Chair of Sustainable Electric Networks and Sources of Energy Smart Grids and Integration of Renewable Energies Professor Kai Strunz, TU Berlin Intelligent City Forum, Berlin, 30 May 2011 Overview 1. Historic Background 2. Power System Structure Today 3. Future Trends 4. Introduction to Smart Grid 5. Smart Grid Solutions 6. Wrap-Up 2
1. Historic Background a) AC vs. DC b) First DC electricity supply c) Origin of voltage drop d) Reducing voltage drop 3 1. Historic Background: AC vs. DC Thomas Edison (1847-1931) Born on 11th of February 1847 in Ohio, USA Died 1931 84 years old Brilliant in math and nature sciences With 1093 Patents in his name one of the greatest inventor of all times Opened his first research laboratory in New Jersey in 1874 One of the most important inventions is light bulb Nikola Tesla (1856-1943) Born on 9th of July 1856 in Croatien Died 1943 86 years old Brilliant with 800 patents Went 1884 in the USA Worked as an assistant in Edison s lab His AC-motor was remarkable Supported DC Developed AC 4
1. Historic Background: First DC electricity supply Historical development The first power plant In 1880 Edison founded the Edison Electric Illuminating Company New York In 1882 the Edison s Pearl Street power plant in Manhattan started operation It is the first power plant for electric lightning Distributed direct current with 110 Volt direct voltage 110 V time A year after the start of the operation 10000 lamps were supplied 5 1. Historic Background: Origin of voltage drop Voltage at a load with direct current I R leiter V Q V last R last V V I R R Q last last last Rlast Rleiter 6
1. Historic Background: Reducing the voltage drop Direct Current (DC) Voltage the load: V V I R R Q last last last Rlast Rleiter Reducing the voltage drop through reducing R leiter Disadvantage: Thicker cables required Heavier cables required Expensive installation Difficulties in practice Alternating Current (AC) With AC, the voltage is transformable V Q can be easily increased with a transformer V Q N1 N2 N2 V Q N1 Victory of AC thanks to technical benefits 7 2. Power System Structure Today a) Hierarchical buildup b) Generation sector c) Transmission sector d) Distribution sector An example of Medium Voltage (MV) distribution network An example of Low Voltage (LV) distribution network 8
2. Power System Structure Today Hierarchical buildup Generation High Voltage Transmission Network Medium Voltage Distribution Network Low Voltage Distribution Network 9 2. Power System Structure Today Generation sector Responsible for generating power demanded by consumers Traditionally based on large power plants: Thermal power plants Fossil-fueled power plants Nuclear power plants Hydro power plants Source: http://www.treehugger.com Source: http://library.thinkquest.org 10
2. Power System Structure Today German generation system Installed capacity Energy production share Main renewable resources in generation sector 137.5 GW (2007) mostly lignite (23.5 %), nuclear (23.3 %) and hard coal (20.1 %) (2008) wind power, hydro power, biomass and solar power 11 2. Power System Structure Today Transmission system Responsible for transmitting electric power from power plants to distribution networks High Voltage transmission system in Germany comprises lines with following voltage levels: 380 kv 220 kv Source: http://www.vnf.com 12
2. Power System Structure Today An example of medium voltage distribution network Feeder 1 Feeder 2 Bus Load Transformer Power switch 13 2. Power System Structure Today An example of low voltage distribution network Load 20 kv Bus Grounding Mast Platform Residence Commerce 400 V 35 m 30 m Industry 14
3. Future Trends a) Large-scale renewable generation b) Distributed Generation (DG) c) Energy storage systems (ESS) d) E-mobility Electric vehicles Interaction with the grid Possible challenges for the grid Approaches to handle EV charging load 15 3. Future Trends Large-scale renewable generation Source: http://papundits.files.wordpress.com Source: http://static.timesofmalta.com Source: http://blisstree.com Off-shore wind farm On-shore wind farm Solar power plant Good news: increasing penetration of large-scale renewable with significant installed capacity Bad news: intermittent generation with a considerable forecast uncertainty 16
3. Future Trends Distributed Generation (DG) Source: http://www.finehomebuilding.com Roof-mounted solar panels Source: http://www.powergenworldwide.com Combine heat and power (CHP) unit Increasing penetration of roof-mounted solar panels and micro combined heat and power (CHP) units in low voltage (LV) distribution network 17 3. Future Trends Energy Storage Systems (ESS) Source: http://softtoyssoftware.com Source: http://www.shpegs.org/cawegs.html Source: http://www.altenergymag.com Battery storage system Compressed air storage system Pumped-storage system Energy storage systems used to compensate intermittency of renewable generation 18
3. Future Trends E-mobility: Definition and realization form Definition: Using electricity as the energy vector for the road electric vehicles Realization form: Large-scale market introduction of plug-in hybrid electric vehicles (PHEV) and battery electric vehicles (BEV) 19 3. Future Trends E-mobility: Electric vehicles Battery electric vehicles (BEVs): The propulsion system consists of an electric motor The electric motor uses the electric energy stored in vehicle battery packs Plug-in hybrid electric vehicles (PHEVs): The propulsion system consists of an electric motor and an internal combustion engine (ICE) The electric motor and the ICE use the energy stored in vehicle battery packs and fuel tank, respectively 20
3. Future Trends E-mobility: Interaction with the grid Massive integration of EVs introduces new challenges and opportunities to the grid From the power system side, EVs can be regarded as: Simple loads: when the EV owner wants to charge the batteries at a certain rate in a specified time (dumb charging) Responsive loads: when the EV owner defines a time interval for the charging process, allowing some management structure to control the charging rate (smart charging) Storage devices: when the EV owner allows batteries to inject power to the grid upon request (vehicle-to-grid operation) 21 3. Future Trends E-mobility: Possible challenges for the grid Significant grid operational problems are expected in case of considering EVs as simple loads, particularly if grid peak time coincides with EV charging periods: Increase in grid overall peak demand Congestion problems in areas of the grid already heavily loaded Voltage profile problems mainly in radial networks 22
3. Future Trends E-mobility: Possible challenges for the grid Effect of dumb charging of EV batteries on Germany s electricity demand assuming a 10% share for electric vehicles: 23 3. Future Trends E-mobility: Approaches to handle EV charging load In the case of congestion due to EV charging, two possible solutions can be suggested: Plan for grid expansion so that the reinforced network is able to handle the new EV battery charging loads Develop a smart management system for charging EV batteries to optimize charging times and fully benefit from EV battery storage potential The first way requires high grid investments The second approach tries to benefit from the already existing infrastructure to minimize new possible investment costs, and is thus preferred where possible 24
4. Introduction to Smart Grid a) Motivation Need for effective integration of new trends Need for changing the role of demand side from passive to active b) Power system structural change under smart grid paradigm c) Key benefits of smart grid 25 4. Introduction to Smart Grid Motivation: Need for effective integration of new trends The new trends in power system offer many challenges and opportunities Current power system paradigm cannot accommodate the new trends in power systems in an effective way For example: Intermittency of large-scale renewable resources makes the traditional dispatching as known from thermal power plants impossible Distributed energy resources close to the consumer alter the power flows on distribution networks Electric vehicles are new resources that are new loads but can also provide support to network operation The smart grid is to support the integration of such new trends 26
4. Introduction to Smart Grid Motivation: Need for changing the role of demand side from passive to active Presently, demand side is a passive part in the power system Changing demand side role from passive to active may offer the following benefits: Decrease in peak demand Delay in grid expansion Better utilization of assets in generation, transmission and distribution sectors Higher energy efficiency of power system More economic operation of the power system To actively involve the consumers in power system operation, they need to be incentivized 27 4. Introduction to Smart Grid Motivation: Need for changing the role of demand side from passive to active Correct incentives to consumers for acting in the optimum way requires providing them real-time or near-real-time data of their consumption costs Providing the consumers with real-time or near-real-time information cannot be achieved using present power system metering and communication infrastructure Smart grid promotes shift to a new paradigm: From Supply follows Demand to Demand follows Supply 28
4. Introduction to Smart Grid Today s hierarchical grid Smart grid 29 4. Introduction to Smart Grid Key benefits of smart grid Effective integration of all types and sizes of electrical generation and storage systems Increase in number of smaller, distributed resources shift to a more decentralized model Improved reliability of supply Improved monitoring, diagnosis, and response to power quality issues Supply of various grades of power quality at different pricing levels Operational improvements Asset management improvements Active involvement of demand side in power system operation through Demand Side Management (DSM) concept Enable aggregation of resources through Virtual Power Plants (VPPs) 30
5. Smart Grid Solutions a) Demand Side Management (DSM) DSM in a Smart Home DSM via control centre DSM and use of energy storage systems Applying DSM in terms of smart charging of EV batteries b) Virtual Power Plant (VPP) VPP concept Structure of VPP Definition of entities involved in VPP operation 31 5. Smart Grid Solutions Demand Side Mangement (DSM) in a Smart Home Smart Home is any private area equipped with smart meter Modern ICT allows energy management of a private household Flexible demand as a function of price Household Connection 32
5. Smart Grid Solutions Demand side mangement (DSM) via control centre Control Centre: Control Generation Demand Smart Meter 33 5. Smart Grid Solutions DSM and use of energy storage systems to compensate intermittency of renewable resources On Off Speicher 34
5. Smart Grid Solutions Applying DSM in terms of smart charging of EV batteries Effect of smart charging of EV batteries in Germany s electricity demand assuming a 10% share for electric vehicles: 35 5. Smart Grid Solutions Virtual Power Plant (VPP) concept Individual capacities of DER units are often too small to enter the market Various DER units including controllable dispersed generation, storage, and loads grouped and coordinated as a single unit can form a VPP The VPP would be able to participate in the market and offer: Generation capacity Ancillary services including voltage support and frequency regulation 36
5. Smart Grid Solutions Virtual Power Plant (VPP) concept Individual capacities of DER units are often too small to enter the market Various DER units including controllable dispersed generation, storage, and loads grouped and coordinated as a single unit can form a VPP The VPP would be able to participate in the market and offer: Generation capacity Ancillary services including voltage support and frequency regulation 37 5. Smart Grid Solutions Structure of VPP 38
5. Smart Grid Solutions Definition of entities involved in VPP operation Aggregator: The entity which aggregates and sells the permission to regulate the power consumption or generation rate of EVs and other DERs within a VPP to the market Charging Point (CP): The place where electric vehicles (EVs) plug in to exchange power with the grid Charging Point Manager (CPM): The owner and the operator of public charging points Disribution System Operator (DSO): The entity responsible for safe and secure operation of distribution network 39 6. Wrap-Up Through the usage of many and new renewable and distributed resources, a complex heterogeneous system emerges A shift in paradigm is essential to the success: From Supply follows Demand to Demand follows Supply Smart Grid technology is critical to this shift 40