It seems like there are 4 or 5 different battery types available that I could use for solar projects. How do I compare the economics between different batteries?

Comments

Thank you for your question.  As you can imagine, we receive a lot of questions about batteries and what is the optimal battery for a particular project. The battery’s LCOE (Levelized Cost of Energy) is perhaps the most important factor in choosing a battery (of course it depends on the use case). When comparing modules it’s pretty safe to compare the cost/watt if making the decision purely on economics. However, there’s slightly more math when looking at batteries.

 

This LCOE for batteries is dividing the battery’s Price by the Battery’s Capacity multiplied by the Number of Cycles, Efficiency %, and Depth of Discharge (DOD); the battery’s efficiency refers to its retention percentage during the charging and discharging cycle. You will then have to add ancillary costs such as freight and additional equipment like cables or combiners. Let’s look at an example with BMZ 7.0 w/ Enclosure:

 

  • Estimated Price: $4,500

  • Capacity (kWh): 6.74

  • Number of Cycles: 5,000

  • Efficiency: 97%

  • DOD: 80%


 

LCOE = Price / (Capacity * # of Cycles * Efficiency % * DOD)

 

This battery would have an LCOE of $0.17/kWh, not including the enclosure. Furthermore, since this battery includes an enclosure the Ancillary Costs would be lower.

 

As mentioned earlier there are more factors than a battery’s LCOE such as battery chemistry and weight, but it is vitally important you look at more data points instead of just a battery’s price and # of cycles.

 

Price

 $4,500.00

 $0.17 Kwh

Nameplate

 6.74

 

DOD

 0.8

 

Cycles

 5000

 

Efficiency

 0.97

 
     

Energy, Life

 33,700

 kWh

Efficiency

 32,689

 kWh

DOD

 26,151

 kWh