Seedling trying to grow in cracked land affected by climate change

CLIMATE CHANGE.

Mercury's activities are deeply connected to nature and the climate, and we recognise the responsibility that comes with this. We are committed to playing our part in the transition to a low-carbon future. On this page you’ll find our climate-related disclosures, which offer insight into the climate risks and opportunities we are managing (Climate Statement), our carbon emissions footprint (GHG Emissions Inventory), the actions we are taking to reduce emissions (Climate Action Plan).

The Waikato river bank, with the surrounding trees and sky reflecting onto the water,

WHAT WE'RE DOING

We love New Zealand and take climate change measures seriously. Our Climate Action Plan outlines in detail the actions we plan to take as we aim to play our part in reducing greenhouse gas emissions and help limit global warming to no more than 1.5°C.

It builds on work we’ve done to reduce emissions and sets out near- and long-term targets we aim to achieve as we work towards a net-zero future while continuing to deliver reliable energy for New Zealand.

Seedlings in different stages of growth in a line, in dirt.

CLIMATE CHANGE AND MERCURY

Impacts from climate change, actions to reduce emissions and the transition to a low-carbon economy are shaping the world around us. Our strategy anticipates that our business will encounter both climate-related opportunities and risks as we pursue our objective of playing a leading role in New Zealand's successful transition to a low-carbon future.

Our Climate Statement is prepared in accordance with the Aotearoa New Zealand Climate Standards and provides a detailed look into how we consider and respond to climate-related risks and opportunities.

Kawerau-Aerial

OUR CARBON FOOTPRINT

We actively measure and monitor our carbon emissions. Our geothermal operations generate greenhouse gas emissions and we are seeking to reduce these emissions each year. Our hydro and wind generation activities are largely emissions free.

Since Mercury exited thermal generation in 2015, our absolute generation-related GHG emissions have decreased by around 60% (as at 30 June 2025). Over the past year we have also completed a materiality assessment across our Scope 3 inventory to better understand the emissions associated with our wider value chain. You can find further detail on these impacts in our latest GHG Emissions Inventory.

Mercury FY22 GHG Emissions Inventory

Mercury FY23 GHG Emissions Inventory

Mercury FY24 GHG Emissions Inventory

Mercury FY25 GHG Emissions Inventory Link

MANAGING NATURAL RESOURCES

There are a number of programmes and surveys that we undertake (or participate in) to ensure we're caring for natural resources. Here are some great examples.

ENVIRONMENTAL INSPECTIONS

  • Our generation facilities are internally audited on a regular basis against resource consent and other regulatory requirements, as well as against Mercury company procedures. We assess for environmental incident readiness, and to obtain feedback from our station personnel. The learnings from these audits are recorded and used to improve our environmental management system.   

 

GEOMORPHOLOGY SURVEYS

  • Since the Waikato River Hydro Scheme resource consent were granted in 2006, surveys have been undertaken on a five-yearly basis to monitor the extent of Waikato River and lakes geomorphic changes. The surveys help to understand the movements and impacts of sediment in the hydro lakes or river channel.   
  • In Lake Taupō, the foreshore is surveyed annually and helps us and others understand how various factors affect the lake edge, particularly beach and foreshore geomorphology.  
  • The results of these surveys are peer reviewed by independent experts, and results are reported to Waikato Regional Council and other agencies, partners and stakeholders.
ECOLOGICAL MONITORING
  • We engage specialist consultants to undertake a range of ecological monitoring programmes around our sites. These include regular surveys for flora, fauna and avifauna.  
  • At our geothermal sites we monitor for rare geothermal plant species and assess for species diversity and density. We also monitor long term trends in geothermal surface features such as chemistry, temperatures and appearance.  
  • At the Waikato hydro lakes we undertake regular bird species counts and assess breeding success, measure wetland extents and composition, and monitor for aquatic macrophytes and invertebrates. 
  • Around our windfarms we undertake a range of monitoring relating to bird species, changes in vegetation and monitoring the success of native restoration projects.  
  • All of these surveys are undertaken by expert consultants, with the results reviewed by independent peer review panels, before the results are shared with our regulators and partners.  
 
OTHER ENVIRONMENTAL ACTIVITIES
  • Sustainability is a key element of Mercury’s energy generation operations.  The catchments and geothermal fields we operate in are carefully managed and monitored to ensure that these resources can be used by future generations. 
  • An extensive range of monitoring activities are undertaken in geothermal fields including surface and subsurface surveys.  These include detailed ground level surveys, physical and chemical studies of geothermal features, gravity and seismic surveys, and fresh and geothermal aquifer conditions.  
  • At the Waikato Hydro lakes Mercury supports iwi partners with an elver catch and release programme to enable tuna breeding.    
RESOURCE CONSENTS
  • Most of our sites have 35 year term consents, including the Waikato Hydro Scheme, development geothermal fields and stations, and our wind farms.  Mercury works hard to ensure it meets its resource consent and other statutory or regulatory obligations.  It has council-approved management plans for how it uses environmental resources.  Our consent conditions and management plans are regularly reviewed by the relevant authorities and we aim to be assessed as having high levels of compliance every year. 

OTHER
  • Mercury collaborates with tangata whenua and key stakeholders, to seek positive outcomes for the environment and communities.  Many of the monitoring activities above are also used to inform local communities and stakeholders about the health of natural resources utilised by Mercury in its operations.  
  • Mercury has a specialist response team that can be mobilised to address environmental incidents on the Waikato Hydro lakes, river and stations or at Geothermal stations and fields.  This team is specialist trained in spill response and has boats, pumps and other specialist clean-up equipment and materials at its disposal.