What SDN does

SDN (에스디엔 주식회사, formerly Seoul Marine), founded in March 1994 and headquartered in Seongnam, South Korea, is a diversified clean energy and marine solutions company operating three distinct business divisions under a single corporate entity. The Photovoltaics Business Division manufactures the proprietary SUNDAY-branded solar module family—bifacial glass-to-glass (GtG) PERC M10 modules at 550-600W, the 600W SUNDAY 10+ Wave (the only KS-certified bifacial floating module in Korea at 21.46% efficiency), and the recent 610W SUNDAY A 10 ABC and 620W SUNDAY S 10+ N-type TOPCon modules—from Gwangju (300MW) and Gangjin (550-600MW) factories, with a 1GW H3 TOPCon/tandem line targeted by 2025. The Engine Business Division is the exclusive domestic distributor for Honda Marine outboard engines in South Korea via a nationwide authorized dealer network. The Shipbuilding Business Division manufactures custom aluminum vessels (work boats, leisure boats, special-purpose craft) incorporating patented solar-hybrid ESS and air-pocket buoyancy systems.

The company generates revenue across five streams: solar module hardware sales to domestic EPC companies and international buyers; Honda outboard engine and parts distribution through the dealer network; solar power plant development and operation (flagship: Bulgaria 42MW, jointly with Korea South-East Power, fully divested via capital reduction in June 2022); custom aluminum vessel sales to fishing cooperatives, maritime businesses, and government agencies; and ODA/government-aid project participation (flagship: ₩166 billion Colombia Sucre rural electrification project with KOTEA). Major customers include Korea Expressway Corporation, Korea Industrial Technology Promotion Agency (KOTEA), Korea South-East Power, domestic major EPC companies, and Honda Motor Co., Ltd. The company recorded FY2023 revenue of ₩75,128M standalone / ₩75,692M consolidated, employs 51-100 people, and is led by founder-Chairman Choi Ki-hyuk (최기혁). Distribution runs through direct project sales for solar/EPC/government contracts, a dealer channel for Honda Marine, and direct inquiry-based sales for vessel manufacturing, with international ambitions into South America, Central Asia, and Africa via TUV certification being pursued.

Name

SDN

Legal name

에스디엔 주식회사

Website

https://sdn-i.com

Company type

Private

Founded year

1994

Operating status

Operating

Headcount range

51–100 employees

Short description

SDN is a South Korean clean energy and marine solutions company operating three divisions: SUNDAY-brand solar PV module manufacturing (TOPCon, ABC, bifacial GtG) for domestic EPCs and ODA projects, exclusive domestic distribution of Honda Marine outboard engines, and custom aluminum shipbuilding with patented solar-hybrid ESS systems.

Ownership category

akta.pro rank

Product category

Solar Photovoltaic Modules

NAICS

Engine, Turbine, and Power Transmission Equipment Manufacturing (3336), Motor and Generator Manufacturing (335312)

SIC

Electronic Components, Nec (3679), Motors & Generators (3621)

akta.pro primary industry

Solar PV Module & Cell Manufacturing (Crystalline, Thin-Film) (EUAMAHAA)

akta.pro secondary industries

Solar Inverters, Power Optimizers & MLPE Manufacturing (EUAMAHAB), Solar EPC & Construction (Utility-Scale, Rooftop, Balance of System) (EUAMABAB), Electric & Hybrid Leisure Craft Manufacturing (IMAJAEAK), Solar Plant Components Supply & Manufacturing (Modules, Cells, Wafers, Mirrors, Heliostats) (EUACAGAK)

Keywords

• Photovoltaic solar modules
• Aluminum shipbuilding
• Marine outboard engines
• Renewable energy systems
• Bifacial solar cells

Headquarters

HQ city

Seongnam

HQ country

South Korea

HQ region

Asia

Offices4 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

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

Revenue model

1. Solar Module Manufacturing and Sales: Production and sale of proprietary SUNDAY brand photovoltaic modules (550W-650W range), including bifacial GtG modules, TOPCon N-type modules, ABC back-contact modules, and water-mounted modules. Revenue recognized upon product shipment. Target customers include domestic EPC companies, large-scale solar project developers, and international buyers. Production capacity at Gwangju factory: 300MW annually.
2. Honda Marine Outboard Engine Distribution: Exclusive domestic distributor (한국총판) for Honda outboard marine engines in South Korea. Revenue from engine sales, genuine parts, and accessories through a nationwide dealer network.
3. Solar Power Plant Development and Operation: Development, investment, and operation of solar power generation plants. Includes domestic projects and overseas projects such as the 42MW Bulgaria solar project. Revenue from power generation, project development fees, and equity returns.
4. Aluminum Ship Manufacturing: Custom design and manufacturing of aluminum vessels including fishing boats, leisure boats, special vessels, and small-scale marine facilities for domestic fishing cooperatives, maritime businesses, and government agencies.
5. ODA and Government Aid Projects: Participation in government-led ODA (Official Development Assistance) energy cooperation projects, such as the Colombia Sucre rural housing self-power generation system project worth 166 billion KRW.

Go-to-market motion1 record

Distribution channels4 records

Marketing channels5 records

Core offering

SDN manufactures the proprietary SUNDAY brand of photovoltaic solar modules in 550W–650W output ranges using bifacial glass-to-glass (GtG), N-type TOPCon, and ABC back-contact cell technologies, and sells solar inverters and complete PV systems. The Engine Business Division is the exclusive South Korean distributor of Honda Marine 4-stroke outboard engines (15HP–350HP), genuine parts, and accessories via a nationwide dealer network. The Shipbuilding Business Division custom-designs and manufactures aluminum vessels including fishing boats, leisure boats, and special-purpose ships, incorporating patented hybrid solar-ESS propulsion technology.

Product overview

SDN is a diversified Korean technology company with three main business divisions. The Photovoltaics Business Division produces the 'Sunday' series of solar modules including bifacial glass-to-glass (GtG) technology, N-TYPE TOPCon modules, and ABC back-contact modules, along with solar inverters and complete renewable energy systems. The Engine Business Division serves as the domestic distributor for Honda marine outboard motors (4-stroke engines ranging from 15HP to 350HP) and related marine accessories including SOLAS propellers and hydraulic systems. The Shipbuilding Business Division manufactures aluminum boats including work boats (2-10 ton), leisure boats, and special-purpose vessels, incorporating hybrid solar-ESS technology and electric propulsion systems. The company also operates power plants and provides ODA international development projects.

Differentiator

Problem solved

Functional benefit

Brands

• SUNDAY: Solar photovoltaic module brand including Sunday 10, Sunday 10+, Sunday A 10, Sunday S 10+ series

Products and services

• SUNDAY 10 (550W GtG Bifacial Solar Module) 550W bifacial glass-to-glass photovoltaic solar module with 21.28% efficiency that absorbs light on both front and back surfaces, increasing power generation by 10% or more depending on installation location. For domestic EPC companies, solar project developers, and international buyers.
• SUNDAY 10+ (600W GtG Bifacial Solar Module) 600W dual-glass bifacial solar module achieving 21.46% efficiency—the industry's highest output for dual-glass modules—with 30-year warranty, KS and carbon certification. For large-scale solar projects and EPC companies.
• SUNDAY 10+ Wave (600W Bifacial Dual-Glass Floating Solar Module) 600W bifacial dual-glass floating (water-mounted) solar module with 21.46% efficiency, KS and carbon certified. Lead-free compliant, resistant to load, high temperature/humidity, durability, abrasion, and rear-glass salt-corrosion resistance. The only domestic bifacial dual-glass water-mounted solar module in Korea.
• SUNDAY S 10+ (620W N-Type TOPCon Bifacial Solar Module) 620W N-type TOPCon bifacial solar module with enhanced PID resistance, high durability sealing on front and rear surfaces, and carbon certification Grade 1/2 options. For large-scale solar projects requiring next-generation cell efficiency.
• SUNDAY A 10 (610W ABC All-Back Contact Monocrystalline Solar Module) 610W ABC back-contact monocrystalline solar module optimized for rooftop installations, using Aiko Solar cells. Provides high efficiency, minimized partial shading and cracking, lower hot-spot degradation, and a -0.26% temperature coefficient. For rooftop solar installers and commercial building owners.
• Solar Inverters (태양광 인버터) Solar inverters for converting DC power from photovoltaic modules to AC power suitable for grid connection. For solar power system integrators and EPC contractors.
• Honda Marine 4-Stroke Outboard Engines Honda outboard marine engines distributed exclusively in South Korea by SDN, covering 15HP to 350HP outputs across models including BF350, BF250D, BF225D, BF200D, BF175D, BF150D, BF135D, BF115J, BF100AK1, BF90DK5, BF80AK1, BF60AK1, BF50DK4, BF20DK2, and BF15DK2. Distributed through SDN's nationwide authorized dealer network with genuine parts, accessories, warranty service, and technical support.
• Honda Marine Accessories and SOLAS Propellers Marine accessories including SOLAS propellers (exclusive domestic sales rights), hydraulic handles, fuel tanks, water separators, and marine boats distributed alongside Honda outboard engines. For boat owners, dealers, and service centers.
• Aluminum Leisure Boats (알루미늄 레저선) Custom aluminum leisure boats including diving boats, water ski boats, pontoon boats, and fishing boats ranging from 0.6 to 7 tons. For leisure operators, recreational fishing businesses, and individual boat buyers.
• Aluminum Special-Purpose Ships (알루미늄 특수선) Special-purpose aluminum vessels including 32-passenger ferries, patient transport vessels, rescue and exploration boats, high-speed patrol boats, administrative vessels, and Han River cleaning boats. For government agencies, public safety authorities, and maritime transport operators.
• Aluminum Work Boats (알루미늄 작업선) Aluminum work boats designed for fishing operations, seaweed harvesting, and aquaculture management, ranging from under 2 tons to under 10 tons. Built with SDN's patented Air Pocket buoyancy structure and hybrid solar-ESS charging system. For fishing cooperatives, commercial fishermen, and aquaculture operators.
• Renewable Energy Power Systems (신재생 발전 시스템) Complete renewable energy power generation systems including design, installation, and integration of solar PV systems (modules, inverters, ESS) for utility-scale, commercial, and specialized installations. For solar project developers, EPC contractors, and government energy projects.
• Solar Power Plant Operation and Maintenance Services Operation and maintenance services for solar power plants to ensure optimal long-term performance, including monitoring, preventive maintenance, and performance optimization. For owners and operators of solar power generation facilities.
• ODA International Development Project Services International Official Development Assistance (ODA) project delivery including design, procurement, and installation of standalone solar power systems for energy-vulnerable communities in developing countries. Flagship project: ₩166 billion Colombia Sucre rural housing self-power generation system serving approximately 2,000 households. For government ODA implementing agencies (e.g., KOTEA).

Quantifiable outcome

• Bifacial GtG modules increase power generation by 10%+ through rear-surface light absorption
• +4 more outcomes

Named customers4 records

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature8 records

Partnerships

Six partnerships are on record, tiered major, minor and core.

• Aiko SolarmajorTechnology or Integration · 1 December 2022Technology partnership for SUNDAY A 10 product using Aiko Solar's ABC (All-Back Contact) monocrystalline cells. SDN sources Aiko Solar cells for its premium 610W ABC module product which achieved KS certification in June 2024.
• Korea Industrial Technology Promotion Agency (한국산업기술진흥원)majorImplementation/ SI/ Consulting Partner · 12 May 2022SDN selected as the lead implementing company for the Colombia Sucre rural housing self-power generation ODA project promoted by KOTEA. Total project value is ₩166 billion, targeting approximately 2,000 energy-vulnerable households in Sucre Department, Colombia. SDN designs, procures, and installs standalone solar power systems.
• Korea Expressway Corporation (한국도로공사)minorOthers · 1 January 2022₩63.4 billion electrical works supply contract for Expressway Route 29 (Sejong-Pocheon), Anseong-Guri section. SDN supplies electrical works materials for highway infrastructure.
• Jeollanam-do and Gangjin-gun / Jeonnam Development Corporation (전라남도, 강진군, 전남개발공사)majorStrategic or Co-development Partner · 14 November 2018Investment agreement signed for SDN's investment in the Gangjin Industrial Complex. SDN established its H2 factory in Gangjin for production of carbon certification Grade 1 and 2 bifacial GtG modules. The agreement also supports SDN's shipbuilding research institute presence in Gangjin.
• Korea South-East Power Co., Ltd. (한국남동발전)coreStrategic or Co-development Partner · 15 March 201150-50 joint venture partner in the Bulgaria 42MW solar power project. Both SDN and Korea South-East Power co-invested in the Bulgarian project entity ASM, RES. The project was financed with support from NH Investment & Securities and Hanzo Asset Management (₩200 billion advance investment MOU). Both partners shared equally in the ₩27.9 billion capital reduction recovery. The project was financed through Unicredit, a South European major bank, with long-term low-interest EU Taxonomy-compliant loans.
• Honda Motor Co., Ltd. (혼다마린)coreChannel Partner/ Reseller/ Distributor · 1 March 1994Since March 1994, SDN (originally Seoul Marine) has been the exclusive domestic distributor (한국총판) for Honda outboard marine engines in South Korea. This exclusive partnership covers engine sales, genuine parts distribution, technical support, and warranty services. SDN also holds exclusive domestic sales rights for SOLAS propellers and distributes Honda Marine products through a nationwide authorized dealer network. The partnership has been maintained for over 30 years.

Scale indicators10 records

Recent moves9 records

Expansion highlights6 records

Direct peers

• Hyundai Energy Solutions: Korean solar module manufacturer (subsidiary of Hyundai Heavy Industries) producing crystalline-silicon PV modules for utility, commercial, and residential markets. Directly comparable to SDN in technology (PERC, bifacial), customer base (Korean EPCs and developers), and market positioning (domestic Korean modules competing with Chinese imports).
• Hanwha Q Cells: One of the world's largest solar module manufacturers headquartered in Seoul, Korea. Directly comparable to SDN as a Korean crystalline-silicon module maker with domestic manufacturing, serving overlapping EPC and rooftop customer segments in the Korean market.
• Shinsung E&G: Korean solar module and EPC company with bifacial and high-efficiency product lines. Directly comparable as a Korean mid-tier module manufacturer targeting the same domestic EPC customers and competing for the same Korean utility-scale and rooftop projects.

Others

• SolarEdge Technologies: Global leader in solar inverters, power optimizers, and module-level electronics. Comparable as an adjacent technology provider in the solar PV value chain where SDN also sells solar inverters; not a direct module competitor but operates in overlapping customer segments (Korean and global EPCs).

Broad incumbents

• LONGi Green Energy: World's largest monocrystalline silicon wafer and module producer with extensive TOPCon and HPBC product portfolio. Comparable as a crystalline-silicon module competitor across all of SDN's target technologies (PERC, TOPCon, back-contact), though at a fundamentally different scale and global footprint.
• JA Solar: Major Chinese crystalline-silicon module and cell manufacturer with TOPCon and bifacial product lines targeting global utility and C&I markets. Comparable in module technology stack (TOPCon, PERC, bifacial) and overlapping Korean market presence through EPC relationships.
• JinkoSolar: Global top-tier crystalline-silicon module manufacturer with TOPCon and bifacial product lines serving utility-scale and distributed generation markets. Comparable product technology overlap with SDN's SUNDAY series, and a key cost benchmark for Korean EPC procurement decisions.
• Canadian Solar: Global solar module manufacturer with TOPCon and bifacial crystalline product lines plus project development arm. Comparable to SDN across both module manufacturing and downstream utility-scale solar project development (similar to SDN's Bulgaria model).
• Trina Solar: Global top-3 crystalline-silicon solar module manufacturer with multi-tens-of-GW capacity and TOPCon/PERC product lines. Comparable to SDN as a competing module manufacturer, but vastly larger scale and globally established brand — represents the cost-competitive incumbent SDN competes against in Korean and export markets.
• First Solar: Leading global thin-film (CdTe) solar module manufacturer focused on utility-scale projects. Broader incumbent in solar module manufacturing; comparable as a competing module supplier for large-scale solar developers, though using a different cell technology than SDN's crystalline-silicon focus.

Market position

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

Compliance4 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles8 records

Subsidiaries1 record

Funding overview

Funding rounds

Investors

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 SDN