The present invention relates to a polymerization process of producing ethylene-alpha-olefin polymer. The polymerization process comprises supplying at a feed temperature a feed containing ethylene, at least one alpha-olefin and optionally, a diene in a solvent, the solvent is supplied at a solvent feed rate; supplying at a catalyst feed rate a catalyst to a reactor, and contacting the feed with the catalyst to produce a reaction mixture containing the polymer. The present invention also relates to processes for improving the energy utilization of polymerization processes, wherein the process comprises decreasing the feed temperature, decreasing the solvent feed rate, and decreasing the catalyst feed rate.