I only shoot in RAW, but for a normal travel trip I don't want to keep all photos in RAW because they occupy a lot of storage space. Is there a plugin in Lightroom to click a photo and convert the RAW format into JPEG format without reimporting into the catalog?
You likely know the advantages of shooting raw (since you usually do it), and especially on trips with their one-time photo opportunities I would always want to keep raw files. Disk space is your limiting factor, maybe because of just having an ultra book with a small SSD disk available.
My suggestion would be to shoot raw+jpg on trips, keep the raw images on your camera's card, and import only the jpgs while on the road. Back home you can import the raw duplicates onto the (presumably) large disk of your desktop computer, sync the develop and metadata settings from the jpegs and finally throw the jpegs away if you don't want to keep them.
Some large memory cards to keep the raw files are usually cheaper than upgrading an SSD disk in a laptop.
There would be no advantage to shooting RAW and automatically converting them to JPEG, it would defeat the purpose of shooting in RAW. Instead either shoot in JPEG with the camera or convert to DNG.
Here is a video on the DNG format from Adobe.
My other recommendation is to get an external hard drive, or 2, and copy all of your images there. This would give you plenty of space to keep your RAW files if you wanted, but even if you choose to shoot JPEG, I still recommend using external drives for backup.
If an image does not exist in 2 places it does not exist!
I can understand why he would need an option to convert to jpg/tiff etc. and delete the RAW.
I always keep the original files for commercial assignments. But for weekends, trips and other snaphots, I only need the RAWs to get the best version of the image. Once they are developed and brought to their best, I only need the final JPGs. After developing I see no reason to go back for further editing that would require the RAW anytime in the near or distant future.
I don't think deleting the raw is like throwing away the film, like some say, because you can still make copies and prints from the JPG.
A plugin or a native option from Lightroom to delete the original files after conversion would be very useful especially for someone with 50k+ photos/year like myself.