Power converters are a key technology to support the massive integration of Renewable Energy Sources and it is therefore important to assess their environmental impact. This work uses the Life Cycle Assessment methodology as a base to assess the environmental impact of a DC Solid State Transformer. The carbon emissions were estimated for the DC SST with different design choices such as the operating frequency, number of semiconductor devices in parallel and the energy mix. The use phase is the biggest contributor of emissions for all cases, but it is likely to reduce with the decarbonation of electricity. Considering monetary value of the CO2 emissions with the carbon tax, an optimal frequency is found for the DC SST. The economic weight of these emissions is expected to increase in the future.