Tech Forum

I note the Church published another announcement today about solar powered (photovoltaic) chapels. These articles discuss "carbon footprint", dollars saved, etc. but never mention (that I've seen) the estimated break even dates of these systems. (when they have saved enough to pay for themselves)

I've looked into residential solar systems a fair amount and it's difficult to break-even in time periods shorter than 20-30 years.

Does anyone know or has anyone heard what the estimated break-even dates are on these chapels?

ckmcdonald wrote:I've looked into residential solar systems a fair amount and it's difficult to break-even in time periods shorter than 20-30 years.

When I looked a year ago, it was 7-8 years. But this was in a area with high electric costs, no batteries installed, and where net metering was available.

Ultimately the payback will depend on your forecast of future energy costs.

I would love to do this kind of thing to my own home but the costs prevent it. I wonder if the church is able to make the numbers work better because, bascially, these buildings only consume power one day per week and are feeding power "back into the grid" six days per week.

7-8 years is pretty reasonable. Power at 6 cents here where I live is nice at bill time but sure makes the payback time on a solar system difficult to justify.

What are you calling a high power rate, 15-20 cents?

The last math I did on a residential system in my area the payback time was 26 years. This was for a net-metered 5KW storageless system. If power here was 20 cents that would bring it down to the 7-8 year range.

Another good question is what a net-metered storageless system does when the grid goes down. Have you heard if our solar chapels are able to run on their own systems if the grid is down?

I ask because the storageless systems I've looked at shut off when the grid goes down. This kind of defeats part of the point in my way of thinking.

ckmcdonald wrote:What are you calling a high power rate, 15-20 cents?

I think my last electric bill was about 20¢/KWH. The real questions are: What is the electric rate at the place the church is installing the system and what kinds of agreements can the church get with the electric companies on selling excess power?

ckmcdonald wrote:I ask because the storageless systems I've looked at shut off when the grid goes down. This kind of defeats part of the point in my way of thinking.

I haven't read the article. I don't know if it's one of the objectives. If it was, that could certainly change the cost justification.