Thanks to its microgrid, North Carolina’s Ocracoke Island was able to restore power three days after Hurricane Dorian sent a tidal wave smashing into its coast line, causing massive flooding.

Initially, both the grid and the microgrid went out of operation when the hurricane struck September 6, and flood waters rose 13 feet. Local service provider, Tideland Electric Membership Corp. (TEMC) said it had no choice but to shut down the microgrid given the wind and water.

“Dorian was a particularly catastrophic storm for Ocracoke that resulted in historic flooding on the island,” said Lisa Crawley, spokesperson for North Carolina’s Electric Cooperatives. “Because of flooding and structural damage, electric meters were pulled from nearly 400 homes — 28% of the island’s meters — making it impossible to deliver electric service to them.”

She added: “The good news is that, when flood waters subsided, after safety inspections to confirm equipment was not damaged, the microgrid’s diesel generator did play a role in restoring power to the island sooner than if restoration were solely dependent upon transmission service.”

TEMC restored microgrid service to the Outer Banks’ island September 9 along with fallen power lines. The next day grid power was also restored.

An island microgrid laboratory
Ocracoke’s population swells from a permanent resident population of some 950 to some 7,000 or more with the onset of summer and the influx of tourists who come to enjoy its North Atlantic Ocean beaches. Electricity is particularly expensive on the remote island — demand charges can run as high as 57 cents of every dollar spent on electricity. Furthermore, overhead power lines are exposed to the elements, leaving them vulnerable to high winds, storms and salt water.

Electric boats may enable floating microgrids that could serve islands that have historically been powered by fossil fuels, according to a report from researchers at the University of New South Wales in Sydney, Australia.

“Powering small islands with reliable, affordable and green electricity is a big challenge due to their dispersed geographical location with a limited number of consumers and the heavy dependence on fossil fuels,” said the study, “Real-Time Load and Ancillary Support for a Remote Island Power System Using Electric Boats.”

Floating microgrids made up of electric boat motors, renewable energy and controls offer a substitute that will help power an island and provide electricity after disasters.

Floating microgrids: Quick way to restore power after hurricanes

“When some natural disaster occurs in dispersed islands, the electricity networks or generation systems are heavily damaged, and residents live without electricity for weeks. In this case, consumers having this technology can immediately get their power, and the ships sent by the government to distribute food can also supply electricity,” said Jayashri Ravishankar, an author of the report, which was published by IEEE.

While electric boats (EB) are similar to electric vehicles (EV), electric boats offer some significant advantages as a microgrid resource. An electric car fitted with roof-mounted solar panels can’t always use available sunlight due to shade from buildings, trees and parking lots. However, electric boats with PV solar don’t have this problem.

Good things don’t always come easily. Microgrids are no exception.

“The process of developing microgrids can be costly. It begins with a feasibility study reaching hundreds of thousands of dollars, even before any design, procurement and installation,” said Kay Aikin, CEO of US-based Introspective Systems.”Moreover, those feasibility studies are filled with disclaimers, and closing the gaps of uncertainty is crucial. Microgrid designs are unique, and therefore it is difficult to scale up the process of those studies without the use of technology.”

Fortunately, artificial intelligence (AI) and machine learning (ML) can help. Aikin’s company, along with Israel-basesd Brightmerge, are incorporating both into a microgrid software platform that determines microgrid feasibility and creates optimal design specs and operational controls.

The partners have several pilot projects underway with the goal of bringing the software platform to alpha stage in the second quarter of 2020 and rolling out production systems in 2021.

One pilot project is moving forward faster — a solar-plus-storage microgrid on Maine’s Isle au Haut that’s due to break ground soon. “We’ll build the system over the next 2-1/2 months with the aim of having it up and running by mid-November,” Aikin said in an interview. The island is served by an aging undersea cable connected to the mainland 20 years past its useful life that could fail at any time.

Transactive energy and microgrids
The Introspective Systems-Brightmerge microgrid software development project is governed under a contract Introspective Systems recently finalized with the Israel-U.S. Binational Industrial Research and Development (BIRD) Foundation. Its unit, BIRD Energy, has been awarding grant funding for projects proposed jointly by US and Israeli companies since November 2009.

Brightmerge and Introspective Systems won a grant in December 2018 to develop and test dynamic grid pricing with edge load responsive device control. The grant was part of $6 million in funding BIRD Energy awarded to seven projects to be carried out jointly by Israeli and US organizations.

Implementing a microgrid requires significant time, effort and investment. There are many cost variables that must be considered when evaluating a microgrid investment which requires significant upfront capital. These variables include capital costs, operating and maintenance costs, utility (electric and gas) rates, interconnection costs, environmental standards, energy load requirements corrected for local weather conditions, and regulatory requirements.

In the last of three microgrid development phases, the project team is entering the project execution phase to develop deliverables or tasks that will be tied to the actual microgrid construction project.

Feasibility studies
The primary purpose of the feasibility study is to determine requirements and estimate the size of the system (e.g. site requirements, load requirements, DER requirements, objectives, drivers, etc.) and provide a cost/benefit analysis that considers multiple options within a specified degree of accuracy. In contrast, the preliminary feasibility studies conducted earlier provide basic information on whether a microgrid is needed or even feasible based on the site and customer load. The feasibility study should consider and assess several microgrid design options that reveal the trade-offs between economic, environmental, and engineering optimality.

Conceptual design phase
The purpose of this analysis is to conduct deeper analysis to confirm if microgrids are a viable option, both financially and technically at your facility. This will include analysis on controls/communication, and system and regulatory requirements.

The conceptual design will provide more detail on the microgrid components, as well as tactical and installation applications. Conceptual designs are typically performed by design and build engineering firms. This work includes site descriptions, microgrid project objectives, design basis and rationale, as well as performance criteria. For example, this will include critical loads, services and power outage considerations, and step-by-step instructions on the microgrid evaluation and analysis. The performance-based design should also leverage energy surety metrics. This phase will include exercises in evaluating, analyzing, and developing microgrid options, and estimating associated benefits and costs.

Battered by Hurricane Michael last year, the City of Tallahassee and researchers are trying to design a storm-hardened microgrid system, one that considers both engineering and human psychology.

The city is working with a cross-disciplinary research team from Colorado State University (CSU) that won a $194,000 grant in June from the National Science Foundation. The team hopes to create a microgrid that would minimize damages and losses even in Category 5 hurricanes.

Hurricane Michael brought down 90% of Tallahassee’s electricity grid and cut the interconnection to a neighboring utility that ultimately affected 1.2 million people in the Southeast. Aiming to avoid damages of that scope, the research team is working with city officials and departments to review emergency preparedness plans and existing utilities and infrastructure.

Their goal is to create a design framework for Tallahassee that can be used by other communities, according to Sid Suryanarayanan, CSU Dept. of Electrical and Computer Engineering professor and project leader.

“We are confident that there is a significant place for microgrids in providing resilience to electricity grids in hurricane-prone regions. What we intend to bring to the table is the use of behavioral psychology and systems engineering concepts of emergency response in the design and operation of these microgrids,” he told Microgrid Knowledge.

Achieving stakeholder buy-in
The CSU research team is applying their collective expertise in electrical power engineering, microgrid design and operation, behavioral psychology, and emergency response to identify and reconcile design trade-offs, Suryanarayanan explained.

A sustainable grid needs to balance costs on three legs: environmental, budgetary viability, and costs passed on to customers, he said.

The developer of a $110-$120 million mixed use project in Manchester, Connecticut plans to incorporate a microgrid that taps into opportunity zone federal tax breaks.

The Manchester Broad Street Parkade microgrid will include around 1 MW of solar PV, 2-3 MW of natural gas-fired combined heat and power, batteries, and a water heating loop.

Developer MSL Group forecasts the microgrid cost to be $15-$25 million and hopes to achieve a $0.05-$0.10 per kWh discount on utility rates for residential and commercial tenants.

“The primary mover is to create a sustainable development, which we believe will improve the attractiveness of the entire project dramatically,” said Michael Licamele, president of MSL Group.

The microgrid will be capable of operating continuously in tandem with the utility grid or autonomously, in island mode, in the event of grid outages.

The town of Manchester owns the 23-acre Broad Street Parkade site. MSL Group is leading development of the entire project as the creator of Manchester Parkade I LLC, having won a request for proposals (RFP). The Manchester Board of Directors and the Manchester Redevelopment Agency awarded the company a contract in early July.

Possible March ground breaking
MSL and other project partners, who have yet to be determined, intend to build between 500,000 and 1 million square feet of apartment rental and commercial space, including a hotel and retail outlets along with outdoor and indoor entertainment and recreational venues, Licamele said.

A solar-plus-storage microgrid in Lebanon is demonstrating a way the country can overcome its pollution and lack of energy access while boosting economic development.

For a month running, Recycle Beirut and an adjacent residential building have been receiving all of the electricity they need with a microgrid that uses 100-kW of solar and a 100 kWh battery energy storage system.

Small as it is, the microgrid’s benefits are large.

Lebanon depends on fossil-fueled generators and experiences regular power cuts that can last as long as 12 hours, according to Florian Stark, project manager at Firebird Energy, which built, operates and maintains the microgrid in partnership with Recycle Beirut.

“Those power cuts are obviously slowing down economic development since there’s a lack of electricity, and it’s produced by diesel generators that produce a lot of air pollution,” Stark told Microgrid Knowledge.

Joining with a group of Chinese solar, battery energy storage and microgrid software developers, Firebird and Recycle Beirut began designing the project in the spring of 2018. They purchased equipment last summer and installed the project between March and June this year.

“Since June 2019 the system has been operating without any interruptions or trouble,” Stark said.

Don’t follow one-time disasters to find microgrid opportunities; look instead to areas with recurring power outages and businesses interested in resilience, says a new study.

Curious about the impact of storms and disasters, Wood Mackenzie, a global research and consultancy business, looked at microgrids sized 100 kW and above that were built after storms and wildfires between 2012 and 2019, said Isaac Maze-Rothstein, research associate with Wood Mackenzie Power and Renewables.

The study found that only 14% of US microgrid capacity was built in areas affected by the seven most costly natural disasters within three years of the incident, he said.

“I was surprised,” said Maze-Rothstein. “I thought that it would be the opposite story — that the microgrid market is moved by natural disasters.” He added that projects were built after disasters like Superstorm Sandy, but not many compared to the total market size during that time period, when 2.18 GW of microgrids were installed and operational in the US.

Recurring outages are a bigger motivator for businesses and manufacturers to consider microgrids for resiliency, the report said. Outages as short as “momentary blinks” in manufacturing facilities can bring down a whole manufacturing line, he noted. If for example, this happens in a metal making plant, the company might have to scrap a whole line.

As for the programs spurred by Superstorm Sandy — such as the New York Prize and the New Jersey Township Microgrid Program — there has been little action, he said.

Recent power shutdowns by Pacific Gas &Electric (PGE) — and the likelihood of more to come — has renewed the urgency of a microgrid feasibility study being carried out for the Northern California City of Calistoga.

California utilities undertake the shutdowns, known as Public Safety Power Shutoffs (PSPS) when wildfire risk heightens. PGE carried out its first PSPS of 2019 in June.

Clean Coalition, which is carrying out the microgrid feasibility assessment, is now working with PGE, Calistoga’s city manager and city council to scope out and design a community microgrid that will encompass a designated resilience zone to ensure electricity for critical public services and facilities during the power shutdowns, said Frank Wasko, Clean Coalition managing director.

“We’re meeting with senior city staff, and we’ll be moving forward and conducting a solar siting survey for all Calistoga. At the same time, we’re implementing stakeholder outreach with key leaders and members of the community to help guide our scoping efforts and allow us to determine an optimal system size and design that can be implemented as soon as possible,” Wasko said in an interview with Microgrid Knowledge.

Searching for the most effective, near-term solutions
Clean Coalition’s project team expects stakeholder outreach to be completed in three to four weeks, said Malini Kannan, program engineer.

“At that point, we’ll have a lot more information…project scoping will be pretty well tightened up, and we’ll be able to proceed with system sizing and design, then proceed to explore all relevant solutions,” she said in an interview.

Kannan added that Calistoga’s city leaders are looking for the most effective, near-term solutions. “So we’re going to be focusing on individual, critical facilities. We have a few front-runners, but we won’t know exactly which will be included in the feasibility assessment until the stakeholder outreach process is completed,” she told Microgrid Knowledge.

With the promise of improved efficiency and resiliency, and a reduced carbon footprint, the total capacity and spending on microgrids is projected to quintuple by 2028. From universities, hospitals, military bases, airports, and even single properties, microgrid projects range from complex retrofits of existing electrical infrastructure to modern greenfield designs. There is belief that we are in the midst of a reverse Copernican Revolution, where generation will be distributed away from the center to the grid’s edge. Microgrids will even import/export power from each other and help support the main grid. Electric utilities’ existing business models are under threat, and they have been forced to pay attention with some even seeing business opportunities.

By definition, a microgrid must be able to island itself and rely on its distributed energy resources (DERs). As the excellent feature article in June’s IEEE Power Electronics Magazine on AC microgrid control and management strategies notes, this “is not an easy task”, involving up to three levels of hierarchal control. At the “local” DER level, Primary Control is typically bundled per DER to maintain voltage and frequency stability, and reliability. Secondary Control, often associated with the microgrid controller, acts on the entire microgrid to manage deviations in voltage frequency and amplitude to ensure power quality and reliability.

HIL will be used to create cleaner vehicles and supply chains, and increase their levels of connectivity to renewable resources and infrastructure.

Tertiary Control covers power import/export to the main grid and to other microgrids. Both Secondary and Tertiary Control Levels can also be implemented using central or distributed approaches with the latter offering potential redundancy and cost benefit. While the Tertiary level is mainly used currently to optimize import/export economics based on electricity and energy markets, it can also serve to improve power quality in the higher-level system. All three control levels serve critical operational or economical functions within the microgrid and are connected relying upon digital communication. Furthermore, while AC microgrids are currently most common, full or partial DC configurations offer certain advantages and are gaining interest.