###### Abstract  
The objective of this investigation is to present a novel concept for the optimum exploitation of volatile electricity from renewable energy sources. The idea of the Carnot battery is extended to a general concept for trigeneration which can be called \"power to XYZ\". This idea is applied for the building sector where there are needs for cooling production, space-heating production/domestic hot water production and electricity. More specifically, volatile electricity feeds a multi-stage heat pump that produces cold storage at 0 \({}^{\circ}\)C for cooling, medium heating storage at 50 \({}^{\circ}\)C for space heating and high thermal storage at around 115 \({}^{\circ}\)C for future utilization in an organic Rankine cycle for electricity production. The storage is performed in three different temperature levels, with latent storage proposed for proper long-term and efficient storage. The use of ice is suggested especially for cold storage in order to make the design a cost-effective one. This work is a theoretical preliminary thermodynamic analysis performed with a model created in Engineering Equation Solver. The results indicate the system's maximum exergy efficiency is found at 45.28%, while the respective energy efficiency is found at 322.16%. Moreover, this work  
choice than the use of sensible storage. In addition, they concluded that the working fluid R1233 zd(E) is the best choice for the sensible storage case, while cyclopentane is the optimal choice for latent storage systems. In another study, [PERSON] et al. [11] suggested the use of flat plate solar technologies for feeding the heat pump; they found that this technique increases the round-trip efficiency to 68.5% compared to 32.1% for the ambient source heat pump. They also calculated the payback period of the solar field investment at about 7.5 years. In the same direction, [PERSON] and [PERSON] [14] suggested a solar and geothermal-driven heat pump with a reversible ORC. This design was proved to be a cost-effective choice with important advantages. Moreover, the idea of the reversible HP-ORC with waste heat recovery has been examined by [PERSON] et al. [15]. They found that the most appropriate fluids are the R-1224 yd(Z) and R-1233 zd(E). The system operates with a coefficient of performance at 2.44 and electrical efficiency of 8.75%. Furthermore, there are interesting studies in the literature that incorporate nuclear energy in thermal-pumped systems [16], as well as geothermal energy [17]. Especially in the case of geothermal energy exploitation, geothermal heat pumps are efficient choices that are promising for future highly efficient systems [18]. The previous literature summary highlights that there is great interest in the domain of Carnot batteries and the respective storage systems. Virtually all the literature studies are focused on systems that exploit grid electricity to an intermediate product \"X\", which is usually high thermal stored energy, and after a period this quantity \"X\" is reconverted to electricity. However, there is a lack of research about trying to convert grid electricity into more intermediate products. In this direction, the present work suggests for the first time a new concept that combines the Carnot battery idea and trigeneration. Specifically, volatile electricity from the grid feeds a multi-stage heat pump that produces cooling, space heating and high thermal stored energy. So, the concept of \"Power to XYZ\" is born with the present work in a trial for the optimal utilization of the electricity grid which is stored in various forms of energy. At this point, it is important to state that the trigeneration systems, especially when they are driven by renewables, are viable choices for future sustainable development [19]. So, the new concept of \"Power to XYZ\" is a critical one because it aims to combine two \"hot topics\": \"Power to X\" and \"trigeneration\".