Role of Detailed Hydro Power Modelling in Investigating Power System Flexibility
Summary
In order to reach a 80% GHG emission reduction by 2050 (based on 1990 levels), a decarbonisation of 95% to 100% of the power supply sector will be necessary. Intermittent renewable energy sources (iRES) such as wind and solar are likely to become important components of such low-carbon power systems, but they require operational flexibility from non-iRES generators in the power system. From the few flexible and dispatchable renewable energy sources which are currently commercialized, hydro power has the largest installed capacity in Europe at the moment and could therefore be a significant provider of operational flexibility in future low-carbon power systems. However, hydro power is vulnerable to periods of drought, which may decrease the reliability of hydro power generation.
In this research, the effects of different natural inflow scenarios on a potential low-carbon European power system are investigated. This is done by including a detailed representation of hydro capacity (including details on hydro storages, natural inflow and complex configurations) in a European low-carbon power system model. In addition, the detailed representation of hydro plants is compared to a more simplistic method of modelling hydro capacity in order to investigate the added value of a detailed approach.
By including 68 detailed hydro power plants in the model, 32% of the total currently installed hydro capacity in Western Europe has been covered. The hydro power plants modelled in detail are clearly influenced by different natural inflow scenarios. Storage (STO) and Run-of-River (RoR) plants generate 79% and 72% more electricity on an annual basis in the maximum natural inflow scenario compared to the minimum natural inflow scenario. For PHS plants, this difference is 8%. These differences are mainly compensated for by gas turbines (GT) and natural gas combined cycle plants (NGCC). In the more simplistic hydro modelling method, these effects of alterations in natural inflow can not be accounted for.
In weeks with high iRES generation, all types of hydro plants (STO, RoR and PHS) provide for generation during hours without sun, both in the detailed and the lumped scenarios.
Based on this study, the main added value of detailed hydro modelling is the sensitivity of hydro plant dispatch to different natural inflow scenarios. If a higher share of the hydro capacity is included in the detailed hydro plant database, the effect of different natural inflow scenarios on total generation profiles is expected to be significant.