Repurposing Waste Automotive Turbochargers for Low-Head Pico-Hydropower: Experimental Performance and Engineering Insights

Low-cost pico-hydropower systems face constraints when conventional turbines are expensive or difficult to obtain. The reviewed study examines whether a waste automotive turbocharger can be repurposed as a hydro turbine under low-head conditions. The authors experimentally evaluate the modified turbocharger at a constant 4 m gross head while varying valve opening, electrical load, and inverter capacity. The study tracks hydraulic input, rotational speed, DC generation, AC output, and overall efficiency. Its central value lies in connecting hydraulic and electrical operating conditions within an experimental framework and documenting the performance of a repurposed automotive component for decentralized pico-hydropower applications.

Bibliographic Information

Item	Information
Article Title	Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine
Authors	Aris Suryadi; Wahyu Gendam Prakoso; Reza Anugrah
Journal	Innovation in Engineering
Volume	3
Issue	2
Publication Year	2026
Pages	149–168
DOI	https://doi.org/10.58712/ie.v3i2.50
Publisher	Researcher and Lecturer Society
License	Creative Commons Attribution 4.0 International (CC BY 4.0)
ISSN	e-ISSN: 3047-5473
Keywords	conversion energy; low-head hydropower; pico-hydropower; sustainable energy; waste turbocharger
Published	20 September 2026

Highlights

Repurposes a waste automotive turbocharger as a low-head hydro turbine.
Tests the system at a constant gross head of 4 m.
Investigates four valve openings: 25%, 50%, 75%, and 100%.
Evaluates five resistive electrical loads from 15 W to 100 W.
Compares three inverter capacities: 500 W, 1000 W, and 1500 W.
Measures flow rate, turbine speed, DC electrical power, AC electrical power, and system efficiency.
Reports a maximum turbine speed of 2,760 rpm in the abstract and a peak overall efficiency of 20.7%.
Identifies hydraulic input and generator loading as important factors governing system performance.

Research Background

The study begins from the challenge of deploying pico-hydropower systems in small-scale and decentralized settings. The authors describe conventional hydraulic turbines as requiring suitable hydraulic conditions, specialized manufacturing, and relatively substantial investment. These constraints motivate investigation of alternative rotating machinery that is commercially available or can be obtained from discarded equipment.

The article places waste automotive turbochargers alongside Pump-as-Turbine approaches as an alternative route for small-scale energy conversion. The authors emphasize that turbochargers possess a compact radial turbine configuration, robust shaft assembly, and high rotational capability. Their proposed application changes the working fluid from automotive exhaust gas to water while retaining the original radial turbine geometry.

The research gap is framed around the limited experimental characterization of waste automotive turbochargers operating as hydro turbines under low-head pico-hydropower conditions. The authors particularly identify the need to examine hydraulic, mechanical, and electrical performance together and to investigate the influence of electrical loading and inverter capacity on the operating characteristics of the modified system.

Research Objective

The primary objective is to experimentally characterize the hydrodynamic and electro-mechanical performance of a waste automotive turbocharger repurposed as a hydro turbine under a constant gross head of 4 m. The study specifically investigates relationships among valve opening, flow rate, turbine rotational speed, electrical loading, DC output, AC output, and overall system efficiency.

The experimental design also seeks to identify an operating condition that produces favorable electrical performance while determining whether inverter capacity materially affects the generated output.

Why This Research Matters

The research addresses a practical engineering question: whether an end-of-life automotive component can be adapted for a different energy-conversion application without redesigning its turbine blade profile. This approach is relevant to low-cost pico-hydropower because it emphasizes component reuse and adaptation rather than manufacture of a dedicated hydraulic turbine.

The study is also useful because it considers the complete conversion chain rather than examining turbine rotation alone. Hydraulic conditions, turbine speed, generator loading, DC generation, inverter operation, and AC output are considered within the same experimental system.

The article therefore provides an experimental reference for researchers investigating unconventional turbine concepts and for engineers evaluating the technical behavior of repurposed rotating machinery under low-head hydraulic conditions.

Research Methodology

Experimental System

The experimental system uses a closed-loop hydraulic circuit consisting of a water reservoir, centrifugal pump, supply pipe, control valve, pressure gauge, electromagnetic flow meter, modified turbocharger, 24 V DC alternator, inverter, resistive electrical load, and measuring instruments. The gross hydraulic head was maintained at approximately 4 m.

The turbine shaft was coupled to a 24 V DC alternator through a pulley-belt transmission system. Three inverter capacities were investigated, namely 500 W, 1000 W, and 1500 W. Five resistive electrical loads of 15 W, 25 W, 60 W, 75 W, and 100 W were applied during testing.

Turbocharger Modification

The compressor wheel and compressor housing were removed. The authors fabricated an adapter flange for the turbine housing, modified the water inlet and outlet arrangement, permanently locked the wastegate, mounted the assembly vertically, and adapted the bearing system for operation without the original high-pressure engine-oil supply.

Importantly, the original radial turbine geometry was retained. The research therefore evaluates adaptation of the existing turbocharger rather than redesigning the turbine runner or changing its internal blade profile.

Experimental Variables

Parameter	Experimental Condition
Gross hydraulic head	4 m
Valve opening	25%, 50%, 75%, 100%
Inverter capacity	500 W, 1000 W, 1500 W
Electrical load	15 W, 25 W, 60 W, 75 W, 100 W
Alternator	24 V DC
Measured parameters	Flow rate, turbine speed, DC voltage, DC current, AC voltage, AC current, AC power
Repeated measurements	Three repetitions for each operating condition

Performance Calculations

The study calculates flow rate from measured water volume and elapsed time. Hydraulic power is calculated from flow rate, water density, gravitational acceleration, and gross head. DC electrical power is calculated from DC voltage and current, while AC output is calculated from AC voltage, current, and power factor under resistive loading.

The manuscript states that overall efficiency represents the ratio of AC electrical output to available hydraulic power. However, Equation (5) in the published PDF displays P_AC/P_DC. This internal inconsistency should be considered when interpreting the reported efficiency values.

Key Findings

Flow Rate and Valve Opening

The study reports that increasing valve opening from 25% to 100% increased the flow rate from 1.9 L/s to 6.2 L/s and the calculated hydraulic power from 74.6 W to 243.4 W. Figure 4 shows the general increase in discharge with valve opening across the three inverter configurations.

Turbine Rotational Speed

Figure 5 shows that turbine speed increased as valve opening increased. The authors attribute this behavior to the greater hydraulic energy supplied to the turbine. Higher electrical loading produced a reduction in rotational speed, which the study associates with increased electromagnetic torque imposed by the alternator.

The reported maximum rotational speed is 2,760 rpm. The results therefore illustrate the coupling between hydraulic input and electrical loading: greater hydraulic input tends to increase shaft speed, while greater electrical demand increases the opposing generator torque.

DC Electrical Output

Figure 6 indicates that DC electrical output generally increased with valve opening. The figure uses a DC power scale extending to approximately 55 W. The authors explain that greater flow increases turbine speed and therefore supports greater alternator voltage and current, while heavier electrical loading can reduce shaft speed and limit further increases in DC output.

AC Electrical Output

Figure 7 shows an overall increase in AC output as valve opening increases. The authors report only minor differences among the 500 W, 1000 W, and 1500 W inverter configurations. The interpretation presented in the paper is that hydraulic input, rather than inverter capacity, primarily limits electrical generation under the tested conditions.

Overall Efficiency

Figure 8 presents overall efficiency for the different valve openings, electrical loads, and inverter capacities. The manuscript states that efficiency generally increased with valve opening and that inverter capacity had a limited influence on overall efficiency.

The paper reports a peak overall efficiency of 20.7%. However, the manuscript contains internal numerical inconsistencies concerning the operating condition and output values associated with this reported peak. The abstract reports a maximum DC output of 54.2 W and maximum AC output of 42.2 W at 100% valve opening and a 15 W load, whereas the comparison and conclusion sections report 100 W DC and 20.7 W AC under a 100 W resistive load. These differences should be clarified by reference to the underlying experimental dataset.

Scientific Contribution

Experimental characterization: The study provides experimental performance data for a repurposed automotive turbocharger operated as a hydro turbine under a fixed low-head condition.
Integrated system perspective: Hydraulic, mechanical, and electrical parameters are evaluated within the same experimental configuration.
Component reuse: The study demonstrates an adaptation pathway that retains the original radial turbine geometry rather than requiring a newly manufactured turbine runner.
Electrical loading analysis: The experiments explicitly examine the effect of different resistive loads on turbine speed and electrical output.
Inverter comparison: Three inverter capacities are investigated to determine their influence on system output.
Experimental reference: The resulting measurements provide a basis for subsequent investigations of turbocharger-based pico-hydropower systems.

Industrial Implications

The study indicates that discarded automotive turbochargers may be adapted as compact hydraulic prime movers for low-head pico-hydropower applications. The proposed approach can reduce the dependence on purpose-built turbine components by reusing an existing rotating assembly.

The authors also identify equipment availability, compact construction, and material reuse as practical characteristics of the proposed system. However, the study does not provide a detailed cost model, manufacturing cost comparison, lifecycle assessment, or field-scale economic analysis. Consequently, the industrial implications should be interpreted primarily as technical feasibility rather than as a demonstrated economic advantage.

For engineering development, the results suggest that hydraulic input, generator matching, and turbine-flow interaction deserve greater attention than simply increasing inverter capacity when the available hydraulic resource remains unchanged.

Research Limitations

The investigation evaluates a single turbocharger geometry.
The experiments use a fixed gross head of approximately 4 m.
The study is conducted under laboratory conditions rather than long-term field operation.
The turbine runner geometry is retained without optimization of the blade profile.
The manuscript does not provide a complete uncertainty analysis for the measured parameters.
The raw experimental dataset is not openly provided; the publisher's article page states that the dataset is currently restricted to the research team and may be made available upon reasonable request.
The published manuscript contains an inconsistency between the textual definition of overall efficiency and the displayed Equation (5).
The manuscript contains differing reported DC and AC peak-output values between the abstract and later sections.
The conclusion identifies 100 W DC and 20.7 W AC output, while the abstract reports 54.2 W DC and 42.2 W AC output.
The study does not establish long-term durability under dynamic hydraulic conditions.

Future Research Opportunities

The authors identify several directions for further investigation. These include Computational Fluid Dynamics modeling to examine and optimize the volute hydrodynamics for incompressible water, evaluation of variable transmission ratios to improve alternator operation, and long-term field durability testing under dynamic hydraulic heads.

The next stage of research could also benefit from resolving the reported numerical inconsistencies and providing a complete measurement-uncertainty assessment. Clear separation of hydraulic, mechanical, generator, inverter, and overall efficiencies would strengthen the technical interpretation of the conversion chain.

Because the present work retains the original runner geometry, future investigations could also examine how alternative inlet arrangements, volute configurations, transmission ratios, or runner geometries affect performance while maintaining the low-cost reuse concept.

Potential for Public Policy Citation

The article is primarily an engineering performance study rather than a policy analysis. Nevertheless, its findings may provide technical background for discussions concerning decentralized renewable-energy technologies, pico-hydropower development, energy access, and reuse of end-of-life automotive components.

For policy-oriented writing, the article should be cited specifically as experimental evidence of the technical investigation of a repurposed turbocharger under a 4 m gross head. It should not be used alone to substantiate claims about national energy policy, large-scale economic feasibility, lifecycle environmental benefits, or field-wide performance because those issues were outside the experimental scope of the study.

Who Should Read This Paper?

Researchers working on pico-hydropower and low-head hydropower systems.
Mechanical and electrical engineers studying turbine-generator systems.
Researchers investigating unconventional or repurposed energy-conversion equipment.
Engineers working on decentralized renewable-energy systems.
Researchers studying circular approaches to engineering component reuse.
Graduate students working in renewable energy, fluid machinery, and energy conversion.
Practitioners interested in experimental evaluation of small-scale hydraulic power systems.

Frequently Asked Questions

What is the main subject of the study?

The study experimentally evaluates a waste automotive turbocharger that has been modified and operated as a hydro turbine for low-head pico-hydropower generation.

What hydraulic head was used?

The experiments were conducted at a constant gross hydraulic head of approximately 4 m.

What valve-opening conditions were tested?

The researchers tested 25%, 50%, 75%, and 100% valve openings.

What electrical loads were investigated?

The tested resistive electrical loads were 15 W, 25 W, 60 W, 75 W, and 100 W.

What inverter capacities were compared?

The study compared 500 W, 1000 W, and 1500 W inverter capacities.

What was the reported maximum turbine speed?

The article reports a maximum rotational speed of 2,760 rpm.

What efficiency did the paper report?

The paper reports a peak overall efficiency of 20.7%. However, Equation (5), the definition preceding it, and the numerical values reported in different sections of the manuscript are not fully consistent. The reported efficiency should therefore be interpreted with attention to these internal inconsistencies.

Does the study redesign the turbocharger turbine blades?

No. The study retains the original radial turbine geometry and focuses on modifying the hydraulic flow path, wastegate, mounting arrangement, bearing system, and power-transmission configuration.

Is the study experimentally validated?

Yes. The study is based on laboratory experiments, and each operating condition was reportedly repeated three times before the average value was used for subsequent analysis.

Suggested Citations

Teknomekanik Style

Suryadi A, Prakoso WG, Anugrah R. Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine. Innovation in Engineering. 2026;3(2):149–168. https://doi.org/10.58712/ie.v3i2.50.

APA 7th Edition

Suryadi, A., Prakoso, W. G., & Anugrah, R. (2026). Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine. Innovation in Engineering, 3(2), 149–168. https://doi.org/10.58712/ie.v3i2.50

IEEE Style

A. Suryadi, W. G. Prakoso, and R. Anugrah, “Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine,” Innovation in Engineering, vol. 3, no. 2, pp. 149–168, 2026, doi: 10.58712/ie.v3i2.50.

Harvard Style

Suryadi, A., Prakoso, W.G. and Anugrah, R., 2026. Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine. Innovation in Engineering, 3(2), pp.149–168. https://doi.org/10.58712/ie.v3i2.50.

Vancouver Style

Suryadi A, Prakoso WG, Anugrah R. Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine. Innovation in Engineering. 2026;3(2):149-168. doi:10.58712/ie.v3i2.50.

Chicago Author-Date

Suryadi, Aris, Wahyu Gendam Prakoso, and Reza Anugrah. 2026. “Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine.” Innovation in Engineering 3 (2): 149–168. https://doi.org/10.58712/ie.v3i2.50.

MLA 9th Edition

Suryadi, Aris, et al. “Performance of a waste automotive turbocharger repurposed as a low-cost hydro turbine.” Innovation in Engineering, vol. 3, no. 2, 2026, pp. 149–168. https://doi.org/10.58712/ie.v3i2.50.

Editorial Note

This review has been prepared from the scientific content of the published article and bibliographic information verified through the official journal webpage. The scientific discussion follows the experimental scope, methodology, results, discussion, limitations, and future research directions reported by the authors. Particular attention has been given to internal numerical and equation inconsistencies in the published manuscript because these issues affect interpretation of the reported efficiency and peak electrical outputs.

Readers should consult and cite the original article published in Innovation in Engineering when using its methods, data, findings, or conclusions in academic publications. The original article should remain the primary scholarly source for any formal citation.

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