When I was born in the 1950s, nuclear power was said to be “too cheap to meter.” Although few and far between, disasters at Fukushima and Chernobyl have laid waste to that claim and, for that matter, entire cities. German Chancellor Angela Merkel, herself a nuclear physicist, led the charge to eliminate her nation’s nuclear power plants in the next few years based on a rational risk analysis. With the decision by Southern California Edison to decommission its San Onofre Nuclear Generating Station (SONGS), we may now see enough data points to reasonably conclude that the nuclear power era is coming to a close.

What is different about the SONGS decision that could lead to such a “straw that broke the camel’s back” conclusion? At one time, this plant provided 17% of the state’s electricity, but owners have now concluded that the growing portfolio of renewables (solar, wind, geothermal) and clean natural gas plants can meet the demand. They also know how effective the energy efficiency measures have been in California, which is now 40% more energy efficient than the rest of the U.S., lowering overall energy bills.  The power plants you don’t build, because of such efficiency initiatives, are of course the cheapest of all.

But the main reason SONGS closure might signal the beginning of the end of nuclear power in America is that the costs of decommissioning will no longer be hidden from ratepayer view, meaning we will get a good look at how “too cheap to meter” is actually “way too expensive to keep doing.” Edison invested $2.1 billion in the plant and related assets and has allocated $2.7 billion for decommissioning, a polite term meaning “clean up the mess,” while admitting this is not all that will ultimately be needed. All in, SONGS will cost California ratepayers over $5 billion plus the cost of fuel. And who knows if the nuclear waste will ever be safely stored (we’ll need hundreds of years for the final answer to that question, regardless of where the waste ends up) or if that will add still more billions to the tally.

If it were operational, SONGS would generate about 2400 megawatts of electricity. That works out to about $2 million per megawatt (plus fuel and the cost of waste disposal), which seems cheap compared to utility-scale solar. The recently unveiled NRG Ivanpah solar power plant cost $2 billion and generates 377 megawatts, or something over $5 million per megawatt. But the cost calculation alone doesn’t capture the real price – – a price that is likely to be paid one day by every American.

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The Price Anderson Nuclear Industries Indemnity Act establishes a “no fault” insurance system for nuclear power plants, which limits claims to the first $12.6 billion for damages related to disasters. Any costs above that would be covered by taxpayers – – much like the estimated $250 billion that Japanese taxpayers are now facing for generations to come to clean up Fukushima. By sharp contrast, the solar industry needs no such taxpayer protection – – in part, because the fuel costs absolutely nothing and there is nothing left over to clean up.

Coal and oil have advanced our economies for decades, but honest cost accounting increasingly shows the need to move beyond both as reliable, affordable sources of energy. It’s time to add nuclear power to that list and embrace alternatives that are less risky and truly more affordable over the long haul – – or risk being left in the dark ages in more ways than one.