01The right time to talk energy
Aerial view of a forked road through forest
Zembl Everything energy

Commercial Energy

12 of the costliest energy contract renewal mistakes

A guide to contract renewal for energy-intensive businesses

Contents

  1. 01

    Talking energy – when and why

    • A rolling discipline, not an event
    • The two renewal windows that catch businesses off guard
  2. 02

    Default rates — the avoidable cost at renewal

    • What a default rate actually is
    • What the default rate cliff cost two Zembl customers
  3. 03

    The 12 costliest renewal mistakes

    • Each mistake explained
    • The cost of getting each one wrong
  4. 04

    The contract renewal playbook — a 13-month timeline

    • Engage, prepare, market, sign, manage
  5. 05

    The Zembl difference

    • Why specialist expertise matters at renewal
    • Three things we promise
  6. 06

    Your renewal-ready checklist

    • Run through it — anything you can't tick is a question worth asking
Foreword

Why this guide exists

Every year, thousands of Australian businesses pay considerably more for their energy than they need to. Not because of a bad negotiation, and not because of a poorly worded clause — simply because the renewal process was handled as administration when it should have been handled as strategy.

When a commercial energy contract expires without a new one in place, the customer is typically moved onto what's known as a default or standing offer. The language varies by retailer. The outcome doesn't: you pay more, often without realising it, sometimes for months before anyone inside the business notices.

This guide is built for the people who are accountable for that cost. Finance leaders, procurement managers, facility and operations heads, and business owners who want to stop treating their energy contract renewal as an administrative task and start treating it as the strategic event it is.

For Commercial & Industrial (C&I) businesses — where energy is a sizeable operational cost, and in many sectors, one of the largest items on the P&L — this isn't a minor inconvenience. It is a material, recurring, and entirely avoidable financial risk.

You'll find 12 mistakes to avoid, a 13-month timeline to follow and a one-page checklist to use right now. None of it is theoretical. All of it comes from the procurement process we run for Commercial & Industrial clients across Australia every day.
A note on language

We use "Commercial & Industrial" (C&I) throughout this guide to refer to businesses with sizeable energy load — typically those that draw >100 MWh of electricity and/or >1 TJ of gas per year, or in dollar terms, spend more than $3000/month on energy.1 Customers above these thresholds are generally treated in Australia as Commercial & Industrial, or 'large business' accounts.

1. Electricity thresholds vary by state: the 100 MWh threshold applies in NSW and QLD. In VIC the threshold is 40 MWh and in SA it is 160 MWh.

Chapter
01

Talking energy – when and why

  • A rolling discipline, not an event
  • The two renewal windows that catch businesses off guard

One common misconception in Commercial & Industrial energy is this: that renewal is something you deal with when the expiry date gets close. It isn't. Not if you want the best outcome.

A rolling discipline

The businesses that consistently land the sharpest contracts, the smartest structures, and the fewest surprises are the ones that treat energy as a rolling discipline — not an event that happens every two or three years when the contract runs out.

They're also the ones that run a lower risk of having their contract expiry happen with no-one noticing — and seeing their electricity costs bump up by 57%^ or even more when they roll onto default energy rates.

How to time your contract renewal approach

A well-run Commercial & Industrial procurement process doesn't try to time the market perfectly – but it does give itself enough runway to act when pricing becomes favourable, rather than being forced to transact on whatever the market looks like the week before expiry.

Start at 13 months and you own the calendar. Start at 6 months and you're on the clock. Start at three months and you're negotiating from the position any buyer wants to avoid: running out of time, with a contract end date looming.

^ Percentage based on Zembl Internal Report, Avg. market Peak Rates from December 2025 to June 2026 when compared with Zembl Peak Panel Rates. Results are based on individual case studies and figures quoted should not be taken as industry averages.

George Coggins, Zembl energy specialist

The pitfalls of doing an energy renewal alone

Without the help of an energy expert, some of the crucial elements of energy procurement can get overlooked. We'll cover this in detail in Chapter 4, but the short version: unless you have days of time available and a thorough knowledge of all things energy, the chances of a good energy outcome are slim.

There are a number of things that can go wrong. Having incomplete energy data to provide to your retailer. Not having the time to traverse a wide enough range of retailers. Facing a time crunch with your contract end date approaching that puts you at the mercy of markets and reduces your options. The list goes on, as we'll explore further in Chapter Three.

Energy timing

The two renewal windows that catch most businesses off guard

Energy contract expiry dates in Australia are not evenly distributed across the calendar. They cluster. The two busiest windows for Commercial & Industrial rollovers are June and July, and November and December. These windows see the largest volume of C&I contract expiries as many contracts were originally signed at the start of financial years or calendar years, making these natural expiry points.

Does your energy contract expire in a peak window?

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
High-risk rollover window Lower-volume months

These months also coincide with internal distractions — end-of-financial-year reporting, Christmas shutdown planning — when energy procurement rarely gets the priority it deserves. The result is a predictable annual spike in businesses left on default pricing, often for one to three months before anyone notices, and sometimes considerably longer.

Timing

Why early is better than late

Every month you delay engaging with your renewal narrows your time window in which to make decisions, which reduces optionality and can put you at the mercy of market movements. And if your energy contract expiry falls within the two most common time periods (June to July or November to December) you’ll be competing in the middle of a retail crunch — which can make retailers less responsive and more selective, once again limiting your options.

Chapter
02

Default rates – the avoidable cost at renewal

  • What a default rate actually is
  • What the default rate cliff cost two Zembl customers

If there’s one concept every person responsible for a C&I energy contract needs to understand, it is this one. The default rate is a large and entirely avoidable cost in business energy procurement — and the one most frequently paid by accident.

What a default rate actually is

Your energy contract is a fixed-term agreement with your retailer: a set rate (or set structure), for a set period. When that period ends, your obligation to that price ends too. What many C&I businesses don’t appreciate is that their retailer’s obligation to that price ends at the same moment — and what replaces it is a standing, non-negotiated rate that exists for one operational reason: to cover customers who have passed their expiry date without a new contract in place.

 

Default rates go by several names depending on the retailer and jurisdiction: default offer, standing offer, evergreen rate, post-contract tariff. The economics are broadly similar across them. These rates are not negotiated. They are not optimised for your consumption profile. They are not tailored to your industry. They are the market’s standing position — a published rate designed to be uniform and administrable, not one designed to reflect your specific load, structure, or history.

How much are we really talking about?

In our experience across Commercial & Industrial renewals in Australia, the gap between a well-negotiated contract and a default rate can be significant – and enough to cause a notable bill cost hike.

Real Zembl data

What the default rate cliff cost two Zembl customers

Here’s a real-world example for two different-sized businesses Zembl assisted between December 2025 and June 2026. The figures show the price impact of rolling onto default rates, versus a properly negotiated rate available at the time. It shows that, whether your business’s energy consumption is larger or small, the cost of remaining ‘rolling’ on a default energy offer can be great — and every month it’s left unchecked is a missed opportunity for your business’s bottom line.

Tertiary Education Provider
Sydney, NSW
857 MWh / year
On default offer
$353K^
On best offer
$221K^
Saved per year
$132K
↓ 37% lower
Real Estate Business
Adelaide, SA
100 MWh / year
On default offer
$58K^
On best offer
$34K^
Saved per year
$24K
↓ 42% lower

^ Percentage based on Zembl Internal Report, Avg. market Peak Rates from December 2025 to June 2026 when compared with Zembl Peak Panel Rates. Results are based on individual case studies and figures quoted should not be taken as industry averages.

What the pricing gap looks like

Looking more broadly, both businesses had rolled onto peak default rates of greater than 29 cents per kWh — in contrast, the average rate across Zembl’s panel of 13 energy retailers for the same period was just 12.9^ cents per kWh — 57% lower. Both scenarios present a sound set of facts in favour of not letting your energy contract lapse — and talking to an expert well ahead of your renewal date.

The default-rate gapPeak rates · Dec 2025 – Jun 2026
If you do nothing
Typical default rate
>29¢/kWh
A standing, non-negotiated peak rate.
›
−57%^
Rate gap
›
With Zembl
Zembl panel average
12.9¢/kWh
Across 11 retailers on Zembl’s panel.
16.6¢/kWh lower per unit consumedSource · Zembl panel · 11 retailers
The default-rate gapPeak rates · Dec 2025 – Jun 2026
BUSINESSES THAT SIGN A CONTRACT FROM ZEMBL’S PANEL PAY
57% less^
per kWh than the typical default rate

12.9¢/kWh available with Zembl’s panel of 13 retailers, versus the >29¢/kWh standing rate a non-negotiated business pays today. 16.6¢ lower on every unit consumed.

¢/kWh, to scale
>29¢
12.9¢
Default
Zembl panel
The default-rate gapPeak rates · Dec 2025 – Jun 2026

How much of the default rate your business doesn’t have to pay on the Zembl panel

12.9¢
The gap · 16.6¢ lower
Zembl panel avg
0¢>29¢ · Typical default
Typical default rate
>29¢/kWh
A standing, non-negotiated peak rate.
Zembl panel average
12.9¢/kWh
Across 11 retailers on Zembl’s panel.
Rate difference
−57%^
16.6¢/kWh lower per unit consumed.

^ Percentage based on Zembl Internal Report, Avg. market Peak Rates from December 2025 to June 2026 when compared with Zembl Peak Panel Rates. Results are based on individual case studies and figures quoted should not be taken as industry averages.

Chapter
03

The 12 costliest renewal mistakes

  • Each mistake explained
  • The cost of getting each one wrong

These are the mistakes we see most frequently when Commercial & Industrial businesses handle energy renewal internally — or when they engage a broker who stops at the signature and disappears. Any one of them can cost tens of thousands of dollars. Several of them, stacked together, can cost six figures over the life of a contract.

If you recognise your business in any of the twelve below, the good news is that every one of them is fixable. The better news is that fixing the first few unlocks the leverage to fix the rest.

01Less optionality, more risk of rollover

Waiting until the last minute

Waiting is one of the most common mistakes that can also be an expensive one. A renewal run in the final weeks before expiry is a renewal run with fewer options and much less market perspective.

Energy procurement done late limits the time available to monitor the market and choose the right moment to engage, ultimately forcing customers to accept prevailing market conditions. The best outcomes come from starting 12 to 13 months out.

"A renewal run in the final weeks before expiry is a renewal run with fewer options and much less perspective."

02Rate is only the start of the story

Comparing offers on the energy rate alone

The headline unit rate (c/kWh) is the most visible number in any offer, and it's the easiest to compare — which is why businesses gravitate to it. But a C&I energy bill has many moving parts: network, market, metering, environmental, demand and retail charges.

A credible renewal comparison models the total delivered cost using your actual interval data, not a headline c/kWh.

03Fine-tuning can pay off

Ignoring how network and market charges are structured

Network charges (poles and wires) and market charges (AEMO, ancillary services) make up a large part of a Commercial & Industrial bill, and can be optimised as part of your energy contract renewal — another reason to have an energy expert in your corner.

Check exactly how network and market charges flow through into your bill — and whether what you're comparing across offers is structurally the same thing.

04Pricing based on reality, not assumptions

Failing to optimise around your load profile

Every C&I site has a distinct load shape: when you consume, how much, and how reliably. When a retailer has full understanding of that shape, it allows them to give you their best price for your business. For some businesses and where operations allow, it may also illuminate opportunities to shift load to times where energy is cheaper, and reduce overall consumption & cost.

Bottom line, load profile is key in energy tendering. Businesses that fail to accurately present it — or without an expert presenting it for them — receive pricing built on assumptions about their profile.

"When a retailer has full understanding of load shape, it allows them to give you their best price for your business."

05Market timing matters

Watching your expiry date, not the market

The right approach to energy contract renewal is to not just be expiry-aware, but market aware. Even though your expiry date is important, the market holds the key to the pricing available.

Forward energy pricing moves daily. An offer that looks strong in March can be average by May. It's yet another argument for not leaving contract renewal to the last minute.

06Silent clauses can become loud later

Overlooking the contract fine print

Commercial & Industrial energy contracts are not standard-form documents. They contain clauses that can materially reshape the deal. Early-termination fees, change-of-use recalculations, credit-support triggers, volume tolerances, force-majeure definitions, and meter-reconfiguration costs all matter.

Several of these clauses are silent until they aren't — and then they are expensive. Every clause should be read, understood, and negotiated before signature.

07Tariff management pays its way

Under-estimating the impact of network tariffs

For many Commercial & Industrial sites, demand charges (kVA or kW) represent a larger portion of the bill than the energy component itself.

Not just at renewal time, but for the entire contract duration, being tariff aware and managing peak demand (if possible) can unearth thousands in savings — or losses if you make the mistake of not managing them well.

$648K^That's the savings energy expert Zembl identified across 148 C&I sites over 7 months (an average of $4,379^ per site reviewed) through Network Tariff Reviews.
08Improve offers on the table

Missing the aggregation opportunity

Multi-site Commercial & Industrial operators often run each site through renewal as a separate event — sometimes with different internal owners, on different timelines, with different retailers.

Bringing multiple sites into a single, coordinated procurement cycle (where the contract calendar allows) typically improves the offers on the table and simplifies ongoing management. Check whether your portfolio can be aggregated — fully or partially — before the next renewal cycle begins.

09Data is the concrete of solid energy foundations

Accepting poor metering and data quality

Quality meter data is key information that retailers need in order to provide their best price — missing intervals, incorrect registration, misconfigured NMI data, or outdated meter service provider arrangements can all lead to less than optimal data, and a renewal run on incomplete or incorrect data is a renewal signed on shaky foundations.

Check meter data quality, meter service provider arrangements, and metering charges as part of renewal prep — not after the contract starts.

"Quality meter data is key information that retailers need to provide their best price."

10Involve your ESG stakeholders, align and save time

Separating sustainability from the renewal conversation

Emissions targets, corporate reporting obligations (NGER, TCFD, climate-related disclosure), and Scope 2 reduction goals are increasingly decided in one part of the business while energy procurement happens in another.

Renewal is the point at which those two workstreams can align. GreenPower, large-scale generation certificates (LGCs), PPAs, and on-site generation are all procurement levers. Bring sustainability and procurement into the same room at renewal.

11Fewer options, more risk of rollover

Not comparing a wide enough retailer range

Today in Australia there are more than 50^ electricity retailers and more than 11^ gas retailers selling to Commercial & Industrial energy buyers, all with their own offers and terms to navigate. Thoroughly traversing them all is a near impossibility; shortlisting those with the best offer for your business is just as hard.

Don't let limited time limit your options. By engaging with an expert, you get the benefit of long-held relationships and knowledge — with experts using the latest technology, their market perspective and understanding of your business to traverse a panel of Australia's most reliable energy retailers.

12Energy management is a commitment, not an event

Going it alone – or using a broker who disappears after signing

This is the mistake that enables most of the others. Commercial & Industrial energy is a specialist discipline. Retailers negotiate energy contracts every day; most businesses negotiate their own contract once every two or three years. The information gap is significant, and it compounds across every one of the previous 11 mistakes covered in this guide.

A proper energy partner is not a comparison tool, and not a one-time broker who takes the signing commission and moves on. It is a specialist who runs the renewal, manages the contract across its full term, catches billing errors, optimises tariffs, and is already preparing for the next renewal months out from the next expiry date.

^ Mistake 2: Based on Zembl internal data. Saving is an average of a number of Zembl examples where individual saving range was between 7% and 14%.

^ Mistake 7: Based on Zembl's Australian commercial and industrial customers and represents annual potential energy savings through Zembl's annual Network Tariff Review service from 1 March 2025 – 30 September 2025 including GST. Savings vary based on individual site usage, network tariff structure, and distributor pricing.

^ Mistake 11: Annual Retail Markets Report, 2024-2025, Published by Australian Energy Regulator (AER).

Chapter
04

The energy contract renewal playbook

  • A 13-month timeline
  • Engage, prepare, market, sign, manage

At Zembl, a typical renewal cycle starts around 13 months out. Energy procurement is not a rigid practice — sometimes the timeline is longer or shorter — but the steps remain largely the same.

13 months to renewal day, and the work that protects your future energy spend

Zembl playbook
13 months out
Engage an expert & sign an LOA
  • Bring in an energy expert if you haven't already
  • Sign a Letter of Authority — permission to go to market on your behalf
9–12 months out
Prepare the energy pack
  • Interval data, consumption forecasts, site profiles, contract end dates
  • Structural preferences
  • Pack quality = the biggest predictor of offer quality
6–9 months out
Go to market
  • Release to a retailer short-list
  • Receive, normalise and model offers against total delivered cost
2–4 months out
Present, lock, sign
  • Present the most competitive and best-fit offers
  • Sign within 3–5 days — offers have short expiry windows
  • If expired before sign-off, return to market and revise
Day 1 · Contract starts
Activate & document
  • Confirm first-bill accuracy against signed rates & structure
  • Document the contract in a live portfolio register
  • Set calendar alerts 12–13 months from next expiry
In-contract
Manage, optimise, consult
  • Bill validation every six months
  • Annual Network Tariff Review
  • Ongoing monitoring for energy efficiency opportunities
Chapter
05

The Zembl difference

  • Why specialist expertise matters at renewal
  • Three things we promise

Why specialist expertise matters at renewal time

Zembl is a Commercial & Industrial energy partner. We're not a comparison tool, and we're not a one-time broker who takes the signing commission and disappears.

We've built the business around a simple idea: energy is too significant a cost — and too complex a market — to be managed as an administrative event, without help every few years. We work closely with the retailers who serve the Commercial & Industrial market. They're essential partners in the Australian energy system, and well-structured, long-term contracts are in everyone's interest — yours, theirs, and ours.

Our role is to make sure the contract that lands on your desk is the right one for your specific business, and to help you manage it across its full life.

Choose Zembl

Choose Zembl and we can promise these three things

01

Renewal done right

We run the renewal. We navigate the market, model offers against your actual load profile, negotiate rates and structure, and catch the clauses that quietly erode value. Our retailer relationships and day-in, day-out market presence mean we're across all relevant market movements and which retailers are most competitive in which segments at any given time.

02

In-contract support

We are with you all contract long. Bill validation. Billing-error recovery. Annual tariff reviews. Early engagement on the next renewal. Account continuity with Zembl Energy Experts who know your business — not a different person on every call.

03

Beyond the bill services

We connect you to efficiency solutions — for solar, batteries, LED, HVAC, Heat Pumps, demand management, power factor correction — with trusted specialists we've vetted. When you choose Zembl for procurement, you unlock all this added value as part of the deal.

Dairy cows feeding in a barn
Energy story

Burnfarmers saves $119K^ with the right partner

"We are a dairy farm, so a big consumer of power — energy pricing impacts our business heavily."

Burnfarmers, a leading Australian dairy farm, overcame surging energy prices with Zembl's tailored energy solutions. Rather than letting a contract roll onto default rates, they engaged a specialist to run the market on their behalf.

Zembl began by understanding their specific energy requirements and operational challenges. Leveraging expert knowledge of the energy market, Zembl sought out a competitive energy deal tailored to the farm's needs.

The results speak for themselves. Burnfarmers achieved $119,000^ in energy bill savings throughout the duration of their contract — an outcome that improved cost predictability and operational efficiency.

^Savings are estimates only and are based on comparing the customer's previous energy rates with the new rates arranged through Zembl, using the customer's historical usage data. Actual savings may vary depending on changes to energy usage, future rates, and other factors outside of Zembl's control. Past savings are not a guarantee of future outcomes.

Tresillian heritage brick building
Energy story

Tresillian secures $16K^ energy savings and $19.6K solar rebate

Beyond energy savings, Zembl's energy efficiency service facilitated Tresillian's solar installation project in collaboration with our partner, Solar Choice.

Zembl assisted Tresillian in securing a $19,686 STC rebate for their solar upgrade, with the 62.04 kW system expected to achieve a 3–4 year payback timeframe and deliver projected annual savings of $17,899.

^Savings are estimates only and are based on comparing the customer's previous energy rates with the new rates arranged through Zembl, using the customer's historical usage data. Actual savings may vary depending on changes to energy usage, future rates, and other factors outside of Zembl's control. Past savings are not a guarantee of future outcomes.

Appendix
06

Your renewal-ready checklist

  • Run through it — anything you can't tick is a question worth asking

Quick checklist. Run through it. Anything you can't tick is a question worth asking — of your team, your retailer, or an energy expert.

0 / 16

Tick items as you confirm them. Your progress is saved on this device.

AKnow where you stand

BPlan the renewal

CPressure test the offer

DManage the contract

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Zembl is everything energy

More than just procuring your energy, we're energy partners. We're the specialists who guide Commercial & Industrial businesses through the complexity of the Australian energy market, working alongside retailers, efficiency providers, and your own team to make every renewal cycle as good as the last.

Zembl Everything energy

This guide was published by Zembl in 2026

Whether your contract ends in a few months or next year, the work that protects your energy spend starts now. Visit zembl.com.au