The question of power plant value has shifted from cost to income. The value in the deregulated environment will depend on what the future income stream from the asset in that particular deregulated regime can reasonably expected to be.
There are four basic lines of inquiry: define deregulation, forecast future input and output prices, look at the players, and the grid.
The first task is to define just how deregulated price of power is. Is it as free as the price of gasoline at the pump? Is it capped? Is the cap based on the maximum price that might be expected? Or is it principally a political statement? If based on average price, then it stands to reason that peak load situations will result in a market imbalance whereby nobody will be willing to provide power at that price. What happens then, and who gets blamed? No prize for the answers.
The second line of inquiry has to do with market perceptions of prices and makes reference to the futures market for electricity. Similarly, the futures market for fuel will give a measure of the probable price of the principle variable cost.
The third line of inquiry is to look at what the energy companies are doing in purchase and construction. While much of this activity is difficult to interpret because of the unique and complex nature of the transactions it is still an essential endeavor to place limits on the probable values attached to future income streams by the most knowledgeable players. After all, who else is likely to buy one?
The fourth consideration is whether the grid can actually accomodate any major amount of power transfer into the region served by the plant in question. If not, then any outside marginal price may be of only incidental interest within the service area.
There is talk of decentralized power generation. It is likely that for the next decade or two in the industrialized world large power plants will be the low cost provider. While there is a belief that deregulation leads to price war, prices must regress to the replacement cost of generating capacity.