By Nina Chestney MADRID/LONDON (Reuters) -Spain’s Iberdrola will invest 47 billion euros ($47 billion) in electricity networks, renewable energy production and customer businesses over the next two years, its chairman said in a strategy update on Wednesday. Iberdrola is pushing to remain one of the leaders in global renewable power at a time when utilities are facing a challenging transition away from fossil fuels, accelerated by the need to cut energy dependence on Russia. In its last strategy update, the company said it planned to invest 75 billion euros in renewable energy, grids and retail…