A high-voltage direct current (HVDC) electric power transmission system uses direct current (DC) for electric power transmission, in contrast with the more common alternating current (AC) transmission systems. Most HVDC links use voltages between 100 kV and 800 kV.
HVDC lines are commonly used for long-distance power transmission, since they require fewer conductors and incur less power loss than equivalent AC lines. HVDC also allows power transmission between AC transmission systems that are not synchronized. Since the power flow through an HVDC link can be controlled independently of the phase angle between source and load, it can stabilize a network against disturbances due to rapid changes in power. HVDC also allows the transfer of power between grid systems running at different frequencies, such as 50 and 60 Hz. This improves the stability and economy of each grid, by allowing the exchange of power between previously incompatible networks.
However, since grids are AC, it’s just to send power to a grid or pull from one.
We also do have some increasingly beefy DC in individual households in some forms:
You mention solar PV systems, but more generally, 12V systems used in vehicles (and the related 24V and 48V systems that are sometimes used to push more power) are more common, with lithium batteries that can do many more charge cycles than lead-acid being available.
USB PD can negotiate pushing up to 240W now at 48V, which is a fair bit.