Was reading an interesting article in today’s Financial Express on the use of Li-ion battery for solar power storage. This article was based on perspectives from Samir Sharan, CEO of Acme, the Indian solar and telecom equipment maker that is unveiling a LIB based solar storage solution called EcoGrid.
Sure, LIB has its advantages – its 4000 cycle, 10 year life (against 3-4 years from lead acid), light weight, lower space requirements and all.
The key question will of course always come down to cost.
According to the article, a typical LIB storage equipment designed for a 5 KVA load with a storage capacity of 6.6 kWh would cost about Rs 3.5 lacs.
I thought I’d try computing the costs using these data sets.
Firstly, the capital cost.
Rs 3.5 lacs as capital cost is a bit too high for most of us in the residential sector, assuming we have a 5 KVA load. This alone can be a huge put off.
But what would be also be interesting to know is the variable cost (per kWh) that gets added if we use batteries.
Let us do this calculation for the above data.
The raw nameplate energy cost comes to about Rs 50000 per kWh (3,50,000/6.6), or about $800/kWh. This is much higher than what I hear as cost in the market, which is about $300/kWh for Li-ion battery.
Now, you might be interested in knowing what would be the extra you would be spending for every unit of energy spent using the battery during its lifetime.
A 6.6 kWh battery that will last 4000 cycles would have in all supplied, a max of 26400 kWh (I am being generous in not assuming any energy losses from battery). So, you are dishing out Rs 3,50,000 to get 26400 kWh. That would mean you are dishing out Rs 13.25 per kWh used, over the lifetime.
Sounds too high once again.
The data I have from the market says that the nameplate energy cost should be about Rs 20,000 /kWh for LIB, which will mean, I spend an additional Rs 5 for ever unit I use through the battery. Still a lot of money, but much less than Rs 13.25.
Can someone respond why the EcoGrid storage should cost two and a half times that for a conventional LIB storage?
By the way, for those interested, costs for deep cycle lead acid batteries, the ones that are typically used for solar power storage, should cost less than $150 per kWh, which means about Rs 10000/kWh nameplate and about Rs 2.5 /kWh as the expense for me for every unit spent using the battery.
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Nice article. Maybe a few comments on the calculations, I think in reality the depth of discharge is around 90% for the EcoGrid and assuming an efficiency of 90% we get the total lifetime energy to be around 21300kWh (6.6 * 4000 * 0.9*0.9). Now this works out to be Rs. 16 /kWh of usage over the lifetime.
However, the $300/kWh of storage capacity that you talk about it purely for the batteries not including the inverter. For example, Tesla’s 7kWh PowerWall is $3000. If you add inverter costs, which can easily be around $2000 for a plug-n-play it brings the cost to $5000 for 7kwh which is $714/kWh, which is in the same ballpark as the ACME EcoGrid, the price of which includes an inverter.
On another note, what are other competitors in India for ACME? Are other companies going big on Li-ion?
It’s a nice and informative article written by you.
However there are many companies using advanced technology such as LiFeYPO4 cells, active balancer etc for lithium batteries. You can refer to http://lithiumbatterywale.com for more information.
Can you pl. provide the full system cost with the inverter, and complete set up for 5KVA .per house.
Pl also define life of the system with recuring cost over 10 years of operation and 30 years of operation.
Dear Phiroze Sir,
You can visit https://www.lithiumbatterywale.com/OneBox.php and have a look at a DIY solution for your solar needs.
Also you can send in a request to them and they will work out the ROI for you.
Hi Narasimhan, this article is awesome, Thanks for sharing the information.