NOVELTY - A thermochemical system comprises a thermal source providing first thermal energy; first reactor at first location converting first thermal energy to chemical energy by decomposing sulfur trioxide (SO3) into sulfur dioxide (SO2) and oxygen (O2); a second reactor at second location converting chemical energy to second thermal energy or electrical energy by oxidizing SO2 with O2; a first storage of liquid SO2; and a second storage of liquid SO3; where output of first reactor is coupled to input of second reactor, and output of second reactor is coupled to input of first reactor.    USE - As thermochemical system (claimed), particularly solar energy storage system, for the capture and storage of solar energy.    ADVANTAGE - The system reduces cost and complexity of the piping system by eliminating the need for high temperature insulation and high temperature materials. The use of SO2 to SO3 provides a thermochemical energy storage system with a high energy density and low capital cost. Since SO2 and SO3 can be stored at ambient temperature as a liquid, this eliminates the need for thermal energy storage at high temperature, eliminates the need for insulation to retain this high temperature stored heat and eliminates any loss of energy through slow loss of heat with time. The use of oxygen as a storage gas in the system is cost effective since it requires very large vessels or compression to high pressures which would consume energy and reduce efficiency.    DETAILED DESCRIPTION - A thermochemical system that transports energy from a first location to a second location where the energy is to be used, comprises: a thermal source providing a first thermal energy; a first reactor at the first location converting the first thermal energy to chemical energy by decomposing sulfur trioxide (SO3) into sulfur dioxide (SO2) and oxygen (O2); a second reactor at the second location converting the chemical energy to a second thermal energy or an electrical energy by oxidizing SO2 with O2 to produce SO3; a first storage of liquid SO2; and a second storage of liquid SO3; where an output of the first reactor is selectively coupled to an input of the second reactor, the first storage of liquid SO2, or both, and an output of the second reactor is selectively coupled to an input of the first reactor, the second storage of liquid SO3, or both. An INDEPENDENT CLAIM is included for a method of transporting energy from a first location to a second location involving: converting the thermal energy at the first location to chemical energy in a first reactor by decomposing SO3 into SO2 and O2; converting the chemical energy to one of thermal energy or electrical energy in a second reactor at the second location by oxidizing SO2 with O2 to produce SO3; using stored SO3 liquid and storing a portion of the SO2 as a liquid when more energy is available at the first location then is required at the second location and; using stored SO2 liquid and storing SO3 liquid when more energy is needed at the second location then is available at the first location.