microgrid, governed by VectorStat, might go something like this: “I can come online, but I cost money and you don’t, so you come online and I won’t.” Professor Mowry added, “ultimately, it costs money to generate power, so when we generate from different sources, we can determine which combination gives us the cheapest power. VectorStat can run algorithms to see how much it costs each source to satisfy load.”
Improving the Quality of Life for Populations Without Electricity
Professor Mowry’s microgrid research is ultimately geared toward deploying systems in parts of the world that lack access to central power grids, which accounts for 17% of the global population, according to the International Energy Agency. Village power partitions into four parts: 1) lighting, 2) education (powering internet, for example), 3) communications (running a cell tower, for example) and 4) water pumping and/or purification. “VectorStat could run that whole portfolio,” said Mowry.
Mowry highlighted the importance of complete reliability for remote microgrid applications. “By providing dependable electricity to people who didn’t have it before elevates safety and quality of life, and due to the nature of the environment where these microgrids will be deployed, it’s important that the systems have a distributed intelligence capability in order to ensure reliability so that a single-point’s failure doesn’t bring the whole area’s power down.”
VectorStat® is a Registered Trademark of Rhombus Energy Solutions, Inc. USA