How I get env values into next.js

config.next.js

require('@remy/envy'); // similar to dotenv, but supports .env.production, .env.local, etc
const webpack = require('webpack');

module.exports = {
  webpack: config => {
    config.plugins.push(
      new webpack.EnvironmentPlugin(
        ['SHOW_SPEAKER'] // array of indiviudal ENV values I want exposed
      )
    );

    return config;
  },
};

// from https://next.training.leftlogic.com