The article claims that they save 2.1 MWh per week (109 MWh per year) with a payback period of 4.5 years in Norway. It doesn't say how much it costs, but Norwegian electricity prices are around 83 EUR/MWh, so we can estimate that the lighting system costs roughly EUR 40k (US$43k).

Wholesale grid prices in the US are around ~$252/MWh at peak, which means the payback period in the US is only 1.5 years give or take, which is not a bad investment.

https://www.eia.gov/electricity/monthly/update/wholesale-mar...