- Jan 1, 1970
Falcon said:It's the Return On Investment (ROI) that's important from Tom's point of
view. In this case not only the current return on the cost of investment is
important; assumptions he has made about the future price of electricity
and maintenance costs are critical. If the assumptions are realistic and
the ROI still compares favourably with other forms of investment, Tom has
made a wise move, regardless of any other considerations.
There's actually far more to this than a simple ROI calculation. Other
important factors are Cost of Capital and Opportunity Cost, plus an educated
guess regarding what's going to happen to them over the next 20 years.
Also, many folks fail to consider the lifetime of the PV installation vs. the
lifetime of the roof surface it's installed over. If you need to replace the
roofing before the PV is junk, then you must either pay for a second
installation or junk the PV early. Either way, you are out money.
(Don't put me in anti-PV group, I own a modest system myself. I just don't
expect it to ever pay for itself.)