Before The problem with renegotiating old agreements is that old projects have higher tariffs as they were built at far higher costs at a time when clean power’s scope was relatively unproven. After Old projects were built at far higher costs at a time when the scope of clean power was relatively unproven. Notes The 'before' version had 'old agreements' and 'old projects' appearing twice, so I rewrote it. clean power's scope - rephrased it to 'scope of clean power' since power is a non-living thing and you avoid making a possessive out of it.