The paper reviews different approaches, technologies, and strategies to manage large-scale schemes of variable renewable electricity such as solar and wind power. We consider both supply and demand side measures. In addition to presenting energy system flexibility measures, their importance to renewable electricity is discussed. The flexibility measures available range from traditional ones such as grid extension or pumped hydro storage to more advanced strategies such as demand side management and demand side linked approaches, e.g. the use of electric vehicles for storing excess electricity, but also providing grid support services. Advanced batteries may offer new solutions in the future, though the high costs associated with batteries may restrict their use to smaller scale applications. Different “P2Y”-type of strategies, where P stands for surplus renewable power and Y for the energy form or energy service to which this excess in converted to, e.g. thermal energy, hydrogen, gas or mobility are receiving much attention as potential flexibility solutions, making use of the energy system as a whole. To “functionalize” or to assess the value of the various energy system flexibility measures, these need often be put into an electricity/energy market or utility service context. Summarizing, the outlook for managing large amounts of RE power in terms of options available seems to be promising.

https://research.aalto.fi/files/6557604/lund_et_al_review.pdf

Review of energy system flexibility measures to enable high levels of variable renewable electricity

Levelized costs of electricity (LCOE) are a common metric for comparing power generating technologies. However, there is qualified criticism particularly towards evaluating variable renewables like wind and solar power based on LCOE because it ignores integration costs that occur at the system level. In this paper we propose a new measure System LCOE as the sum of generation and integration costs per unit of VRE. For this purpose we develop a conclusive definition of integration costs. Furthermore we decompose integration costs into different cost components and draw conclusions for integration options like transmission grids and energy storage. System LCOE are quantified from a power system model and a literature review. We find that at moderate wind shares (~20%) integration costs can be in the same range as generation costs of wind power and conventional plants. Integration costs further increase with growing wind shares. We conclude that integration costs can become an economic barrier to deploying VRE at high shares. This implies that an economic evaluation of VRE must not neglect integration costs. A pure LCOE comparison would significantly underestimate the costs of VRE at high shares. System LCOE give a framework of how to consistently account for integration costs and thus guide policy makers and system planers in designing a cost-efficient power system.

System LCOE: What are the Costs of Variable Renewables?

The impact of wind power generation on the electricity price in Germany

http://www.mcc-berlin.net/fileadmin/data/pdf/Publikationen/Ueckerdt_Hirth_Luderer_Edenhofer_System_LCOE_2013.pdf

System LCOE: What are the costs of variable renewables?

The merit order effect of wind and photovoltaic electricity generation in Germany 2008–2016: Estimation and distributional implications

Wind power integration and power system flexibility–An empirical analysis of extreme events in Germany under the new negative price regime

The intermittency of wind power has a decreasing effect on day-ahead spot prices. Data from Germany illustrate this effect and explain the underlying relationships. This short-term price effect leads to an adaptation process in the conventional generation capacity mix. In the long-run, a higher peak load plant share is required to cope with the increasing volatility of the residual demand. The result is an adapted merit-order. This merit-order intersects with an increasingly volatile residual demand curve and leads to a higher price volatility in the power market, which is going to trigger further adaptations. Therefore this article concludes with a list of open research questions, which can be derived from the illustrated relationship. These research questions should be investigated as soon as possible in order to induce the required adaptations in time.

The Impact of an increasing share of RES-E on the Conventional Power Market — The Example of Germany

Ist der Merit-Order-Effekt der erneuerbaren Energien richtig bewertet?

Bislang erfolgt die Forderung erneuerbarer Energien in Europa auf Basis unterschiedlicher Fordersysteme der Mitgliedstaaten. Eine EU-weite Harmonisierung der Fordersysteme, wodurch sich Effizienzgewinne und eine hohere Effektivitat erhofft werden, ist jedoch aktuell politisch nicht durchsetzbar, da Uneinigkeit bezuglich des „richtigen“ Forderinstruments besteht.

Marco Nicolosi

Papers

Wind power integration and power system flexibility–An empirical analysis of extreme events in Germany under the new negative price regime

The Impact of an increasing share of RES-E on the Conventional Power Market — The Example of Germany

Ist der Merit-Order-Effekt der erneuerbaren Energien richtig bewertet?

Der EU Richtlinienvorschlag für erneuerbare Energien — Eine Analyse der Transferrestriktionen von Herkunftsnachweisen