It doesn’t seem to me that the idiot index can be used to predict prices the way you’re using:
For example, currently you’re using an estimate of an idiot index of 100 for fusion, and fuel costs at $4K/kg for Deuterium.
Lets say Deuterium was twice as cheap or expensive. Would your estimate for fusion costs halve or double? If so why? The cost of Deuterium provides almost no evidence of the cost of the complicated parts of building a fusion reactor.
I agree the idiot index is useful for establishing a minimum threshold for cost, and is a useful indication for which processes have a lot of potential savings with further optimisation and those that don’t. But I don’t see any justification for using it to predict future costs.
Fair point. A different way of putting this: when the raw materials are a significant fraction of overall costs, overall costs really do move in proportion to raw material prices. Because in this case, the relative cost of raw material to equipment actually matters for the design of of the product.
But when idiot index is high, small changes in raw material cost have ~zero effect on the cost optimization of other components. So index 100 is too far of an extrapolation.
Perhaps for fusion I need to look at the capital cost and lifetime of superconducting magnets and radiation shielding instead.
I would think of it as: as the raw material becomes a greater percentage of the total cost, decreasing total cost becomes harder, both in relative terms (because it’s impossible to halve total cost if raw material is already the majority of the cost) and in absolute terms (because if any decrease in system complexity causes the raw material to be used less efficiently, that will erode savings from the decreased complexity).
In that sense the idiot index acts like pressure making it harder to squeeze costs when they’re low but with very little impact when they’re high.
It doesn’t seem to me that the idiot index can be used to predict prices the way you’re using:
For example, currently you’re using an estimate of an idiot index of 100 for fusion, and fuel costs at $4K/kg for Deuterium.
Lets say Deuterium was twice as cheap or expensive. Would your estimate for fusion costs halve or double? If so why? The cost of Deuterium provides almost no evidence of the cost of the complicated parts of building a fusion reactor.
I agree the idiot index is useful for establishing a minimum threshold for cost, and is a useful indication for which processes have a lot of potential savings with further optimisation and those that don’t. But I don’t see any justification for using it to predict future costs.
Fair point. A different way of putting this: when the raw materials are a significant fraction of overall costs, overall costs really do move in proportion to raw material prices. Because in this case, the relative cost of raw material to equipment actually matters for the design of of the product.
But when idiot index is high, small changes in raw material cost have ~zero effect on the cost optimization of other components. So index 100 is too far of an extrapolation.
Perhaps for fusion I need to look at the capital cost and lifetime of superconducting magnets and radiation shielding instead.
I would think of it as: as the raw material becomes a greater percentage of the total cost, decreasing total cost becomes harder, both in relative terms (because it’s impossible to halve total cost if raw material is already the majority of the cost) and in absolute terms (because if any decrease in system complexity causes the raw material to be used less efficiently, that will erode savings from the decreased complexity).
In that sense the idiot index acts like pressure making it harder to squeeze costs when they’re low but with very little impact when they’re high.