The possible contributions of the SOHO to the Solar Terrestrial Energy Program are discussed. Several SOHO measurements and observations will be of interest for the study of the energy flow in the solar terrestrial system: - the total solar irradiance or solar constant will be monitored with an accuracy of about 0.15% by solar radiometers in one of the helioseismology instruments, - the solar EUV irradiance will be measured directly by an EUV monitor (at 305 Å) and obtained at several wavelength bands between 150 and 1600 A by integration of spectroscopic images, - synoptic maps of the sun at different levels of the chromosphere, transition region and lower corona obtained in extreme ultra-violet (EUV) will be produced by the SOHO telescopes and spectrometers, - solar magnetograms with about 4 arc second resolution (2'' pixels) will be produced several times per day, - the evolution of the large coronal structures that shape the solar wind, as well as the coronal mass ejections will be followed by two coronagraphs and by a solar wind anisotropy measuring instrument; the latter generate the solar wind disturbances that are cause of the most energetic magnetic events in the geosphere, - the elemental, isotopic and charge state composition and energy distribution of the ions that form the solar wind, as well as of the energetic particles that will reach the earth magnetosphere, are determined in SOHO by a set of time-of-flight and solid state detectors.