Abstract: A pumped heat storage apparatus has a prime mover, a power take off, first and second fluid working machines functioning as a compressor (8) and as an expander (10), a working fluid circulation pathway with high and low pressure sides, and high and low temperature heat exchangers (18A-B). The heat exchangers operate using direct contact between gaseous working fluid and solid thermal storage media, such as glass beads, which move in opposite directions, typically using an augur (44). The system is reversible between energy storage and energy recovery modes and when it reverses, the direction of movement of the working fluid and the thermal storage media reverses. The apparatus may very rapidly swap between energy storage and energy recovery while having a high capacity and energy throughout.