Ken Aramaki of Hawaiian Electric on Resilience and Microgrids

Courtesy of Hawaiian Electric. Lineman servicing replacing an old wooden distribution line support structure in a remote location with a new hardened steel structure to better withstand extreme weather conditions. These remote structures carry some of the most important lines but take huge a beating from tougher weather. This is an example of HECO’s ongoing resilience program.

Ken Aramaki is the Director of Transmission, Distribution and Interconnection Planning for Hawaiian Electric. His primary job is to plan for reliable power delivery, incorporating various considerations such as the ability to withstand short-term problems or significant extreme weather events like hurricanes. The planning and strategy involved in ensuring Hawaiian Electric can continue to serve its 468,000 customers in good times and bad is called resilience. He defines resilience as “the ability of a system or its components to adapt to changing conditions and withstand and rapidly recover from disruptions.”

Ken explained there is a difference between reliability and resilience.  In general terms, planning for a reliable electric system entails ensuring system stability, managing and balancing resources, planning for and maintaining transmission and distribution assets, ensuring there are adequate generating resources, and taking other actions to provide electric service during the vast majority of days/hours.  Resilience planning, on the other hand, looks at high-impact but less frequent events.

What can those disruptions entail? The main resilience challenges Ken identifies are hurricanes, storms, earthquakes, wildfires, tsunamis, flooding, lava flows and “other extreme events.”  Cybersecurity raises another level of resilience challenges. 

Hawaiian Electric employs a multi-faceted approach to addressing and planning for such events.  They include infrastructure, cybersecurity, emergency response training, mutual aid agreements with other utilities and organization, and inventory management which include carrying strategic spare equipment.

It’s a complex task that must align with the commitment of Hawaiian Electric and State to reach 100% renewable energy by 2045, even though all the technology and infrastructure needed is not yet in place to completely support this transition.  Hawaiian Electric believes that part of the solution involves microgrids – locations with independent, self-generation attached to the traditional grid network - that will continue supplying power to limited numbers of customers even if traditional grid does not.

One of the particular challenges faced by Hawaiian Electric is planning resilience programs for communities on five islands with no interconnections among them.  Maui, Lanai, Molokai, Oahu and Hawaii islands each has separate challenging geographies. Each requires a distinct and studied approach.  Customers on these islands make up 95% of Hawaii’s population. 

Hawaiian Electric is proud that 35% of the power used by customers is generated from rooftop solar and other renewable resources. In 2007, it had 370 rooftop systems on its grids.  As of  2021 there are over 91,000. However, in the case of disaster, renewables alone cannot guarantee resilience as PV panels and equipment may sustain damage, and there is not enough energy storage to meet the entire islands’ needs.  Further, to ensure resilience, the grid infrastructure – lines, poles, equipment must also be planned, designed, and constructed to withstand the disaster.

Hawaiian Electric categorizes resilience investments based on solutions to prevent outages or damage, or solutions that can either reduce the impact of a failure or facilitate recovery of the failure to reduce the consequences of an event.  Both types of solutions are complementary and needed to improve resilience.

Hawaiian Electric - resilience by cutting back vegetation on transmission lines

The following are solutions to prevent outages or damage:

·      Transmission hardening

·      Hardening critical circuits

·      Pole and Line Relocation

·      Wildfire prevention by keeping undergrowth clear of wires that could generate sparks

·      Substation flood mitigation

·      Vegetation management

·      Undergrounding

The following are that can either reduce the impact of a failure or facilitate recovery of the failure to reduce the consequences of an event:

·      Microgrids/Minigrids

·      Critical Customer Hubs

·      Customer resources

·      Backup generators &   distribution ties

·      New transmission lines

·      Emergency response and restoration

Schofield Generating Station - Microgrid in Hawaii

Microgrids in particular provide the following.

·      They can help make sure that critical customers or areas such as hospitals and water pumping stations always have power.

·      They depend on customer resources like rooftop solar and batteries, backup generators and distribution ties

·      They can assist in emergency response and restoration

Hawaiian Electric is that working with the Federal Department of Energy Transitions Partnership Programs to develop a map of areas on Oahu that may be developed as hybrid (full, partial and feeder) microgrids.

In conclusion, preparing for resilience is an ongoing process rather than a particular task and microgrids can play a role in the event of an outage due to an unforeseen natural or human-caused event. This is the nature of resilience planning.