Renewable Energy DC Microgrids
Microgrids are in the news as recent hurricanes have severely damaged or destroyed electrical grids at home and abroad. Local renewable energy microgrids may have allowed pockets of power to survive these storms. As we discuss the future of renewable energy microgrids, there is an argument for internal DC electricity grids. DC electricity is now an attractive alternative to AC power for a number of reasons including:
- Photovoltaic power is is intrinsically DC, is on the rise, and is becoming the least expensive power source in many areas.
- Many common electrical loads, such as LED lights, and computers, are DC appliances.
- Batteries, the power source for electric cars, and increasingly common in renewable energy systems, are DC.
- High power semiconductors have made DC-DC voltage conversion almost as efficient as AC transformers.
These four changes in the world of power systems taken together suggest that power networks at the scale of microgrids may be more efficient and cost effective using DC power rather than AC power. To test this hypothesis we have built a small DC power system, a nanogrid, at Clark University, consisting of 1.6 kW of solar panels, a vertical and a horizontal wind turbine, battery storage, and a bidirectional tie to the University AC grid. The system will be used to power lights in offices and classrooms in the building. As part of the project, we are also monitoring electricity in rooms that are powered by the standard building AC system. The design of the system and our plans for monitoring power usage and efficiency during the next semester of classes will be discussed.
C. Agosta is a low temperature experimental physicist who was originally trained to study the properties of fluids at very low temperatures. His present research interests are lower dimensional superconductors in very high magnetic fields, heat transfer in gas boundary layers, and renewable energy.
As a professor he teaches many of the core courses in the Clark University Physics Dept., but specializes in two signature courses, Astronomy and The Technology of Renewable Energy. His renewable energy course is focused on the technical and social issues of creating renewable energy microgrids. He directs a project on campus using renewable energy and leveraging the cogeneration plant on campus to create a local DC nanogrid. This project has been supported by National Grid, the local energy utility.
Agosta is also CEO and co-founder of Machflow Energy, Inc., a clean-tech company that is developing highly innovative heat transfer technologies. Machflow has created a disruptive Bernoulli Principle-based heat pump that works in a closed cycle using noble gasses that have no adverse effects on the environment, such as global warming. Machflow has six patents and was funded by Kleiner Perkins, the DOE, and prominent angel investors.
Host: Professor Yousef Mahmoud