Assessing the Availability and Adoption of Advanced Battery Storage Systems for Solar Photovoltaic Applications in Saudi Arabia Residential Buildings

Abstract

The use of solar photovoltaic systems for power generation requires efficient battery energy storage systems to ensure a steady and constant supply for self-sufficient power generation and off-grid areas. “Vision 2030” is Saudi Arabia’s strategy for reducing the country’s dependence on oil by 50% through investment in clean, renewable resources by 2030. This paper reviews the latest advancements in battery technologies designed for solar photovoltaic panels through a detailed comparative analysis of performance, energy storage capacity, efficiency, lifespan, cost, safety, and environmental impact for residential applications in the Kingdom of Saudi Arabia and those available in the United States of America. The performance of the advanced lithium-ion battery technology available in the USA surpasses that in the Kingdom of Saudi Arabia. The findings underscore the need for investments by the Kingdom of Saudi Arabia in advanced battery manufacturing technologies to improve the availability of different battery types and capacities and achieve the objectives outlined in the Kingdom of Saudi Arabia’s Vision 2030.

1. Introduction

Renewable energy can provide a constant supply of power without exhausting natural resources, making it crucial for a sustainable future. Energy produced from renewable sources releases no greenhouse gases during its generation process, significantly reducing air pollution and mitigating the impact of climate change [1,2,3]. Additionally, renewable energy promotes energy independence, reducing reliance on fossil fuels and supporting economic growth by creating new job opportunities [4,5,6,7].

Renewable energy sources such as solar, wind, hydropower, biomass, and geothermal energy contribute to a resilient energy system and sustainable resource use. Solar energy harnesses sunlight through photovoltaic cells, while wind energy generates electricity by capturing wind kinetic energy via turbines. Biomass energy is derived from organic materials such as plants and animal waste, while geothermal energy harnesses the heat from the Earth’s crust [8]. Each renewable energy source comes with unique benefits and applications that contribute to the stability of the energy system and, thus, to a sustainable planet. However, the characteristics of renewable energy are classified as intermittent and random, which can cause a mismatch between energy demand and supply. Therefore, to address this shortcoming and provide alternatives that are economically beneficial to households and environmentally acceptable, an energy storage system is required. For both ways of either residential connection to the local energy grid or being off-grid for energy supply, an option is needed for storing, stabilizing, and sharing the output of renewable energy, such as solar and wind. The stability of energy supply without compromising efficiency and economic considerations enhances the utilization of renewable energy [9].

In residential buildings, solar energy is recognized as one of the most accessible and dependable renewable energy sources [10,11]. Solar energy systems consist of two key components: solar panels and batteries [12,13]. The solar panels contain photovoltaic cells that convert sunlight into electricity. They can be installed on the rooftops of existing structures or seamlessly integrated into the design of new buildings. The second component, batteries, is essential for storing the generated energy and has greatly expanded in terms of types and manufacturers, offering diverse sizes and capabilities to meet various energy storage needs [14].

Furthermore, understanding occupant behavior and occupancy numbers in buildings is crucial to ensure the effective use of renewable energy, particularly when aiming to optimize energy consumption in high-density buildings. Research has been conducted to predict occupancy levels in such buildings, focusing on space optimization, which can directly contribute to reducing energy consumption [15,16]. Additionally, other studies have analyzed occupancy data to identify patterns across various building types, providing valuable insights that can also be utilized for developing energy-saving strategies [17,18].

1.1. Solar Photovoltaic Systems

The advantages of solar energy encompass both financial savings and environmental benefits. Solar panels produce electricity using the sun’s radiation, which does not harm the atmosphere or cause pollution [19], resulting in a significant reduction in carbon footprints when compared with fossil fuel power plants. Additionally, the adoption of solar panels decreases dependency on non-renewable energy sources, helping to preserve natural resources [20]. From an economic standpoint, solar energy can lower electricity bills and provide long-term savings, which may vary based on government incentives such as tax credits and rebates [21,22,23,24]. The cost-effectiveness of solar energy is further enhanced by its low maintenance requirements and long lifespan. Overall, numerous studies have confirmed the benefits of solar energy [25,26,27,28,29,30,31,32], highlighting its contributions to energy independence, environmental sustainability, and public health.

A study conducted by Bauner and Crago [33] aimed to assess the effects of installing solar panels on energy savings in residential buildings located in Massachusetts, USA. The energy savings were determined by considering the electricity price and the performance of the installed energy systems. The results varied depending on the price of electricity. As electricity prices increased, the potential savings also increased. Conversely, lower electricity prices can impact long-term savings, making them inadequate to cover the initial costs of installing a solar energy system. A similar study by Islam and Meade [34] examined the impact of adoption timing for electricity generation in residential buildings in Ontario, Canada. The greatest energy savings arose primarily from reduced installation costs, which subsequently decreased reliance on fossil fuels. A survey of 298 respondents indicated that they would likely adopt the technology for at least 10 years. Furthermore, several parameters affecting adoption time were identified, including climate and the energy consumption behavior of the household. Kaya et al. [35] examined the advantages of installing solar panels for saving energy and improving air quality in rural residential buildings in Poland. The amount of energy saved was calculated on a monthly basis, considering average electricity bills and the cost of solar panels. A survey was conducted in Poland in 2015 to collect energy data from rural households. The results revealed several benefits of using solar panels at different levels. At the household level, the utilization of solar panels reduced the reliance on fossil fuels, resulting in significant savings on monthly energy bills for families. At the national level, the increased adoption of a renewable energy mix would contribute to a reduction in overall greenhouse gas emissions (GHGs) and enhance air quality.

In another study, Klepackab et al. [36] discussed the benefits of investing in solar panels for rural households in Poland. A survey identified the important factors influencing household decisions. The results indicated that the use of solar panels can help lower emissions and energy costs while also reducing the dependence on fossil fuels, ultimately resulting in improved air quality. Another advantage was that the government in Poland supports households by offering subsidy programs designed to lower energy bills. A study by Samad et al. [37] reported the benefits of solar panels in Bangladesh. The benefits of adopting solar energy systems in the rural areas of the country include providing children with more opportunities to study at night and reducing kerosene consumption, which can improve health and reduce the impact on the environment. The adoption of this energy system is crucial, given that over 55% of rural areas have no access to electricity. Samad et al. [36] analyzed household financing schemes for the installation of solar panels and found that a 10% reduction in government electricity subsidies results in an increase in the demand for solar energy. Additionally, the financial stability of households enhanced the likelihood of adopting solar energy. Another study conducted by Palm [38] investigated the motivation for installing solar panels in Sweden. A total of 54 households were surveyed, and their motivations for installing solar panels were analyzed. The results indicated that households experienced significant advantages from the ease of installing the energy system despite the high initial costs. The high costs were mitigated by available subsidies. Additionally, households had the option to sell any excess energy back to the grid. Asrami et al. [39] aimed to determine the optimal scenario for utilizing PV in an urban residential area. The methods employed involved comparing three scenarios: grid-connected with battery, without battery, and full feed-in. The case study building selected was a five-story residential apartment building in Iran. The PV system was simulated using MATLAB, while environmental data were modeled using OpenLCA software program (V1.7.0). The results showed that full feed-in offers the best outcomes, which works by selling the produced energy from the system to the grid and then buying the required energy for operating the building back from the grid.

1.2. Battery Energy Storage System

Another key component of solar energy systems is the battery storage system. Studies have evaluated the advantages of incorporating battery storage into residential buildings, demonstrating its utility for both grid-connected and off-grid applications [40,41,42,43,44,45,46,47,48]. Batteries are available in various sizes, capacities, and types, each having specific characteristics and uses. Additionally, incorporating battery storage can enable a building to be self-sufficient in terms of electricity, thereby decreasing reliance on the power grid and minimizing the need for extensive infrastructure [49,50]. However, the economic factor can pose a challenge for households, as investing in these systems may involve a lengthy payback period, often spanning 10 to 15 years. However, this payback period could be reduced if the government provides support programs or incentives for households, whether they are connected to the grid or not.

Over the past few years, technology in lithium-ion batteries has advanced, particularly in solid-state batteries and silicon anode technologies. Improvements in these battery technologies have enhanced energy density and safety while reducing environmental impact. Solid-state batteries developed by several companies, such as Stellantis and Factorial Energy, have created a solid-state cell with a capacity of 375 Wh/kg of energy density. However, the battery can only operate within a limited temperature range of −30 °C to 45 °C [51]. TDK has surpassed lithium-ion batteries by developing a solid design with 100 kWh of energy density. However, it is for small-scale applications [52].

Tesla Megapack 2 and CATL sodium-ion batteries are commercial products available for large-scale storage systems. The Tesla battery has an energy capacity of up to 3.9 MW/h, with output ranging from 1.28 to 1.92 MW, depending on the version. The unit employs a thermal management system for monitoring and safety, as lithium-ion batteries are sensitive to temperature changes [53]. Sodium-ion batteries have broad applications; they can be used in electric vehicles and energy storage. The capacity of the second generation exceeds 200 Wh/kg, with a rapid charging capability of up to 80% in 15 min. This battery system offers thermal stability for safety and enhances performance [54].

Sharma et al. [55] analyzed the impact of integrating photovoltaic systems with battery storage on energy expenses for grid-connected residential buildings in Australia. The results indicated that utilizing battery storage can lead to significant savings on energy bills. By implementing time-based tariffs along with energy storage, households can reduce their annual energy costs. Moreover, the use of batteries can reduce the peak load on distribution feeders by up to 35%. Another study conducted by Srikranjanapert et al. [56] investigated the economic benefits of integrating battery-based storage systems with photovoltaic panels for households in Thailand by developing and comparing the following three scenarios: (a) installing only photovoltaic systems, (b) combining photovoltaic with management systems, and (c) combining photovoltaic with management systems and batteries. The results showed that integrating photovoltaic panels with energy management systems and batteries can result in energy savings, which can significantly reduce energy bills. However, the battery costs are still high and may reduce savings or increase investment returns. Similarly, Koskela et al. [57] evaluated the economic benefits of utilizing photovoltaic systems in combination with energy storage batteries for residential buildings in Finland. This study considered several electricity metrics and prices to determine the optimal number of photovoltaic panels and battery capacities required. The results showed that using energy storage batteries can increase the number of photovoltaic panels. However, using both photovoltaic and batteries can be more profitable than the use of photovoltaic panels alone. Moreover, incentives played a crucial role in lowering the initial cost of the energy system. Schopfer et al. [58] assessed the economic benefits of using photovoltaic batteries for households in Switzerland, collecting data related to energy consumption from a total of 4190 households. This study developed a machine learning algorithm to predict the future profits of a system. Their results revealed high levels of profit potential even in the absence of subsidies. Forty percent of the households studied realized revenue by integrating the energy system. In a different cost scenario, almost all of the households benefited from utilizing both photovoltaic and battery systems.

Uddin et al. [59] analyzed the economic benefits of battery energy storage in residential buildings in the United Kingdom. The advantages of using batteries include the financial benefits of reduced utility bills and the potential for financial returns from incentives. Over the course of a year, the electricity demand of the household and the energy generated by photovoltaic systems were monitored. This study employed several models to evaluate the benefits of long-lasting photovoltaic systems and batteries. The cost–benefit analysis showed that relying on batteries can lead to savings and revenue generation through the export of excess energy to the grid. Shah and Al-Awami [60] discussed the financial benefits of utilizing batteries in 6 kW installed photovoltaic panels for households in California. Several factors, including output power, battery size, charging and discharging rate, and lifespan, were taken into consideration. Scenarios included four configurations with and without the use of batteries and photovoltaic panels. This study spanned 6 months in 2015, revealing fluctuations in costs throughout the months. Notably, the scenarios that incorporated batteries were the most efficient, making it cost-effective to store electricity for use at night. A study conducted by Uctug and Azapagic [61] examined the level of environmental impact and benefits when using both photovoltaic systems and batteries in Turkey. Electricity consumption and storage data were collected in hourly intervals, as well as data on household behavior. Subsequently, electricity grid consumption, cost, and associated emissions were evaluated. The results showed that the system could generate five to eight times more energy over its life cycle than the household consumed. Moreover, the energy system comprising photovoltaic panels and batteries had a lower environmental impact in terms of reducing carbon dioxide emissions compared with grid electricity.

Regarding self-consumption buildings, Schram et al. [62] studied the integration of battery storage with photovoltaic systems for a household in a Dutch city to assess its self-consumption. A simulation model using MATLAB was used to determine the optimal capacity size of the battery. Open-source data from 79 households were obtained for a period of 1 year, spanning November 2013 to October 2014. This study determined the optimum capacity of the storage battery considering the maximum kWh usage of the house and the price. The capacity of the selected battery had to be sufficient to meet the peak demand hours for the household in order to achieve self-consumption. However, this size could not be standardized across all households studied, as each household exhibited unique energy consumption behavior. In another study, Nyholm et al. [63] investigated the dependency of electricity self-consumption on storage batteries in Swedish households. This study aimed to align annual consumption patterns. The results showed that households can achieve self-consumption by selecting the appropriate battery capacity. Therefore, utilizing batteries to store photovoltaic-generated electricity can increase self-sufficiency by up to 30% compared with households relying only on photovoltaic panels. A study conducted by Mulder et al. [64] demonstrated the process of deciding the optimal battery size for storing electricity from photovoltaic panels for a certain number of days. The aim was to determine the optimum battery capacity to cover the entire household energy consumption. Therefore, it was essential to install as many photovoltaic panels as possible to compensate for the annual reduction in their efficiency. The results, obtained from analyzing real data collected over 1 year from seven houses in Belgium, revealed that the maximum cover of these systems for a typical household energy consumption was 73%. Moreover, this study concluded that the optimal factors for selecting battery size included the efficiency of the battery, voltage limitation, number of charging and discharging cycles, and lifespan. Souza and Junior [65] evaluated the benefits of connecting PV to the grid alongside the availability of an energy storage system. The case study was conducted in a university building in Brazil. The PV system had a capacity of 10.72 kWp and was paired with a 57.6 kWh lead-acid battery. The objective was to reduce dependence on electricity from the grid, particularly during peak demand hours. The results indicate an economic advantage during off-peak hours, which helps mitigate the high costs associated with peak hours.

Overall, integrating PV and battery storage systems into residential buildings offers notable advantages. It leads to financial savings by lowering energy bills, enhances air quality by minimizing reliance on fossil fuels and carbon emissions, provides governmental incentives, and alters household energy consumption patterns. Additionally, these systems present benefits for developing nations such as Bangladesh, where solar panels contribute to better health, education, and rural electrification. Rural communities experience increased energy independence and improved cost efficiency. However, households still need to modify their energy consumption behaviors to fully realize self-sufficiency and long-term gains.

The main contribution of this work was to highlight the limitations of existing battery technologies in the Kingdom of Saudi Arabia (KSA) by drawing a comprehensive comparison between two different battery technologies utilized in different countries. This analysis involved analyzing various parameters to enhance both financial and technological benefits. Furthermore, this work promotes the importation of cutting-edge technologies into the KSA by showcasing the potential benefits of these advanced technologies.

This paper is divided into three sections. Section 1 introduces the renewable energy concepts and the advantages of their utilization, with a focus on solar photovoltaic panels (Section 1.1) and battery energy storage systems (Section 1.2) for residential buildings. Section 2 outlines the methodologies used in battery selection (Section 2.1), parameter identification (Section 2.2), and data collection methods (Section 2.3). Section 3 analyzes collected data based on the selected parameters and discusses the results of this study.

2. Methods

This section provides a comprehensive analysis of the battery selection criteria observed in two countries. Followed by a detailed discussion of the parameters utilized for comparison. Additionally, it outlines the methodology employed for data collection, including the sources and processes involved in gathering relevant information to ensure a robust and reliable comparison.

2.1. Battery Selection

Batteries selected for this study originated from retail markets in the KSA and USA and represent the readily available technologies in the respective markets for residential uses. This aimed to identify the leading battery models from each country. The selection process involved a thorough review of market supply, manufacturers, and supported companies in the national grid of each country. The advancements in battery technology have prioritized selecting the highest battery capacity available. Consequently, it was unnecessary to replicate all features, such as capacity, since the primary objective was to identify the most effective technology that could address battery challenges in the KSA.

2.2. Parameters

In order to draw a comprehensive comparison, this study considered several relevant parameters, including the type of battery in terms of chemical composition and photovoltaic system capabilities, for instance, lithium-ion and lead-acid; voltage (V); current (A) output. The capacity of a battery (kWh) was determined along with its life cycle (the number of battery charging and discharging cycles). The dimension and weight of the battery were also considered to determine the space required and the ease of transport/installation. To reflect the economic investment, the warranty period and retail cost (market price) of each battery were recorded from various authorized retailers and online platforms. The battery’s sensitivity to the environment was also recorded, including temperature and humidity, in terms of capacity and performance. The potential for increasing capacity by connecting batteries in series was evaluated. The extent of battery deterioration and lifespan were determined. Finally, the safety performance of the battery was compared, including thermal runaway, gas emission, environmental hazards, and temperature resilience. These comprehensive parameters were selected for a detailed comparison of the battery technologies.

2.3. Data Collection

The data collection process related to the batteries’ selected parameters was based on the manufacturers’ official documentation, battery specifications, published brochures, and authorized retailers in the KSA and USA.

The data collection process for batteries was carried out using a comprehensive and systematic approach, focusing on gathering reliable, accurate, and up-to-date information from a variety of credible sources. Key parameters related to battery performance, capacity, efficiency, lifespan, and cost were identified. To ensure data accuracy, official documentation from manufacturers was the primary information source, including technical datasheets, white papers, and detailed product specifications. These documents were retrieved from manufacturers’ websites and certified technical publications. Additionally, battery specifications were cross-verified using published brochures to maintain consistency and reliability.

3. Results

Data collected from two battery retailers in the two countries were analyzed to compare in terms of performance and characteristics of their respective technologies. The selected lead-acid and lithium-ion batteries from two retailers in the KSA and USA, respectively, correspond to the top options for residential uses in their respective markets.

Table 1. Parameters used for comparisons between the regulated lead-acid battery and the lithium-ion battery.

Parameter	KSA Retailer	USA Retailer
Type	Regulated Lead-Acid Battery	Lithium-Ion Battery
Series	NPD Series	LiFePO4
Volts	12	51.2
Amperes	200	100
Capacity kwh	2.4	5.12
Cycle	550 at 50% DOD	8000 at 50% DOD
Dimension	52.2 (L) × 23.8 (D) × 22.2 (H) cm	48.26 (L) × 48 (D) × 17.78 (H) cm
Weight	59.5 kg	44.45 kg
Cost/USD	USD 360	USD 900
Cost/kWh	USD 150/kWh	USD 175.78/kWh
Warranty	3 months	4 years
Series connection	16 connected batteries totaling 38.4 kWh	10 connected batteries totaling 51.2 kWh

presents several parameters used for comparisons of each battery. The regulated lead-acid battery (NPD Series) is widely used in the KSA for its ability to handle high temperatures along with a high surge current [66]; however, it has a slow recharging capacity, taking up to 16 h to fully charge, short lifespan of 3 years, and potential of hydrogen gas generation. On the other hand, the lithium-ion battery (LiFePO4 Series) used in the USA has a high energy density, which makes it lightweight and compact [67]. Its lifespan is longer than other batteries, reaching up to 10 years. Other battery types have a high discharge rate, which can affect battery applicability. According to the manufacturers, the lithium-ion battery has a low discharge rate of 2% per month [67].

Other comparison parameters included voltage, current, storage capacity, and charging cycle. The battery used in the KSA (lead-acid battery) was 12 V with 200 A and a capacity of 2.65 kWh. However, a higher battery current reaching up to 3000 amperes is available in some countries but not in the KSA markets. The number of recharging cycles of the battery can reach up to 500 at 50% charging. In contrast, the battery sold in the USA has better capabilities. The battery has a high voltage of 48 V with 100 A and a capacity of 5.12 kWh. The battery has a high charging cycle value of 6000 at 50% charging. The comparison shows that the lithium-ion USA battery has a four-times higher voltage, five times higher current, and 45% higher battery storage capacity and charging cycles compared with the one available in the KSA.

The cost per kW was calculated based on the battery storage capacity. The cost per kW of the lead-acid battery that has a capacity of 2.4 kWh was USD 150/kWh, with a battery cost of USD 360, while the cost for the lithium-ion battery with a 5.12 kWh capacity was USD 175.78/kWh for the lithium-ion battery, with a battery cost of USD 900. Although the price of the lithium-ion battery is higher per kWh, it has the advantage of smaller space requirements and lighter weight compared with the lead-acid battery. Therefore, in order to calculate the required space of the two different battery types, their dimensions and weight were considered. The dimensions of the batteries are 23.80 (D) × 52.20 (W) × 22.20 (H) cm and 48.00 (D) × 48.26 (W) × 17.78 (H) cm for the lead-acid and lithium-ion batteries, respectively. The lead-acid battery is 33% smaller in size compared with the lithium-ion battery. However, to match the capacity of the lithium-ion battery, the lead-acid battery would require 25% more space. Moreover, applying the system to off-grid residential buildings would require more storage batteries. Consequently, households would gain advantages from utilizing lithium-ion batteries, which can be linked together with up to 10 additional units, providing a total capacity of 51.2 kWh while occupying a smaller footprint. These batteries can be stacked five batteries high. In contrast, lead-acid batteries can connect up to 16 units but only offer a capacity of 38.4 kWh and require more space with additional safety and thermal management considerations. The connection of batteries required additional percussion, concerning the performance and safety aspects. Lithium-ion batteries can be affected by changes in temperature, which affect the performance and the lifespan of the battery. The generation of heat in the battery comes from the chemical reactions in the event of charging and discharging. For that, a thermal management system for the batteries is crucial for maintaining and observing the temperature of the batteries [68].

Lithium-ion batteries offer significantly longer warranty coverage, with manufacturers in the USA typically providing a four-year warranty. This is a substantial improvement over the limited three-month warranty typically offered for lead-acid batteries in the KSA. This difference in warranty periods highlights the higher reliability and durability associated with lithium-ion technology, reflecting its advanced performance and suitability for long-term use compared with traditional lead-acid batteries. Moreover, the extended warranty for lithium-ion batteries is indicative of the greater confidence of manufacturers in the battery’s durability and resilience under various usage conditions.

Figure 1 illustrates a comparison of the self-discharge rates over time for lead-acid and lithium-ion batteries under different temperatures. Battery capacity and ambient temperature affect energy storage [67]. In lithium-ion batteries at 40 °C, the battery capacity dropped to 50% after 15 months. At a lower temperature (30 °C), the battery took at least 2 years to reach 50% self-discharge. Moreover, a battery can have a self-discharge rate of almost 4 years when stored at a room temperature of 20 °C. Lead-acid battery capacity is more sensitive to high temperatures [66]. The battery capacity dropped to 50% in 5 months at 40 °C. At 30 °C, the self-discharge could take up to 11 months. In the case of storing at a room temperature of 20 °C, self-discharge can last up to 16 months. Therefore, the lithium-ion battery performed much better than the lead-acid battery, especially since the 5% decrease in battery capacity over 45 days at a high temperature of 40 °C was notably slower compared with the rapid 15 day decrease observed in the case of the lead-acid battery capacity.

The Depth of Discharge (DoD) in the context of batteries refers to the percentage of used capacity or the discharge related to the overall battery capacity. The optimal percentage of discharge varies based on battery types. However, different discharges have different impacts. Shallow discharges, which fall between 20% and 50% DoD, can significantly extend the lifecycle of the battery. In contrast, deep discharges, which range from 80 to 100% DoD, can increase degradation, leading to a reduced lifespan of the battery. In lead-acid batteries, it is recommended to charge them when they reach 50%, which maximizes their performance. However, discharging beyond the recommended percentages can decrease the number of cycles. In lead-acid batteries, using the entire battery capacity can yield a maximum of 250 cycles, while using 50% DoD can increase it to 550 cycles. Using 30%, DoD can reach 1250 cycles. On the other hand, lithium-ion batteries show a better number of cycles for different DoDs compared with lead-acid batteries. They provide 8000 cycles with 50% DoD, 4000 cycles with 80% DoD, and the least number of cycles at 3000 with 100% DoD [66,67].

Figure 2 and Figure 3 illustrate the charging and discharging characteristics of the two batteries. Figure 2 shows the performance of the lithium-ion battery during charging and discharging at 40 °C [67]. There was stability in the voltage in the range of 30–90% of the battery capacity. A rapid increase in the voltage at the end of charging when reaching 90% capacity and a similar one during discharging at the same percentage, but with a voltage drop, was also observed. Such an increase and decrease in the battery voltage is a disadvantage of the lithium-ion battery and should be considered in order to prevent battery damage and maximize battery life. Figure 3 shows a different pattern for battery charging voltages for the lead-acid battery, as the voltage increases gradually throughout the charging cycle [66]. However, the voltage curve changed based on whether the discharge percentages were 50% or 100%.

Table 2. Differences in the charging and discharging characteristics of lithium-ion and lead-acid batteries.

Characteristic	Lithium-Ion Battery	Lead-Acid Battery
Charge voltage behavior	- Voltage rises rapidly at first, then remains flat until the final stage. - Sharp rise near full charge.	- Voltage gradually increases from ~11 V to ~15 V over time. - Higher final charge voltage.
Charging time	- Generally fast charging (hours).	- Slow charging, taking up to 20 h.
Voltage stability	- More stable voltage during charge/discharge.	- Gradual voltage increases during the charge cycle.
Charging efficiency	- High efficiency, minimal energy loss.	- Lower efficiency, with higher energy loss (due to heat).
Charge behavior	- Flat voltage curve for most of the charge cycle, steep rise at the end.	- Slower, steady voltage increase. Charging behavior depends on the initial discharge level (50% or 100%).

provides a detailed summary of the charging and discharging characteristics of the two batteries.

Therefore, during charging and discharging, lithium-ion batteries showed a faster and more stable voltage, making them more efficient with less energy loss. In contrast, lead-acid batteries exhibited slower charging with a gradual increase in the voltage over time and different charging behavior depending on the discharge battery level (50% vs. 100%), which affects the battery efficiency, energy loss, and energy density.

Figure 4 illustrates the impact of temperature on capacity for the two battery types. The effects under low- and high-temperature conditions were compared. The lithium-ion battery capacity reached 100% at 30 °C and slightly increased under high temperatures (up to 60 °C) at a 0.5 C discharge rate. Therefore, the battery was able to maintain a stable and high capacity under high temperatures. However, as the temperature dropped to −20 °C, the battery lost about 30% of its capacity. Despite this drop in capacity, the battery performed well under both low and high temperatures. On the other hand, the lead-acid battery could not reach 100% capacity, which highlights the impact of high temperatures on the battery. Under high temperatures, the capacity of the battery reached only 70%. The faster the discharge rate, the greater the effect of high temperature. In extreme cold conditions, the battery lost 40% of its capacity. Although the battery capacity improved as the temperature increased, even at room temperature (25 °C), the battery capacity could not reach 100%. These observations demonstrate the sensitive relationships between battery capacities, temperature, and discharge rates.

Thus, temperature can affect both battery types, though at different rates. At high temperatures, lithium-ion batteries retained higher capacity levels and reached 100% at 20 °C with a 0.5 C discharge rate, compared with lead-acid batteries that cannot reach 100% until the discharge rate is reduced to 0.05 C.

Table 3. Main differences in the effect of temperature on battery capacity.

Parameter	Lithium-Ion Battery	Lead-Acid Battery
Capacity at –20 °C	~70% at 0.5 C	40% at 1 C, 80% at 0.05 C
Capacity at 25 °C	~100% at 0.5 C	~60% at 1 C, ~100% at 0.05 C
Capacity at 40 °C	~100% at 0.5 C	~75–80% at 1 C, ~100% at 0.05 C
Effect of discharge rate	Moderate impact 0.5 C stable across temperatures	Significant impact Higher rates show more loss
Cold temperature	Better capacity retention	Significantly worse at higher discharge rates
High temperature	Stable at higher temperatures	Capacity increases at low discharge but decreases at 1 C

provides a comprehensive summary of the impact of various temperature levels on battery capacity. Under low temperatures, the lithium-ion battery was able to preserve more capacity than the lead-acid battery. The lead-acid battery had an acceptable performance at lower temperatures but still could not compete with lithium-ion battery levels. The reason for this is that the lead-acid battery is more sensitive to temperature and discharge rates than the lithium-ion battery.

Table 4. Comparison of safety performance characteristics between lead-acid and lithium-ion batteries across key risk and environmental parameters.

Parameter	Lead-Acid Batteries	Lithium-Ion Batteries
Risk of Thermal Runaway	Low risk because of their aqueous electrolyte and lower energy density.	High risk leading to rapid temperature increases and potential fires.
Environmental Hazards	High impact producing hydrogen gas in the event of overcharging, contains lead and sulfuric acid, posing an explosion risk if not properly ventilated, and environmental risks if improperly disposed of the battery.	Moderate impact can lead to fire if gases accumulate and ignite, contain toxic metals, and improper disposal can lead to environmental contamination.
Temperature Resilience	Operates well in a range of temperatures; less prone to fire propagation.	Sensitive to high temperatures, fires can propagate quickly between cells.
Battery Management System (BMS) Dependencies	Does not require a BMS as the battery operation is a simpler system.	Rely heavily on BMS for safety; the failure of the system can cause overheating and overcharging, which can lead to potential fires.

presents a comparison of the safety performance characteristics of the two battery types. Safety measures are crucial since batteries will be used in residential buildings. For this, several parameters were taken into consideration for the comparison, and the results varied according to the properties of each battery.

The thermal runaway in lithium-ion batteries is significant, which can lead to a potential fire because of the rapid increase in temperature. On the other hand, lead-acid batteries produce hydrogen gas when they are overcharged, which poses a risk of explosion if not properly ventilated. To avoid overheating and overcharging, lithium-ion batteries rely on a battery management system (BMS) for safety and control, compared with the simpler system in lead-acid batteries. In terms of environmental hazard, lead-acid batteries have a significant impact because of their lead and sulfuric acid content, compared with the lesser impact of lithium-ion batteries, which contain toxic metals. However, the contents of both battery types can pose an environmental risk and cause contamination if not disposed of properly [69,70].

4. Conclusions

This study presents a comprehensive comparison of two battery storage systems used in solar photovoltaics available in the KSA and the USA. Comparisons were performed based on several parameters to evaluate the performance and capabilities of the selected batteries (lithium-ion and lead-acid) available from different retailers in the two countries. Several parameters, including the type of batteries, voltage (V), current capacity (amperes; A), energy storage capacity (kWh), number of cycles, size, weight, cost (USD), cost/capacity (USD/kW), connection series, charging and discharging capabilities, and safety performance characteristics were used for evaluation to highlight the important role of battery storage systems in supporting the KSA Vision 2030. The findings revealed that lithium-ion batteries, widely used in the USA, have more advantages than the lead-acid batteries used in the KSA in terms of several parameters, including capacity (5.12 kWh vs. 2.4 kWh), performance under high temperature, number of cycles (6000 cycles vs. 500 cycles), and higher voltage (48 V vs. 12 V). The cost analysis revealed that the lithium-ion battery is more expensive per kWh than the lead-acid battery (USD 175.78/kWh vs. USD 150/kWh, respectively). However, the higher cost is associated with higher efficiency, reduced space requirements, and longer lifespan, which make these batteries more cost-efficient in the long run. Moreover, the ability to be stacked makes this battery type more appealing since it can be used in residential buildings where space and safety are critical, especially under the high-temperature conditions typical for the KSA. Lithium-ion batteries are favored for their performance and safety, which are critically important in the context of residential energy storage systems. Therefore, all the above comparisons between the two batteries support the recommendation to transition to lithium-ion batteries.

This study also provides a detailed description of the lead-acid battery commonly used in residential buildings in the KSA. This battery is initially more affordable but has many drawbacks, such as sensitivity to the high temperatures of the country (which can reach 60 °C in the summer). Another drawback is that fluctuating conditions limit battery reliability, as seen in the comparative analysis of the impact of temperature on battery capacity (Figure 4). This battery is less suitable for such climate conditions, yet it is used in the KSA along with several measures to overcome this issue. These measures include placing batteries in a thermally controlled room (which can occupy a space inside the house), or a shaded area constructed for it with separate air conditioning for thermal control. All of these drawbacks make it less efficient for modern energy storage needs. These data and comparative graphs highlight the technological limitations of the battery options available in the KSA compared with those in the USA, emphasizing the importance of adoption by the KSA of the more advanced lithium-ion battery storage systems. Such an adoption will enhance energy storage capabilities, leading to a reduction in dependency on fossil fuel-generated power from the grid. Therefore, the objective of adopting this technology to achieve the goals of the KSA Vision 2030 for increasing the use of renewable energy by 50% should not be limited to investing in renewable energy sources such as solar power but should also include the importation and integration of advanced energy storage systems.

Future research will concentrate on building-level case studies in the KSA. The aim is to evaluate building an energy storage system on KSA energy prices by developing a Monte Carlo simulation. Moreover, a simulation model will be developed to determine the optimal number, size, and capacity of photovoltaic panels and batteries to support self-consumption buildings. By comparing various configurations, this study can inform the development of energy and cost-efficient photovoltaic and battery systems to address grid demand and reduce fossil fuel dependence. Additionally, this study will help elucidate the economic and environmental impacts of renewable energy adoption across similar regions, enhancing sustainable practices and design.