Energy Resilience for New Zealand.

Why Resilience Must Be Planned in Advance

Most ordinary outages are repaired relatively quickly. Major events are different because crews may face widespread damage, blocked access and competing priorities.

Cyclone Gabrielle demonstrated this distinction. Flooding disabled critical Transpower substations and interrupted supply across Hawke's Bay and Tairāwhiti. Grid supply was progressively restored over hours and days, but Transpower’s recovery work continued for months and some areas operated with reduced security while damaged infrastructure was repaired.

The lesson is not that every building should operate independently for months. It is that an emergency system must bridge the period between the initial failure and restoration of a dependable service - and that this period varies greatly by location and consequence.

Preparation also prevents a common mistake: buying a generator, battery or solar array without identifying what it must power.

A resilient plan begins with services, not equipment. It determines the critical loads, how much energy they use, whether they can be reduced, their maximum allowable interruption, and the conditions under which people can operate and refuel the system safely.

How Long Should an Outage Plan Cover?

There is no single correct duration.

The national Get Ready guidance says households may be stuck at home for three days or more, and advises keeping at least three days of essential supplies. Workplaces are also advised to provide supplies for everyone onsite for three days. This is a useful minimum civil-defence baseline, but it is not necessarily enough energy autonomy for every site.

A practical planning framework is:

These are planning bands, not promises about restoration time. A household in a well-connected urban area and a remote settlement at the end of one road should not necessarily choose the same standard. Nor should a retail office and a wastewater pumping station.

The correct duration should be based on the longest credible event, not the average outage.

• A hospital, communications site or hazardous industrial process may allow almost no interruption and require duplicated systems.
• A business may decide that refrigeration, security, data and a small operational area must survive for three days even if full production stops.
• A community hub may prioritise lighting, communications, device charging, medicine refrigeration, water pumping and a warm shared space rather than attempting to power every normal household load.

Good Solutions for Communities and Businesses

The strongest solution is usually layered. No single technology covers every time scale and failure mode.

Know and Reduce the Critical Load

Separate essential circuits from discretionary demand. Efficient lighting, insulation, efficient refrigeration and controllable water heating reduce the generation and storage needed. Document what must stay on, what can cycle, and what can be turned off. A smaller critical load makes every backup resource last longer.

Use Batteries for Immediate Continuity

Batteries and uninterruptible power supplies respond almost instantly. They are well suited to communications, controls, medical or IT equipment, short outages and shifting solar electricity from day to night. Their duration depends on both stored energy and the connected load: the same battery may support a few essential circuits for a day or an entire building for only a short time.

Combine Solar with Storage and Outage-Capable Controls

Solar can replenish a battery during an extended event and lower everyday electricity costs. However, ordinary grid-connected solar normally shuts down during an outage for safety. Resilience requires a suitable inverter, switchgear, protection, islanding capability and circuits arranged to supply priority loads. Solar output will still vary with weather and cannot by itself guarantee power overnight.

Retain Firm Backup for Prolonged Shortages

A correctly sized and maintained generator may remain the most practical long-duration safeguard for many sites. Fuel must be safe to store, rotated before it degrades, accessible during an emergency and supported by more than one resupply route where possible. The generator should be tested under load; an untested unit with a flat starter battery is not a resilience plan.

Develop Community Energy Hubs

A marae, school, hall or other trusted building can concentrate resilient electricity where it has the greatest public benefit. EECA’s Community Renewable Energy Fund supports solar and battery systems at buildings intended to serve communities during emergencies. A hub can provide communications, lighting, refrigeration, cooking support and device charging without requiring every home to install a large independent system.

Use Flexible Demand and More Than One Energy Source

Pumps, refrigeration, water heating, vehicle charging and some production can be scheduled when energy is plentiful. A hybrid system might combine the grid, solar, a battery and a generator, with an energy-management system deciding how to preserve the emergency reserve. Diversity helps, provided components do not share one vulnerable switchboard, control system or fuel source.

Plan the Human and Logistical System

Nominate decision-makers and trained operators. Keep diagrams, shutdown procedures and supplier contacts available offline. Test black-start and island operation, practise load-shedding, inspect equipment and agree how stored energy will be rationed. Include water, communications, access, security and staff availability: electricity equipment cannot compensate for a plan that assumes roads and mobile networks will always work.

How Hydrogen Could Help Now

Hydrogen is an energy carrier rather than a primary source.

Renewable electricity can be used in an electrolyser to separate water into hydrogen and oxygen. The hydrogen can then be stored and later converted into electricity in a fuel cell, used in suitable combustion equipment, or delivered as fuel for transport and industry.

Its present resilience role in New Zealand is selective. A fuel cell can provide quiet, low-emission point-of-use power for telecommunications, remote equipment, critical facilities or a microgrid. Stored hydrogen can extend a solar-and-battery system beyond the hours usually covered by the battery. It may also power fuel cell vehicles or mobile generators able to take electricity to an emergency site.

A particularly useful configuration is a battery-hydrogen hybrid. The battery handles rapid changes, starts the local electrical system and covers frequent short cycles efficiently. The fuel cell is reserved for a longer outage, when the battery would otherwise be exhausted. If hydrogen is already stored for vehicles or an industrial process, the same regional supply chain could potentially support emergency power - provided compatible equipment, reserve rules and delivery arrangements are established beforehand.

Current practicality is constrained by cost and availability. Hydrogen must be produced or delivered, compressed, stored in approved equipment and handled by trained people.

Fuel cells, pressure vessels and refuelling or connection systems require capital and maintenance. A site cannot assume that a hydrogen delivery will arrive after a disaster, so its autonomy is limited by the fuel physically available and usable onsite.

Hydrogen should therefore be compared with batteries, diesel or renewable diesel generators, bioenergy and network reinforcement. It is most credible where long duration, low point-of-use emissions, quiet operation, transportability or an existing hydrogen demand provides value beyond emergency power alone.

Hydrogen's Possible Future Role

As New Zealand builds more renewable electricity and hydrogen infrastructure, the resilience opportunity could expand in four ways.

First, electrolysers could make fuel when renewable electricity is abundant and reduce production when the grid is constrained. This turns hydrogen production into flexible demand rather than an additional fixed peak load.

Second, larger hydrogen stores could hold energy for days, weeks or potentially seasons. Batteries are more efficient for short-duration storage, but their cost grows with the amount of energy that must be held. Hydrogen may become useful for infrequent, extended events because the storage capacity can be expanded separately from the power rating of the electrolyser or fuel cell.

Third, a network of hydrogen production and refuelling sites could support both ordinary commercial activity and emergency logistics. Fuel cell trucks, buses, specialist vehicles and portable generators could provide transport or power when liquid-fuel supply is disrupted. This dual use would be more economic than building equipment solely for rare emergencies.

Fourth, hydrogen can be converted into ammonia, methanol or other fuels and products that may be easier to store or useful in their own right. Regional production could diversify fuel supply for industry, heat, marine operations and remote power.

EECA’s hydrogen guidance identifies dispatchable storage and electricity-system resilience as possible benefits, while also noting significant efficiency losses. Electrolysis loses about 20-30% of the input energy, compression and storage require further energy, and conversion back to electricity creates another loss.

For this reason, hydrogen is unlikely to displace batteries for routine short outages. Its potential advantage is storing a large reserve for much longer periods or serving several fuel and industrial uses.

Plan for Services, Not Just Technology

New Zealand needs resilient energy plans because its essential services are interconnected, its geography can make restoration difficult and its natural hazards can damage electricity, transport and communications simultaneously.

Three days or more is a sound minimum preparedness baseline for households and ordinary workplaces. Remote communities, essential infrastructure and high-consequence businesses should examine seven-day or longer scenarios and maintain plans for an extended regional recovery.

The best preparation combines efficient critical loads, batteries, outage-capable renewable generation, firm backup, secure fuel arrangements, community hubs and people who know how to operate the system. The mix should be tested against local hazards and the consequences of failure.

Hydrogen can already contribute in specialised long-duration, remote and low-emission applications. In the future, wider production and distribution could make it a strategic complement to batteries and renewable electricity. It should not be included merely because it is innovative; it should be included when its storage duration, mobility and versatility solve a resilience problem more effectively than the alternatives.

Resilience is ultimately the ability to keep the most important services running while the wider system recovers. Achieving it requires realistic outage assumptions, multiple layers of protection and investment made before the emergency begins.