Mercury scaling geothermal platform

The Mercury Building, 33 Broadway, Newmarket 1023
PO Box 90399, Auckland 1142





STOCK EXCHANGE LISTINGS: NZX (MCY) / ASX (MCY)

ANNOUNCEMENT

Mercury scaling geothermal platform, with up to $1
billion investment in next phase

14 May 2026 – Mercury is scaling its geothermal platform, committing $75 million to geothermal
appraisal drilling for two projects at existing sites near Taupō as part of its next growth phase.

Together, the projects at Ngā Tamariki and Rotokawa, could total up to $1 billion investment and add
1TWh of new geothermal generation – the equivalent of powering an additional 125,000 homes. First
generation is targeted for 2030.

Mercury Chief Executive Stew Hamilton said Mercury’s geothermal growth would be progressed in
phases, with major capital decisions to follow appraisal results, technical work and investment
approvals.

“Scaling our geothermal platform will strengthen our renewable portfolio, support long-term contracting
with major energy users, and help meet New Zealand’s growing demand for affordable, reliable and
renewable electricity.

“We have a credible, investable and repeatable geothermal platform, a strong pipeline of opportunities,
and the capability and partnerships to deliver.”

Mercury is funding the growth from its own balance sheet, within clear financial guardrails. It is expected
to be a value accretive investment, supporting resilient earnings and balance sheet strength.

“Our investment in geothermal will add further long-term value for our customers, partners,
communities, shareholders and New Zealand,” Mr Hamilton said.

Mercury’s near-term focus is on maximising value of conventional geothermal. It is also positioning for
long-term next-generation geothermal options, including harnessing superhot geothermal as technology
advances.

“Our team is match fit, having successfully completed the $220m expansion of the Ngā Tamariki
Geothermal Station on budget and on time in March,” Mr Hamilton said.

“We have deep geothermal expertise, a strong track record of geothermal exploration, development and
operations, and enduring, multi-decade relationships with our iwi partners.”

Mercury’s investment would support the Government’s goal of doubling geothermal use by 2040 and
enable geothermal, which runs 24/7, to play a greater role in firming weather dependent renewables,
helping ensure the lights to stay on during winter peaks and dry years.

The Mercury Building, 33 Broadway, Newmarket 1023
PO Box 90399, Auckland 1142
Mercury’s geothermal portfolio and growth strategy:

• Mercury has five geothermal stations operating in the central North Island, which following completion
of the Ngā Tamariki expansion, deliver total annual generation of approximately 2900GWh.
• Mercury has up to 5TWh of conventional geothermal options across multiple, diverse, scalable
reservoirs and horizons. 2.5TWh of which are in active development, including 1TWh (Ngā Tamariki
and Rotokawa projects) entering feasibility.
• Further information about Mercury’s geothermal growth strategy is being presented to investors today.
See Mercury’s Geothermal Investor Day presentation.
• A video and summary of Mercury Geothermal Investor Day will be available on Mercury website
tomorrow.

ENDS
Howard Thomas
General Counsel and Company Secretary
Mercury NZ Limited




For investor relations queries, please contact:
Paul Ruediger
Head of Business Performance & Investor
Relations
027 517 3470
investor@mercury.co.nz

For media inquiries, please contact:
Catherine Morab
09 282 1158
mercurycommunications@mercury.co.nz


ABOUT MERCURY NZ LIMITED
Mercury’s generation assets produce electricity from 100% renewable sources: hydro, geothermal and
wind. We’re also a retailer of electricity, gas, broadband and mobile services. We’re listed on the New
Zealand Stock Exchange and the Australian Stock Exchange with the ticker symbol ‘MCY’, with foreign
exempt listed status. The New Zealand Government holds a legislated minimum 51% shareholding of
Mercury.
Visit us at: www.mercury.co.nz

---

GEOTHERMAL INVESTOR DAY
14 MAY 2026
STEW HAMILTON
CHIEF EXECUTIVE
BETTER
BUILDING
BRIGHTER
TODAY
TOMORROW
TOGETHER

NAU MAI, HAERE MAI
WELCOME
NGĀ TAMARIKI GEOTHERMAL STATION

DISCLAIMER
3
This presentation has been prepared by Mercury NZ Limited and its group of companies (“Company”) for informational purposes. This disclaimer
applies to this document and the verbal or written comments of any person presenting it.
Information in this presentation has been prepared by the Company with due care and attention. However, neither the Company nor any of its
directors, employees, shareholders nor any other person gives any warranties or representations (express or implied) as to the accuracy or
completeness of this information. To the maximum extent permitted by law, none of the Company, its directors, employees, shareholders or any other
person shall have any liability whatsoever to any person for any loss (including, without limitation, arising from any fault or negligence) arising from
this presentation or any information supplied in connection with it.
This presentation may contain projections or forward-looking statements regarding a variety of items. Such projections or forward-looking
statements are based on current expectations, estimates and assumptions and are subject to a number of risks, and uncertainties, including
material adverse events, significant one-off expenses and other unforeseeable circumstances, such as, without limitation, hydrological conditions.
They do not constitute guidance of any kind. There is no assurance that results contemplated in any of these projections and forward-looking
statements will be realised, nor is there any assurance that the expectations, estimates and assumptions underpinning those projections or forward-
looking statements are reasonable. Actual results may differ materially from those projected in this presentation. No person is under any obligation
to update this presentation at any time after its release or to provide you with further information about the Company.
The information in this presentation is of a general nature and does not constitute guidance, financial product advice, investment advice or any
recommendation. The presentation does not constitute an offer to sell, or a solicitation of an offer to buy, any security and may not be relied upon in
connection with the purchase or sale of any security. Nothing in this presentation constitutes legal, financial, tax or other advice.
MAY 2026GEOTHERMAL INVESTOR DAY

4
TOPICPRESENTERS
Geothermal growth strengthens our renewable platform
Scaling Mercury’s renewable platform
GeoPlatform development and commercialisation
Partnering with mana whenua
Capital allocation and outlook
CE Wrap
Stew Hamilton
Matt Tolcher
Ben Pezaro
Mana Newton
RichardHopkins
StewHamilton
Lunch
AGENDA
MAY 2026GEOTHERMAL INVESTOR DAY

5
StrategicFramework
ASPIRATIONS
FY35
PRIORITIES
FY30
STRATEGICOBJECTIVES
OURPURPOSE
Tiakina te anamata, mā te
tūhono i ngā tāngata
me ngā wāhi o te inamata.
Taking care of tomorrow,
connecting people and
place today.
Delivermorereliable
andrenewableenergy
Achievewhatmattersmost
throughfinancialgrowth
Acceleratetheshift
toalow-carbonfuture
Performwithanadaptive
cultureenabledbytechnology
Createsuccesswithothers
KAITIAKITANGA
Stewardship
Ourassetsandthenatural
environmentarethriving.
ARUMONI
Commercial
Weareleaders
in commercial growth.
KIRITAKI
Customer
Customersareat
theheartofwhatwedo.
NGĀTĀNGATA
OurPeople
Welearnandadapt
to realiseourfull potential.
KŌTUITANGA
Partnerships
Wearethetrustedpartner
ofchoice.
Generation
developmentuplift
Earnings
transformation
Capturingenergy
transitiongrowth
Connectedandinclusive
employeeexperience
Rebuildsector
confidence
OUR STRATEGIC PRIORITIES DELIVER SUPERIOR VALUE
MAY 2026GEOTHERMAL INVESTOR DAY

6
SUPERIOR PORTFOLIO WITH TWO LEADING GROWTH PLATFORMS
Renewable generation
•Baseload geothermal, intermittent
wind, flexible hydro
•Diversified, complementary, low-cost,
renewable fuel sources
Superior asset location
•North Island generation
close to demand centres
•Rain-fed hydro aligned with winter
peak demand
Growth platforms (wind and geothermal)
•High quality options
•Realise scale and repeatability benefits
•Capability and partnerships
•Proven supply chain
•Geothermal directly supports our
strategy because it adds firm renewable
growth, improves portfolio resilience and
supports long-term contracting
Waikato (1,120MW) 4,200GWh
Rotokawa (34MW) 286GWh
Kawerau (106MW) 875GWh
Ngā Awa Pūrua (90MW) 490GWh
Ngā Tamariki (85MW) 731GWh
Tararua (160MW) 560GWh
Mahinerangi 1 (36MW) 100GWh
Ngā Tamariki 5 (46MW) 390GWh
Turitea (221MW) 840GWh
Waipipi (133MW) 455GWh
Kaiwera Downs 1 (43MW) 147GWh
Operation & Construction:
Kaiwera Downs 2(155MW) 525GWh
Kaiwaikawe (77MW) 221GWh
Puke Kapo Hau 550GWh
Waikokowai / Puketoi 1,015GWh
HydroGeothermalWind3rd Party SolarBESS (MW RHS)
Third party solar 500GWh
Whakamaru Up to 200MW
GeoPlatform Expansion 1000GWh
Planned to 2035: 1000GWh
Hydro Rehabs (76MW) 87GWh
Planned to 2035
Planned to 2030
In-Construction
Portfolio core
and firming
Mercury’s growth platforms
Short term
portfolio peaking
Selective growth
Current4.2 TWh2.8 TWh2.6 TWh0.03 TWh
Plan by 20354.3 TWh3.8 TWh5.4 TWh0.5 TWh200 MW
MAY 2026GEOTHERMAL INVESTOR DAY

7
DEMAND GROWTH TO SUPPORT OUR DELIVERY APPROACH
Strong long-term electricity demand
•Strong demand growth anticipated, lifting
from ~40 TWh to ~49 TWh by 2035.
•High confidence of +4 TWh of demand
growth from 2025 to 2030
•Demand growth led primarily by data
centres and industrial electrification
A number of key areas impact NZ market
outcomes
•Demand growth (GDP, data centres,
electrification, rooftop solar)
•Generation build rate (delivery delays,
consenting and grid connection constraints)
•Gas price (major industry exits, exploration,
LNG, flex)
•LRMC of new generation (WACC and
technology costs for wind, solar and
geothermal)
•Government policy
Electricity Demand
(TWh, Calendar Year)
40.3
45
52
43
47
38
40
42
44
46
48
50
52
54
20152020202520302035
HistoryTealMercury MidMaroon
Aligns with BCG 'High', Transpower
'Aotearoa Intelligence' and MBIE 'Reference'
scenarios
Aligns with BCG 'Low', Transpower
'Patchwork Nation' and MBIE
'Constraint' growth paths.
MAY 2026GEOTHERMAL INVESTOR DAY

8
AFFORDABLE, RELIABLE, RENEWABLE GEOTHERMAL SUPPORTS MAJOR ENERGY USERS
Our geothermal platform is well suited to major energy users that need reliable, renewable electricity
over the long term
Geothermal is more than new generation. It strengthens our portfolio, supports long-term
contracting and positions us to support major energy users.
Resilient earnings
Portfolio balance
Disciplined growth
Strategic platform
Supports NZ growth
Major energy users need reliable
electricity for many years
Steady demand is a good
match for geothermal output
Data centres are one example
of new major electricity demand
Major energy users are also
looking to lower emissions
Supports New Zealand’s digital
and industrial growth
WHY MAJOR ENERGY
USERS MATTER
BENEFIT
Reliable renewable generation
supports long-term contracting
Geothermal reduces reliance on
hydro inflows and wind
Repeatable projects build scale
and capability
Firm renewable electricity is
scarce
Supports electrification and
renewable infrastructure
WHY GEOTHERMAL
MATTERS
MAY 2026GEOTHERMAL INVESTOR DAY

9
GROWTH PLATFORMS HAVE INCREASED OUR MARKET SHARE
GeoPlatform
Scale and diversity: NZ’s largest portfolio of geothermal options
People capability and partnerships: deep expertise
in exploration, development, operations and iwi partnerships
Repeatable execution: modular growth options integrate
across the geothermal value chain
0%
2%
4%
6%
8%
10%
12%
14%
Jan-05
Jul-05
Jan-06
Jul-06
Jan-07
Jul-07
Jan-08
Jul-08
Jan-09
Jul-09
Jan-10
Jul-10
Jan-11
Jul-11
Jan-12
Jul-12
Jan-13
Jul-13
Jan-14
Jul-14
Jan-15
Jul-15
Jan-16
Jul-16
Jan-17
Jul-17
Jan-18
Jul-18
Jan-19
Jul-19
Jan-20
Jul-20
Jan-21
Jul-21
Jan-22
Jul-22
Jan-23
Jul-23
Jan-24
Jul-24
Jan-25
Jul-25
Jan-26
Jul-26
Jan-27
Mercury’s geothermal and wind share of national generation (rolling 12 months)
Kawerau Geothermal
Station
Ngā Awa Pūrua
Geothermal Station
Ngā Tamariki
Geothermal Station
Turitea N &
Waipipi Wind
Farms
Turitea Sth & KD1
Wind Farms
Mahinerangi
Wind Farm
OEC5, KD2 &
Kaiwaikawe
WindPlatform
Scale and diversity: large and active development pipeline,
regionally diverse with a North Island weighting
People capability and partnerships: experienced internal team and
supply chain partners. Successful consenting enabled through a
deliberate focus on deepening trust with stakeholders
Repeatable execution: successful delivery of Waipipi, Turitea KD1,
KD2, and Kaiwaikawe wind farms. Nearing consent and FID on
Puke Kapo Hau
MAY 2026GEOTHERMAL INVESTOR DAY

GEOTHERMAL PLATFORM DRIVING OUR MOMENTUM
•Baseload renewable
•Premium firm value
Global geothermal trends: accelerating through the energy transition
Mercury in NZ: scale, growth and execution options to 2040+
CORE VALUE GROWTH
•Capital and policy support
•Cost curve improving
INVESTMENT
•Future next-generation geo
technology upside beyond
conventional resources
NEXT-GEN OPTIONS
Mercury’s three
geothermal
horizons
Horizon 1 to 2035:
Brownfield development
and appraisal drilling
Horizon 2 to 2040:
Add greenfield development
and position for Next-gen geo
Horizon 3 to 2050:
Next-gen geo – Enhanced Geo
Systems and Superhot options
Up to 5 TWh of conventional geo growth options
MAY 2026GEOTHERMAL INVESTOR DAY10

11
SCALING OUR GEOTHERMAL PLATFORM FOR VALUE
Our geothermal platform is a competitive advantage because it combines scale, specialist people, trusted
partnerships and repeatable delivery
•Up to 5 TWh of options across multiple, diverse, scalable reservoirs and horizons
•2.5 TWh under active development
•1 TWh entering feasibility with first generation targeted for 2030
•$75m FY27–FY28 geothermal appraisal drilling campaign committed
Building
Tomorrow
Brighter
Together
•GeoPlatform with scale, diversity, capability, partnerships and repeatability
•Disciplined growth across horizons with incremental investment and development
•Well positioned for next-generation geothermal
Better
Today
•Existing GeoPlatform has 525 MW / 4.4 TWh under operations (2.8 TWh owned)
•100% success rate on recent eight well drilling programme
•Ngā Tamariki OEC5 geothermal generation delivered on time and budget
MAY 2026GEOTHERMAL INVESTOR DAY

SCALING
MERCURY’S
RENEWABLE
PLATFORM
MATT TOLCHER
EGM GENERATION DEVELOPMENT
NGĀ TAMARIKI GEOTHERMAL STATION

6080100120140
Geothermal
Solar
Wind
LCOE
Indicative LCOE of Recently Disclosed NZ Projects
13
WIND AND GEOTHERMAL FUNDAMENTALS DELIVER WINNING PROJECTS
•Recent geothermal has proven highly competitive
and Mercury has benefited
•Greenfield and future geothermal likely to
benchmark higher in range
•LCOE is comparable across wind and solar, but
LCOE alone doesn’t guarantee value
Indicative LCOE of disclosed NZ projectsPrice capture across technology typesBut project value matters in the end
0
20
40
60
80
100
120
140
KWK WindKD2 WindOEC5
Geothermal
MCY Brownfield
Geo
Solar -
Central NI
LRMC real at AucklandLRMC real at SiteLCOE real at Site
$114
$108
$82
$130
Project economics – LCOE & LRMC ($/MWh)
1
Post-FID projects
•Geothermal price capture remains robust as more
geothermal is built – presenting a clear case for
long-term value
•Wind price capture reduces over time, but we see
opportunity to de-risk by developing in areas with
lower correlation
•Solar price capture significantly reduces with
minimal location diversity, high summer renewability
and NZ’s winter peaking demand
•Hydro is the beneficiary of solar and wind reducing
•Project fundamentals: We target projects that
can deliver more energy for less cost
•Market fundamentals: We target a pipeline that
can deploy the right technology in the right
location, at the right time
•Wind and geothermal are the highest value
technologies in New Zealand
Brownfield
1
As at FID for each generation project. LCOE real at Site (grid location) refers to the required year 1 average revenue ($/MWh) to achieve WACC return, this considers long-term inflation. LRMC real at Site refers to the required year 1
average spot price to achieve WACC return. This considers GWAP/TWAP profile over time. LRMC real at Auckland reflects the location factor adjustment to scale the site grid price to Auckland. Geothermal forward view as at FY27.
0.0
0.2
0.4
0.6
0.8
1.0
1.2
GWAP / TWAP
GeothermalWindSolar
Wind
Solar
Geothermal
Greenfield
$110 +/-
Generic projects
MAY 2026GEOTHERMAL INVESTOR DAY

OUR WIND AND GEOTHERMAL PLATFORMS UNDERPIN NZ’S LEADING PIPELINE
Scale and Diversity
People Capability and Partnerships
Repeatable Execution
•17 TWh pipeline of wind and geothermal prospects and projects across
the development lifecycle
•Geographically diverse, with a North Island bias
•Flexibility to stage technologies and projects to respond to demand
•Market leading in wind with NZ’s most successful wind team
•Internationally recognised geothermal team, connected to international
innovations, with capability across the value chain
•A proven supply chain and a long standing record of partnering well
•Optionality across technologies and locations
•Disciplined delivery with structured investment gates
•Track record of delivering value accretive projects to plan
14
Pipeline uplift
Pipeline uplift
MAY 2026GEOTHERMAL INVESTOR DAY

15
OUR MULTI-RESERVOIR GEOPLATFORM GENERATES REPEATABLE VALUE CREATION
Maximise brownfield-conventional first.
Advance greenfield options. Position for
long-term opportunity in next-gen geo
Undertake targeted exploration and
appraisal drilling to open new resource
areas and improve confidence in long-
term field deliverability
Build a diversified portfolio of high-
quality projects by leveraging extensive
land holdings, multi-reservoir access, and
decades of operations and data collection
Pursue modular 30-75MW
executable options to support
repeatable geothermal growth
Balance risk and pace by progressing
multiple opportunities, providing
flexibility to advance our best projects
against visible demand growth
Commit major capital after projects
progressed through technical,
commercial and investment gates
Harness our internationally recognised
expertise and capability to deliver
across the value chain
Execute our strategy with discipline,
maintaining a deliberate focus on our
people and partnerships
Unlock long-term growth with our key
geothermal commercial partners -
Tauhara North No.2 Trust, Tuaropaki Trust,
and Rotoma landowners
KAWERAU GEOTHERMAL STATION
People Capability
and Partnerships
Repeatable Execution
Scale and Diversity
MAY 2026GEOTHERMAL INVESTOR DAY

OUR SCALE, DIVERSE RESERVOIRS AND LANDHOLDINGS POSITION US FOR GROWTH
Lake Taupō
Taupō
Rotorua
Kawerau
Rotomā (Greenfield)
Rotokawa
Ngā Tamariki
Mōkai
Current Capacity: 0MW
Potential Additional: 50-100MW
Current Capacity: 106MW
Potential Additional: Under assessment
Current Capacity: 132MW
Potential Additional: 50-130MW
Current Capacity: 173MW
Potential Additional: 50-130MW
Current Capacity: 113MW
Potential Additional: Under assessment
Other Greenfield
Current Capacity: 0MW
Potential Additional: 50-100MW
MCY & Partner Reservoirs
MCY & Partner Land Interests
33,000 hectares
FY27-28 Drilling Campaign
5 TWh Opportunity
Rotomā
Ngā
Tamariki
Rotokawa
Other
Brownfield &
Greenfield
Under
Assessment
NZ’s current geo: 9-10 TWh
MCY’s current geo: ~3 TWh
MCY’s geo growth opportunity: 5 TWh
Our 33,000 ha landholding positions us for:
•Horizon 1 & 2 brownfield expansion
•Horizon 2 & 3 greenfield expansion
•Horizon 2 & 3 next-generation expansion
16
MAY 2026GEOTHERMAL INVESTOR DAY

OUR GEOTHERMAL STRATEGY DELIVERS VALUE TODAY AND POSITIONS US FOR THE FUTURE
BUILD CONVENTIONAL GEOTHERMAL
Prioritise development of 1 TWh at Ngā Tamariki
& Rotokawa, with first generation targeted for
2030
Investment in appraisal wells at Ngā Tamariki &
Rotokawa, suitable for future production
Disciplined exploration and development of next
phase of brownfield and greenfield projects
(additional 1.5 TWh)
Deliver conventional pipeline up to 5 TWh
across multiple, diverse & scalable reservoirs
Unlock new greenfield options
Pilot next-gen e.g. Enhanced Geothermal
Position for Superhot
MAXIMISE CONVENTIONAL GEOTHERMAL
Ready to deploy next-gen as economics support
Geothermal station renewals
Harness Superhot as technology advances
LEAD NEXT-GEN ENHANCED AND SUPERHOT
HORIZON 1 TO 2035
HORIZON 2 TO 2040
HORIZON 3 TO 2050
NGĀ TAMARIKI GEOTHERMAL STATION
17
MAY 2026GEOTHERMAL INVESTOR DAY

EXPLORE
OUR VERTICALLY INTEGRATED GEOTHERMAL CAPABILITY DRIVES VALUE AND REDUCES RISK
Strong technical reservoir
and geoscience capability
SUBSURFACE
ENGINEERING
Deep multi-reservoir
experience
DRILLING & TESTING
Proven in-house drilling
management capability
and systems
Deep capability across
environment, consenting,
& stakeholder
engagement
CONSENTING
Dedicated optimisation,
operations and
maintenance teams
delivering safe, reliable,
geothermal generation
OPERATIONS &
MAINTENANCE
Decades of in-house
subsurface modelling
experience
200+yrs of geothermal
science and engineering
expertise
~50 wells successfully
targeted
NZ leader in drone
geothermal technology

Partner in NZ SuperHot
Successful 2023-2025
8 well Drilling Campaign
– 100% met or exceeded
objectives
Strategic partnership
approach with drilling
services contractors
Recent wind and geo
consenting success
Demonstrated
partnership capability
across multiple sites
New Safety Intelligence
Programme
Geo machine learning
generating additional MW
DEVELOP, CONSENT, & DELIVER
GENERATE
Experienced in-house geo
project delivery capability
across procure, construct
and commission
PROJECT DELIVERY &
CONSTRUCTION
OEC5 delivered safely to
plan over 250,000 hours
of construction
$1B growth capex across
geothermal and wind
delivered in parallel
EXPLORATION
MAY 2026GEOTHERMAL INVESTOR DAY18

GEOPLATFORM
DEVELOPMENT &
COMMERCIALISATION
BEN PEZARO
HEAD OF GEOTHERMAL DEVELOPMENT
NGĀ TAMARIKI GEOTHERMAL STATION

HORIZON 1 GEOPLATFORM: CONVERTING SCALE OPPORTUNITY TO INVESTMENT READY
5 TWh Opportunity 2.5 TWh Active Development 1 TWh Entering Feasibility
5 TWh Opportunity
Ngā Tamariki Resource
Up to 830GWh
NTM Expansion
Up to 620 GWh
Rotokawa Resource
Up to 830GWh
RKA Expansion
Up to 420 GWh
Rotomā Resource
GWh TBD

~ 2.5 TWh
Active Development
1 TWh
Technical Assessment
and Planning
Future Opportunity
- Other brownfield options (including Mōkai and Kawerau)
- Higher risk brownfield and greenfield expansion
- Medium temperature options and new sites

Fields
Resource Potential
Projects
~ 2.5 TWh
Construct &
Commission
FID
Production
Drilling
Consenting
Feasibility
Exploration
Drilling
Advanced
Prospecting
Early
Prospecting
Rotomā
Ngā
Tamariki
Rotokawa
Other
Brownfield &
Greenfield
Under
Assessment
Fields
Resource Potential
MAY 2026GEOTHERMAL INVESTOR DAY20

21
NG
Ā
TAMARIKI RESERVOIR POTENTIAL
Current Capacity132MW
Future Capacity Up to 180-260MW
NG
Ā
TAMARIKI EXPANSION DETAILS
Project Ngā Tamariki Expansion
Type New generation
Project Status Entering feasibility
Next milestone Appraisal (pre-development) drilling
Target Capacity / Output75MW / 620GWh
Project Cost $6.5-8m/MW
Timing Earliest FID late CY28
RequirementsResource Consent
NGĀ TAMARIKI EXPANSION
NEW PROJECT - ready for appraisal drilling, up to 620GWh
High quality
reservoir,
extensive
acreage, modern
environmental
development
MAY 2026GEOTHERMAL INVESTOR DAY

22
ROTOKAWA RESERVOIR POTENTIAL
Current Capacity175MW
Future Capacity Up to 225-300MW
ROTOKAWA EXPANSION DETAILS
Project Rotokawa Expansion
Type New generation
Project Status Entering feasibility
Next milestone Appraisal (pre-development) drilling
Target Capacity / Output50MW / 420GWh
Project Cost $6.5-8m/MW
Timing Earliest FID late CY28
RequirementsResource Consent
ROTOKAWA EXPANSION
Hottest reservoir
in NZ, inspiring
history and
partnership
NEW PROJECT - ready for appraisal drilling, up to 420GWh
MAY 2026GEOTHERMAL INVESTOR DAY

23
Key messages
•$75m committed growth capital
for geothermal appraisal drilling
•Targeting high-value,
high-confidence geothermal
opportunities
•Data driven, pre-development
drilling aiming to prove 150MW
new reservoir capacity
•Appraisal wells suitable for future
production (up to 20% of total)
•MBIE Funded: NZ Government has
committed $60m to support the
development of Superhot in NZ
Platform enablers
•Strategic drilling supply chain
•Strong in-house geothermal
capability with deep expertise
•Proven execution via recent
successful eight-well campaign
DISCIPLINED EXPANSION OF OUR GEOTHERMAL WELL DRILLING PROGRAMME
23
Rotokawa + NgāTamariki
Appraisal Drilling (3 Wells)
Rotokawa Superhot
Well (MBIE Project)
Replacement make up well
drilling for existing generation
Growth
Capital
SIB
Capital
MBIE
Funded
Follow up Appraisal Drilling
(subject to board approval)
FY27
FY28FY29
MAY 2026GEOTHERMAL INVESTOR DAY

24
TECHNOLOGY OPPORTUNITY: CONVENTIONAL GEO FIRST, POSITION FOR NEXT-GEN GEOTHERMAL
Next-gen geothermal opportunity
•Long-term opportunity as costs fall and
technology matures
•Strong global momentum with pathways
increasingly relevant to NewZealand’s
geology and energy needs
•Early stage today with commercial scale and
long-term performance still being proven
Integrated GeoPlatform
•Prioritise conventional geothermal
•Actively learning, testing and collaborating
across a portfolio of next-gen geothermal
options
•Policy, R&D and partnerships are critical
enablers to accelerate NZ deployment
•Early mover in next-gen superhot
geothermal, with the Rotokawa well led by
NZ Government and supported by
Mercury/TN2T and geothermal industry
•Current MCY operations
•Natural reservoirs
•Hot temp, natural fluid
and permeability
•Artificial reservoirs
made by fracturing
•Horizontal paired wells
•Needs hot, dry rock
•Needs fluid
•Underground closed
loop
•No fracturing
•Needs hot, dry rock
•Needs fluid
•Superhot
temperatures
•Natural reservoirs with
supercritical fluid
Proven commercial
No global commercial operations
CONVENTIONAL
NEXT-GENERATION
MAY 2026GEOTHERMAL INVESTOR DAY

25
GEOPLATFORM DEVELOPMENT AND COMMERCIALISATION TAKE-OUTS
1 TWh
of development
projects entering
feasibility
5 TWh
GeoPlatform
pipeline
2030
target for first
generation

$75m
Board approved
appraisal drilling in
FY27-FY28
MAY 2026GEOTHERMAL INVESTOR DAY

PARTNERING
WITH MANA
WHENUA
MANA NEWTON
GROUP CHIEF EXECUTIVE
TAUHARA NORTH NO.2 TRUST
NGĀ TAMARIKI GEOTHERMAL STATION EXPANSION (OEC5) OPENING

TAUHARA NORTH AND MERCURY PARTNERSHIP
Enduring Partnership
Multi-decade collaboration grounded in
trust, shared outcomes, and connection to
land and people
Responsible Stewardship
Kaitiakitanga guiding long-term,
sustainable management of high value
geothermal resources
Sustainable Value Delivery
Disciplined growth and development
delivering enduring value for partners,
communities, and shareholders
27
MAY 2026GEOTHERMAL INVESTOR DAY

CAPITAL
ALLOCATION
AND OUTLOOK
RICHARD HOPKINS
CHIEF FINANCIAL OFFICER
NGĀ AWA PŪRUA GEOTHERMAL STATION

MERCURY’S CAPITAL ALLOCATION DISCIPLINE
Value Accretive Returns
•Invest only where projects are expected to be value accretive
•Prioritise value over simple MW growth
•Scale, diversity and modularity support better project selection
•A pipeline of 30-75MW executable options supports repeatable
conventional geothermal growth over time
•Assuming $6.5-8m/MW the 1 TWh of projects entering
feasibility equates to an investment of $0.8b to $1.0b
Demand Led Timing
•Invest against visible demand growth
•Avoid building ahead of the market
•Demand growth from major energy users improves confidence
in timing
•Long-term contracting supports investment confidence
Geothermal must compete for capital on value, timing, risk and funding.
This is not growth for growth’s sake. It is responsible capital deployment behind a platform Mercury is well
placed to execute.
Risk Managed Investment
•Projects progress through clear technical, commercial and
investment gates before major capital is committed
•The Board approved drilling programme is expected to be a
positive NPV investment
•If outcomes fall short, the downside would be a one-off write-
off rather than ordinary operating cost
Balance Sheet Strength
•Invest within clear balance sheet guardrails
•Capital has been committed to the next $75m appraisal
geothermal drilling campaign across FY27-FY28
•On our current plan, leverage peaks at around 2.6x before
declining, consistent with our S&P settings
29
MAY 2026GEOTHERMAL INVESTOR DAY

WHY THIS MATTERS FOR SHAREHOLDERS
Earnings Quality
•Firm renewable generation is easy to talk about, but hard to
deliver - Mercury can do it
•Geothermal adds renewable baseload and 24/7 firm supply
that is not weather dependent
•Over time, that should support an even stronger business risk
profile and durable earnings
Better Growth Visibility
•Appraisal drilling, consent progression and development
milestones reduce uncertainty before major capital is deployed
•Rising digital load and data centre demand improve confidence
in market need and timing
•Geothermal is not just more generation – it’s affordable, reliable
and renewable energy that supports long-term contracting with
data centres and other major energy users
Disciplined geothermal growth can strengthen returns, resilience and long-term value.
For shareholders, the point is simple: Mercury is not just describing geothermal opportunity - we are
committing capital to progress it in a disciplined, fundable and value accretive way.
Balance Sheet Resilience
•Growth is pursued within clear financial guardrails
•Significant investment can be accommodated within our
balance sheet settings
•We are funding significant investment while continuing to
support progressive dividends
Long Term Upside
•Mercury’s geothermal footprint and growth opportunity are
unmatched in New Zealand
•We are already actively developing around 1 TWh of
conventional geothermal opportunities, with up to 5 TWh
identified across Horizons 1 and 2
•Next-generation options such as superhot and EGS add further
upside over time
30
MAY 2026GEOTHERMAL INVESTOR DAY

CE WRAP
STEW HAMILTON
CHIEF EXECUTIVE
NGĀ TAMARIKI GEOTHERMAL STATION

32
GEOTHERMAL GROWTH STRENGTHENS OUR RENEWABLE PLATFORM
Up to 5 TWh across
diverse reservoirs and
horizons, including
2.5 TWh under active
development and 1 TWh
entering feasibility
Two near-term projects
at Ngā Tamariki and
Rotokawa, supported by
committed appraisal
drilling, with first
generation targeted for
2030
Leading geothermal
growth platform
Near-term
projects
Firm renewables. Disciplined growth. Long-term shareholder value
We have shown a credible pathway from geothermal options to value accretive growth
OEC5 delivered on time
and on budget, backed
by deep geothermal
expertise across the
value chain
Proven delivery
capability
Staged investment, clear
decision gates and
growth funded within
balance sheet
guardrails
Disciplined capital
allocation
MAY 2026GEOTHERMAL INVESTOR DAY