Scientists warn a solar storm could leave Britain and the United States without power for days or even months as solar activity approaches a peak in 2015. A joint study by Lloyd\'s of London and the U.S. firm Atmospheric and Environmental Research says a solar storm of sufficient strength could damage electrical transformers and leave Western nations without electricity for months because of the time needed to build replacements, The Daily Telegraph reported Friday. A five-month power outage in Europe and North America would cost the economies of the regions $2.6 trillion, Lloyd\'s estimated. Solar storms are large explosions in the sun\'s atmosphere that can send massive amounts of energy toward Earth, where it can enter the planet\'s magnetic field and disrupt networks dependent on electricity on the ground. Huge surges of energy flowing into power lines could overwhelm national grids, resulting in widespread power outages from transformer failures, the study authors said. \"The duration of these outages will depend largely on the availability of spare replacement transformers,\" the report said. \"If new transformers need to be ordered, the lead-time is likely to be a minimum of five months.\"