Electrical Power Requirements Research Articles

Modeling and Impact of Hyperloop Technology on the Electricity Grid

This paper provides an overview of hyperloop technologies, including a brief discussion of key components of a hyperloop system that determine the electric power requirements as a function of time. At-scale hyperloop systems do not yet exist, so a model was used to generate a set of load profiles for conceptual hyperloop realizations at four locations in the United States: two systems in California and one each in Colorado and Ohio. In all four cases, the modeled hyperloop load profiles included pulses in both active and reactive power. Grid modeling was performed to estimate the grid impacts and for discussing grid integration challenges. The paper discusses how energy storage systems might be used to eliminate the pulsating load characteristics or significantly reduce it to accommodate current grid planning guidelines.

Long-term renewable electricity planning using a multistage stochastic optimization with nested decomposition

Renewable energy plays a key role in mitigating climate change and promoting the energy transition. In this context, we address two crucial consequences for planning the electricity transition: (a) substantially more complex uncertainties in variable renewable energy and (b) a requirement to co-ordinate extensive transmission investment with the newly located generating facilities. These features combine to present a major modelling challenge both for countries that have a liberalized electricity market, where long terms plans are needed to support subsidy policies, as well as for those countries which have retained central planning. This paper develops a new multistage stochastic mixed-integer model which uses a new decomposition algorithm based on stochastic dual dynamic integer programming, with a two-phase acceleration method. The scalability of the approach is demonstrated by application to China’s electric power requirements and it performs well in terms of computational tractability and policy insights.

Estimating Electric Power Requirements for Mechanically Shredding Massage Chairs and Treadmills at a Recycling Plant

South Korea has operated under laws to collect and recycle the waste of electrical and electronic equipment (WEEE) utilizing a system based on the Extended Producer Responsibility (EPR) system since 2003. In 2020, the number of products managed by the EPR increased from 27 to 50. Among the 50 products, massage chairs and treadmills are recognized as the items avoided in recycling centers or by recyclers due to their large volume, large weight, and long disassembly times. This study was a preliminary study in which the physical shredding process for massage chairs and treadmills could be introduced, and the electrical power requirements calculated. In the methodology, Vickers hardness was measured by sampling two actual products, and the tensile and shear strength were calculated from the hardness. Based on the shear strength, the force affecting the cutter was calculated and converted into torque and horsepower. In particular, the actual specifications of the crusher, designed and operated in the recycling center, were applied to the study, and the design was based on the treatment capacity of 10 tons per hour. Conclusively, the proper electrical power for crushing the massage chair and treadmill was analyzed as 719.5 and 459.7 HP, respectively.

Micro Satellite Orbital Boost by Electrodynamic Tethers.

In this manuscript, a method for maneuvering a spacecraft using electrically charged tethers is explored. The spacecraft’s velocity vector can be modified by interacting with Earth’s magnetic field. Through this method, a spacecraft can maintain an orbit indefinitely by reboosting without the constraint of limited propellant. The spacecraft-tether system dynamics in low Earth orbit are simulated to evaluate the effects of Lorentz force and torques on translational motion. With 500-meter tethers charged with a 1-amp current, a 100-kg spacecraft can gain 250 m of altitude in one orbit. By evaluating the combined effects of Lorenz force and the coupled effects of Lorentz torque propagation through Euler’s moment equation and Newton’s translational motion equations, the simulated spacecraft-tether system can orbit indefinitely at altitudes as low as 275 km. Through a rare evaluation of the nonlinear coupling of the six differential equations of motion, the one finding is that an electrodynamic tether can be used to maintain a spacecraft’s orbit height indefinitely for very low Earth orbits. However, the reboost maneuver is inefficient for high inclination orbits and has high electrical power requirement. To overcome greater aerodynamic drag at lower altitudes, longer tethers with higher power draw are required.

Magnetic amino-functionalized metal-organic frameworks as a novel solid support in ionic liquids-based effervescent tablets for efficient extraction of polycyclic aromatic hydrocarbons in milks

Herein, a kind of novel multi-layer core-shell nanocomposites (NSPN) was prepared by employing SiO2 and polyvinylpyrrolidone (PVP) polymers as modifiers and amino-functionalized metal-organic frameworks (NH2-MIL101(Fe)) as coating. It was referred to as the NSPN and ILs-based effervescence-assisted dispersive solid-phase microextraction, hereafter abbreviated as NIE-DSM. In terms of extraction efficiency, SiO2 and PVP as modifiers and NH2-MIL(Fe) as coating onto the surface of NiFe2O4 cores played a synergistically enhancing effect on adsorption/extraction. Effervescent tablets were prepared by integrating the NSPN magnetic nanoparticles as adsorbents with imidazolium-based ionic liquids (ILs) as extractants as well as acidic and alkaline sources. Under vigorous dispersion of CO2 bubbles, the NIE-DSM method realized the goal of rapidly diffusing and separating the adsorbent/extractant (~3 min) without needing conventional vortexing or centrifugation step. Consequently, the NIE-DSM approach combined dispersion and adsorption/extractant in a synchronous way. Under optimized conditions, the NIE-DSM/HPLC-FLD method gave low limits of detection (0.008–0.034 μg kg−1) and satisfactory extraction recoveries (74.1–101.6%) for five polycyclic aromatic hydrocarbons (PAHs; fluorene, anthracene, pyrene, chrysene and benzo(a)pyrene) in milk samples. The intra-day and inter-day precision, expressed as relative standard deviations, was < 5.9% and 6.5%, respectively, demonstrating a high precision. Owing to no requirement for electrical power, this method shows great potential for outdoor monitoring of trace-level PAHs in food matrices.

High-sensitivity inter-satellite optical communications using chip-scale LED and single-photon detector hardware

Small satellites have challenging size weight and power requirements for communications modules, which we address here by using chip-scale light-emitting diode (LED) transmitters and single-photon avalanche diode receivers. Data rates of 100 Mb/s have been demonstrated at a sensitivity of -55.2 dBm, and simulations with supporting experimental work indicate ranges in excess of 1 km are feasible with a directional gain of up to 52 dBi and comparatively modest pointing requirements. A 750 m, 20 Mb/s link using a single micro-LED has been demonstrated experimentally. The low electrical power requirements and compact, semiconductor nature of these devices offer high data rate, high sensitivity communications for small satellite platforms.

Application of the cascade system to increase the capacity of a pico-hydro power generation

The Pico-hydro power generation is a power plant with a scale below 5 kW. This type of power generation is suitable for areas with streams or rivers with low water levels. One area that has natural conditions like this is the Javan Langur Centre (JLC), a rehabilitation facility for one of the endangered primate species, the langur. To support the operation of JLC, a pico-hydro power plant has been built, which has a capacity of 300 watts. However, due to the water discharge is quite low, the efficiency of the generator is less than 10%, of which, the total output power from the pico-hydro generator is about 27,3 watts. While the electrical energy requirements in JLC is around 50 watts for lighting. To meet the shortage of electricity supply, it is necessary to increase the power generated by the existing pico-hydro power plant, i.e. by applying a cascade system. This system utilizes water from the existing pico-hydro power plant drainage channel as the intake flow for the new pico-hydro power plant. This system also utilizes differences in elevation or water level to make the terraces. With the application of the cascade pico-hydro system, the electrical power requirements at JLC can be met.

Analysis on the design and temperature field of switched reluctance motor for electric vehicle

Specific to the wide speed range and large instantaneous power of the motor for electric auto-mobile, a 110kW auto-mobile switched reluctance motor is designed. The electromagnetic torque, induce voltage are calculated and the electromagnetic performance is met the requirement of electric vehicle power. The copper loss and core loss are obtained based on finite element model. In addition, the coefficient of thermal conductivity is obtained based on physical properties of materials. At last, the 3-D temperature field model is established based on ANSYS workbench and the distribution of temperature is calculated. The results show that the motor winding temperature is running smoothly under water-cooling condition. The rotor temperature is maximum, the temperature of stator winding is slightly higher than the temperature of stator core, which conforms to the thermal design requirement of motor and lays certain foundation for the optimized analysis of such kind of motor.

Study of Series-Parallel and Power-Split DHT for Hybrid Powertrains

Dedicated hybrid transmission (DHT) is the developing trend of hybrid transmissions. This paper studies different types of DHTs regarding the structure, function, and performance. Firstly, the structure and function of different well-known DHTs in the market are discussed and analyzed. Through the analysis, the reasonability and necessity of the different modes and the electric motor power requirements that lie behind different DHTs are derived. Secondly, the dynamics of different DHTs are further compared with the driving areas in different modes under different driving conditions. Then, the basic or minimum dynamic requirements are defined and taken into consideration before the economic comparison. To ensure the effectiveness of the comparison, the optimization of the configurations for each kind of DHT is carried out with the modular simulation model. The economic comparison is conducted under the premise of excluding the influences of the configurations in the results. Finally, the sensitivity and influence of different engine characteristics for different DHTs are studied to find out the sensibilities of the two kinds of DHTs with engine technology. Through these studies, the essential differences and features of different DHTs can be derived to help better understand the decision in choosing the technical route for the original equipment manufacturers.

Failure Modes and Reliability Oriented System Design for Aerospace Power Electronic Converters

Aircraft electrification has been a major trend in aviation industry for past 20 years. Given the increasing electrical power requirement for future more electric aircraft and hybrid electric aircraft, research efforts has been ongoing in high power electrical conversion for air-borne systems. Safety critical nature of aviation systems places reliability of aerospace power converters as a critical design concern. In this paper, power electronic system reliability is studied with emphasis on lifetime limiting factors of critical sub components. Reliability of voltage source power converters at different system voltage levels are modelled for a starter generator drive converter. A key observation is that Si IGBT devices are sufficient with respect to reliability requirements in low and medium voltage systems (up to 540 V). At higher system voltages (above 540 V), multi level topologies are necessary for designing with Si IGBTs. In constant power profile drive, system reliability is minimally affected by wear-out failure of film capacitors in converter DC links. In multi level topologies without enhanced voltage derating, system reliability is dominated by cosmic ray induced random failures. Simulation results demonstrate that at high system voltages (810 V), 2 L topology with SiC mosfets outperform Si IGBT based 3 L topology with respect to reliability.

Recent advances in net-zero energy greenhouses and adapted thermal energy storage systems

In agricultural greenhouses, employment of energy-saving strategies along with alternative energy sources has been identified as a potential solution to address the intensive energy consumption of these cultivation facilities. This study investigates the integration of renewable energy technologies, including solar thermal, solar photovoltaic (PV) and photovoltaic-thermal (PVT), geothermal, and biomass with greenhouse cultivation systems as net-Zero Energy Greenhouses (nZEGs). Solar energy is the most abundant renewable energy source that has been successfully used to provide thermal and electrical power requirements of greenhouses. The use of geothermal heat in greenhouses will save primary energy sources (more than 20%) and reduce operating costs. Utilizing solid biomass not only provides heating and cooling demands of greenhouses but also can supply their CO2 requirements. In terms of energy storage, the use of Sensible Thermal Energy Storage (STES) can cause a 3–5 °C increase in the inside air temperature while resulting in almost 28 kWh/m2 energy saving per area of the greenhouse. Phase Change Materials (PCMs) are extensively used in TES systems and provide high thermal efficiencies and reduce energy consumption (around 30–40%) with the main drawbacks of low thermal conductivity, associated environmental concerns, and high costs.

Utilisation of Ram Air Turbine on a Fighter Platform for Energy Extraction Failure Mode Study

Aircraft electrical system needs to be robust enough to cater for electrical power requirements of all the systems of the aircraft and all the safety/degraded mission critical systems in failure modes. Designing such a robust electrical system for a developmental aircraft program is a challenge. A developmental aircraft during its various phases would involve integration of additional systems and new weapons (in case of fighter aircraft). Integration of newer systems imposes fresh challenges in managing the electrical system architecture especially in failure modes. Weapon integration in a prototype fighter program is dynamic as newer contemporary weapons are developed at faster pace and ever evolving. Power crisis through existing on-board power generation systems in failure mode was felt during an indigenous aircraft development program. A novel idea of introducing a Ram Air Turbine and utilize the power generated during main alternator failure for critical systems was studied. The intention of this paper is to cover the details of the study carried out towards utlisation of such a Ram Air Turbine in landing phase for extraction of energy in case of main alternator failure.

Modeling the electrical power and energy consumption of automated guided vehicles to improve the energy efficiency of production systems

Due to the advancing energy system transformation and the increasingly complex and dynamic environment in which factories have to operate, the energy efficiency and flexible design of production systems are becoming more important. Since the use of automated guided vehicles is a promising approach to enhance the flexibility of intralogistics, their electrical power requirements are analyzed. Based on the measurement data obtained, different movement modules of an automated guided vehicle are identified and then modeled using physical laws. These movement modules are the translatory movement, rotary movement, and the lifting and lowering of the load-carrying platform. The measurement data show, for example, that the energy requirement for translational and rotational movement increases in relation to the payload weight. At the same time, however, it is also shown that an increase in speed of the automated guided vehicle leads to a lower energy requirement, although the power requirement grows. Consequently, one result is that an automated guided vehicle works most efficiently when the maximum payload is transported at the highest speed. With regard to the lifting and lowering of loads, the result is an increasing energy requirement depending on the payload weight. The comparison between the collected measurement data and the outcomes of the implemented simulation model shows only minor deviations. Thus, the implemented simulation model of automated guided vehicles can be used with regard to their electrical power consumption, for example, in production planning to comprehensively raise the energy efficiency of production systems.

Thermochemical conversion of oil palm Fiber‐LDPE hybrid waste into biochar

AbstractTypical municipal solid waste (MSW) is composed mainly of biomass and polymers. In this study, the co‐conversion of a feedstock obtained from a mixture of both constituent materials is investigated. The goal of this study was to determine the suitability of a low‐temperature process for achieving biochar with properties that can make it amenable to multiple energy and environmental applications. Co‐carbonization of oil palm (Elaeis guineensis) fiber (OPF) and low‐density polyethylene (LDPE) was conducted at a peak temperature of 529 °C for 80 min in a top‐lit updraft biomass conversion reactor using retort heating. The biochar yields for OPF and OPF‐LDPE were 15.9 wt% and 62.7 wt%, respectively, with the higher yield of the latter attributed to a polymer effect. The OPF and OPF‐LDPE biochars were mesoporous with relatively large specific surface areas of 352.9 and 391.4 m2 g−1, respectively. The addition of LDPE to the OPF feedstock was observed to be advantageous as it improved the biochar yield, carbon content, specific surface area, and pore volume. Consequently, the technology of choice for solid waste management offers key environment‐friendly benefits such as no electrical power requirement, an excellent waste‐to‐wealth approach, and the capacity to be used globally (in remote locations). © 2020 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

An Adaptive Control Scheme for Variable Speed Wind Turbines Providing Frequency Regulation in Isolated Power Systems with Thermal Generation

The lack of synchronous inertia, associated with the relevant penetration of variable speed wind turbines (VSWTs) into isolated power systems, has increased their vulnerability to strong frequency deviations. In fact, the activation of load shedding schemes is a common practice when an incident occurs, i.e., the outage of a conventional unit. Under this framework, wind power plants should actively contribute to frequency stability and grid reliability. However, the contribution of VSWTs to frequency regulation involves several drawbacks related to their efficiency and equipment wear due to electrical power requirements, rotational speed changes, and subsequently, shaft torque oscillations. As a result, wind energy producers are not usually willing to offer such frequency regulation. In this paper, a new control technique is proposed to optimize the frequency response of wind power plants after a power imbalanced situation. The proposed frequency controller depends on different power system parameters through a linear regression to determine the contribution of wind power plants for each imbalance condition. As a consequence, VSWTs frequency contribution is estimated to minimize their mechanical and electrical efforts, thus reducing their equipment wear. A group of sixty supply-side and imbalance scenarios are simulated and analyzed. Results of the case study are compared to previous proposals. The proposed adaptive control reduces the maximum torque and rotational speed variations while at the same time maintaining similar values of the load shedding program. Extensive results and discussion are included in the paper.

ANALISIS PERBAIKAN FAKTOR DAYA MENGGUNAKAN KAPASITOR BANK DI PLANT 6 PT. INDOCEMENT TUNGGAL PRAKARSA Tbk. UNIT CITEUREUP

PT. Indocement Tunggal Prakarsa Tbk. is a company that produces cement. Large electrical power requirements are a major factor in running production process. The low power factor caused load system in Plant 6 not to run optimally. For industries, low power factor conditions could not be avoided due to varying motor loads. The power factor improvement used capacitor banks. The power factor is the ratio of active power with apparent power. Capacitor banks are a set of several capacitors connected in parallel to improve the quality of electrical power by increasing the power factor. This study used a quantitative method in which there was clarity of purpose, approach, data sample, and abundantly use of number. Moreover, data analysis was undertaken after all data had been collected. By raising the Cos to 0.95, for the main feeder AA 5 (from main transformer 6.1), a capacitor of banks with a capacity of 6172.33 kVAR must be installed, and for main feeder AA 8 (from main transformer 6.2), a capacitor of banks with a capacity of 5388.88 kVAR must be installed in order that the quality power produced was more optimal.

The Sabatier Electrolyzer: Harnessing Proton-Conducting Ceramics to Upgrade Carbon Dioxide into Methane

We present our development of the Sabatier Electrolyzer incorporating Sabatier catalysts into proton conducting ceramic membranes to synthesize CH4 and O2 from CO2 and H2O feed streams. Our work seeks to combine steam electrolysis and hydrogen production with carbon dioxide hydrogenation into a single Sabatier Electrolyzer reactor based on proton conducting ceramic membranes and Sabatier catalysts. Proton-conducting ceramic membranes transport reasonable rates of H+ ions at lower overall cell voltages at 400 - 500 ºC with low overpotentials for H2O splitting. The decreased electric power requirements for the Sabatier Electrolyzer are further enabled by autothermal operation; ohmic heating maintains the electrolysis cell at the necessary temperatures for high H+ conduction and effective Sabatier chemistry. Integration of the catalyst with the electrolyzer simplifies the system, improves reliability, and provides increased performance within a smaller package.Figure 1 illustrates the Sabatier Electrolyzer concept. H2O and CO2 are fed to opposing electrodes of a protonic-ceramic electrolysis cell. Steam is electrolyzed with the product O2 exhausting from the cell. The product protons are driven across the protonic-ceramic membrane to the fuel electrode, where they react with CO2 to form CH4 and H2O. The combination of processes can match the exothermicity of CO2 hydrogenation with the endothermicity of H2O electrolysis, promoting thermal balance and high efficiency.The Sabatier Electrolyzer cell features a BaCe0.4Zr0.4Y0.1Yb0.1O3-δ (BCZYYb4411) electrolyte, a Ni-BCZYYb4411 fuel electrode support, and a BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) steam electrode. The Ni-cermet fuel electrode serves as the CO2-upgrading catalyst. To date, we have CO2 conversion and CH4 selectivity were demonstrated to be 28% and 43%, respectively, at 450 °C. This result is encouraging but still much lower than the thermodynamic predictions (~70% for CO2 conversion and ~95% for CH4 selectivity). In this presentation, we will review our efforts to achieve the thermodynamically predicted CO2 conversion and CH4 selectivity of 70% and 95%, respectively. Figure 1

Investigation of reducing electricity consumption in the refrigerator by using domestic refrigerant MC-22

A household refrigerator was machine that operates continuously throughout the day to keep food fresh. So that a little savings in electricity consumption was very beneficial. The purpose of this study was to obtain savings in refrigerator electricity consumption by replacing R-134a working fluid with Musicool-22 (MC-22) as natural refrigerant. Furthermore, to reducing global warming potential of the earth’s surface due to HFCs refrigerants. The study was designed experimentally with the retrofit refrigerant drop in substitute method on refrigerator. The test was started by measuring the performance of refrigerators using R-134a working fluid. Then the working fluid R-134a was retrofitted with MC-22 with a mass of 15%, 20%, 25%, 35%, 45%, and 65% of the mass of R-134a. Finally, the performance of the refrigerator that has been retrofitted using the MC-22 was measured as a measurement of the performance of the refrigerator using the R-134a. The test results showed that, when the refrigerator was retrofitted using MC-22 with a mass of refrigerant 25% mass of R-134a refrigerant, the performance of the refrigerator increases. Electricity consumption was more efficient with a marked decrease in electrical power requirements to 12.2%. In addition, the freezer room temperature is lower at 6.9 °C compared to when operating with R-134a working fluid.

SCHEDULING UAV FLEETS FOR THE PERSISTENT OPERATION OF UAV-ENABLED WIRELESS NETWORKS DURING NPP MONITORING

Motivation. During nuclear power plant (NPP) monitoring, unmanned aerial vehicles (UAVs) can be used as an affordable and cost-efficient tool to deploy a UAV-enabled wireless network (UEWN) for providing the crisis centre (CrS) needed monitoring data from monitoring stations (MSs) of the automated radiation monitoring system in case of damage of wired networks. However, because of the high electrical power requirement, the normal operation time of a UAV of a multi-rotor type (MUAV) is just 20 to 30 min, limiting the operation time of a UEWN during NPP monitoring missions. The subject matter of the paper is the process of ensuring the persistent operation of a UEWN. The aim of this paper is to develop a queuing theory based approach to scheduling MUAVs for persistent operation of a UEWN during NPP monitoring. The objectives of the paper are: to propose a scheme of deployment of a UEWN to connect a MS with the CrS of Zaporizhzhia (ZNPP) in case of damage of the wired network between the MS and the CrS; to introduce the main parameters characterizing the automatic battery charging station (ABCS) as a multi-channel queuing system; to develop and describe in detail a queuing theory based approach to scheduling MUAVs of the UEWN for persistent NPP monitoring. The following results were obtained. A scheme of deployment of a UEWN, consisting of LoRaWAN and WiFi segments, to connect a MS with the CrS of ZNPP in case of damage of the wired network between the MS and the CrS was proposed and described. A shift schedule for 3 MUAV fleets to ensure the persistent operation of the UEWN during ZNPP post-accident monitoring missions was built. It was shown that the ABCS can be considered as a multi-channel queuing system, in which two or more channels (battery charge points at the ABCS) are available to handle arriving MUAVs. A queuing theory based approach to scheduling MUAV fleets of the UEWN for persistent NPP monitoring is developed and described in detail. It was evaluated and illustrated by means of plots how the number of occupied channels of the ABCS depends on: 1) the battery charging time for the MUAV at the ABCS, and 2) the flight distance for the MUAV between its location point in the WiFi segment and the ABCS. The next research steps can cover issues regarding to: 1) scheduling MUAV fleets for numerous UEWNs, 2) developing models of a UEWN operation using a LiFi segment for transmission of monitoring data, and 3) developing reliability/survivability models of a UEWN taking into account UAV failures or/and wireless signal interference.

Reduction of Harmful Emissions from Domestic Power Generator Usage in Nigeria -A Tribological Approach

Worldwide concern for the release of harmful emission from Internal Combustion (IC) engines requires the optimization of the quantity of fuel used, types of fuel blend used and type of lubrication utilized. In Nigeria, the electrical power requirements of many households rely more on alternative sources such as Solar systems and fossil fuel-powered generators. The use of these generators is known to produce exhaust fumes that are harmful to humans and the environment. This study investigated the effect of using two different commercially available lubricating oils for gasoline-fueled power generators for domestic applications in comparison to used oils. These are SAE 40 and SAE 20W50. The effect of Boron additive on the two oil brands and used oils (or aged oils) at different speeds on emission from the exhaust stream from the generator was investigated. This is to provide a better understanding of the behavior of Boron additive with SAE 40, SAE 20W50, and aged oils. The study also compared results of torque and emission measurements from oils containing boron to oils without the Boron additives at different speeds. The instruments used to carry out the measurement are a digital tachometer, torque meter (contact type), and 5-gas exhaust analyzer. Results from this study indicated a general decrease in torque with increased speed for all the lubricating oils. This is in agreement with the results of similar studies on torque outputs from IC engines with increasing speeds. However, oils lubricated with Boron additives minimized this loss at a different speed more in SAE 20W50, SAE 40 than in used oils. Carbon monoxide emission from these results indicated that generators lubricated by aged oils are highest at all speed ranges irrespective of Boron additive inclusion. Cleanliness from a gasoline-powered generator is possible if Boron additive is added to lubricating oils. The concentration of NOx emission was found to rise considerably only when operated at the highest speed for aged oils. The results of this study indicated that tribofilms formed by boron-containing oils played a role in preventing torque reduction or power loss and CO emissions from power generators for domestic use. This behavior was attributed to the friction-reducing boric acid and wear resistance borate glass contained within the trilayer. However, tribofilms formed by used oils on tribological parts of the engine gave poor torque reduction results in comparison to that provided by fresh oils. This indicated that when lubricating oils in power generators used in homes are aged beyond the recommended interval for replacement, substantial power loss and harmful emissions are released to the surroundings.