This is a very interesting ongoing debate. Both the technical applications (as here) are debated, and the economics. With rapidly falling new battery costs, there is a question as to whether second-life batteries will really be cheaper than new. Clearly though, the auto manufacturers, Nissan and BMW in particular are investing heavily in second-life EV batteries for stationary storage.
The article makes an interesting point though that can't be ignored. Recycling. Using second-life batteries at best delay the need for the battery to be recycled. If there is no market for them then that brings the issue forward significantly. Let's hope there is also significant R&D spend, and investment in creating a viable and easy Lithium battery recycling capability and capacity.
Cycle life is a critical metric in many stationary storage applications, as it directly impacts the lifetime of a system. Unlike vehicles, for which some consumers will pay a higher price for added luxury, stationary systems are driven by economics and performance alone. The high capital costs of installing stationary systems rely on revenues generated by its usage to become profitable over time, so concessions in cycle life mean sacrifices to system profitability. Furthermore, Li-ion cells make up less than 30% of total system costs in most cases, due to the high cost of engineering, permitting, and constructing the systems. This means savings of more than 15% are unlikely in most applications, and given the performance sacrifice in second-life cells, new cells are often the better choice.