Duke Energy gets go-ahead for solar + storage microgrid in North Carolina’s Madison County

duke energy microgrid

Madison County will soon be home to an innovative microgrid installation after the North Carolina Utilities Commission (NCUC) approved Duke Energy’s renewable energy project.

In the town of Hot Springs, the company will proceed with a solar and battery-powered microgrid system that will help improve electric reliability, provide services to the overall electric system and serve as a backup power supply to the town of more than 500 residents.

“Duke Energy’s research work on microgrids has led to a large-scale effort that will better serve, not only these customers in a remote area, but also help us gain experience from this pilot project to better serve all customers with additional distributed energy and energy storage technologies,” said Dr. Zak Kuznar, Duke Energy’s managing director of Microgrid and Energy Storage Development. “Projects like this will lead to a smarter energy future for the Carolinas.”

The Hot Springs microgrid will consist of a 2-megawatt (AC) solar facility and a 4-megawatt lithium-based battery storage facility. The microgrid will not only provide a safe, cost-effective and reliable grid solution for serving the Hot Springs area, but the microgrid will also provide energy and additional bulk system benefits for all customers. This will include reliability services to the electric grid, such as frequency and voltage regulation and ramping support and capacity during system peaks.
The project is part of Duke Energy’s plan to meet power demand by balancing public input, environmental impacts and the need to provide customers with safe, reliable and affordable energy.

Don’t miss our Solar + Storage issue in July — subscribe to Solar Builder magazine (print or digital) for FREE today

Another component of that plan is in the city of Asheville where Duke Energy will connect a 9-megawatt lithium-ion battery system at a Duke Energy substation site in the Rock Hill community – near Sweeten Creek Road. The battery will primarily be used to help the electric system operate more efficiently and reliably for customers.

Together, the two projects will cost around $30 million and should be operational in early 2020.

Also in the region, Duke Energy is closing a half-century-old, coal-fired plant in Arden by January 2020 – and replacing it with a new 560-megawatt cleaner-burning combined-cycle natural gas plant.

Duke Energy has a smaller microgrid project in North Carolina already operating. In Haywood County, N.C., Duke Energy has a 95-kilowatt-hour zinc-air battery and 10-kilowatt solar installation serving a communications tower on Mount Sterling in the Smoky Mountains National Park that has been operating since 2017. It is also currently working on proposed projects in South Carolina.

— Solar Builder magazine

Siemens awarded $6.4M by DOE to develop solar’s role in grid resilience

solar corporate funding

Siemens’ central research and development unit in the U.S., Siemens Corporate Technology (CT) US, was selected for a $6.4 million research award from the U.S. Department of Energy Solar Energy Technologies Office (SETO) to advance solar energy’s role in strengthening the resilience of the U.S. electricity grid. This project will create an innovative Energy Management System that can coordinate distributed microgrids to work together. The system will utilize diverse technologies to increase grid resilience against natural disasters or cyber-attacks as well as autonomously restore power during a blackout using smart inverters.

CT US was selected as a part of the Energy Department’s effort to invest in new projects that enable grid operators to rapidly detect physical and cyber-based abnormalities in the power system and utilize solar generation to recover quickly from power outages. Siemens is one of several projects that will develop grid management technologies that show how solar energy will enhance power system resilience, especially at critical infrastructure sites. Collaborative efforts between Siemens and the DOE are expected to begin by Summer 2019.

Don’t miss our Solar + Storage issue in July — subscribe to Solar Builder magazine (print or digital) for FREE today

“Siemens technologies are helping to modernize the U.S. electric grid and develop stronger, more resilient power systems that can detect and defend against physical and cyber-threats and support smart infrastructures,” said Ulrich Muenz, Siemens CT Head of the Autonomous Systems and Control Research Group. “This project advances innovative research and development for technologies that could one day become standard across the industry to enhance and protect critical infrastructure through autonomous and resilient energy management systems.”

The Siemens CT team will be led by Ulrich Muenz and Sindhu Suresh and work with partners from DOE’s National Renewable Energy Laboratory (NREL), Columbia University, Siemens Digital Grid and Holy Cross Energy to develop, validate, and demonstrate a highly innovative, three-layer Energy Management System (EMS) for Autonomous and Resilient Operation of Energy systems with RenewaAbles (AURORA).

In January 2019, CT signed an MOU with National Renewable Energy Laboratory (NREL), Oak Ridge National Laboratory (ORNL), and Pacific Northwest National Laboratory (PNNL), to conduct integrated experiments within their respective research and development facilities to help integrate innovative power electronic devices with the electric grid, including smart inverters for solar panels, batteries, and electrical vehicles that are capable of supporting the nation’s power system.

“The increasing deployment of distributed solar resources gives grid operators like Holy Cross Energy an opportunity to rethink the design and operation of our electric power system, in ways that utilize these local assets to not only deliver value to the consumer, but also to enable and enhance the reliability and resilience of the power systems in which they are embedded. By working with Siemens and collaborators in this very important project, we will get a window into the future self-driving grid and discover the most important steps we need to take to get ourselves ready for it,” says Bryan Hannegan, CEO of Holy Cross Energy.

— Solar Builder magazine

Caterpillar to start selling Cat-branded SunPower solar panels through its distribution network

Cat Hybrid Energy Solutions - Shingled Cell Solar Panels
SunPower is now providing high-efficiency SunPower Performance Series (P-Series) solar panels under the Caterpillar brand. Offered as part of the Cat Hybrid Energy Solutions suite, the monocrystalline, shingled-cell Cat PVC395 MP solar panels are currently available through the Cat dealer network in Southeast Asia, Africa, South America, and the Middle East.

Providing efficiency, performance and dependability, Cat PVC395 MP solar panels are rated at 395 watts per panel and achieve efficiencies of over 19 percent through an innovative shingled-cell design with multiple redundant paths for electricity flow. This eliminates many of the reliability challenges of traditional front-contact solar panels. Additionally, the panels use a unique parallel circuit architecture that significantly limits power loss from shade and soiling.

“Backed by SunPower’s product and power warranty, the P-Series solar panel technology offered through our relationship with Caterpillar can generate up to 32 percent more energy than conventional panels in the same space over 25 years,” said Peter Aschenbrenner, executive vice president for SunPower. “Our technology is the most sold shingled-cell solar panel in the world, maximizing production and delivering long-term value. We’re pleased to collaborate with Caterpillar, an exceptional brand with a strong commitment to sustainability.”

Check out the 2018 Solar Builder Projects of the Year!

Cat PVC395 MP solar panels are the latest addition to the Cat Hybrid Energy Solutions suite, an innovative lineup of power systems that combines environmentally friendly solar panels, state-of-the-art energy conversion and storage technologies, and advanced monitoring and control systems with Caterpillar’s traditional line of reliable power generation equipment.

“SunPower shares Caterpillar’s commitment to developing an impressive portfolio of technologies with proven durability and performance in the field,” said Joel Feucht, general manager in Caterpillar’s Global Power Solutions Division. “By expanding our global solar offering, the world-class Cat dealer network can better serve the growing customer demand for cost-effective solar energy, backed by the reliable power of Cat standby- or prime-rated generator sets.”

The Cat Hybrid Energy Solutions technology suite is designed to reduce fuel expenses, lower utility bills, decrease emissions, and reduce the total cost of ownership while increasing energy resiliency in even the most challenging environments. Key offerings in the Cat Hybrid Energy Solutions suite include:

• The Cat Master Microgrid Controller (MMC), which keeps loads continuously energized with high-quality power at the lowest cost by managing the flow of power from every source in the system;

• Cat Connect Remote Asset Monitoring, which offers real-time collection and remote monitoring of site performance data in Cat Microgrid applications; and

• Cat Bi-Directional Power (BDP) inverters, which provide real and reactive power with grid-forming and grid-following capabilities.

— Solar Builder magazine

Two advanced microgrids up and running in Montgomery County, Maryland via Schneider Electric


Montgomery County, Maryland, saw the official activation of two advanced microgrids at its Public Safety Headquarters (PSHQ) and Correctional Facility. The microgrids are on-site clean power generation systems, which permit both facilities to operate independently from the power grid to ensure continuity of operations in the event of a catastrophic storm or major power outage.

The completed project is provided through an innovative public-private partnership with Schneider Electric and Duke Energy Renewables that required no upfront costs for the County. The on-site power generation at these two sites is anticipated to reduce greenhouse gas emissions equal to removing 765 cars off the road or planting 94,000 trees.

The Montgomery County PSHQ microgrid also achieved Performance Excellence in Electricity Renewal (PEER) certification from Green Business Certification Inc. (GBCI) and is the first Maryland project and public safety headquarters to earn certification. PEER is the world’s first certification program that measures and improves power system performance and electricity infrastructure. Through certification, PEER recognizes industry leaders for improving efficiency and sustainability, day-to-day reliability and resilience in the face of severe events.

“Montgomery County is one of the first jurisdictions in the nation to incorporate resilient energy resources, enabling essential public facilities to be self-sufficient and reduce our overall carbon footprint,” said Leggett. “The Public Safety Headquarters and the Montgomery County Correctional Facility are essential to protecting our communities. The solar panels and other advanced systems added to these facilities will generate clean power and take stress off the grid during extreme weather conditions and other emergencies.”

Public-private partnership

Given the Schneider Electric and Duke Energy Renewables public-private partnership (P3) made the project possible with no upfront capital costs, the County’s other budget priorities were not affected. As part of the agreement, Duke Energy Renewables will own and operate both microgrids with the assistance of its subsidiary, REC Solar, and Schneider Electric. The two advanced microgrids will produce approximately 3.3 million kilowatt hours of solar energy annually, as well as 7.4 million kilowatt hours of combined heat and power.

“This microgrid project is a major benefit for Montgomery County and the entire National Capital Region,” said Riemer. “This P3 with Schneider Electric and Duke Energy Renewables ensures continuity of critical services at our Public Service Headquarters and Correctional Facility during power losses and saves our residents millions of dollars.”

— Solar Builder magazine

Inside the complex microgrid design of Quinnipac University

Quinnipiac Campus 1

A unique power control system for Quinnipiac University’s York Hill Campus, located in Hamden, Connecticut, ties together a range of green energy power generation sources with utility and emergency power sources. The powerful supervisory control and data acquisition (SCADA) system gives campus facilities personnel complete information on every aspect of the complex system. Initially constructed when the term microgrid had barely entered our consciousness, the system continues to grow as the master plan’s vision of sustainability comes into fruition.

Focus on energy efficiency and sustainability

In 2006, Quinnipiac University began construction on its New York Hill campus, perched high on a hilltop with stunning views of Long Island Sound. Of course, the campus master plan included signature athletic, residence, parking, and activity buildings that take maximum advantage of the site. But of equal importance, it incorporated innovative electrical and thermal distribution systems designed to make the new campus energy efficient, easy to maintain, and sustainable. Electrical distribution requirements, including primary electrical distribution, emergency power distribution, campus-wide load shedding, and cogeneration were considered, along with the thermal energy components of heating, hot water, and chilled water.

The final design includes a central high-efficiency boiler plant, a high-efficiency chiller plant, and a campus-wide primary electric distribution system with automatic load shed and backup power. The design also incorporates a microturbine trigeneration system to provide electrical power while recovering waste heat to help heat and cool the campus. Solar and wind power sources are integrated into the design. The York Hill campus design engineer was BVH Integrated Services, PC, and Centerbrook Architects & Planners served as the architect. The overall campus project won an award for Best Sustainable Design from The Real Estate Exchange in 2011.

Implementation challenges for the complex system

The ambitious project includes numerous energy components and systems. In effect, it was a microgrid before the term was widely used. Some years after initial construction began, Horton Electric, the electrical contractor, brought in Russelectric to provide assistance and recommendations for all aspects of protection, coordination of control, and utility integration – especially protection and control of the solar, wind and combined heating and power (CHP) components. Russelectric also provided project engineering for the actual equipment and coordination between its system and equipment, the utility service, the emergency power sources, and the renewable sources.

Alan Vangas, current VP at BVH Integrated Services, said that “Russelectric was critical to the project as they served as the integrator and bridge for communications between building systems and the equipment.”

Startup and implementation was a complex process. The power structure system infrastructure, including the underground utilities, had been installed before all the energy system components had been fully developed. This made the development of an effective control system more challenging. Some of the challenges arose from utility integration with existing on-site equipment, in particular the utility entrance medium voltage (MV) equipment that had been installed with the first buildings. Because it was motor-operated, rather than breaker-operated, paralleling of generator sets with the utility (upon return of the utility source after power interruption) was not possible in one direction. They could parallel the natural gas generator to the utility, but the generator was also used for emergency power, so they could not parallel from the utility back to their microgrid.

Power distribution controls

In response to the unique challenges, Russelectric designed, delivered, and provided startup for a unique power control system, and has continued to service the system since startup. The system controls all power distribution throughout the campus, including all source breakers – utility (15kV and CHP), wind, solar, generators, MV loop bus substations, automatic transfer switches (ATSs), and load controls.

As might be expected, this complex system requires a very complex load control system. For example, it has to allow the hockey rink chillers to run in the summer during an outage but maintain power to the campus.

Here is the complete power control system lineup:

• 15 kilovolt (kV) utility source that feeds a ring bus with 8 medium voltage/low voltage (MV/LV) loop switching substations for each building. Russelectric controls the open and close of the utility main switch and monitor’s the utility main’s health and protection of the utility main.

• 15kV natural gas 2 megawatt (MW) Caterpillar CAT generator with switchgear for continuous parallel to the 15kV loop bus. Russelectric supplied the switchgear for full engine control and breaker operations to parallel with the utility and for emergency island operations.

• One natural gas 750kW Caterpillar generator used for emergency backup only.

• One gas-fired FlexEnergy micro turbine (Ingersoll Rand MT250 microturbine) for CHP distributed energy and utility tie to the LV substations.

• Control and distribution switchgear that controls the emergency, CHP, and utility.

• 12 ATSs for emergency power of 4 natural gas engines in each building.

• 25 vertical-axis wind turbines that generate 32,000 kilowatt-hours of renewable electricity annually. The wind turbines are connected to each of the LV substations. Russelectric controls the breaker output of the wind turbines and instructs the wind turbines when to come on or go off.

• 721 rooftop photovoltaic panels gathering power from the sun, saving another 235,000 kilowatt-hours (kWh) per year. These are connected to each of the 3 dormitory LV substations. Russelectric controls the solar arrays’ breaker output and instructs the solar arrays when to come on or go off.

The system officially only parallels the onsite green energy generation components (solar, wind and micro turbine) with the utility, although they have run the natural gas engines in parallel with the solar in island mode for limited periods.

Since the initial installation, the system has been expanded to include additional equipment, including another natural gas generator, additional load controls, and several more ATSs.

SCADA simplifies the complexity

Another feature of the Russelectric system for the project was the development of the Russelectric SCADA system, which takes the complexity and detail of all the systems and displays it for customer use. Other standard SCADA systems would not have been able to tie everything together – with one line diagrams and front views of equipment that provide the ability to visually see the entire system.

What really made this project stand out is Russelectric’s ability to handle such an incredibly wide variety of equipment and sources without standardizing on the type of generator or power source used. Rather than requiring use of specific players in the market, the company supports any equipment the customer wishes to use – signing on to working through the challenges to make the microgrid work. This is critical to success when the task is controlling multiple traditional and renewable sources.

Steve Dunn is the Aftermarket Product Line Manager for Russelectric Inc.

— Solar Builder magazine