A lot of these financial structures ultimately boil down to being a form of government guarantee, which means that they can’t be scaled up to “solve” countries’ power problems because the governments cannot carry all the liabilities. Countries try to introduce the private sector into power generation precisely to reduce such guarantees, which then end up returning through the back door in the form of government support.
Fixed-rate, long-term (contract) plans provide stability in electricity rates. If market energy costs suddenly trend upward where you live, you can rest assured that you won’t have to pay more out of pocket. However, if you want to switch to a different, lower-cost plan before the end of the contract term, you’ll likely have to pay a cancellation or early termination fee.