The current USB Power Delivery specification supports up to 100W of power being delivered. That is enough for phones (well, most phones) and laptops that use 15W processors, but not enough for more power-hungry devices such as a gaming laptop.
The USB Implementers Forum has designed a new specification called USB PD Extended Power Range (EPR) that can deliver up to 240W. This will be done at 50V and 5A (with some safety margin), which is a lot of power – to ensure everything runs smoothly, only Electronically Marked cables will be supported (these include a little chip that can tell the host device what features are supported by the cable).
There will be an EPR identification icon on the cable itself so that users can identify 240W-capable cables visually. The older 100W Power Delivery standard is now called Standard Power Range (SPR). Current cables that can handle 5A of current will be deprecated in favor of EPR cables. All cables that can carry 3A or higher will need to be Electronically Marked.
Keep in mind that SPR and EPR are unrelated to the data-carrying portion of the USB cable. There will be some USB 2.0 cables that support the full 240W, as well as some USB 3 and 4 cables. In fact, USB 2.0 cables may prove to be desirable as they can be longer than the faster cables.
USB-C connectors will be required on both ends, however, regardless of the USB version supported. Cables that have a USB-A or microUSB end top out at 3A.
You can download the new USB specification from here, but be warned – it’s a 410 page document.