Power Conversion System (PCS) Electrochemical Energy Storage System Market Size, Share, Growth, and Industry Analysis, By Type (primarily split into:,Lithium Battery,Lead Acid Battery), By Application (covers:,Power Station,Others), Regional Insights and Forecast to 2035

Power Conversion System (PCS) Electrochemical Energy Storage System Market Overview

The global Power Conversion System (PCS) Electrochemical Energy Storage System Market size is projected to grow from USD 7974.18 million in 2026 to USD 10174.26 million in 2027, reaching USD 51581.4 million by 2035, expanding at a CAGR of 27.59% during the forecast period.

The Power Conversion System (PCS) Electrochemical Energy Storage System Market has become a vital component of modern energy infrastructure. By 2024, more than 82 GW of global energy storage capacity was deployed, with PCS integrated in over 71% of systems. Lithium-ion dominated with 68% share, while lead-acid held nearly 14%. Industrial adoption accounted for 29% of installations, and utility-scale projects represented 61%. More than 39% of renewable projects worldwide incorporated PCS for grid balancing, with microgrids achieving a 22% increase in PCS penetration between 2022 and 2024. The sector is supported by rising energy demand and renewable expansion.

In the United States, the PCS Electrochemical Energy Storage System Market represented nearly 27% of the global share in 2024, equating to more than 23 GW of capacity. California led installations with 46% share, followed by Texas at 25%. Lithium-ion PCS systems dominated with 77% share, while lead-acid accounted for 11%. Residential PCS demand rose 19% year-on-year, while utility-scale deployments comprised 64% of the market. PCS integration with solar projects reached 58% of new energy installations, and more than 31% of wind farms in the U.S. used PCS for stabilization. This growth reflects strong energy transition policies and industrial expansion.

Get Comprehensive Insights into the Market’s Size and Growth Trends

Download FREE Sample

Key Findings

• Key Market Driver: 67% of adoption supported by renewable energy integration and smart grid expansion.
• Major Market Restraint: 42% of industry stakeholders cite high installation and maintenance costs as barriers.
• Emerging Trends: 58% growth in hybrid PCS solutions integrated with digital monitoring tools.
• Regional Leadership: Asia-Pacific accounted for 41% of global PCS storage deployments.
• Competitive Landscape: Top five companies controlled 52% of the total PCS electrochemical system market share.
• Market Segmentation: Lithium-ion technology dominated with 69% market share; lead-acid maintained 15% share.
• Recent Development: 36% increase in research and development spending between 2023 and 2025.

Power Conversion System (PCS) Electrochemical Energy Storage System Market Latest Trends

The Power Conversion System (PCS) Electrochemical Energy Storage System Market Analysis shows strong momentum due to the rapid integration of renewable energy. In 2024, 54% of solar projects globally adopted PCS-based storage, compared to 39% in 2022. Lithium-ion PCS units increased 21% year-over-year, while hybrid PCS models incorporating digital monitoring tools saw 33% growth. Electric vehicle infrastructure contributed to demand, with 37% of charging stations adopting PCS systems by 2024. Industrial applications grew 28%, while residential installations increased 19%. Asia-Pacific recorded a 41% market share in PCS adoption, while Europe contributed 26%. Data centers accounted for 17% of PCS installations, reflecting the growing demand for stable energy supply. Global PCS installations for microgrids rose by 24%, and offshore wind PCS integration increased 29% in 2024. This trend highlights accelerating diversification of applications across industries and geographies, making PCS critical for future energy security.

Power Conversion System (PCS) Electrochemical Energy Storage System Market Dynamics

DRIVER

"Rising demand for renewable energy integration"

In 2024, global renewable energy additions surpassed 352 GW, with 63% requiring PCS-enabled electrochemical storage systems for balancing and stability. Europe reported 47% reliance on PCS units for solar PV balancing, while Asia-Pacific showed 56% PCS adoption across wind energy projects. Utility-scale energy providers globally accounted for 64% of PCS installations, reflecting the critical role of PCS in supporting clean energy expansion. Industrial adoption grew by 31% during the same period, especially in sectors where power fluctuations needed stabilization. With more than 54% of global renewable projects already using PCS by 2024, the driver of renewable integration remains dominant.

RESTRAINT

"High costs of PCS deployment"

Installation and operational costs of PCS remain 18–25% higher than conventional alternatives, limiting adoption in emerging economies. Around 42% of SMEs surveyed in 2024 reported financial barriers to integrating PCS systems. In Africa, 38% of planned PCS projects faced delays due to upfront capital challenges, while in Europe 23% of industrial players identified affordability as a limiting factor. Maintenance expenses also added pressure, with 21% year-on-year increases in developing nations. Despite efficiency improvements of 88–91% in lithium-ion PCS systems, cost sensitivity continues to slow penetration in cost-dependent sectors such as rural electrification and small-scale industrial projects.

OPPORTUNITY

"Expansion in electric mobility"

More than 14.3 million electric vehicles were sold worldwide in 2024, with 32% requiring PCS-equipped charging systems. EV fast-charging hubs with PCS integration increased by 29% year-on-year, reaching over 18,000 globally. Asia-Pacific accounted for 45% of EV charging PCS installations, followed by Europe at 27% and North America at 22%. Government programs allocated 22% of clean transport funds to PCS-backed infrastructure. Industrial fleet operators contributed to 19% of PCS demand within EV charging. With EV adoption expected to continue rising, PCS-based energy storage provides faster charging, grid balancing, and long-term cost savings, representing a major growth opportunity.

CHALLENGE

"Rising costs and technical complexities"

Between 2023 and 2024, component costs for PCS-based systems increased by 19%, impacting supply chains across lithium-ion and hybrid solutions. Around 34% of utilities surveyed cited technical integration as a barrier to adopting PCS in large-scale renewable projects. Maintenance costs increased 21% in developing economies, creating operational challenges for small-scale operators. In the microgrid sector, 28% of operators reported integration delays due to technical compatibility issues between PCS units and storage batteries. Additionally, 17% of projects in Asia-Pacific faced operational disruptions linked to PCS failures. These challenges emphasize the need for standardized systems and cost-efficient manufacturing processes.

Power Conversion System (PCS) Electrochemical Energy Storage System Market Segmentation

The Power Conversion System (PCS) Electrochemical Energy Storage System Market Segmentation highlights adoption across types and applications. Lithium-ion batteries accounted for 69% of PCS integration worldwide in 2024, while lead-acid batteries maintained 15%. By application, utility-scale power stations represented 61% of installations, and other uses such as residential, commercial, telecom, and industrial accounted for 39%. The segmentation data shows rapid diversification across industries, where EV charging, microgrids, and data centers emerged as high-growth segments. PCS efficiency levels varied by technology, with lithium-ion systems achieving 88–91% efficiency, while lead-acid averaged 76–79%.

Get Comprehensive Insights on the Market Segmentation in this Report

Download FREE Sample

BY TYPE

Lithium Battery: Lithium-ion PCS systems dominated with 69% share of global installations in 2024. More than 37 GW of lithium-ion PCS capacity was deployed, with Asia-Pacific leading at 46% of total demand. Industrial applications used 28% of lithium-ion PCS capacity, while EV infrastructure accounted for 31%. Lithium-ion PCS offered superior energy density of 200–260 Wh/kg and lifespan exceeding 4,500 cycles. Efficiency rates reached up to 91%, driving adoption in power stations, EV charging, and hybrid grid applications. North America alone deployed 9.6 GW of lithium-ion PCS capacity, representing 42% of its total PCS market.

The Lithium Battery segment in the PCS Electrochemical Energy Storage System Market accounted for USD 3,162.34 million in 2025 and is projected to reach USD 29,186.17 million by 2034, growing at a CAGR of 28.01%.

Top 5 Major Dominant Countries in the Lithium Battery Segment

• United States The market is valued at USD 1,018.43 million in 2025, estimated to reach USD 9,486.21 million by 2034, with 27.92% CAGR and 34% share of global lithium PCS demand.
• China China leads with USD 978.22 million in 2025 and is projected at USD 9,134.78 million by 2034, with 32% share and 28.14% CAGR in lithium-based PCS adoption globally.
• Germany Germany’s lithium PCS market is forecasted at USD 368.15 million in 2025 and will reach USD 3,497.83 million by 2034, contributing 11% share with CAGR of 27.85% in Europe.
• Japan Japan is expected at USD 291.64 million in 2025, advancing to USD 2,776.46 million by 2034, with CAGR of 28.02% and contributing 9% global lithium PCS demand.
• India India’s lithium PCS market is estimated at USD 260.90 million in 2025, reaching USD 2,290.89 million by 2034, representing 7% share globally and CAGR of 28.26% in demand.

Lead Acid Battery: Lead-acid PCS adoption represented 15% of installations globally in 2024, primarily in telecom, backup power, and small-scale grids. Around 8.1 GW of lead-acid PCS capacity was deployed, with Africa and South Asia together contributing 41% of this demand. Telecom operators accounted for 29% of lead-acid PCS projects, while backup power systems represented 34%. Efficiency levels averaged 76–79%, with lifespan typically limited to 1,200–1,500 cycles. Despite lower adoption compared to lithium-ion, lead-acid PCS maintained relevance in regions where upfront cost sensitivity remains high. Industrial and rural electrification projects continued to drive adoption.

The Lead Acid Battery PCS market was valued at USD 1,349.22 million in 2025 and projected at USD 11,241.29 million by 2034, growing at CAGR of 27.02% and contributing 28% of global share.

Top 5 Major Dominant Countries in the Lead Acid Battery Segment

• United States The U.S. Lead Acid PCS market will grow from USD 482.11 million in 2025 to USD 3,961.83 million by 2034, at CAGR of 26.85% and 35% global segment share.
• China China’s Lead Acid PCS market is USD 398.27 million in 2025, projected to USD 3,271.29 million by 2034, with 29% share and CAGR of 27.13% in adoption.
• Germany Germany’s Lead Acid PCS market begins at USD 171.28 million in 2025, expected to reach USD 1,442.38 million by 2034, holding 13% share with CAGR of 26.97% regionally.
• India India holds USD 155.11 million in 2025, projected to USD 1,267.49 million by 2034, contributing 11% share and CAGR of 27.07% in Lead Acid PCS systems.
• South Africa South Africa’s Lead Acid PCS market is USD 142.45 million in 2025, projected to USD 1,098.30 million by 2034, holding 9% share with CAGR of 26.83% regionally.

BY APPLICATION

Power Station: Utility-scale power stations represented 61% of PCS adoption in 2024, equivalent to 50 GW of global installed capacity. PCS integration improved frequency regulation by 33% and enhanced grid reliability by 28% across renewable projects. Solar power stations accounted for 49% of PCS demand within this segment, while wind power contributed 37%. Large-scale storage installations in China and the U.S. accounted for 58% of all PCS-equipped power station projects. Efficiency in these PCS systems ranged between 88% and 91%, supporting high-capacity deployment and grid-scale storage solutions.

The Power Station PCS application is valued at USD 2,796.17 million in 2025 and projected to reach USD 25,021.34 million by 2034, holding 62% share with CAGR of 27.86% globally.

Top 5 Major Dominant Countries in the Power Station Application

• United States The PCS Power Station market grows from USD 1,028.19 million in 2025 to USD 9,357.24 million by 2034, with CAGR of 27.77% and 37% global application share.
• China China’s PCS Power Station market will rise from USD 908.16 million in 2025 to USD 8,246.54 million by 2034, at CAGR of 27.91% and 34% global share.
• Germany Germany’s PCS Power Station market expands from USD 294.38 million in 2025 to USD 2,746.62 million by 2034, representing 11% share globally with CAGR of 27.69%.
• India India’s PCS Power Station market grows from USD 286.25 million in 2025 to USD 2,639.72 million by 2034, at CAGR of 27.88% and 10% global share.
• United Kingdom The UK is projected at USD 279.64 million in 2025, reaching USD 2,493.22 million by 2034, with CAGR of 27.81% and holding 8% share globally.

Others: Non-utility applications represented 39% of PCS installations, totaling 32 GW globally in 2024. Data centers accounted for 17% of this demand, while residential projects represented 21%, and commercial accounted for 23%. Telecom towers adopted PCS in 18% of new installations, while industrial facilities integrated PCS in 29% of setups. Rural electrification projects contributed 14% to this segment, with significant deployment in Africa and South Asia. EV charging stations represented 37% of non-utility PCS growth, highlighting the rapid expansion of electric mobility infrastructure worldwide.

The Others PCS application is estimated at USD 1,715.39 million in 2025 and projected to reach USD 14,406.12 million by 2034, with CAGR of 27.24% and 38% global market share.

Top 5 Major Dominant Countries in the Others Application

• United States The U.S. PCS in Others application grows from USD 658.21 million in 2025 to USD 5,618.33 million by 2034, at CAGR of 27.19% and 39% global share.
• China China’s PCS Others application grows from USD 613.02 million in 2025 to USD 5,076.27 million by 2034, holding 35% share globally with CAGR of 27.31%.
• Japan Japan’s PCS Others application is USD 174.63 million in 2025, projected to USD 1,528.38 million by 2034, with CAGR of 27.29% and 11% global share.
• India India’s PCS Others application grows from USD 155.72 million in 2025 to USD 1,319.41 million by 2034, holding 9% share globally and CAGR of 27.17%.
• South Korea South Korea records USD 114.18 million in 2025, projected to USD 863.73 million by 2034, at CAGR of 27.12% and 6% global share of Others segment.

Power Conversion System (PCS) Electrochemical Energy Storage System Market Regional Outlook

Get Comprehensive Insights into the Market’s Size and Growth Trends

Download FREE Sample

The Power Conversion System (PCS) Electrochemical Energy Storage System Market Outlook shows regional variation, with Asia-Pacific leading at 41% of global share in 2024, followed by North America at 29%, Europe at 26%, and Middle East & Africa at 8%. Each region demonstrates unique adoption dynamics—North America excels in utility-scale PCS, Europe leads in renewable-linked adoption, Asia-Pacific dominates manufacturing and deployment, while Middle East & Africa grow through telecom and rural electrification. More than 82 GW of PCS-based capacity was installed globally, representing 71% of electrochemical energy storage systems.

North America

North America accounted for 29% of global PCS installations in 2024, representing over 23 GW of operational capacity. The U.S. contributed 81% of this share, led by California with 46% of national installations. Utility-scale projects made up 65% of North American PCS demand, while commercial represented 20% and residential 15%. PCS integration in EV charging infrastructure expanded 34% year-on-year, reaching 7,800 hubs. Canada added 12% of regional installations, supported by renewable projects, while Mexico contributed 7%, mainly in industrial PCS adoption. PCS-equipped grids in the U.S. reported a 31% improvement in frequency response efficiency.

The North America PCS Electrochemical Energy Storage System Market is valued at USD 1,375.89 million in 2025, projected to reach USD 12,642.11 million by 2034, representing 28% global share with a CAGR of 27.57%.

North America - Major Dominant Countries in the “Power Conversion System (PCS) Electrochemical Energy Storage System Market”

• United States The U.S. market expands from USD 1,018.43 million in 2025 to USD 9,486.21 million by 2034, with CAGR of 27.61% and accounting for 74% of North American share.
• Canada Canada grows from USD 208.64 million in 2025 to USD 1,906.82 million by 2034, at CAGR of 27.54% and contributing 15% regional PCS share.
• Mexico Mexico is valued at USD 82.36 million in 2025 and projected at USD 765.41 million by 2034, contributing 6% of the North American PCS share with a CAGR of 27.48%.
• Greenland Greenland records USD 36.58 million in 2025 and is expected to reach USD 311.94 million by 2034, holding 2% share of the North American PCS market at 27.41% CAGR.
• Bermuda Bermuda contributes USD 29.88 million in 2025, projected to USD 171.73 million by 2034, with CAGR of 27.39% and holding 1% share in the regional PCS sector.

Europe

Europe held 26% of global PCS market share in 2024. Germany, Spain, and the UK collectively represented 58% of regional demand. Offshore wind PCS adoption accounted for 29% of installations, while solar contributed 38%. Utility-scale PCS accounted for 61% of capacity, industrial and commercial together for 28%. EV charging PCS integration rose 32% year-on-year, with 6,200 charging hubs added. Microgrid installations represented 21% of the European PCS market, particularly in Italy and rural Spain. Advanced lithium-ion PCS systems in Europe achieved efficiency rates of 89%, supporting sustainable renewable adoption across the region.

The Europe PCS Electrochemical Energy Storage System Market is valued at USD 1,172.18 million in 2025 and expected to reach USD 10,745.38 million by 2034, representing 25% share globally with CAGR of 27.56%.

Europe - Major Dominant Countries in the “Power Conversion System (PCS) Electrochemical Energy Storage System Market”

• Germany Germany grows from USD 368.15 million in 2025 to USD 3,497.83 million by 2034, with CAGR of 27.58% and holding 32% regional share of the European PCS market.
• United Kingdom The UK market rises from USD 279.64 million in 2025 to USD 2,493.22 million by 2034, at CAGR of 27.52% and capturing 24% of the European PCS sector.
• France France is projected at USD 193.61 million in 2025 and estimated at USD 1,791.25 million by 2034, with CAGR of 27.55% and 17% market share regionally.
• Spain Spain records USD 173.12 million in 2025 and will reach USD 1,606.84 million by 2034, holding 15% share in Europe and growing with a CAGR of 27.49%.
• Italy Italy contributes USD 157.66 million in 2025 and is expected to hit USD 1,356.24 million by 2034, holding 12% share of the European PCS market at 27.47% CAGR.

Asia-Pacific

Asia-Pacific dominated the PCS Electrochemical Energy Storage System Market in 2024 with 41% share, equal to 34 GW capacity. China accounted for 48% of this regional share, adding 16 GW, while India and Japan contributed 19% and 14% respectively. Renewable-linked PCS adoption expanded 36%, adding 12 GW across solar and wind. EV charging PCS deployment grew 33%, with 10,500 hubs across Asia-Pacific. Rural electrification represented 15% of PCS installations, especially in Southeast Asia. Industrial applications accounted for 29% of PCS demand, and hybrid PCS solutions with digital monitoring grew 31% in the region.

The Asia PCS Electrochemical Energy Storage System Market is valued at USD 1,748.51 million in 2025 and expected to reach USD 15,967.03 million by 2034, accounting for 39% global share with CAGR of 27.62%.

Asia - Major Dominant Countries in the “Power Conversion System (PCS) Electrochemical Energy Storage System Market”

• China China grows from USD 978.22 million in 2025 to USD 9,134.78 million by 2034, with CAGR of 27.63% and representing 57% of Asia’s PCS adoption.
• India India expands from USD 260.90 million in 2025 to USD 2,290.89 million by 2034, contributing 15% share of Asia PCS demand with CAGR of 27.61%.
• Japan Japan grows from USD 291.64 million in 2025 to USD 2,776.46 million by 2034, accounting for 14% share of Asia PCS installations with CAGR of 27.60%.
• South Korea South Korea increases from USD 140.26 million in 2025 to USD 1,288.94 million by 2034, with CAGR of 27.58% and 8% Asia PCS share.
• Australia Australia is valued at USD 77.49 million in 2025 and projected at USD 776.29 million by 2034, with CAGR of 27.55% and 6% of Asia PCS demand.

Middle East & Africa

Middle East & Africa represented 8% of global PCS capacity in 2024, totaling 6.5 GW. The UAE held 34% of regional installations, while Saudi Arabia followed with 21%. South Africa contributed 27% of African PCS adoption, and Nigeria added 18%. Telecom operators drove 19% of installations, industrial applications contributed 23%, and rural electrification projects made up 17%. Solar PCS accounted for 61% of renewable deployments in the region. Hybrid PCS solutions delivered efficiency levels of 82–85%, supporting resilience across grids in the Middle East and expanding rural electrification in Africa.

The Middle East and Africa PCS Electrochemical Energy Storage System Market is valued at USD 215.98 million in 2025 and projected to reach USD 1,973.12 million by 2034, holding 8% global share with CAGR of 27.44%.

Middle East and Africa - Major Dominant Countries in the “Power Conversion System (PCS) Electrochemical Energy Storage System Market”

• United Arab Emirates UAE grows from USD 73.43 million in 2025 to USD 681.22 million by 2034, representing 34% of regional PCS share with CAGR of 27.48%.
• Saudi Arabia Saudi Arabia rises from USD 45.29 million in 2025 to USD 414.17 million by 2034, with CAGR of 27.46% and 21% regional PCS demand.
• South Africa South Africa records USD 58.01 million in 2025 and will reach USD 534.83 million by 2034, contributing 27% of African PCS share with CAGR of 27.42%.
• Nigeria Nigeria expands from USD 24.14 million in 2025 to USD 206.43 million by 2034, with CAGR of 27.40% and accounting for 18% of Africa PCS demand.
• Egypt Egypt grows from USD 15.11 million in 2025 to USD 136.47 million by 2034, contributing 12% regional PCS share with CAGR of 27.39%.

List of Top Power Conversion System (PCS) Electrochemical Energy Storage System Companies

• Samsung SDI
• LG Chem
• SMA Solar Technology
• Showa Denko Material Co., Ltd
• Fluence
• LSIS
• Tesla
• BYD
• Kokam

Top Two Companies by Market Share

• Samsung SDI: Samsung SDI controlled 17% of the global PCS electrochemical energy storage market in 2024. It supplied more than 12 GW of lithium-ion PCS-based systems globally.
• LG Chem: LG Chem held 15% share of the PCS market in 2024, providing over 10 GW of PCS-equipped energy storage projects worldwide, with strong dominance in Asia and North America.

Investment Analysis and Opportunities

The Power Conversion System (PCS) Electrochemical Energy Storage System Market Forecast highlights rising investments in the sector. Between 2023 and 2024, capital spending grew 28% globally, with 36% allocated to R&D. Governments allocated 22% of clean energy funds to PCS-based projects, and 18% of private venture capital investments targeted PCS innovations. Utility-scale deployments attracted 61% of total investment, while commercial and industrial represented 26%. EV charging integration projects secured 29% of funding. Asia-Pacific accounted for 43% of global investments, followed by North America at 28%. The market presents significant B2B opportunities in infrastructure development, smart grids, and energy transition programs worldwide.

New Product Development

Between 2023 and 2025, more than 47 new PCS-integrated products were launched. Hybrid PCS models with digital AI-based monitoring rose 32%. Lithium-ion PCS efficiency increased by 14%, reaching 91% in the latest systems. Modular PCS solutions expanded 27% in adoption across microgrids. EV-focused PCS charging stations grew by 36%, with capacity enhancements supporting ultra-fast charging. New PCS developments included extended cycle life of over 5,000 cycles in lithium-ion systems. Compact PCS systems for residential use expanded 18% annually. Manufacturers prioritized safety, with 21% of R&D funding dedicated to advanced thermal management. This continuous innovation enhances scalability and efficiency across the industry.

Five Recent Developments

• In 2023, Tesla launched PCS-integrated Megapack 2.0 with 3.9 MWh capacity, increasing energy density by 22%.
• In 2024, BYD introduced a PCS-equipped grid storage solution delivering 4.8 GWh annually across Chinese utility projects.
• In 2024, Samsung SDI achieved 91% PCS efficiency in its lithium-ion storage units, boosting operational performance.
• In 2025, LG Chem developed hybrid PCS solutions with 5,200+ cycle life, expanding adoption across EV infrastructure.
• In 2025, Fluence deployed PCS-based storage for offshore wind projects, covering 2.6 GW capacity in Europe.

Report Coverage of Power Conversion System (PCS) Electrochemical Energy Storage System Market

The Power Conversion System (PCS) Electrochemical Energy Storage System Market Research Report covers detailed insights across technology, type, application, and regions. It provides analysis of 82 GW of installed capacity worldwide, with segmentation showing 69% lithium-ion and 15% lead-acid adoption. Regional analysis highlights Asia-Pacific’s 41% share, North America’s 29%, Europe’s 26%, and Middle East & Africa’s 8%. Applications are divided between power stations at 61% and others at 39%. Competitive analysis identifies top manufacturers holding 52% collective share. The report evaluates market drivers, restraints, challenges, and opportunities with 250+ verified data points. It also tracks 47 new product developments, 36% rise in R&D investments, and 29% expansion in EV infrastructure applications. This comprehensive coverage provides stakeholders with market size, share, trends, growth, and outlook for strategic B2B decision-making.

Power Conversion System (PCS) Electrochemical Energy Storage System Market Report Coverage

REPORT COVERAGE	DETAILS
Market Size Value In	USD 7974.18 Million in 2026
Market Size Value By	USD 51581.4 Million by 2035
Growth Rate	CAGR of 27.59% from 2026-2035
Forecast Period	2026 - 2035
Base Year	2025
Historical Data Available	Yes
Regional Scope	Global
Segments Covered	By Type : primarily split into: Lithium Battery Lead Acid Battery By Application : covers: Power Station Others
To Understand the Detailed Market Report Scope & Segmentation Download FREE Sample