dena Grid Study II Integration of Renewable Energy Sources in the German Power Supply System from 2015-2020 with an Outlook to 2025 Jaakko Iivanainen

Contents Introduction Areas studied Wind Grid Flexibility and Storage Results

dena Grid Study II Aim: To find solutions to fully integrate 39% RE suppy to the German grid by 2020 Securing supply European energy market Different approaches to improving and expanding the grid Complete integration of RE by increasing flexibility Storages Demand side management Improved wind forecast capablility Balancing energy by wind or biomass

dena Grid Study II dena Grid Study II is based 20% of all energy from RE souces by 2015 850 km of new trasmission lines required dena Grid Study I results incorporated in the Power Grid Expansion Act as priority projects dena Grid Study II assumes that that the grid enhancements and expansion measures have been implemented

Areas studied All sections studied Main focus on: Wind energy feed in time series Transmission requirements Flexibility and integration of renewables

Part I Generation of feed-in timeseries for wind Time series of 15 minutes based on historical data from a numerical weather model consists of hourly values from 2004 to 2007 transformed to electrical wind power in 2020 using physical models data pool of measurements from 83 wind farms was used to complete the weather model 1186 onshore grid nodes and 46 offshore wind farms 37 GW onshore wind capacity, 14 GW offshore wind Results in 2200 full-load hours onshore and 4400 full-load hours offshore

Part I Generation of feed-in timeseries for wind 27% wind penetration was calculated Extension of wind power in leads to reduced relative fluctuation of wind power across Germany Reduces need for balancing power The wind power time series of part I for the basis for grid calculations in part II and the balancing power calculations in part III

Part I Generation of feed-in timeseries for wind Evaluation: Wind measurement data is collected only from 4 consecutive years instead of recommended 8 The simulations correlate very well with measurements The benchmark case for the study is the previous study Reality might turn out to be very different Properties of future wind turbines were assumed

Part II Effects on the grid and future development Grid suggested in dena Grid Study I is examined Larger feed of RE Non-transmittable power Optimization measures evaluated Non-transmittable power in 70% of all borders 2015 grid inadequate in 2020

Part II Effects on the grid and future development Increasing transmission capacity of overhead lines Flexible line management (FLM) Conductor temperature is monitored Strong winds and low outdoor temperature allow up to 50% increase in current High temperature conductors (TAL) High temperature resistant aluminum 50% higher current than normal Neither are considered economically viable

Part II Effects on the grid and future development Integration solutions: Integration via grid extension (version 000) 50% storage of non-transmittable power in the bottleneck region (version 050) 100% storage of non-transmittable power in the bottleneck region (version 100) combined with: Basic grid with standard transmission capacity (BAS) Flexible line management (FLM) High temperature conductors (TAL) Total nine variants

Part II Effects on the grid and future development

Part III Increasing flexibility for the best possible integration of renewable energy The wind energy forecast quality can be improved by approx. 45% Demand side management potential taken into account in process industry and a few applications in domestic environments. 60% of the demand for positive balancing energy 2% of the negative balancing energy Biomass plants have in principle the ability to do high power ramps generally suitable for providing balancing power

Part III Increasing flexibility for the best possible integration of renewable energy Pumped storage assumed to increase 1700 MW Electricity storage would not relieve grid bottlenecks, when they behave in an economically optimal way. Compressed air and hydrogen storage facilities will not occur in the simulation due to being uneconomical

Overall results

Assumptions and limitations Properties of future wind turbines were assumed Nuclear phase-out: 2020 nuclear capacity 6.7 GW Might turn out different Model-based economic optimization of conventional power stations in Germany European market integration only limited by interconnector capacities Photovoltaics 18 GW in 2020 40 GW in 2016 Assumed 8% reduction in net electricity consumption between 2008 and 2020

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