Electricity Storage is widely considered to be an effective solution to the intermittency of renewable energy generation, most notably wind and solar energy (but also tidal and wave), to turn their intermittent output into dispatchable and baseload energy supply. Considerable amounts of time and effort have been allocated to researching promising storage technologies, as well as innovative concepts which could disrupt the current paradigm in the Energy Sector, such as vehicle-to-grid demand-side response.However, many of these research efforts into paradigm-shifting concepts often rely on small-scale storage units, typically electrochemical in nature. Meanwhile, the potential of technologies which are more economical when applied on large-scale applications, such as pumped hydro-storage, will frequentlybe overlooked.In this thesis, a market analysis shall be conducted of the potential applicationsinwhich large-scale electricity storage units may profitably participate, like performing electricity price arbitrage or providing balancing services to the electric grid.Basic technical requirements for some balancing services shall be identified, as well as existing procurement structuresand payment practices.The trend of greater renewable energy penetration in electric grids and the subsequent effectson the potential profitability of price arbitrage and balancing services shallalsobe discussed, alongside theimpact of legislation and regulations on possible business opportunities.The concept of “revenue-stacking” is exploredand a potential methodology is studied, as well as examples testing its feasibility, resorting to historical data from the Netherlands and Germany. The impact of information availability and accessibility on the construction of a revenue-stack is discussed, just like the potential role of optimization algorithms in obtaining better solutionsforrevenue-stacking.