Zero Terrain

What Zero Terrain does

Zero Terrain (operating through its Estonian legal entity Energiasalv Pakri OÜ) is an energy technology company developing underground pumped hydro storage (UPHS) systems. Founded in 2009 and headquartered in Tallinn with operational roots in Paldiski, the company has spent over 15 years engineering a novel geotechnical method that places lower reservoirs approximately 750 meters underground and uses seawater as the working fluid, enabling pumped hydro storage to be deployed on flat terrain anywhere in the world — a structural departure from conventional pumped hydro, which is limited to mountainous regions. The flagship implementation is Energiasalv Paldiski, a 500 MW facility designed to store up to 15 GWh of renewable energy (30-hour discharge at full power) by pumping water between underground reservoirs and Paldiski Bay, with 80% round-trip efficiency and a 100-year design lifespan.

The technology platform is modular, with stated power scalability from 500 MW to 2,000 MW and storage durations from 6 to 30 hours, and includes a high-value byproduct stream: roughly 38 million tonnes of crystalline gneiss excavated during construction, which the company markets as a premium road construction aggregate with 5–6 times the abrasion resistance of limestone. The Paldiski project has held EU Project of Common Interest (PCI) status since 2013, is included in the ENTSO-E 10-year network development plan, and has completed permitting including a building permit; construction is scheduled to begin in 2026, with initial operational readiness in 2032 (6 GWh) and full 15 GWh capacity in 2038.

The business model is B2B infrastructure with three revenue streams: energy storage services (selling stored renewable electricity back to the grid), gneiss aggregate sales, and technology licensing for international deployments. The target customer base is national utilities and grid operators (primary), energy-intensive industrial facilities and data centers, and national governments pursuing renewable transition and energy security. Zero Terrain is currently pre-revenue, backed by five institutional investors (Sunly, Alexela, Combiwood, Warmeston, Vool) and supported by an advisory consortium including KPMG (financial advisor), Roland Berger (risk), Fichtner and Norconsult (technical due diligence), Sorainen and COBALT (legal), Thema Consulting (market study), Civitta (life-cycle assessment), and Miltton (government communications). The €1 billion Paldiski project anchors the commercial pipeline, with global replication intended across Europe, Asia (Vietnam operations already seeded), the Middle East, Africa, and the Americas.

Name

Zero Terrain

Legal name

Energiasalv Pakri OÜ

Website

https://zeroterrain.com

Company type

Private

Founded year

2009

Operating status

Operating

Headcount range

11–50 employees

Short description

Zero Terrain is an Estonian energy technology company developing underground pumped hydro storage for global licensing. Its flagship 500 MW Energiasalv Paldiski project stores renewable energy using 750m-deep underground reservoirs, serving utilities, governments, and industrial energy users.

Ownership category

akta.pro rank

Product category

Pumped Hydro Energy Storage Infrastructure

NAICS

Hydroelectric Power Generation (221111)

SIC

Cogeneration Services & Small Power Producers (4991)

akta.pro primary industry

Pumped Storage Hydropower (PSH) (New Build, Expansion, Conversions) (EUAMADAJ)

akta.pro secondary industries

Geologic & Underground Energy Storage (CAES Caverns, Hydrogen Caverns, Reservoir-Based) (EUAFADAF), Hydropower Plant Development & Permitting (Greenfield/Brownfield) (EUACAEAE), Hydropower Grid Services & Dispatch Optimization (Ancillary Services, Scheduling) (EUAMADAH), Hydropower EPC & Construction (Civil Works, Electromechanical) (EUACAEAF)

Keywords

• Underground pumped hydro
• Long duration energy storage
• Grid scale storage
• Renewable energy storage
• Pumped hydro technology

Headquarters

HQ city

Paldiski

HQ country

Estonia

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Infrastructure, Technology or R&D, Personnel, Operations, Marketing or Sales

Revenue model

1. Energy Storage Services: Zero Terrain generates revenue through providing large-scale energy storage infrastructure services. The Paldiski facility (Energiasalv) stores renewable energy when surplus exists and releases it during peak demand, selling electricity back to the grid. The facility can deliver 15 million kWh over a 30-hour cycle, serving as a grid balancing asset.
2. Gneiss Aggregate Sales: Revenue generated from the sale of approximately 38 million tonnes of crystalline gneiss aggregate extracted during construction of underground reservoirs. This high-quality construction material replaces imported igneous aggregates and domestic limestone, creating additional income stream.
3. Technology Licensing: Zero Terrain's modular underground pumped hydro technology can be licensed for deployment globally across Europe, Asia, Middle East, Africa, and the Americas, near industries, urban centers, or renewable parks. The company develops projects internationally as a Nordic energy technology company.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels7 records

Core offering

Zero Terrain develops and deploys Underground Pumped Hydro Storage (UPHS) technology that locates upper and lower reservoirs underground, enabling pumped hydro energy storage on flat terrain where conventional pumped hydro is not feasible. Its flagship reference project is Energiasalv Paldiski, a planned 500 MW underground pumped hydro storage facility in Estonia targeting long-duration grid-scale energy storage. The company offers modular configurations from 500 MW to 2,000 MW with 6 to 30 hours of storage, and licenses the technology for deployment in additional geographies.

Product overview

Zero Terrain operates as an energy storage infrastructure company offering its proprietary Underground Pumped Hydro Storage (UPHS) technology as the core product. The flagship implementation is the Energiasalv Paldiski project in Estonia—a 500 MW underground battery that stores renewable energy by pumping water between underground reservoirs and Paldiski Bay. The technology can be deployed on flat terrain globally, differentiating it from traditional pumped hydro that requires mountainous topography. As a byproduct of construction, the company produces and sells GNEISS aggregate material for road construction. The company is structured around a technology platform and a flagship infrastructure project, with modularity allowing power scaling from 500MW to 2000MW and storage duration from 6 to 30 hours.

Differentiator

Problem solved

Functional benefit

Brands

• Energiasalv: 500MW underground pumped hydro energy storage facility to be built in Paldiski, Estonia. A sub-brand/product line under Zero Terrain for long-duration energy storage solutions.

Products and services

• Underground Pumped Hydro Storage (UPHS) Technology Proprietary technology platform that locates upper and lower reservoirs underground, enabling pumped hydro energy storage on flat terrain where conventional pumped hydro is not feasible. Sold/licensed to project developers and infrastructure partners for deployment in additional geographies.
• Energiasalv Paldiski (500 MW Underground Pumped Hydro Storage Facility) Flagship 500 MW underground pumped hydro storage facility developed under legal entity Energiasalv Pakri OÜ in Paldiski, Estonia. Provides long-duration grid-scale energy storage to balance renewables and support grid stability. Configured modularly from 500 MW to 2,000 MW with 6 to 30 hours of storage capacity.
• GNEISS Aggregate (Construction Byproduct) Crushed gneiss rock generated as a byproduct of underground reservoir excavation, sold commercially to partially offset construction costs of UPHS projects.

Quantifiable outcome

• Reduces peak electricity prices by €131 million annually for Estonian consumers
• +4 more outcomes

Segments3 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Twelve partnerships are on record, tiered minor.

• FichtnerminorImplementation/ SI/ Consulting PartnerLeading independent engineering consultancy that provided geological investigations, risk analyses, and Front-End-Engineering-Design (FEED) report for the project.
• Roland BergerminorImplementation/ SI/ Consulting PartnerInternational management consultancy that provided detailed risk assessment and mitigation plan to secure project financing.
• Thema ConsultingminorImplementation/ SI/ Consulting PartnerLeading energy sector consultancy that provided the project's price impact assessment and technical feasibility studies, including the Baltic Power Market Study.
• CivittaminorImplementation/ SI/ Consulting PartnerLeading consultancy in CEE & Nordics that provided life cycle assessment report studying the project's potential carbon footprint and environmental impact.
• KPMGminorImplementation/ SI/ Consulting PartnerInternational corporate finance advisory serving as main financial advisor, responsible for leading revenue guarantee impact assessment, ESaaS contracting, and financial modelling.
• Ernst & YoungminorImplementation/ SI/ Consulting PartnerAssisted Energiasalv with preliminary financial model development for the project.
• SorainenminorImplementation/ SI/ Consulting PartnerInternational business law firm serving as main legal advisor on the project, supporting the permitting process and other general legal topics.
• NorconsultminorImplementation/ SI/ Consulting PartnerLeading Nordic multidisciplinary consultancy responsible for preparing independent technical due diligence report for investors.
• MilttonminorImplementation/ SI/ Consulting PartnerLeading Nordic communications advisory responsible for advising strategic communication with governmental institutions.
• COBALTminorImplementation/ SI/ Consulting PartnerOne of the leading legal service providers in the Baltics with over 250 professionals across Estonia, Latvia, and Lithuania.
• Mike McWilliamsminorStrategic or Co-development PartnerHydropower specialist with 45+ years of international experience serving on the Zero Terrain Global Advisory Board. Authored independent report on global need for underground pumped storage hydro.
• TalTech (Tallinn University of Technology)minorStrategic or Co-development PartnerConducted studies assessing the benefits of gneiss used as road construction aggregates in the pumped hydro storage project, demonstrating superior durability compared to limestone.

Scale indicators10 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• Hydrostor: Canadian developer of Advanced Compressed Air Energy Storage (A-CAES) targeting long-duration grid storage of similar duration to Zero Terrain's UPHS. Hydrostor is the closest analog as a privately funded LDES infrastructure developer with utility-scale projects and similar commercial timelines.
• Highview Power: UK-based developer of Liquid Air Energy Storage (LAES) for long-duration grid-scale applications. Directly comparable to Zero Terrain as a long-duration storage infrastructure company competing for the same utility customers and policy support in Europe.
• Energy Vault: Listed (NYSE: NRGV) gravity-based and hybrid LDES developer with commercial deployments and a similar target customer base of utilities and grid operators. Closely comparable as a publicly visible competitor in the long-duration storage infrastructure space.
• Form Energy: US iron-air battery developer targeting 100+ hour grid storage at low cost. Directly comparable as a long-duration storage technology company with utility-scale pilots, competing for the same energy storage procurement contracts.

Emerging players

• Quidnet Energy: US-based developer of Geomechanical Pumped Storage (GPS), which like UPHS stores energy by pumping water underground using subsurface geology. Highly comparable technology concept — both leverage subsurface reservoirs to enable pumped storage on flat terrain.
• Malta Inc. Developer of pumped heat energy storage (PHES) for grid-scale long-duration applications backed by Breakthrough Energy Ventures. Comparable as an emerging long-duration storage technology company targeting similar utility customers and duration profiles.
• Corre Energy: Norwegian-headquartered (with Nordic presence) compressed air energy storage developer with European project pipeline. Relevant as a regional LDES peer competing for similar Nordic and European utility customers.

Broad incumbents

• Voith Hydro: Global incumbent supplier of turbines, generators, and pumped hydro equipment with a broad hydropower portfolio. Relevant as a potential EPC partner or competitor for UPHS deployments and as a comparable infrastructure-scale hydropower player.
• ANDRITZ Hydro: One of the world's largest hydropower equipment suppliers, building turbines, pumps, and electromechanical systems for conventional and pumped hydro plants. Comparable as a major incumbent in the broader pumped hydro ecosystem that UPHS may partner with or compete against.
• GE Vernova (Hydro Solutions): Global incumbent in hydropower turbines and pumped storage equipment through its Hydro Solutions business. Comparable as a large established player whose pumped hydro technology overlaps with Zero Terrain's UPHS offerings and serves the same utility market.

Market position

Strengths1 record

Weaknesses1 record

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• Instagraminstagram.com/zeroterrain/?igsh=dG5zYXc0eWt5cHNx
• Facebookfacebook.com/energiasalv
• LinkedInlinkedin.com/company/zeroterrain

Revenue estimate

Valuation estimate

Number of profiles

Profiles9 records

Funding overview

Funding rounds1 record

Investors1 record

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Zero Terrain