We don’t have any longwave stations in this country, other than the governments failed attempt at using long wave (WGU-20) for emergency communications in the 1970s and 80s. In Europe, Longwave continues to be used, mainly because of its excellent ground wave propagation can cover large distances without fading or interference. Several have closed in recent years due to the expense of maintaining tall radio towers and higher quality programming sources.
500KW is quite a bit of power. The antenna mast is 248 meters, or 813 feet tall. Interestingly, RTE discontinued service on MW (AKA AM broadcast or standard broadcast) but left this signal on the air. Reportedly, this station has less power but better coverage.