( Keynote Address | ipec

The 10th International Power and Energy Conference

IPEC 2012

12 - 13 December 2012

Sheraton Saigon Hotel & Towers

Ho Chi Minh City, Vietnam

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Keynote Address

 

 

David  

Professor David J. Hill, Sydney University, Australia

Abstract

FUTURE GRIDS – SCENARIOS, ASSESSMENT, RESILIENCE

The modernization of electricity networks to accommodate increasing renewable energy targets and new technologies, such as electric vehicles and demand management, leads to system control and planning challenges. The term ‘smart grids’ has arisen around the anticipated greater use of information technology in the operation of electricity networks, particularly at distribution levels. While much talk on smart grids relates to marketing more than fundamentals, it is clear that all these advances when seen over the long-term present a series of analytical challenges. To name two, we will have to deal with much greater uncertainty and scale in computations. For example, the latter arises from the increasing granularity of control devices across transmission and distribution. Related to uncertainty, we can no longer see the future in terms of steady load growth and incremental additions to the network.
This presentation is based on a Future Grid (FG) project in Australia funded by the CSIRO and four universities. Closely related projects, which are running in the USA and Germany, will also be discussed. These take a long-term view out to 2030 at least and in some cases 2050. The focus in FG is on delivering the first analytical framework of its kind to systematically investigate the most economically efficient energy network (electricity and natural gas) configurations for Australia.  With this framework, Australia will be able to identify the lowest cost pathway to integrate significant amounts of large and small scale renewables into the grid with existing technologies while maintaining operational stability. Thus it will pave the way for significant emissions reductions in Australia’s most carbon intensive economic sector. Advanced modelling and analytical techniques will be developed to provide a suite of tools to expand our understanding of:

  • The total costs of transmission and distribution systems for standard and alternative grid topologies
  • The development and treatment of methods to deal with increasing renewable energy supply of 20% and beyond
  • Potential market failures in current system planning and operations in dealing with intermittent renewable generation
  • The full benefit of demand side measures in reducing total system cost, i.e. the investment and operating costs of generation, storage, transmission and distribution assets
  • Potential policy and regulatory models that would help Australia implement the most optimal, technologically feasible outcome 

To make assessments on these timescales, a huge amount of uncertainty must be allowed for. This is being done by following a tree structure of alternative scenarios according to technology and policy changes, probabilistic modeling of generation sites and outputs, use of Monte Carlo methods with learning, network science methods, automated scanning tools for system properties such as stability and multi-objective stochastic optimization on networks for planning. In addition, paradigm shifts must be considered such as in the alternative possibilities for transmission from a minor role connecting self-contained clusters to supergrids and in how to deal with the trade-offs between carbon, cost and reliability limits. One way or another, grids must become more adaptive and resilient to changing power supply and demand, failures and attacks through coordinated planning and control more than ever before. And this raises issues on how to achieve substantial new capabilities of effectiveness and efficiency.
This talk will outline the current research on future grids with emphasis on the long-term issues and analytical challenges arising around alternative scenarios, their assessment at scale and planning for resilience.

Speaker’s Biography

 

     
Milanovic  

Professor Jovica Milanović, Manchester University, UK

Abstract

CHALLENGES FACING OPERATORS OF FLEXIBLE POWER SYSTEMS OF THE FUTURE

It is widely anticipated that there will be enough public support and sustained political will to build enough renewable generation capacity to produce 50%, or more, of the demand for electrical energy. Many of renewable energy sources (RES) have a low energy density and are therefore distributed. Majority of RES will be connected to the network through power electronics interface. Some of them are intermittent (driven by astronomical factors) and other stochastic (dependent on meteorological conditions). The exploitation of low intensity renewable resources requires large investments that are economically viable only if the utilization of the primary energy is maximized.  Intermittent RES thus provides little control and causes much uncertainty in the operation.  Because of the intermittency the renewable generation capacity will have to represent a significantly larger fraction of the total installed capacity.

Currently major type (by volume and installed capacity) of renewable generation, large off-shore wind farms, will be most likely, connected to an off-shore sub-marine transmission grid first and then to the shore. Grid connections and off-shore networks could be either AC or HVDC cables. It is envisaged that power electronics will play increasing role in the grid to facilitate the bulk (cross-boarder) transfer of power and required network flexibility. This proliferation will be spearheaded principally by HVDC links to assist in stability and power flow control, generator-grid interfaces and increased application of FACTS devices to “soften” existing transmission network. Because their cost is not likely to decrease significantly FACTS devices will probably remain somewhat auxiliary to the main AC transmission and distribution networks in immediate future. The HVDC, in particular Variable Source Converter controlled HVDC, lines on the other hand, are largely expected to form meshed supergrid on top and in conjunction with existing AC grid to shift  large amount of electrical power over large distances.

Depending on the country, required energy mix and to ensure energy security, nuclear plants may represent a significant fraction of the remaining generation capacity. Thermal generating plants burning fossil fuels will continue to provide the balance of the capacity.  These plants though will be subject to a carbon tax or will operate under an effective and efficient “cap and trade” mechanism for emissions trading. This will ensure that their operating costs are higher than the cost of producing energy using generation that does not produce green house gases.

This new generation mix may not be able to keep the system in balance if it is operated in the traditional way, i.e. the generation is ramped up and down to follow the load and re-dispatched to resolve transmission constraints. Replacing the current “supply-follows-load” control philosophy by a “load-follows-supply” approach might be considerably cheaper as the heat, cold, energy or material storage that is naturally incorporated in many domestic and industrial appliances and processes can be harnessed to adjust the demand to match the supply. Furthermore, electric and plug-in hybrid vehicles (whose number is expected to grow rapidly in the future) and distributed energy storage could provide an additional and particularly flexible control resource though at the same time may  place additional demands on power network requiring higher network flexibility and operability.

Therefore, future power systems will be characterised by  mix of wide range of electricity generating technologies, responsive and highly flexible demand/storage with significant temporal and spatial uncertainty, proliferation of power electronics (HVDC and to certain extent FACTS devices) at transmission system level, flexible hierarchical control structure and blurred boundaries between transmission and distribution system (with distribution system becoming more “transmission like”) and significantly higher reliance on the use of global (Wide Area Monitoring) signals for system identification and control and Information and Communication Technology embedded within the power system network and its components.

In order to successfully control such system and its parts and to ensure its stability and security the control strategies and simulation tools for future power networks would need to cater for: i) Increased uncertainties in controlled  system, both in terms of model uncertainties and operational uncertainties ii)   Increased reliance on global (WAM) signals for state estimation, dynamic equivalents and application for control & stability; iii) Increased penetration of power electronic devices (RES interface, HVDC, FACTS devices), i.e., static and dynamic models, system integration and control & stability contribution; iv) New types of intermittent and stochastic generation, i.e., new static and dynamic aggregate models; v) Less distinctive boundaries between transmission and distribution network and possibility of their interchangeable roles, i.e., flexible hierarchical control strategies; vi) Responsive flexible demand which may exhibit temporal, spatial and functional variation, i.e., static and dynamic models of demand and system integration; v) integral control and facilitation of efficient  energy (electrical, heat, gas) flow  and utilisation in small or larger geographical parts of the network.

Speaker’s Biography

 

     
Yokoyama  

Professor Akihiko Yokoyama, Tokyo University, Japan

Abstract

MASSIVE INTEGRATION OF RENEWABLE ENERGY INTO POWER GRID TO REDUCE ENERGY’S ENVIRONMENTAL IMPACT AFTER 3.11 DISASTER IN JAPAN

In recent years, global warming, energy saving, and energy security have become major issues. In
Japan, huge Tohoku Earthquake and Tsunami occurred on March 11, 2011, and seriously damaged
thermal and nuclear power plants and power system transmission and distribution systems on the
east coast in Tohoku district. There are 54 nuclear reactors of about 49 GW in Japan as shown in
Fig.1 and all of them stopped their operation to check their safety by May 5 in 2012. But only two
nuclear reactors in Kansai EPCO restarted their operation in July, 2012 because of power supply
shortage in this summer in Kansai area. The 3.11 disaster triggered the change of the energy policy
and the change of the criteria on the power system planning and operation in Japan from the
viewpoint of nuclear power generation and renewable energy.

 

Fig. 1 Current Status of Nuclear power plant operation in Japan

 

As a result, large-scale development of renewable energy sources such as wind and photovoltaic
(PV) power generation has been planned as shown in Fig. 2. However, reliance on the renewable
energy sources may cause problems in power system operations, such as surplus power from PV
power generation, frequency fluctuation, and distribution voltage rise. Smart Grid in Fig.3 is a
new and better approach to the future power system, enabling us to resolve the above mentioned
problems in the power system operations using information and communication technology (ICT).
This presentation introduces the concept, features, and challenges associated with the realization
of Smart Grid, especially when the integration of renewable energy sources into the grid is
expanded.

 

Fig.2 PV Installation Plan in Japan

 

Fig. 3 Smart Grid in the Japanese Context

 

Battery Energy Storage System (BESS) is a well-known and effective technology to solve the
problems in the power system operations. Because of the high cost of the BESS, it is preferable to
keep its installation capacity as small as possible. To do so, output suppression control of roof-top
PVs and wind power generations is proposed in Japan as shown in Fig.4. Furthermore, the output
control of controllable small-size distributed generators (DGs) and controllable customer
equipment such as Heat Pump Water Heater (HPWH) and Electric Vehicle (EV) will also be
considered for their contribution to the power system control such as the supply and demand
matching control and the system frequency control. In this presentation, a number of HPWHs and
EVs, which are energy efficient-use customer equipment with energy storage equipment, are
considered as controllable loads for regulating the system frequency as shown in Fig 5. The
effective utilization of the customer equipment for the power system control, e.g. the frequency
regulation and the emergency control considering customer benefit or customer comfort is one of
the key elements in the concept of smart grid in Japan.

 

Fig. 4 Roof-top PV Output Control

 

Fig 5 EV and HPWH Control

 

In order to realize the smarter grid with massive integration of renewable energy in Japan, Micro
Grid, Smart Micro Grid and Smart Grid related national demonstration projects have been carried
out since 2001, which have been partially supported by Japanese Government. One of the current
national projects on a smart grid in Japanese context, which is called optimal control technologies
for the next-generation transmission and distribution systems, is presented here. In order to solve
the problems associated with massive penetration of PV mentioned above, this project is focusing
on the following four technical sub-issues: (1)Methodology for allocation and control of voltage
regulating devices in distribution system (2)High-performance voltage regulating devices on
distribution line (compactness, low cost, etc.) (3)Methodology for controlling customer equipment
such as PV, HPWH and EV according to demand and supply imbalance shown in Fig.6
(4)Methodology for planning of power grid operation and its real-time operation considering
cooperation with customer equipment.

 

Fig.6 Schematic Image of Experimental Facilities in the Univ. of Tokyo

 

In the last part, the countermeasure cost against the problems in the power system operations and the transmission and distribution reinforcement cost associated with massive integration of
renewables into the grid are discussed. In Japan, a large amount of both costs will be necessary for
massive integration of PV and Wind power generations into the grid, which will lead to a big raise
of the electricity rate. The electricity consumers have to consider carefully the balance or trade-off
of the electricity rate raise and the CO2 emission reduction when introducing a large amount of
renewable energy.

In conclusion, for establishing the smart grid, we still have some important and difficult issues in
three areas of technology, economy and institution shown in Fig.7. Cyber security and personal
information security problem should also be solved as early as possible.

 

Fig. 7 Remaining Issues in Smart Grid

 

Speaker’s Biography