HomeMagazine ArticleThe US explores microgrid tech as viable redundancy system

The US explores microgrid tech as viable redundancy system

‘Resilience’ can be defined as the capacity to recover quickly from difficulties; or toughness – and is therefore a crucial factor when considering the modernisation of critical power infrastructures for the durability and longevity of the electric grid. Having torn through the US Northeast in 2012, Superstorm Sandy left some 8.5 million people in the dark, acting as a timely catalyst for US leaders and policy makers to investigate the overdue upgrade and reinforcement of the aging regional electricity grid. Like many 20th century electrical models around the world, the country’s legacy infrastructure was not designed to withstand the extreme pressure it has been subjected to in recent years.

Today’s power utilities are not only expected to keep up with escalating demand and the changing needs of the modern consumer, but are also faced with the arduous task of combating the adverse effects of severe storms, whilst at the same time attempting to maintain a secure, uninterrupted power of high quality regardless of a compromised grid.

Traditionally, backup power systems in the form of diesel generators would be the typical solution to keep the grid going in the event of a power failure; representing one of the earliest forms of the microgrid. This concept has evolved and continues to revolutionise the grid to which we are accustomed and could essentially ‘leapfrog’ the necessity to be connected to conventional utilities in order to receive power. By US DoE definition, a microgrid is “a group of interconnected loads and distributed energy resources (DER) with clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid (and can) connect and disconnect from the grid to enable it to operate in both grid-connected or island mode”. Its architecture creates an environment for interoperability amongst microgrid enabling technologies culminating in a robust electricity network, and thereby creating a viable off-grid solution for sustained distribution of power amongst employing entities.

It also allows for the incorporation of renewable energy (predominantly wind and solar) for locally produced power, reducing reliance on dirty power and having the added benefit of zero-emission generation. Drawing on natural cleaner sources, which are becoming increasingly cost effective, microgrids provide an incentive to transition to a model that enables the bulk of electricity to be generated from renewables. Surplus power can also be sold back to the central grid, in a process known as net metering. Apart from making the grid greener and more resilient, distributed generation sources like CHP and fuel cells along with advances in energy storage, smart islanding inverters, automated demand response, electric vehicle charging and microgrid software and hardware controls all contribute to developing a smarter, ‘harder’ grid. S&C Electric rightfully describes it ‘as an old idea with new potential’ as the usefulness of this approach continues to be explored and its functionality re-examined as a decentralised alternative for increasing reliability and quality of power supply. Depending on the need, microgrid technology can be adapted to accommodate the operator’s requirements, yielding a host of economic and system efficiency benefits.

These include:

  • Reduction in transmission loss with use of direct current microgrid technology
  • Overall lower energy intensity rating and optimum use of available resources
  • Close to 100% uptime for critical loads (important in military applications)
  • Stable supply to meet consumers’ exact energy requirements
  • Increased control and allows for two-way communication in utility distribution microgrids (UDM’s).
  • Cost savings through locally generated power from renewable sources and energy storage systems
  • ‘Plug and Play’ capabilities

As much as microgrid use is supported, it has traditionally faced equal opposition from electricity utilities who have historically had the monopoly on power supply to end users. Investor-owned utilities are reluctant to embrace the microgrid as it is perceived to be a ‘disruptive technology for their current business model’. Apart from regulatory and legal issues that have come to the fore, there exist grievances around the imposition on a utility’s revenue stream and the financial burden of interconnection costs incurred with the implementation of utility distributed microgrids. Utilities are called upon to recognise the value of microgrids in taking on the customary utility functions when the central grid is affected. This notion is further supported by Peter Asmus, principal research analyst with Navigant Research, who in a recently released report said: “In the United States, in particular, the increasing frequency of severe weather is prompting utilities to reconsider their historic opposition to customer-owned microgrids that can disconnect from the larger grid and continue to function, allowing critical mission functions to stay up and running.”

An example of this co-operation can be found in Hartford, Connecticut, where cities and universities will be allowed to link up to bulk power systems across utility right of way. Despite regulatory difficulties experienced by many US states looking into microgrids, Connecticut was also the first to implement an $18 million state-wide rollout of nine microgrid projects enabling the sustenance of power to critical facilities in eight cities in preparation for future power disruptions. When Metering & Smart Energy International spoke to Alex Kragie, Deputy Chief of Staff at the Connecticut Department of Energy and Environmental Protection (DEEP), he noted that resilience represented a ‘key political driver’ in overcoming some of the regulatory barriers faced by others and that state Governor Dan Malloy’s fervour for the safety and security of citizens, together with leadership’s responsibility to large commercial and industrial sectors in providing operational assurance, ‘led the charge’ in seeing the proposed programme being written into Connecticut law in 2012. He believes the microgrid is a more cost-effective approach than the hype around underground power lines to realise energy surety and security.

As for his predictions of how he sees the microgrid changing the face of long-established utilities: “That all depends on what happens within the next 2-3 years; there is potential for the microgrid to transform the central grid – but not completely replace it.” As for future development: “The sky is the limit; however, there needs to be considerable proof of concept in workability and economic sustainability apart from government subsidisation”. He says that battery storage will be an increasingly popular trend in microgrid set-ups, in cases of unanticipated power shortages.

In San Diego a microgrid hotspot and “leading laboratory” for grid technologies, UC San Diego is currently generating 92% of its electricity to power the 1,200 acre campus from two 13.5MW natural gas turbines which produce electricity and usable heat. Adding to its renewable portfolio are its pilot programmes, using retired electric car batteries to store electricity; and its 2.8MW fuel cell for power generation collectively saving $800,000 – $850,000 pm. In other efforts, San Diego is capitalising on its inherent sun potential with an electrical circuit at its Naval Base Point Loma powered by 58kW solar carports. The combination of expertise engineering, military and telecommunications expertise as well as its avidity towards its renewable goals, lends itself to befit the creation of microgrids.

New York University and Princeton, New Jersey, both operating cogeneration plants, presented “beacons of light” amidst Sandy’s chaotic path. Taking into account that New York is hit by approximately 100 storms annually, has necessitated local government to address this reality and consider the implications of non-action in tackling the worn regional grid that simply does not possess the fortification needed to withstand excessive trauma. New York state leadership was swift in its actions to repair the damage that was done and have put in place extensive plans to minimize the detrimental effects of extreme weather events. New York State Governor, Andrew Cuomo and Vice President Joe Biden recently unveiled the “Reimagining New York initiative”. This programme is projected to pump $17 billion dollars of federal funds into the development of New York’s infrastructure, transport networks, energy supply, coastal protection, weather warning system and emergency management to increase citizens’ preparedness to “weather the storm”. The programme has allocated just under $1.4 billion to improving grid resilience and dedicated $40 million in a competition to build 10 microgrids across the state to serve approximately 40,0000 residents.

Military installations

The US Department of Defence’s Environmental Security Technology Certification Program (ESTCP), realised the Army’s first grid tied microgrid at Fort Bliss, Texas in May 2013. Installed with an intelligent microgrid control system, it enabled tying together of the base’s 300 kW battery system, its existing backup generators and its 120 kW solar arrangement into a mini-grid. This is just one example of the military’s extensive efforts using microgrid technology to achieve energy security: a perpetual concern, being an entity dependent on a reliable, uninterrupted stream of energy to carry out its base operations and missions. According to Pew Research, the Department of Defence (DoD) owns one of the world’s largest inventories of real estate, with 550,000 buildings and structures encompassing an estimated 2.3 billion square feet equivalent to 21,367,6992 square meters all requiring power. The US Department of Defence reportedly consumes the largest quantity of fuel globally, with its military operations constituting the largest consumer of power worldwide.

Microgrids or ‘Mil grids’ are key in driving the evolving energy paradigm of the armed forces with this hybrid approach populating an increasing number of army bases and navy hangers. It provides a credible solution in achieving energy surety and assisting military facilities achieve “Net Zero” status – the ability to produce as much energy as you use over a one year period, a vital consideration as the largest consumer of fuel on the battlefield is electricity generation. Military contingents are taking full ownership and are taking decisive steps to ensure that their respective operations remain unaffected by factors affecting the centralised grid. Much of the appeal lies in the micro grid’s versatility and its ability to function apart from the grid – with the principal concerns relating to T&D service disruptions, and poor inconsistent power quality, prompting the military’s review of its current service delivery model. This study has led the DoD to the conclusion that the best way to boost its ability to secure power may very well be through microgrid technology it can have increased ownership and control over. Microgrids allow stationary and forward operating bases to sustain operations, regardless of factors affecting the central grid or in the theatre of war. These microgrid networks can also provide tactical operations support with the current exploration into mobile tactical microgrids – “modular, small systems that may be deployed within a matter of days and then deconstructed and moved to a new location, per tactical mission”. As aforementioned, the military’s efforts far go beyond the civilian market for microgrids, although university and public institution segments follow as very close contenders.

SPIDERS is an all-encompassing programme in a joint effort with the DoE, DoD and the Department of Homeland Security to standardise microgrid enabling technologies as an industry wide benchmark. Testing is currently underway at Fort Carson, Colorado as well as at Pearl Harbour – Hickam Air Force Base and camp Smith in Hawaii. The Marine Corps Air Station Miramar, California presently generates 45% of its renewable energy from the Miramar Landfill and is looking to be totally self-sufficient by 2017. In a statement by Col. John Farnam, MCAS Miramar commanding officer: “[A microgrid] gives us the ability to generate and move energy where we want it as well as energy assurance. “I can control (whether) buildings get energy or not, when we need to turn it on and off; and when we couple that with the constant energy coming from the landfill we have the ability to support ourselves should the rest of California go dark.”

An area that remains of concern, is the fully burdened cost of fuel (FBCF), a concept defined by the DoD as “the commodity price for fuel plus the total cost of all personnel and assets required to move and, when necessary, protect the fuel from the point at which the fuel is received from the commercial supplier to the point of use.” Armoured vehicles carrying fuel to various points where it is needed, represents a grave security risk and presents itself as a target for attack.

With the worldwide microgrid market forecast to increase by $40 billion annually by 2020, according to Navigant Research, we continue to see the microgrid evolve and unfold, highlighting other thriving energy trends such as nanogrids, it presents itself as a sea of untapped potential. Already in Africa we see such developments with commercially operating grids in South Africa, Kenya, Democratic Republic of Congo (DRC) and Nigeria. The most recent one being installed in the Virunga National Park in the DRC, which installed three solar microgrids at three ranger stations to support the daily duties of the rangers. Home to the world’s last remaining mountain gorillas, park rangers have been challenged by poachers and increased deforestation, which could be reduced by access to a reliable supply of power. Classified as a UNESCO World Heritage Site, the microgrids were installed by US-based company SolarCity through the support of the Give Power Foundation, a nonprofit organisation, and Empowered by Light, an organisation aimed at socio-economic upliftment through renewable energy technologies. With this system becoming more popular this is certainly a space to watch.