I think the combined Brayton and inverse Brayton cycle is a good cycle for moderate power plant, but it is not yet realizable.

The Steam Injection Gas Turbine (STIG) and Regenerative STIG (RSTIG) are good cycles too.

According to my research experience I have noticed that The Super-critical steam power plant gives the best result in the techno-economic point of view. Though this type of cycles are costlier but when we consider both energy and economy, then Super-critical steam power plant gives the best result. It produces cheaper electricity in $/MWh.

The same thing is applicable for super-critical CO2 cycle when this type of cycle is used for waste heat recovery or integrated with some other cycles in the downstream. According to my experience, the results may vary if we only consider the  super-critical CO2, ethane, helium or HAT cycles as the main power generating cycle.

Thank you.

It depends on the boundary you are considering for the cycle. Which indicator do you use for comparing the techno-economic performance?

Most of studies refer to teorethical conditions and simplifying assumptions, so there could be considerable difference between the theory and the practice.

The superiority of any power plant from a techno-economic point of view depends on several economic parameters that vary from a country to another namely: fuel cost, C&M cost, electricity selling price... Then, we can not say that a power plant is better than another absolutely. Each case study has its own results. However, I suggest you to add the combined cycle in the set of your power plants since it has shown interesting results in a large range of economic and thermodynamic parameters.

 Maybe a more holistic approach is needed . Burning carbon compounds in oxygen will produce pure co2, which can be stored , The pure oxygen would be produced by a fuel cell on charge . The fuel cell would produce electricity using hydrogen and oxygen from the air.  So we have a cycle that combines elements of  both energy storage and energy production. Each part of this cycle would be used as needed, but some balancing with other systems would be needed.

A privacy reminde

There is no generic optimum - it depends on the site-specific circumstances and economics. Also, the optimum design should consider factors such as operability (safety, reliability) and manintainability.  Water is the preferred working fluid because of safety and east availability of equipment.  The key to good economics is correct integrated design concept, not these so-called advanced thermodynamic cycles.  If the overall design concept is correct, the efficiency and economics of steam-based systems cannot be beaten.

For example in desert regions like the middle east and north Africa with plentiful cheap gas and scarcity of water,, the optimum design would be GT based combined cycle, with LP exhaust from the back-pressure steam turbine used for seawater desalination by MED.

In water-rich regions like Europe or northern/eastern Americas, the ideal design would be to have power plants located as a hub within industrial parks, with the LP steam from a combined cycle power plant being exported to the adjacent industrial plants.

The other optimum solution from a regional point of view is to have "distributed generation" grid, but ill-conceived government policies that do not permit export of surplus cogenerated power from industrial sites are a barrier to achieving national energy efficiency.  In short, the solution lies in the political arena, not technical.

Recent advances in Feed Pump Technology do not apply equally over the various options. Specifically they don't apply to steam application, as far as I am aware, (there is some early reading), but the advances promise major approach temperature closure, and other benefits. A simple explanation is that heat exchanges involving at least one liquid, can operate with peer or same pressure advantage, both sides of the equation, both when receiving heat and when dispelling heat, a virtual bridge between pressures, physically bypassing thick conduction/pressure walls. And the new methodology, a PV=PV swap phenomenon, mocks the traditional Feed Pumps ability to mimick the above option, with a 100 fold plus, method overhead cost saving.

If you can cannot imagine a Stirling Device operating at 1000 Bar plus, linked to wet bulb cooling and buffer on the cool side, with practically zero approach temp, and a molten salt buffer to intrude into the pressure vessel on the hot side, also with practically zero approach, where the interface between the influences and the working fluid was less than .2mm copper, and surface area no issue, if you cannot imagine that, I suggest you consider the 3 lines of maths, and the 3 minutes of reading attached.

So Dawid, I suggest you cannot ever determine which system will be best in the future, because as I have shown, it's all up in the air right now.