Australian: ENERGY giants Origin and AGL have been busy beefing up their wind-farm portfolios in recent months in preparation for the upgraded Renewal Energy Target — should it make its way through parliament. But perhaps the most revealing aspects of presentations both companies made last week was their faith in geothermal energy as a significant source of base-load power in the future. Wind power is expected to dominate the early years of the RET scheme, which will require that 20 per cent of …