Extreme ultraviolet (EUV) spectroscopy was recorded on microwave discharges of helium with 2% hydrogen. Novel emission lines were observed with energies of q x 13.6 eV, where q = 1, 2, 3, 4, 6, 7, 8, 9, 11 or these discrete energies less 21.2 eV corresponding to inelastic scattering of these photons by helium atoms due to excitation of He (1s(2)) to He (1s(1)2p(1)). The average hydrogen atom temperature was measured to be 180-210 eV versus approximate to3 eV for pure hydrogen. The electron temperature T-e for helium-hydrogen was 30,500 +/- 5% K compared to 7400 +/- 5% K for pure helium. Dominant He+ emission and an intensification of the plasma emission observed when He+ was present with atomic hydrogen demonstrated the role of He. as a catalyst. Using water bath calorimetry, excess power was observed from the helium-hydrogen plasma compared to control krypton plasma. For example, for an input of 8.1 W, the total plasma power of the helium-hydrogen plasma measured by water bath calorimetry was 30.0 W corresponding to 21.9 W of excess power in 3 cm(3). The excess power density and energy balance were high, 7.3 W/cm(3) and -2.9 x 10(4) kJ/mole H-2, respectively. (C) 2003 Elsevier Science B.V. All rights reserved.