Executive summary
It's too early to tell what the resale value is, as contemporary turbine designs are not as old as the lifetime of a wind-turbine, so we have very little experience of the economic value that results from decommissioning 1.5MW turbines; however, a rough first-order calculation puts the scrap value of the metals, based on Feb 2016 UK prices, at gb£14k/MW, or us$30k for a 1.5MW turbine.
Too early to tell; and reuse vs scrapping
We don't know, because it is too early to tell: there isn't yet a large post-first-life industry for wind turbines. And the reason for that is that large-scale deployment of the now-industry standard horizontal-axis three-blade megawattt-plus wind turbine as we know it, dates back less than the lifetime of a wind turbine.
We do have some experience from the large Danish repowering exercise (2002-3), when a change in incentives caused a burst of decommissioning of older, smaller turbines; they were replaced with newer, high-power turbines. But the decommissioned turbines generally got sold on to be refurbished and reused elsewhere: so resale value for reuse must have been significantly higher than scrap value, given the additional transport costs implied by selling for reuse.
So, with a first life of 20-25 years, and with a second life for maybe another 10-20 years, it's still too early to say what the optimal end-of-first-life outcome is for wind turbines.
NPV of scrap is low enough that no one's really counting
And because the first life is so long, then that 20-25 years of economic discounting of any end-of-life value, means that it's not really yet a consideration when reviewing the economics: anything that's achieved at end-of-life is considered a bonus as far as the business case is concerned.
A first attempt at scrap value
There is value in pretty much all of the materials: the last I saw, it was expected that 95% of materials (by weight) could be reused or recycled (see LCA below). Even the poured concrete base can be recycled as subcore. All the copper, steel, aluminium, neodymium (if present) and so on already have existing recycling industries, but the value of each is constantly in flux as global commodity prices move around.
For offshore wind, the picture is even less clear, as large-scale offshore deployment is much younger than onshore; and the world's first commercial offshore windfarm (Vindeby in Denmark, which became operational in 1991) is still generating after 24.4 years (as of Feb 2016).
You could look at a bill of materials from one of the life-cycle analyses - from that Vestas 2MW one, we see:
- large metal components are assumed to be 98% recycled
- cables 95% recycled
- other steel, aluminium, copper: 90% recycled
That LCA shows per MW capacity (based on a 50MW plant consisting of 25 x 2MW gridstreamer turbines):
- about 120 tonnes of iron & steel
- 13 tonnes of aluminium (& alloys thereof);
- 3 tonnes of copper
- 0.18 tonnes of permanent magnet (neodymium, dysprosium alloy)
This could enable you to get a rough estimate for value, depending on where you are in the world, and what the price of the various scrap metals are near you today.
In the UK, ferrous metals are ~£50/t, aluminium ~£600/t, copper ~£300/t.
Multiplying those figures together, just using 95% as an average recycling rate, gives 0.95 * (120 * 50 + 13 * 600 + 3 * 300).
Which is £14k per megawatt, or about us$30,000 for a 1.5 MW turbine, excluding scrap value of the blades
Blade composition and value
It's only recently that we've seen increasing use of carbon fibres as structural spars in blades, so in general this won't apply to older turbines.
If your estimate of us$450k for the blades of a 1.5MW turbine are correct, the value of the blades swamps everything else. I'd have though that there's a good chance they'd have more value as sale for reuse rather than sale for recycling.
However, regarding your calculation of blade composition: I understand from elsewhere that only 6% of the blade composite by weight is carbon fibre, and even a monster 100m blade (no one's making them that big yet) would weigh between 35-50 tonnes; so that would be 2-3 tonnes of carbon fibre for one 100m blade, or 6-9 tonnes for a whole 10MW turbine; let's call it 0.6-1 tonnes per Megawatt, which is between one sixteenth and one-tenth of the figure you have. On that basis, the blades are still worth more than everything else (us$30,000-45,000 per 1.5MW turbine), using your number for carbon fibre scrap value (I couldn't find a price when I looked), assuming the carbon fibre can be separate out from the rest of the blade cheaply.
