**The Color of Money – Part IV**

In my post of February 27^{th}, The Color of Money – Part I, I gave the big picture answer to Cap’s query. In February 28^{th}’s follow-up post we delved into the details of depreciation. On my Leap Day post we deliberated discounting. Today, in the fourth and last post of the series, we will tie up loose ends and cover the rest of the assumptions.

**Rejuvenation Technology Inputs**

In cells B12, B13 and B14, the name for “Product X”, the fully absorbed cost for product X, and the warranty length are entered respectively. Cells B16, B17 and B18, hold the same values for “Product Y.” Cell B20 is the ratio of the warranty length of Product Y divided by the warranty length of Product X. The accounting lives are assumed to be the respective warranty lives. The actual life multiplier in cell B21 is the ratio of the actual life of Product Y divided by the actual life of Product X. The warranty life is an approximate indicator of the actual life, as the technology suppliers use some combination of experience, accelerated life experiments, and accelerated life simulations to arrive at reliable life expectations.

For individual large and stable firms, such as most utilities, the spread or difference between the discount factor in cell B3 and the inflation rate in cell B6 is quite constant. If inflation increases, discount factors increase too. The 5.9% spread in the example is typical for the power distribution industry in North America.

**Accounting Treatment of Warranty Remittance**

GAAP would suggest that warranty remittances are handled as negative capital expenditures. That is, the cost of replacement is reduced by the amount of the warranty remittance. Any remaining undepreciated value associated with rejuvenation is written off in the year of the failure on both the tax books and the rate-making books. Individual circuit owners may treat these warranty refunds differently. Write to me to tell me how your firm accounts for these warranty payments. I’ll enhance the model to accommodate your method.

**Residual Value**

For any net present value analysis there has to be an assumption regarding the handling of residual values at the end of the analysis period. Where two rejuvenation technologies with different actual lives are compared, the technology with the longer life will have a greater residual value than the product with lesser life. For the purposes of this analysis a single replacement cycle is executed after the rejuvenation cycle has completed and future value is calculated to a one century horizon. Cash flows after 100 years are ignored. This assumption favors the technology with the shorter life, since the product with the longer life would have the greater residual value.

**Bottom Line**

This rigorous analysis confirms and quantifies what should be self evident. The longer the life – the greater the value.

Greener is better,

Thermonuclear Frog