You can find previous vintages of LTO data in the Long-Term Outlooks section of the North America Power Service (NAPS) landing page - Wood Mackenzie | North America Power Service - including our 2019/2020 profiles:
For example, clicking on the H2 2019 link provides access to the accompanying Excel files containing capacity price data: Wood Mackenzie | The view to a non-constrained 2050: North America Power and Renewables long term outlook H2 2019 No (Federal) Carbon case
