I have no idea of the qualifications of this poster but he makes...

I have no idea of the qualifications of this poster but he makes the point that while the installed cost per watt of renewables you have to install far more renewables because of the low capacity factor and then add the cost of storage to the cost of renewables.


Darwin Grigg.

I have been seeing posting after posting in this and other climate related forums regarding how much cheaper constructing 'renewable' electric generating plants are than any other alternative. Climate alarmists are demanding, at a very minimum, all coal-fired plants must be replaced, not just with a 'cleaner' technology, but a 'renewable' one. The alarmists then quote the following construction cost numbers (in terms of dollars per watt of design nameplate capacity): wind, $1.66 per watt; natural gas, $0.81 per watt; solar, $2.92 per watt; and nuclear, $5.14 per watt.

Before going further, these numbers are misleading. The nuclear cost estimate is based solely on the construction of the Watts Bar No. 1 plant, since it is the only contemporary reactor to be constructed and actually go on line. I contend this is not representative of what the industry is capable of. Following completion of construction, the Watts Bar plant went through nearly a decade of reviews and litigation before it was allowed to enter into operation phase...during which time it had to be fully staffed and the independent investigators paid for their efforts, and which expense got wrapped into construction cost. Just to make it crystal clear, I am not arguing TVA did not deserve that kind of scrutiny, I spent a year and a half of my working life at Watts Bar as one of those investigators, and in my opinion, TVA management brought that delay down around their heads all on its own. However, it would be misleading to think that, just because TVA made poor management decisions during the construction of Watts Bar, all utilities would handle its construction process equally as badly. Similarly, the construction cost of commercial solar and wind generating stations is misleading. Construction cost of nuclear and natural gas include the purchase cost of the land that the stations sit upon. The land for wind and solar are leased, not purchased, and the lease costs are accounted as operating cost, not construction cost, thus understating construction cost relative to nuclear and natural gas. That said, I will ignore that, because like the recent election, yes there was fraud but probably not enough to make a difference in the outcome.

Now to look at the the 'rest of the story' for construction cost comparison. The stated purpose of the alarmists is to totally replace a coal fired generating station with a cleaner technology, preferably something 'sustainable.' I am going to insist that when such a replacement is made, the replacing technology must be at least as reliable and dispatchable as the coal plant and for the same operating lifetime. By dispatchable, I mean that its electrical power output can, with a high degree of confidence, be scheduled into the future: that is, the power is actually there to be used at the time we plan to used it. As a baseline, a coal-fired generating station typically has a useful operating lifetime of at least 80 years and, when politics are removed from the equation, have a capacity factor of around 90% on a non-seasonable (year around) basis, and are dispatchable.

First, natural gas. I see no reason that natural-gas fired generating stations should not have a useful lifetime equal to that of a coal-fired plant It has a capacity factor (reliability) equal to that of coal plants, if not a bit better., And, it is every bit as dispatchable as coal, Conclusion: a construction cost of $0.81 is pretty accurate for purpose of deciding our energy future.

Now nuclear. At the beginning of the industry, it was felt that nuclear generating stations would have a lifetime of 40 years at the most. This was largely based on a belief that neutron embrittlement of the reactor vessel would make it unsafe to use past that point. The actual operating history of nuclear plants has shown that to not be the case. Current literature is indicating an operating lifetime of at least sixty years, and very likely eighty years for nukes. So, comparable lifetime. Nuclear has an even better capacity factor than coal. And nuclear is at least as predictable (dispatchable) as coal; if anything, even more so as it is not affected by disruptions to the fuel supply. In conclusion, I'm good with $5.12 per watt construction cost for comparing the technologies.

Now we get to the good stuff. First, solar. Most sources give solar an average capacity factor of 25%. Note I said average...for solar capacity factor is very much seasonal in nature, and depending on latitude and seasonal weather patterns, can drop to 15% or even lower. If the solar is gong to be a stand-alone replacement for coal, one needs to use the worst case seasonal capacity factor, not the average. What does that mean? It means to replace the power output of a coal plant, one needs to build six solar stations with the same nameplate capacity as the coal plant you are replacing. That jacks up the construction cost for solar to $17.52 per watt. And that ain't the half of it (or even a third of it). The lifetime of a solar plant is considered to be 25 years, and operating experience is showing that to be a pretty good number. So, one is going to have to build those six solar stations three times to replace that one coal station. That increases construction cost to $52.56 per watt. Now we need to factor in dispatchability. Should the customers be silly enough to want the lights to come on after dark, we need some way of storing power. Battery backup is the only currently feasible technology for doing that. Cost of battery storage is about $0.10 per watt-hour. To deliver 1 watt continuously from a solar power station during worst case conditions (dead of winter) requires in the order of 16 watt-hours of battery capacity AS A BARE MINIMUM. That does not factor in that in the winter, there are often intervals of no direct sunlight for days at a time. Many in the electrical industry recommend 72 hours of storage capacity, not 16, So, add another $1.60 to $7.20 per watt of (initial) construction costs, Now (you guessed it) comes the final piece of the puzzle....batteries nave a miserable lifetime compared to a coal plant. I'll be real generous and assume next-generation batteries can have a 20-year useful lifetime, so add a 4x multiplier to the storage construction costs, or between $6.40 to $28.2 per watt. Grand total....for there to be an apples-to-apples comparison, the construction cost of a stand-alone solar plant is between $58.96 to $80.76 per nameplate watt.

To quickly cover wind...,.minimum capacity factor and operating lifetime of wind is close enough to solar as to use the same overall multiplier of 18 for the generating equipment and the same adder for the additional storage costs. That would give an effective construction cost for wind of $36.28 to $58.05 per nameplate watt.

Now, if you absolutely insist that none of our electric power be derived from (oh, horror) fossil fuels, the construction cost of $5.14 per watt looks damn good compared to either wind or solar. And here comes the 'you are just shilling for nuclear power' Trolls. If I am shilling for anything, it is for a plentiful, inexpensive, and reliable source of power for my children grand children, and so on down the line. Based on present cost numbers, if I were to be starting my career today instead of in 1966, what I could be advocating is natural gas. So trolls, GFY. However, since the average attention span of trolls is a tweet, and not the paper required to refute a tweet, I seriously doubt any of the trolls on the site actually have read this far.