The invention is a device for electrical load-leveling and/or electrolysis. A housing contains pairs of electrodes made from or containing a porous material. The electrodes are filled respectively with an anolyte and a catholyte, which is an ionic couple such as Vanadium +2/+3. A non-permi-selective barrier membrane with openings may be included to substantially separate the electrode pair. The device results in reduced resistive, over-potentials and polarization losses, and may be scaled-up for integration into an electric utility.