ASML earnings call for the period ending December 31, 2020.
Peter Wennink -- President and Chief Executive Officer
I think our capacity, our capability internal in the Netherlands, in Veldhoven, to build 50 systems is there in terms of people and square meters. Now we have to build those systems out of modules, which we don't produce. It's in the supply chain. And it's just a reflection of what happened last year in Q2 and Q3 where -- as clearly our key foundry customer came back and said, listen, our key customer for N3 is now blacklisted. So we cannot ship. So we need to adjust our 2021 outlook for EUV systems. Which was followed by another customer and said, well, we're going to delay the roadmap, which also means that this will be pushed back one [Phonetic] year, which actually led to a situation where we actually reduced the number of planned system 2021 for EUV, because customer said these are the two reasons and they were two big customers.
So, what we did, we went to the supply chain and said, sorry, we need those lenses and lasers, very expensive pieces of equipment, we need them actually later. You need to realize that the integral lead time between the installation of an EUV tool and a start of a module production, that is 20 months. So when you at seven, eight months -- then finally customers come to the realization that is not as bad as they've thought and they want those machines, and we have an issue with getting the modules on time and that's the only issue. The only issue is just to resolve, it's a function of the fact that our customers changed their mind in Q2 and Q3 and then rechanged their mind back in Q4 and -- today. There is nothing we can do about it, which actually means that we're all prepared to do 50 units next year, as is in 2022. It will just shift to 2022. So it's -- there -- so as you could say it's supply chain limitations by design, because the customers told us, we don't need them, and then coming back and said, oops! we might have been wrong.
Here is the revenue recognition per quarter over the last three years: