Our goal is to manage the environmental impacts of our electricity network and operations throughout their life cycle. We strive to minimise the adverse effects of our operations on the environment and maximise the positive effects by taking into account circumstances relating to the natural environment at all stages of our operations.

  • We continued the implementation of our network improvement programme, which reduces grid losses, and carried out other energy efficiency measures. Our investments in improving the reliability of supply allowed us to reduce grid losses by approximately 1 GWh.
  • In 2017, Kuusakoski processed about 32% of the demolition materials from Caruna’s network projects and the rest was dealt with by contractors through their contractual partners.
  • In 2017, we phased out approximately 350 pole transformers from groundwater areas in order to reduce the risk of groundwater contamination caused by oil spills.
  • We launched an investigation into the life cycles of our materials to discover what is done to further process our demolition waste and where it ends up after this.
  • Furthermore, the number of oil leaks was significantly reduced, with only one leak involving more than 100 kg of oil.
  • Caruna’s environmental certificate was updated in accordance with the ISO 14001:2015 standard.
  • The solar panels on the roofs of our Perkkaa premises and Keilaniemi primary substation generated a total of 47 MWh of electricity for our own use.

Key environmental impacts

We identify and assess our environmental impacts on a regular basis. We last updated our records on our environmental impact in the autumn of 2017 as part of the business planning process.

The following table lists the most important environmental impacts associated with our operations, as well as the main measures for managing them.

Environmental impact Target Management measure Indicator
Use of materials
  • Ensuring the safety of the materials throughout their life cycle
  • Improving the utilisation factor of dismantled materials
  • A waste handling and recording process that is complete in coverage
  • Using materials that comply with material regulations and whose life-cycle impacts have been taken into account
  • Ascertaining the composition, properties and disposal method of new materials and making sure they are safe to use
  • Appropriate handling, utilisation and disposal of dismantled materials
  • Careful selection of contracting partners and ascertaining the compliance of their operations with the relevant regulations
  • Instructions, follow-up and monitoring
  • Quantity of new materials (number by type)
  • Waste recording (tonnes and euros)
  • Recycling rate of demolished material (%)
  • Contractor and supplier audits (number)
Energy efficiency
  • Improving Caruna’s own energy use
  • Contributing to customers’ energy efficiency measures
  • Optimising the structure of our electricity networks, careful selection of materials and switching status optimisation
  • Active development of energy efficiency communications, guidance and services for customers
  • The effects of the electricity network regeneration programme on relative grid losses (%)


Climatic effects
  • Promoting actions to combat climate change
  • Efficient processes
  • Optimisation of the electricity network’s structure for the changing energy market and customers’ needs
  • Promoting decentralised renewable energy production and energy reserves (flexible connection to the electricity network)
  • Enabling demand side response as a producer of information
  • Optimised way of building that comprises entire large systems
  • Joint construction with other operators (municipalities and other infrastructure networks)
  • Increasing underground cabling and network automation, which reduces the need for field work (inspections, maintenance, fault repairs)
  • Number of renewable energy connections and storage registrations (number & MW)
  • Proportion of joint construction in all construction (%)
Responsible land use and biodiversity
  • Minimising adverse effects on the environment and landscape already during planning
  • Strengthening positive effects
  • Reducing land use restrictions
  • Planning and building underground cables for electricity networks, routes and structures
  • Systematically considering environmental conditions, protected areas and other special areas in all of the electricity network’s operations throughout its life cycle
  • Smooth land use and permit-related collaboration with landowners and other stakeholders
  • Ensuring the environmental maintenance of the areas surrounding project sites during and after the work
  • Customer feedback management and their utilisation in developing our operations
  • Level of cabling (%)
  • Land that becomes free for agriculture and forestry use (ha)
  • Site inspection observations (number)
  • Customer feedback (number)
  • Stakeholder satisfaction (NPS, feedback (number))
Leaks into the environment
  • Prevention of oil leaks
  • Prevention of SF6 leaks
  • Absolute prevention of serious and permanent environmental damage
  • Elimination of risky items by renovating pole transformers situated within groundwater areas
  • Prevention of oil leaks into the environment by installing oil collectors for substation transformers, building transformer rooms and pad-mounted secondary substations
  • Methodical handling of cases of environmental damage and ensuring the effectiveness of the measures taken
  • Controlling SF6 gas balance, ensuring contractors’ awareness and competence
  • Pole-mounted transformers/all secondary substations in groundwater and other areas
  • Number of oil leaks
  • Number of SF6 gas leaks

Use of materials

Dismantling and recycling of electricity networks

As we replace overhead networks with underground cables, considerable amounts of material needs to be disposed of, such as transformers, iron, conductors, cables, general waste, impregnated wooden poles, glass, porcelain, concrete and copper.

Until the autumn of 2015, most of the dismantled materials (excluding poles and transformers) were handed over to our contractors. The contractors’ contracting partners handled the demolished material, and the quantities of dismantled materials were reported to us regularly.

In August 2015, we signed a service contract for the transport and processing of dismantled materials with Kuusakoski Oy. As agreed, Kuusakoski is responsible for the collection of such material from worksites and its further processing. Impregnated poles are an exception to this procedure; Kuusakoski only transports them from work sites to the appropriate plants for further processing. We monitor all materials recycled by Kuusakoski in real time.



In 2017, Kuusakoski processed approximately 32% of the demolition waste from our network projects. This figure grows as Caruna’s contracting agreements are renewed.

In 2017, more than 4,600 tonnes of impregnated wooden poles were dismantled from Caruna’s electricity networks. Their processing and disposal is subject to strict regulations. A previously common impregnant, CCA contains toxic and carcinogenic substances and its use on new poles has been banned since 2006. Creosote is another commonly used but carcinogenic impregnant, but Caruna has not used any creosote-treated poles since 2007.

If we notice any loss of poles at the dismantling sites, we report it to the police.

Material procurement

We have made large investments to ensure a weatherproof and reliable electricity network. The numbers of purchased components for network building and the quantities of raw materials these contain are also considerable. Underground cables, pad-mounted secondary substations and distribution transformers are the main components of networks.

We subject our material acquisitions to strict requirements right from the time tenders are invited. Environmental impacts and safety aspects are given considerable weight in the consideration of these tenders.

We subject our material acquisitions to strict requirements right from the time tenders are invited. Environmental impacts and safety aspects are given considerable weight in the consideration of these tenders. We investigate the component material compositions, potentially dangerous and hazardous characteristics, safe use and correct recycling at the end of their life cycle during the acquisition stage.

We connect almost 4,000 new distribution transformers to our electricity network every year. In terms of raw materials, this signifies nearly 400 tonnes of aluminium, 1,500 tonnes of steel and over 600 tonnes of mineral oil. The new distribution transformers we use comply with the Ecodesign Directive.

The electric cables we use contain only aluminium as their conductive material. Annually, we acquire approximately 3,500 kilometres of cable which contains about 3,000 tonnes of aluminium.

We acquire the majority of the materials we use ourselves and some indirectly via our contractors. In 2017, we increased our direct acquisition of materials, especially for cables and transformers. This improves the management of the materials throughout their life cycle, as well as follow-up and reporting.

Energy efficiency

The majority of the energy used by Caruna consists of electricity network transmission and transformer losses. The transfer and distribution of electricity always involves some loss, and the network owner is responsible for it. We strive to enhance the energy-efficiency of our networks and to reduce losses.

We use CO2-free electricity to compensate for grid losses.

Since the autumn of 2015, all new distribution transformers used by Caruna are low-loss ECO transformers compliant with the updated EU Directive.

We use CO2-free (zero carbon dioxide emissions) electricity to compensate for grid losses. In 2017, we purchased 380 GWh of electricity to compensate for network losses.

In addition, the reserve power plants in our network area require small amounts of fuel. Our contractors procure the fuel needed.

Energy Efficiency Agreement

Energy efficiency is a key part of Caruna’s environmental responsibility and customer cooperation. We have been involved in the National Energy Efficiency Agreement and the Energy Conservation Agreement preceding it since the beginning of the agreement system in 1997. The previous agreement term closed at the end of 2016, and Caruna also acceded to the contract of the new agreement season 2017–2025.

Energy efficiency is a key part of Caruna’s environmental responsibility and customer cooperation.

We are committed to taking energy efficiency into account in all our internal operations and to make our own energy consumption more effective, especially when it comes to grid losses. Our extensive network improvement programme reduces transfer and distribution losses over the network. We also reduce losses through careful network planning, our choice of components and the optimisation of the basic connection state.

We have analysed the effects of Caruna’s investments on the electricity network’s losses. We estimate that, as a result of our electricity network improvement measures, the relative losses in the network have been reduced by roughly 1 GWh in 2017.

In addition, we are committed to increasing our customers’ awareness of their own energy consumption and the potential for making it more efficient, and in this way supporting our customers in their efforts to improve their energy efficiency. We offer them, for example, an energy monitoring service, energy efficiency counselling and guidance in getting started with generating their own electricity.

Own consumption of energy

Caruna’s own consumption of energy mainly consists of the electricity and heat energy used in our office buildings. The majority of our own energy consumption takes place at our premises on Upseerinkatu in Espoo where we moved in September 2015. In 2017, we consumed 2.1 GWh of electricity and 1.8 GWh of heat energy.

In our Upseerinkatu premises, the majority (nearly 75%) of the energy is used for cooling down the servers and the substation control room, as well as for cooling, heating and ventilating the rest of the building. Other significant energy consumption functions are water heating and lighting, for instance. The energy consumption of the restaurant operating in the building has not been taken into account in Caruna’s energy consumption.

In the Upseerinkatu offices, we use ground heat as well as district heating.

Own energy production

Caruna has two production sites for solar power whose main purpose is to collect first-hand experience of decentralised energy production.

At the end of 2015, we had 110 solar panels installed on the roof of our offices on Upseerinkatu. The nominal output of these solar panels is roughly 29 kWp. In 2017, their total energy production was roughly 24 MWh, which we utilised on the premises.

In addition, there are 119 solar panels on the roof of our primary substation in Keilaniemi, Espoo. In 2017, their total energy production was roughly 23 MWh. We used about 10.5 MWh of this at the substation and transferred the rest to our distribution network to compensate for network losses.

In 2017, we also utilised 0.15 GWh of ground heat in the heating and cooling of our premises.

Effects on climate

With our actions, Caruna contributes to the battle against climate change. We optimise our electricity network to meet the demands of the changing energy market and our customers and offer a flexible platform for various measures designed to facilitate more efficient energy consumption and the reduction of emissions.

We strive to boost our own operational processes by building electricity networks in a way that covers large systems, by increasing joint construction with other operators, such as municipalities and teleoperators, and by reducing the need for field work with the help of underground cables and network automation.

Greenhouse gases

Sulphur hexafluoride, or SF6, is a potent greenhouse gas, but also an excellent insulator in electrical devices. Due to the use of the gas, SF6-isolated devices are equipped with moisture protection, which decreases the risk of inadvertent electric shocks and enhances both the safety of the network and the occupational safety of our contractors.

We monitor all equipment for potential SF6 gas leaks and minimise the possibility of environmental impacts resulting from such leaks by systematic control, inspections and maintenance.

We monitor all equipment for potential SF6 gas leaks and minimise the possibility of environmental impacts resulting from such leaks by systematic control, inspections and maintenance. We also monitor the SF6 gas status of all equipment while carrying out regular inspections. Any gas leaks and doubts related to gas meters are documented and recorded. We keep a record of our SF6 gas balance and leaks, and report this data to the branch organisation Finnish Energy (Energiateollisuus ry) once a year. We require all contractors handling SF6 gas to hold the required qualifications.

In 2017, the quantity of SF6 gas in Caruna’s electricity network increased significantly due to the fact that, with new contracts on pad-mounted secondary substations, we began to use more and more entirely sealed, gas-insulated SF6 medium voltage switchgear. They are more reliable and safer to use than ever.

In 2017, the total quantity of SF6 gas in Caruna’s high voltage and medium voltage networks was approximately 14,400 kg. Of the 30,600 secondary substations in Caruna’s distribution network, roughly 2,700 contained SF6 gas. The amount of SF6 gas emitted into the atmosphere was 4.8 kg, representing 0.03% of the total quantity of the gas.

Responsible land use and biodiversity

Electricity networks have both a physical and visual impact on their environment. Considerable investments into weatherproof underground cable networks reduce the restrictions and harmful effects related to the use of land near electricity networks and free the land and forests for other uses. Landscapes and sceneries also improve as overhead cables are eliminated.

Underground cabling protects biodiversity and lessens the impact of electricity networks on plants and animals.

We strive to reconcile the needs and expectations expressed by various stakeholders, regarding the selection of power network routes and structures. Whenever possible, new electricity networks are built alongside roads and in public areas. Smooth collaboration with land owners, municipalities, ELY Centres, the National Board of Antiquities, environmental organisations and other stakeholders in all matters regarding land use is of primary importance.

Underground cabling protects biodiversity and lessens the impact of electricity networks on plants and animals. We also do our best to prevent the risk of bird collisions and electric shocks by installing marker balls on overhead lines and landing perches on poles.

We assess the impacts of our network improvement programmes on biodiversity right from the planning stage and when applying for the necessary licences.

Environmental damage

In our type of operations, a typical example of environmental damage can be leakage of transformer oil into the environment as a result of a damaged transformer. In Finland, more than half of all transformer damage is caused by lightning strike.

Oil collectors are installed under building and pad-mounted secondary substations and primary substations, to prevent oil leaking into the environment because of transformer damage. Pole-mounted transformers are susceptible to weather conditions and do not have integral oil collectors. Each pole transformer contains roughly 100 to 200 kg of mineral oil, but usually only a small amount of this would end up in the environment even if the transformer suffers damage.

In case of an accident, we clear up any oil leaks as soon as possible and verify the effectiveness of the purification process from soil samples. Information about oil leaks and purification process reports are submitted to the authorities; in this case to the local ELY Centre.

Information about oil leaks and purification process reports are submitted to the authorities.

In 2017, our electricity network suffered a total of 29 oil leaks, of which one was slightly over 100 kg in magnitude. There were no extensive oil leaks or environmental damage caused by oil leaks. The small number of oil leaks was the consequence of both favourable weather conditions and the diminishing number of open pole-mounted transformers, which are the result of our network improvement measures.

In 2016, we launched a renovation programme for pole-mounted transformers in groundwater areas with the target of minimising the risk of groundwater contamination caused by oil spills. We plan to replace all pole-mounted transformers in groundwater areas with pad-mounted secondary substations equipped with oil collectors. From 2016 to 2017, we removed roughly 600 pole-mounted transformers from groundwater areas. A larger share of dismantled old transformers than predicted will take place in the winter of 2018, which is why we fell behind our target level for 2017.

Contrary to our previous estimate, some of the work to renew pole-mounted transformers in groundwater areas will continue in 2019.​ This regards transformer renewals associated with the reliability of supply investments made in the overhead line network. The goal is to remove the remaining roughly 800 pole-mounted transformers in groundwater areas by the end of 2019.

Environmental goals

We intend to keep increasing our positive environmental impact, improving the energy and materials efficiency of our operations, decreasing any adverse effects on the environment and enhancing the recycling of used materials.

In 2018, we aim to significantly cut down the number of pole-mounted transformers in groundwater areas, both as part of our network improvement programme and our renovation programme for pole-mounted transformers in groundwater areas. The number of oil spills will fall as our network improvement programme progresses.

We will also strive to raise the recycling rate of dismantled networks.

We will also strive to raise the recycling rate of dismantled networks in collaboration with Kuusakoski. Our target is for Kuusakoski to process the dismantled material in 75% of all our projects in 2018.

Our key environmental goals for 2017 are recorded in the table on corporate responsibility goals and all our environmental goals are listed at the beginning of the chapter on the environment.

In order to achieve our environmental goals and succeed in reducing the environmental impacts of our operations, we train both our own employees and our contractors. Read more about training.