New distributed energy resources Challenges and new roles for the distribution grid

Transcription

1 New distributed energy resources Challenges and new roles for the distribution grid Conferencia regional de generación distribuida (GD) 25 Oct 2016, Santiago de Chile Simon Müller Head of Unit System Integration of Renewables Unit OECD/IEA OECD/IEA

2 OECD/IEA Three domains of change Technical: more complex power flows New technologies, role of data Economic: new value streams Innovative business models change customer engagement in energy markets Social fairness at stake: tariffs and taxation Institutional: new roles and responsibilities Inconsistencies between commercial arrangements and grid operations Technological changes challenge today s institutional setting and regulatory paradigms Sources/loads Technical Market participants Economic Roles Institutional Energy Capital Information

3 OECD/IEA Modularity: German case Key point: Managing intgeration of a very large number of decentralised plants connected to low- and medium voltage grid often challenging

4 OECD/IEA Non-synchronous generation PV: non-synchronous, non-mechanical generation Wind: non-synchronous, mechanical generation Source: Integrating Wind in Ireland: Experience and Studies Mark O Malley Director, MIT Wind Week January 21th 2011 Key point: Technical connection standards critical to ensure safe operations, in particular for distributed generation

5 OECD/IEA Distributed PV and the (rural) grid Voltage rise common issue Smart inverters and transformers help Voltage rise in a rural distribution system in Germany Transformer Transformer Voltage level deviation O% +9%

6 kw kw kw kw kw OECD/IEA Impacts on the grid will vary by type of DG uction (Residential) Match of PV supply and power demand for a residential/commercial customer in France Day of peak production (Residential) Day of peak injection (Residential) Day of peak injection (Residential) Consumption Consumption PV Injection-Withdrawal PV Injection-Withdrawal Week of high production (Office building) Week of high production (Office building) Self-consumption higher for: Some office and commerce buildings with high daily consumption, and relatively small systems on multistorey dwellings Self-consumption potentially increased with DSI, storage Source: ETP 2014, EDF

7 Distributed PV and the grid Power flows across HV-MV transformer in Bavaria, Germany Voltage rise common issue Reverse flows no fundamental technical issue But upgrades to equipment may be needed to operate securely From Transmission to Distribution From Distribution to Transmission Source: Bayernwerk, Fraunhofer IWES OECD/IEA

8 OECD/IEA Smart solar PV systems as part of the solution Add information from analysis in Hawaii

9 OECD/IEA Additional technical issues 1 Example: Islanding any situation where the source of power from the network operator s distribution system is disconnected from the network section in which the generator is connected, and one or more inverters maintain a supply to that section of the distribution system or consumer s installation Safety concerns: can expose utility workers to dangers of shocks and burns Possible damage to customer s appliances Possible inverter damage Ending the failure: Reclosing the circuit onto an active island may cause problems with the utility's equipment Key point: To avoid islanding issues, it is recommended that all distributed generators shall be equipped which devices to prevent islanding, i.e. anti-islanding

10 Additional technical issues 2 Example: Local forecasting 30 second GHI ramp forecast from the Total Sky Imager, San Diego Change in cloud cover across systems on MV feeder Leads to tap changing operation in transformer (increases wear and tear) Forecasts help to minimise tap operations Key point: Under specific circustances implementing local solar PV forecasts can bring benefits for the operation of the distribution grid. Source: IEA PVPS OECD/IEA

11 National penetration scenario (TSO) Regulatory barriers OECD/IEA Impact of rooftop PV on grids High penetration Distributed PV as a major electricity source 3 Distribution grids (stage 2) Transmission grids: Reverse power flows from distribution grids, V dip impacts Increased need to recoordinate protection settings Regulatory barriers 1 Potential localised overvoltage issues (particularly in rural grids) Potential localised overloading issues (particularly in rural grids) 2 Distribution grids: Significant over-voltage Significant over-loading Changes in reactive power balance Transmission grids: Reverse power flows from DSO Increased necessity for re-dispatch and congestion management Low/Medium penetration Distribution grids High penetration Source: IEA PVPS Key point: The impact of rooftop solar PV installations on local and bulk transmission grids will change as installation levels increase

12 Changing TSO DSO relationship Key areas for coordination & collaboration: congestion management grid monitoring balancing voltage support islanding & re-synchronization generation / load forecasts Suppliers Tech giants Regulator Utility Aggregators Future energy system interactions TSO DSO DER Operational Signals Services Power flow Key point: The transmission distribution interface is becoming a juncture of economic value. This calls for strengthened cooperation between TSOs and DSOs Adapted from Birk et al (2016) OECD/IEA

13 RES control using smart grids Smart Grids Functionalities BB WiMax RES Observability and Monitoring HV/MV SS Voltage Control Automatic Fault Detection Linea MT MV/LV SS1 MV/LV SS2 Optical Fiber MV/LV SS3 Optical Fiber MV/LV SS4 MV/LV SS5 Boundary Anti Islanding Information flow to the TSO VPN Telecontrollo PG PI Ancillary services Existing Communication Remote Control System New communication implemented AMM MV CONSUMER MV GENERATOR Demand Response Broad Band infrastructure connecting all the main nodes of the distribution network Source: ENEL, FY 2013 OECD/IEA

14 Planning of local grids Historically: Focused on sizing to match peak load Single loading scenario Load flow simulations Revision towards Uncertainties Distributed generation EVs Storage / DSM Non-grid options Raises importance of data to simulate variety of loading scenarios Source: PlanGridEV Towards stronger integration in planning local grids OECD/IEA

15 OECD/IEA These loads may arrive sooner than you think Renault ZOE40 Please replace pictures with correct car models 40 kwh 3*32A / 3*64A TESLA Model 3 60 kwh 3*32A / 3*64A Chevy Bolt EV 60 kwh 3*16A

16 Conclusions Adding distributed generation gradually impacts low- and medium voltage grids Change can happen quickly so better be prepared Most common technical issues voltage rise, line and transformer loading (depend on network setting) Smart inverters can help increase hosting capacities Growing shares of distributed generation change the nature of interface between transmission system and local grids Smartening of medium- and low-voltage grids can be cost effective Planning standards need to be adapted to new reality Linked with transmission level planning Robust against uncertainty Incorporate all relevant technological trends (DG, demand side response, electric vehicles) OECD/IEA