The 2035 4.0 report shows that large-scale reconductoring with advanced conductors can rapidly expand transmission capacity and contribute to cost-effective clean energy deployment over the next 10 years. In many cases, advanced conductors can double existing transmission line capacity at less than half the cost and a fraction of the time as new lines. A programmatic approach to reconductoring can unlock lower cost renewable energy sources across the US, saving tens of billions in energy system costs.