@RichardJMurphy Quibble 2. Marginal pricing encourages cheaper producers to build new generation as there is profit in undercutting the expensive price setters. However until the most expensive generation is squeezed out the only people who benefit are the generators not the customer. Which is taking _decades_ (“efficient” markets, Bah!). You somehow need to encourage capital to invest in new generation, so segmenting as you suggest or splitting the difference between bid and most expensive.