Hydro power flexibility for power systems with variable renewable energy sources: an IEA Task 25 collaboration

Abstract

Hydro power is one of the most flexible sources of electricity production. Power systems with considerable amounts of flexible hydro power potentially offer easier integration of variable generation, e.g., wind and solar. However, there exist operational constraints to ensure mid-/long-term security of supply while keeping river flows and reservoirs levels within permitted limits. In order to properly assess the effective available hydro power flexibility and its value for storage, a detailed assessment of hydro power is essential. Due to the inherent uncertainty of the weather-dependent hydrological cycle, regulation constraints on the hydro system, and uncertainty of internal load as well as variable generation (wind and solar), this assessment is complex. Hence, it requires proper modeling of all the underlying interactions between hydro power and the power system, with a large share of other variable renewables. A summary of existing experience of wind integration in hydro-dominated power systems clearly points to strict simulation methodologies. Recommendations include requirements for techno-economic models to correctly assess strategies for hydro power and pumped storage dispatch. These models are based not only on seasonal water inflow variations but also on variable generation, and all these are in time horizons from very short term up to multiple years, depending on the studied system. Another important recommendation is to include a geographically detailed description of hydro power systems, rivers' flows, and reservoirs as well as grid topology and congestion.

Reconstruction of Multidecadal Country-Aggregated Hydro Power Generation in Europe Based on a Random Forest Model

“…Hydro power, in particular through reservoir-based power plants, plays a critical role in providing flexibility to the European power systems. With the EU renewable energy target of 32% by 2030 [2], the role of hydro power will be even more important in a low-carbon scenario, where the capacity of non-dispatchable electricity sources (mostly wind and solar) will be much higher than today [3].…”

Opportunities for Research and Development of Hybrid Power Plants

“…Pumped hydro systems have been applied to a range of system types, including: (1) off-grid and distributed electricity generation (Pali and Vadhera 2018), (2) smaller or islanded grid systems (Norconsult 2013;Coburn et al 2014), or even (3) very large utility-scale systems (MWH 2009;Huertas-Hernando et al 2017). The objectives of pumped hydro differ, depending on the type of system of interest.…”

The role of hydro power, storage and transmission in the decarbonization of the Chinese power system

“…The 41 selected hydro stations' annual generation explains over 80% of the national hydroelectricity production, and in the model, their capacities are assumed to be fixed, even though a long list of major dams are currently in plan or under construction [44]. Indeed, the technically exploitable hydro power capacity is estimated to be 542 GW [45], and only 341 GW were put to use until 2017 [46]. The location of planned hydro stations may be known, but we are not able to validate the inflow or approximate the head heights until dam discharge measurement recorded.…”