Decode : Chapter 1 – Understanding BESS and its Applications

We present the first chapter of DECODE, a unique initiative launched by Cleantech Hero, where we talk to various industry leaders and Subject Matter Experts about their informative opinions and insights across various domains in the clean and sustainable energy ecosystem.

We had the good fortune of getting in touch with Dr. Rashi Gupta, the founder of Vision Mechatronics, to gain valuable insights about Battery Energy Storage Systems (BESS) and the kind of impact BESS can have across industries. Dr. Rashi Gupta, often referred to as ‘Batterywali of India’ is a Subject Matter Expert on Battery Storage and its applications.

Question – Energy storage has historically been more expensive than energy generation, do you think BESS will become more popular in coming times? If yes, can you talk about its impact on the renewable energy eco-system?

Answer – Yes, BESS is poised to become significantly more popular in the coming times. Several factors are driving this:

• Decreasing Battery Costs: Lithium-ion battery prices have plummeted, making BESS more economically viable.
• Increasing Renewable Energy Penetration: Intermittent renewable sources like solar and wind require energy storage to ensure grid stability and reliability.
• Grid Modernisation: BESS supports grid modernisation by providing ancillary services such as frequency regulation, voltage support, and peak shaving.
• Policy Support: Many governments are incentivising BESS deployment through subsidies, tax credits, and favourable regulations, mandating 2hours storage for large RE plants.

Impact on Renewable Energy Ecosystem:

• Enhanced Grid Stability: BESS balances supply and demand fluctuations caused by intermittent renewables.
• Increased Renewable Energy Integration: It allows for greater integration of renewables into the grid by storing excess energy during peak production and releasing it during low production.
• Reduced Curtailment: BESS minimises the amount of renewable energy that is wasted due to grid limitations.
• Decentralised Energy Systems: BESS enables the development of micro-grids and off- grid renewable energy systems, improving energy access in remote areas.

Question – Today, does it make sense for MSMEs to shift to BESS? Which industries can it make the most impact in?

Answer – Whether it makes economic sense for MSMEs to shift to BESS today is becoming increasingly favourable, especially when considering the emergence of the second-life battery market.

First-Life BESS for MSMEs: For some energy-intensive MSMEs or those highly susceptible to power outages, investing in a new (first-life) BESS can already be justified. This is particularly true if they can leverage BESS for multiple benefits like:

• Backup Power: Ensuring business continuity during grid failures.
• Demand Charge Reduction: Lowering electricity bills by discharging the battery during peak demand periods.
• Renewable Energy Integration: Maximising the self-consumption of on-site solar power.
• Power Quality Improvement: Protecting sensitive equipment from voltage fluctuations.

However, the upfront cost of a first-life BESS can still be a significant barrier for many MSMEs.

The Second-Life Battery Game Changer: This is where the concept of “second-life” batteries, particularly facilitated by Vision Mechatronics’s “RELIVE” Battery, becomes a game-changer. Second-life batteries are electric vehicle (EV) batteries that no longer meet the stringent performance requirements for vehicles but still retain a significant amount of their energy storage capacity (typically 70-80%).

How Second-Life BESS Benefits MSMEs:

• Significant Cost Reduction: Second-life batteries are substantially cheaper than new batteries, often 30-50% less. This dramatically lowers the initial investment for an MSME looking to adopt BESS.
• Sustainability: Utilising second-life batteries contributes to a circular economy by giving valuable resources a second life, reducing e-waste and the environmental impact of battery manufacturing.
• Viable ROI: The lower upfront cost of second-life BESS makes the return on investment much more attractive for MSMEs, potentially leading to quicker payback periods through reduced energy costs and avoided downtime.

Industries Where BESS (Including Second-Life) Can Make the Most Impact for MSMEs:

• Manufacturing: Small and medium-sized manufacturing units often face high energy costs and production losses due to power interruptions. Second-life BESS can provide reliable backup and help manage peak demand, improving profitability.
• Hospitality (Small Hotels, Restaurants): Ensuring uninterrupted power for essential services, refrigeration, and customer comfort is crucial. Second-life BESS offers a cost-effective way to achieve this.
• Agriculture and Food Processing: Maintaining cold chains and powering essential equipment in rural areas with unreliable grid access can be significantly improved with affordable second-life BESS coupled with renewable energy.
• Small Data Centres and IT Services: Even smaller businesses rely on consistent power for their IT infrastructure. Second-life BESS can provide a budget-friendly backup power solution.
• Commercial Buildings (Small Offices, Retail): Reducing peak demand charges and providing backup for critical systems like lighting and security can lead to significant cost savings.

Question – What are the most common BESS sizes currently being deployed in industries? What is the difference between them in terms of cost and energy storage?

Answer – BESS sizes vary significantly depending on the application. Common industrial sizes include:

• Small-scale (100 kW – 1 MW): Used for peak shaving, demand management, and backup power for individual facilities.
• Medium-scale (1 MW – 10 MW): Deployed for grid support, frequency regulation, and integrating larger renewable energy projects.
• Large-scale (10 MW+): Used for large-scale grid stabilisation, renewable energy integration, and providing ancillary services.

Cost and Energy Storage Differences:

• Larger BESS installations generally have lower per-kWh costs due to economies of scale.
• Energy storage capacity and power rating influence the cost. Higher capacity and power ratings increase the overall cost.
• The type of battery technology also affects the cost, with LFP batteries often being more cost-effective than other lithium-ion chemistries.

Question – In India, how important is BTMS in BESS? Which should be preferred, air cooling or liquid cooling?

Answer – In India, Battery Thermal Management Systems (BTMS) are crucial due to the country’s high ambient temperatures.

Cooling Preferences:

• Liquid Cooling: Generally preferred for larger BESS installations and high-power applications due to its superior heat dissipation capabilities. It is more efficient in hot climates, which is very important in most of India.
• Air Cooling: Suitable for smaller BESS installations and applications with moderate power demands. It is less complex and less expensive but may struggle to maintain optimal battery temperatures in extreme heat.

In India, due to the high ambient temperatures, liquid cooling is generally more effective at maintaining battery health and longevity.

Question – What are your thoughts on trending sodium-ion batteries in BESS? How do they fare against Lithium-ion / LFP batteries in terms of performance, cost and efficiency?

Answer – Sodium-ion batteries are emerging as a promising alternative for Battery Energy Storage Systems (BESS), driven by the abundance and lower cost potential of sodium compared to lithium. In terms of performance, current sodium-ion batteries generally have lower energy density (100-160 Wh/kg) compared to Lithium-ion (150-250 Wh/kg) and Lithium Iron Phosphate (LFP) batteries, which could impact their suitability for applications where space and weight are critical.

However, they often exhibit superior performance in terms of safety, with a lower risk of thermal runaway, and a wider operating temperature range, including better performance in cold temperatures. Cycle life for sodium-ion batteries is improving, with some may reaching levels comparable to LFP batteries in the coming years.

Regarding cost, while the raw material cost of sodium is significantly lower than lithium, the current production cost of sodium-ion batteries is not necessarily lower than LFP due to the lack of large-scale production. However, as the technology matures and production scales up, sodium-ion batteries are expected to become more cost-competitive. Efficiency-wise, sodium-ion batteries have shown comparable, and in some cases better, charge/discharge rates and can often be discharged to 0V without damage, unlike lithium-ion. Considering the different strengths of these technologies, exploring hybrid battery systems, such as a sodium lithium combination, could be a beneficial approach. This could potentially leverage the high energy density and longer cycle life of lithium-ion in certain aspects while utilising the cost-effectiveness and safety advantages of sodium-ion for other operational demands.

Vision Mechatronics’ MW-scale lead-lithium hybrid battery project in Gurugram serves as a relevant example of how combining different battery chemistries can optimise performance and cost for specific energy storage needs. Despite the promising advancements in sodium-ion technology, lithium-ion batteries, particularly LFP, are well- established and continue to improve in performance and cost, indicating that lithium is likely to remain a dominant player in the BESS landscape for the foreseeable future, with sodium-ion carving out its niche in specific applications.

Question – Depending on the region, should one choose different batteries for different temperature surroundings? If yes, which ones in which environments?

Answer – Yes, battery selection should consider regional temperature variations.

Hot Climates (like many parts of India): LFP (Lithium Iron Phosphate) batteries are a good choice due to their high thermal stability and longer cycle life. Liquid cooling BTMS is recommended.

Cold Climates: Some Lithium ion chemistries perform better in colder conditions.Heating systems within the BTMS become very important.

It is always very important that the BTMS is very well developed for the regional climate and is very well integrated into the Battery Management system.

Question – How does depth of discharge affect the cycle life of a BESS? Optimally, what should be the depth of discharge for a BESS?

Answer – DoD significantly affects BESS cycle life. Higher DoD reduces cycle life.

Optimal DoD: Generally, a DoD of 80% or less is recommended to maximise cycle life. Some LFP batteries are very tolerant of higher DoD usage, but generally, less DoD equates to more life. Operating within the battery manufacturer’s recommended DoD range is crucial for longevity.

Question – BESS can be a fairly expensive endeavour, how often does it need maintenance?

Answer – Considering the current affordability of Battery Energy Storage Systems (BESS), it’s important to acknowledge that maintenance frequency is influenced by several key factors. These include the battery type, with Lithium Iron Phosphate (LFP) generally requiring less upkeep compared to other chemistries, the operating conditions, where harsh environments necessitate more frequent attention, and usage patterns, with high-cycle applications demanding more intensive maintenance. Typical maintenance procedures involve regular inspections of connections, wiring, and cooling systems, comprehensive battery health monitoring and diagnostics, software updates and calibration, and periodic cleaning and component replacement.

While modern BESS systems benefit from sophisticated monitoring capabilities that have significantly reduced maintenance demands compared to earlier systems, at Vision Mechatronics, we have further enhanced this with our indigenously developed preventive and predictive monitoring system. This advanced tool is capable of detecting potential failures up to 15 days in advance, providing a highly effective means to avert complicated situations and problems, ensuring optimal performance and longevity of the BESS.

Also read: BESS & Demand Response | What’s the Connection?