Duke Energy Studying Next-Generation Energy Products at Emerging Technology Office

Background

The transition to clean energy — and utilities’ pursuit of carbon neutrality over the coming decades — is bringing unprecedented changes to every level of the electric power grid. Before new and emerging technologies are deployed in utility-owned infrastructure and customer facilities, however, it is essential that they be tested to ensure they are reliable and perform as expected. That’s the purpose of the Duke Energy Emerging Technology Office (ETO): to evaluate innovative technologies early in the development cycle.

Formed in 2007 with the purpose of exploring technologies that would influence Duke Energy’s business, the ETO started evaluating potential pilots. It began testing microgrid technology at the McAlpine Creek Substation in Charlotte, North Carolina, in 2013 and took over an existing Duke Energy facility in Mount Holly, North Carolina, in 2016 to expand its capabilities. The Mount Holly Technology and Innovation Center provides the ETO an environment to test hardware and software both in a laboratory and under controlled field conditions. The site was constructed to be powered as a fully islanded (or off-grid) microgrid with 150 kilowatts (kW) of solar, 650 kW of battery storage, a generator and microturbines. It can transition seamlessly between off grid — how it operates over 90% of the time — and grid connected.

As technology gets integrated into the utility business, Duke Energy evolves the facilities at Mount Holly to stay ahead. In 2020, the utility renovated the shop building to support customer-sited technology demonstrations. There is also a 1.5-mile test distribution feeder under construction that resembles a real-world neighborhood distribution feeder, allowing testing to go beyond simulation or the evaluation of components in isolation. It will ensure that numerous devices can be studied and perform together in a native 12-kilovolt environment typical to a residential neighborhood feeder.

The ETO originally evaluated technologies that were likely to impact Duke Energy about a decade down the road; it now also assesses applications much closer to customer deployment, potentially in the 0- to 3-year time frame. The ETO collaborates with many partners along the journey from technology identification to testing, including national labs, universities, Advanced Energy and the Duke Energy Florida Energy Wise Lab.

“We have been a partner with Duke Energy since 1980 to research energy technologies with a focus on those that are being commercially deployed. That we are in the most disruptive and innovative time in the industry only intensifies the necessity of centers like the ETO. Some components just cannot be tested at customer facilities and must be evaluated in more controlled environments. There will still be lessons learned from field research and pilot programs to optimize results, but the ETO helps ensure that those lessons don’t negatively impact customers’ daily lives, business or wallets.”

– David Farmer, engineering supervisor of Advanced Energy’s renewables team

Grid-Edge Controls and Distributed Intelligence

One theme of the ETO’s testing is the integration of equipment with existing and future control systems that balance supply and demand in real time. Utility control centers have traditionally focused on the bulk power system — generation and power delivery at the transmission level — and have had limited communications and control with the distribution system or customer loads. The next step for grid management will be a fully integrated system for bulk power generation, distributed assets and customer devices.

Devices close to customers are generally referred to as “grid-edge” devices and represent the latest frontier in energy and demand management. Utilities will manage load using these devices in a way that reduces demand without adversely impacting consumer comfort, cost or reliability. The Mount Holly Innovation Center provides a place to understand the interoperability — the capability of systems or components to exchange and use information — of new products with distributed intelligence and control. In other words, if a utility sends a command, do devices respond as expected and communicate back with meaningful data.

Several years ago, an early success of the ETO was the formation of a coalition of other utilities, researchers and vendors to develop the Open Field Message Bus (Open FMB^TM) architecture, a field device interoperability framework. The ETO team continues to employ Open FMB and work on distributed security as part of the continual evolution toward distributed intelligence.

Energy Storage as a Supply-Side Resource

Both short- and long-duration energy storage will be critical to complement the renewable energy in our state. Today, there are 120 megawatts of battery energy storage systems installed on the Duke Energy grid, with a near-term action plan to deploy 2.7 gigawatts by 2031 as stated in the Carolinas Resource Plan.

Initially, short-duration energy storage, typically two-to-four hours using lithium-ion batteries, is being deployed. However, as we get higher penetrations of renewables and more phasing out of traditional carbon-based generation resources, longer-duration storage (8-to-10 hours or longer) must be available too. The ETO is exploring multiple types of long-duration battery chemistries and applications, including hydrogen. Several new chemistries and manufacturing approaches have performed well in beta tests and are being piloted.

Vendors, though, may face challenges as they scale up manufacturing and reach full commercialization. Testing technologies early in the development cycle gives Duke Energy engineers the opportunity to compare vendor specification data with performance aspects, for example, charge and discharge profiles or cycling. It also gives them firsthand experience with safety requirements or other equipment to operate, such as cooling systems. The ETO transfers knowledge gained to Duke Energy business units to build into future pilots or full-scale procurement programs.

Grid-Edge and Customer Programs for Electrification and Demand Flexibility

While the utility works to integrate new energy supply technologies, there is also an unprecedented evolution on the load side, including the rise of electric vehicles (EVs). Currently, North Carolina has more than 74,000 EVs on the road. Although they represent less than 1% of the total vehicle fleet for Duke Energy in the Carolinas, they are projected to grow to 26% in 2035. Duke Energy is vetting the integration of equipment for light-duty and medium-/heavy-duty EVs at Mount Holly and in field demonstrations. Some initiatives underway include support for EV managed charging solutions and a fleet depot for medium- and heavy-duty vehicle charging.

Related to managed charging, the ETO plans to test and monitor the impact of charging multiple EVs on local infrastructure, such as distribution transformers. In a typical neighborhood system, a transformer might serve two to five homes or more, depending on development density. What happens when five or more EVs on the same transformer are charging simultaneously? What is the impact to a battery’s life and state of charge if the charging load is managed by the utility by ramping its rate up or down to mitigate adverse impacts to utility infrastructure? Questions like these will be explored at the ETO through the distribution test feeder mentioned earlier.

Load control represents another shifting customer-impact area. Load control has historically emphasized appliance-level management, using controls on customer equipment such as water heaters, heating and cooling systems, or washing machines. While that approach still exists, there are now vendors offering more centralized and flexible control through smart breaker panels, coordinating many loads through one device. Load control can be achieved as well through behind-the-meter battery storage systems, which also provide resilience benefits. Technologies commercially available to customers have been tested both at Mount Holly and at Duke Energy Florida’s Energy Wise Lab to inform pilot programs.

Robotics, Sensors and Safety

Other topics of interest for the ETO are robotics, sensors and safety. Advanced machines and maintenance technologies can save millions of dollars per year in operations. An example is a robotics solution like the SPOT Robot dog, which can be programmed to perform inspections in areas that are difficult or unsafe to access, such as substations or power plants.

Closing

According to Tom Fenimore, director of the ETO, Duke Energy is committed to reliability and affordability. The ETO team is taking essential steps to safely and effectively tackle the challenges of the clean energy transition while maintaining or improving the grid.

“I have visited other research centers throughout my career, but the Mount Holly Innovation Center was unique. Duke Energy engineers are not just doing research and simulation; they are systematically reproducing real-world conditions that their customers will experience. Their diligence to ensure that technologies can integrate with one another before they roll out across the business impressed me and the Advanced Energy engineering team.”

– David Farmer, Advanced Energy