This paper proposes an application of type-1 and interval type-2 fuzzy logic for DC power flow analysis of electric networks with high levels of renewable energy penetration. The proposed methodology can be used for real time analysis, power system planning, and day-ahead energy markets. The uncertain variables in the DC power flow, weather-based renewable energy power generation, load and network parameters, are modelled as trapezoidal fuzzy variables using historical data from the Bonneville Power Administration's Transmission Database. DC power flow is then computed using the proposed algorithm. The method is tested on an IEEE standard 30-bus power system with a wind generator connected to the network. Line flow results computed using the proposed method show the impact of the intermittent behavior of the renewable energy generation unit on the given power system.