Deal all,

I would like todiscuss the problem of retirements and scrappage in LEAP's stock turnover calculations when doing a transport analysis.

I understand that the number of retired vehicles is defined by the lifecycle profile. However when we introduce a scrappage scheme shouldn't the retirements increase? Imagine I use a scrappage scheme for removing 10000 diesel vehicles every year. When I compare the results for the two scenarios (with and without scrappage) shouldn't the number of retired diesel vehicles be larger (by 10000) in the scenario with scrappage?

I was surprised to find out this is not the case. Apparently the two quantities (retirements and scrappage) are not related. Could you confirm that?

Actually, if you include scrappage then you should see it in the result Demand: Device Retirements. This result does take into account vehicles that are scrapped as well as retired "naturally" (as a result of their old age).

If that's not what you're seeing, can you provide me with a specific example (or a LEAP model) that illustrates this, together with the values that you would expect to see in the Results View?

Please also be sure you're on the latest version of LEAP.

Best,

Taylor

Hi Taylor, thanks for your reply.

I'm doing the following analysis: scrappage of 50 000 passenger cars/year (75% diesel, 25% petrol) where each scrapped car gives rise to the sale of a battery electric car.The period under study is 2021-2030.

I'm only interested in analysing the differences with a reference scenario and so I would expect 50 000 extra electric cars each year and 50 000 less ICE cars each year. You can see in the slides attached (part 1) that this is OK for the electric cars but the decrease in ICE cars is much smaller than expected. You will see in the "Retired vehicles" graph that the proportion 75%diesel/25%petrol is not maintained.

The only way I could obtain a decrease in ICE cars close to the scrappage values is by considering a very unrealistic survival curve that places a huge stock in the oldest vintage (see part 2 of the slides). In this case the decrease in stock of ICE vehicles is close to what is expected from the scrappage values. However, we only see a difference in the retirement of electric vehicles (which is acceptable, given that there are more of them in the stock).

Looking forwards for your advice!

Kind regards

Rui

My best advice here is to carefully reproduce this calculation in Excel using the lifecycle profiles that you've included in LEAP. This is what I would need to do to explain the results you're seeing.

When I last did this myself I found that I was able to generate all results shown in LEAP, independently, and it helped to understand the subtleties of the calculation. If in doing this you find a result that is inconsistent with LEAP, please flag this for us (by sending your Excel and LEAP documents) and we can investigate that issue specifically.

Taylor