A physical review revealed that use of hot water occurred only at end of work periods (break-time, lunch, end of day). Otherwise, the system was maintaining 50 gallons of hot water during off periods (such as evenings and weekends).
An on-demand system would not work due to the heavy load that occurs upon lunch time as an example, when all the workers are using actively washing up before a meal.
A 6 gallon tank was found to be the right size for our peak use. The tank takes up less room, and doesn't require the venting like the former natural gas fired tank.
The comparison of costs and determining payback of investment is offered via this government website.
The system has been in place for 2 months, and functions as projected. We have ample electricity surplus from our PV solar array, so we have eliminated a natural gas purchase for the energy, as well as have eliminated the pollutants from burning the gas. All hot water in our facility comes from electric heaters, with electricity gathered from our Photo-voltaic array of panels.