&gt; And in that same case, the power company is out some infrastructure and maintenance costs.<p>As I understand my bill, PG&amp;E still bills you for that as a separate item.<p>&gt; But either way, you state that as though power grids have some fundamental property that necessitates the same rates for purchase and sale, a property that most other exchanges do not have.<p>That property would be &quot;legal monopoly&quot;.