Features of SMART GRID!

Features of the smart grid

The smart grid represents the full suite of current and proposed responses to the challenges of electricity supply. Because of the diverse range of factors there are numerous competing taxonomies and no agreement on a universal definition. Nevertheless, one possible categorization is given here.

 

  1. Reliability

The smart grid will make use of technologies, such as state estimation, that improve fault detection and allow self-healing of the network without the intervention of technicians. This will ensure more reliable supply of electricity, and reduced vulnerability to natural disasters or attack.

Although multiple routes are touted as a feature of the smart grid, the old grid also featured multiple routes. Initial power lines in the grid were built using a radial model, later connectivity was guaranteed via multiple routes, referred to as a network structure. However, this created a new problem: if the current flow or related effects across the network exceed the limits of any particular network element, it could fail, and the current would be shunted to other network elements, which eventually may fail also, causing a domino effect. A technique to prevent this is load shedding by rolling blackout or voltage reduction (brownout)

2. Flexibility in network topology

Next-generation transmission and distribution infrastructure will be better able to handle possible bidirection energy flows, allowing for distributed generation such as from photovoltaic panels on building roofs, but also the use of fuel cells, charging to/from the batteries of electric cars, wind turbines, pumped hydroelectric power, and other sources.

Classic grids were designed for one-way flow of electricity, but if a local sub-network generates more power than it is consuming, the reverse flow can raise safety and reliability issues. A smart grid aims to manage these situations.

 

3. Efficiency

Numerous contributions to overall improvement of the efficiency of energy infrastructure are anticipated from the deployment of smart grid technology, in particular including demand-side management, for example turning off air conditioners during short-term spikes in electricity price, reducing the voltage when possible on distribution lines through Voltage/VAR Optimization, eliminating truck-rolls for meter reading, and reducing truck-rolls by improved outage management using data from Advanced Metering Infrastructure systems. The overall effect is less redundancy in transmission and distribution lines, and greater utilization of generators, leading to lower power prices.

 

4. Load adjustment/Load balancing

The total load connected to the power grid can vary significantly over time. Although the total load is the sum of many individual choices of the clients, the overall load is not a stable, slow varying, increment of the load if a popular television program starts and millions of televisions will draw current instantly. Traditionally, to respond to a rapid increase in power consumption, faster than the start-up time of a large generator, some spare generators are put on a dissipative standby mode.

 A smart grid may warn all individual television sets, or another larger customer, to reduce the load temporarily (to allow time to start up a larger generator) or continuously (in the case of limited resources). Using mathematical prediction algorithms it is possible to predict how many standby generators need to be used, to reach a certain failure rate. In the traditional grid, the failure rate can only be reduced at the cost of more standby generators. In a smart grid, the load reduction by even a small portion of the clients may eliminate the problem.

5. Peak curtailment/leveling and time of use pricing

To reduce demand during the high cost peak usage periods, communications and metering technologies inform smart devices in the home and business when energy demand is high and track how much electricity is used and when it is used. It also gives utility companies the ability to reduce consumption by communicating to devices directly in order to prevent system overloads. Examples would be a utility reducing the usage of a group of electric vehicle charging stations or shifting temperature set points of air conditioners in a city. To motivate them to cut back use and perform what is called peak curtailment or peak leveling, prices of electricity are increased during high demand periods, and decreased during low demand periods. It is thought that consumers and businesses will tend to consume less during high demand periods if it is possible for consumers and consumer devices to be aware of the high price premium for using electricity at peak periods. This could mean making trade-offs such as cycling on/off air conditioners or running dishwashers at 9 pm instead of 5 pm. When businesses and consumers see a direct economic benefit of using energy at off-peak times, the theory is that they will include energy cost of operation into their consumer device and building construction decisions and hence become more energy efficient. 

 According to proponents of smart grid plans. this will reduce the amount of spinning reserve that atomic utilities have to keep on stand-by, as the load curve will level itself through a combination of "invisible hand" free-market capitalism and central control of a large number of devices by power management services that pay consumers a portion of the peak power saved by turning their device off.

6. Sustainability

The improved flexibility of the smart grid permits greater penetration of highly variable renewable energy sources such as solar power and wind power, even without the addition of energy storage. Current network infrastructure is not built to allow for many distributed feed-in points, and typically even if some feed-in is allowed at the local (distribution) level, the transmission-level infrastructure cannot accommodate it. Rapid fluctuations in distributed generation, such as due to cloudy or gusty weather, present significant challenges to power engineers who need to ensure stable power levels through varying the output of the more controllable generators such as gas turbines and hydroelectric generators. Smart grid technology is a necessary condition for very large amounts of renewable electricity on the grid for this reason.

 

7. Market-enabling

The smart grid allows for systematic communication between suppliers (their energy price) and consumers (their willingness-to-pay), and permits both the suppliers and the consumers to be more flexible and sophisticated in their operational strategies. Only the critical loads will need to pay the peak energy prices, and consumers will be able to be more strategic in when they use energy. Generators with greater flexibility will be able to sell energy strategically for maximum profit, whereas inflexible generators such as base-load steam turbines and wind turbines will receive a varying tariff based on the level of demand and the status of the other generators currently operating. The overall effect is a signal that awards energy efficiency, and energy consumption that is sensitive to the time-varying limitations of the supply. At the domestic level, appliances with a degree of energy storage or thermal mass (such as refrigerators, heat banks, and heat pumps) will be well placed to 'play' the market and seek to minimise energy cost by adapting demand to the lower-cost energy support periods. This is an extension of the dual-tariff energy pricing mentioned above.

 

8. Demand response support

Demand response support allows generators and loads to interact in an automated fashion in real time, coordinating demand to flatten spikes. Eliminating the fraction of demand that occurs in these spikes eliminates the cost of adding reserve generators, cuts wear and tear and extends the life of equipment, and allows users to cut their energy bills by telling low priority devices to use energy only when it is cheapest.

Currently, power grid systems have varying degrees of communication within control systems for their high-value assets, such as in generating plants, transmission lines, substations and major energy users. In general information flows one way, from the users and the loads they control back to the utilities. The utilities attempt to meet the demand and succeed or fail to varying degrees (brownout, rolling blackout, uncontrolled blackout). The total amount of power demand by the users can have a very wide probability distribution which requires spare generating plants in standby mode to respond to the rapidly changing power usage. This one-way flow of information is expensive; the last 10% of generating capacity may be required as little as 1% of the time, and brownouts and outages can be costly to consumers.

Latency of the data flow is a major concern, with some early smart meter architectures allowing actually as long as 24 hours delay in receiving the data, preventing any possible reaction by either supplying or demanding devices.

9. Platform for advanced services

As with other industries, use of robust two-way communications, advanced sensors, and distributed computing technology will improve the efficiency, reliability and safety of power delivery and use. It also opens up the potential for entirely new services or improvements on existing ones, such as fire monitoring and alarms that can shut off power, make phone calls to emergency services, etc.

10. Giving Consumers Control

The Smart Grid is not just about utilities and technologies; it is about giving you the information and tools you need to make choices about your energy use. If you already manage activities such as personal banking from your home computer, imagine managing your electricity in a similar way. A smarter grid will enable an unprecedented level of consumer participation. For example, you will no longer have to wait for your monthly statement to know how much electricity you use. With a smarter grid, you can have a clear and timely picture of it. "Smart meters," and other mechanisms, will allow you to see how much electricity you use, when you use it, and its cost. Combined with real-time pricing, this will allow you to save money by using less power when electricity is most expensive. While the potential benefits of the Smart Grid are usually discussed in terms of economics, national security, and renewable energy goals, the Smart Grid has the potential to help you save money by helping you to manage your electricity use and choose the best times to purchase electricity. And you can save even more by generating your own power.

11. THE SMART HOME

How will the Smart Grid affect your home? It won’t look very different, but behind the scenes a lot will be happening. Even right now, in many cities across the nation, new equipment, appliances, and software are available that use emerging Smart Grid technologies to save energy, seek out the lowest rates, and contribute to the smooth and efficient functioning of our electric grid.

A key element that allows all of the emerging Smart Grid technologies to function together is the interactive relationship between the grid operators, utilities, and you. Computerized controls in your home and appliances can be set up to respond to signals from your energy provider to minimize their energy use at times when the power grid is under stress from high demand, or even to shift some of their power use to times when power is available at a lower cost.

12. Smart Meters and Home Energy Management Systems

Smart meters provide the Smart Grid interface between you and your energy provider. Installed in place of your old, mechanical meter, these meters operate digitally, and allow for automated and complex transfers of information between your home and your energy provider. For instance, smart meters will deliver signals from your energy provider that can help you cut your energy costs. Smart meters also provide utilities with greater information about how much electricity is being used throughout their service areas.

This energy information coming to and from your home through your smart meter can be run through a home energy management System (EMS), which will allow you to view it in an easy-to-understand format on your computer or hand-held device. A home EMS allows you to track your energy use in detail to better save energy. For instance, you can see the energy impact of various appliances and electronic products simply by monitoring your EMS while switching the devices on and off.

An EMS also allows you to monitor real-time information and price signals from your utility and create settings to automatically use power when prices are lowest. You can also choose settings that allow specific appliances and equipment to turn off automatically when a large demand threatens to cause an outage—avoiding peak demand rates, helping to balance the energy load in your area, and preventing blackouts. Your utility may provide financial incentives for doing so.

 

13. Smart Appliances

In your smart home, many of your appliances will be networked together, allowing you to access and operate them through your EMS. An EMS provides the ability to turn on your heater or air conditioner from work when you’re about to go home or keep track of the energy use of specific appliances or equipment—like tracking the energy use of your pool pump, or seeing how much energy you saved with your new Energy Star dishwasher.

Smart appliances will also be able to respond to signals from your energy provider to avoid using energy during times of peak demand. This is more complicated than a simple on and off switch. For instance, a smart air conditioner might extend its cycle time slightly to reduce its load on the grid; while not noticeable to you, millions of air conditioners acting the same way could significantly reduce the load on the power grid. Likewise, a smart refrigerator could defer its defrost cycle until off-peak hours, or a smart dishwasher might defer running until off-peak hours..

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14. Integration of Renewable Energy Sources

 As these resources begin to supply increasing percentages of power to the grid, integrating them into grid operations will become increasingly difficult. The Smart Grid will be able to make better use of these energy resources. It will give grid operators new tools to reduce power demand quickly when wind or solar power dips, and it will have more energy storage capabilities to absorb excess wind and solar power when it isn't needed, then to release that energy when the wind and solar power dips. In effect, energy storage will help to smooth out the variability in wind and solar resources, making them easier to use. Building an electric superhighway can also help solve the problem, as it will help to ship the power to where it is needed. Studies have shown that connecting wind resources from a diversity of geographic locations helps to balance out fluctuations in wind power. In other words, when the wind isn't blowing in Iowa, in may be blowing in North Dakota or Wyoming. Having such geographically diverse wind resources on a single electric superhighway will result in a more steady supply of wind power to the nation's power grid, making it easier for grid operators to make full use of this resource.

 

15. The "Self-Healing" Power Distribution System

Outage response is one aspect of distribution intelligence that is commonly referred to as distribution automation (DA). DA may actually be the oldest segment of the Smart Grid, because utilities have been automating their distribution systems since the 1960s. But while DA initially focused just on remote control of switches, the Electric Power Research Institute now considers distribution intelligence to mean a fully controllable and flexible distribution System. Combining DA components with a set of intelligent sensors, processors, and communication technologies will lead to distribution intelligence. When fully deployed, distribution intelligence will enable an electric utility to remotely monitor and coordinate its distribution assets, operating them in an optimal matter using either manual or automatic controls.

16. Helping the Grid Run More Efficiently and Reliably

Along with outage detection and response, another potential application of distribution intelligence is the ability to optimize the balance between real and reactive power. Devices that store and release energy, such as capacitors, or that use coils of wire to induce magnetic fields, such as electrical motors, have the ability to cause increased electrical currents without consuming real power; this is known as reactive power. A certain amount of reactive power is desirable within a power System, but too much reactive power can lead to large current flows that serve no purpose, causing efficiency losses as they heat up the distribution System wires. An intelligent distribution System can use power electronics to maintain the proper level of reactive power in the System. Distribution intelligence can also help to protect and control the feeder lines, the power lines that make up the distribution System. Most feeder lines are now protected by breakers or relays that trip when high currents flow through the line, a situation normally caused by a fault somewhere in the System. These relays sometimes incorporate time delays to allow for momentary flows of high current, which may be caused by industrial equipment powering up, rather than a fault. Protection systems are often a combination of instantaneous breakers with high current settings and time-delayed breakers or relays with lower settings. These systems of automated breakers and relays end up being a balancing act: they must allow the System to operate with high currents when needed but protect the System and the people around it from high current flows when a fault exists. Distribution intelligence can provide a more elegant approach to protecting the feeder lines, using sophisticated monitoring and controls to detect and correct for faults while maintaining the highest level of System reliability during non-fault conditions. An intelligent System could even detect and isolate faults in specific pieces of equipment and route power through a backup System instead, maintaining power reliability. Distribution intelligence can also incorporate more sophisticated ground-fault detectors to minimize the possibility that people can be shocked or electrocuted when encountering downed power lines. Most utilities are only starting on the road to true distribution intelligence, but the market is expected to boom in the coming years.

17. CONSUMER ENGAGEMENT

The Smart Grid offers many opportunities for consumers to save energy and for utilities to operate the grid in a more efficient, effective, and reliable way. But some features enabled by the Smart Grid also involve some sacrifice on the part of consumers, such as holding off on running your dishwasher until later in the evening.

A smart consumer will ask, "What's in it for me?" And the answer is: money. Specifically, participating in these programs will earn consumers extra savings on their energy bills. And for people who generate their own power, it can even result in something you never thought you would see: your utility could mail a check to you.

Many utilities already offer their customers ways to save extra money on their utility bills. For people with central air conditioning systems, for instance, some utilities will place a remote-control switch on the air conditioner to cycle the air conditioner on and off during times of peak power demand. In return, customers receive a credit on their electrical bill.

The Smart Grid will allow programs like these to operate in more sophisticated ways, resulting in greater energy savings with less inconvenience to businesses and homeowners. Some examples include time-of-use pricing, net metering, and compensation programs for plug-in electric vehicles (PEVs).

 

18. Time-of-Use Programs

One of the most important ways you can get involved with the Smart Grid is to take advantage of time-of-use programs when they become available in your area.

What is time-of-use pricing? Throughout the day, the demand for energy changes: it’s usually lowest in the middle of the night and highest from about noon to 9 p.m., but it can vary according to weather patterns and what’s happening during that time. Power plants and utilities have to work harder to meet the needs of electric consumers when the demand is highest.

During peak energy usage, utilities sometimes have to bring less-efficient—and often more-polluting—power generation facilities on line or purchase power from neighboring utilities at a higher cost. In the worst cases, utilities may have to institute rolling blackouts or reduce the voltage of the system, an approach called a "brownout."

Time-of-use rates encourage you to use energy when the demand is low by giving you a lower price for electricity during those times. Distributing the demand more evenly ensures that a steady and reliable stream of electricity is available for everyone.

Home energy management systems will help you to make the most of time-of-use pricing. Accessed with a home computer or hand-held mobile device, you will be able to see when prices are highest, which appliances use the most electricity, and even—at some point down the line—be alerted when prices go up, so you can remotely turn off unnecessary appliances until demand lowers and prices go back down.

19. Net Metering

For people that generate their own power at home—using a rooftop solar power system, for instance—net metering is an option already available in many states. In general, net metering involves the use of a meter that can record power flows back into the grid as a credit. Some mechanical meters will literally spin backwards, although today most utilities are using digital meters for net metering.
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