//  [python]
def plot_annual_emissions_comparison(self, df, column_for_grouping, color_map, output_dir):
        # Summarize annual emissions by fuel

        # Columns to summarize
        weighted_ghg_units='co2e_mmt'
        cols_to_summarize = {
            self.col_name_to_weighted(self.GHG_ELEC_EGRID, weighted_ghg_units): np.sum,
            self.col_name_to_weighted(self.GHG_NATURAL_GAS, weighted_ghg_units): np.sum,
            self.col_name_to_weighted(self.GHG_FUEL_OIL, weighted_ghg_units): np.sum,
            self.col_name_to_weighted(self.GHG_PROPANE, weighted_ghg_units): np.sum,
        }

        # Disaggregate to these levels
        group_bys = [
            None,
        ]

        for col, agg_method in cols_to_summarize.items(): # loops through column names and provides agg function for specific column

            for group_by in group_bys: # loops through group by options

                # Summarize the data
                if group_by is None:
                    # No group-by
                    g = sns.factorplot(
                        data=df,
                        x=column_for_grouping,
                        hue=column_for_grouping,
                        y=col,
                        estimator=agg_method,
                        order=list(color_map.keys()),
                        palette=color_map.values(),
                        kind='bar',
                        size=6,
                        aspect=1.5,
                        legend=False
                    )
                else:
                    # With group-by
                    g = sns.factorplot(
                        data=df,
                        y=col,
                        estimator=agg_method,
                        hue=column_for_grouping,
                        x=group_by,
                        order=self.ORDERED_CATEGORIES[group_by],
                        hue_order=list(color_map.keys()),
                        palette=color_map.values(),
                        kind='bar',
                        size=6,
                        aspect=2
                    )
                    g._legend.set_title(self.col_name_to_nice_name(column_for_grouping))

                fig = g.fig

                # Extract the units from the column name
                units = self.nice_units(self.units_from_col_name(col))

                # Title and axis labels
                if group_by is None:
                    # No group-by
                    title = f'{self.col_name_to_nice_name(col)}'
                    for ax in g.axes.flatten():
                        ax.set_ylabel(f'{self.col_name_to_nice_name(col)} ({units})')
                        ax.set_xlabel('')
                        ax.tick_params(axis='x', labelrotation = 90)
                else:
                    # With group-by
                    title = f'{self.col_name_to_nice_name(col)}\n by {self.col_name_to_nice_name(group_by)}'
                    for ax in g.axes.flatten():
                        ax.set_ylabel(f'{self.col_name_to_nice_name(col)} ({units})')
                        ax.set_xlabel(f'{self.col_name_to_nice_name(group_by)}')
                        ax.tick_params(axis='x', labelrotation = 90)

                # Formatting
                fig.subplots_adjust(top=0.9)

                # Save figure
                title = title.replace('\n', '')
                fig_name = f'{title.replace(" ", "_").lower()}.{self.image_type}'
                fig_path = os.path.abspath(os.path.join(output_dir, fig_name))
                plt.savefig(fig_path, bbox_inches = 'tight')
                plt.close()