CT Energy Info

Current Demand - FAQ

What is the CT Power Update Graph?

The CT Power Update Graph shows the amount of electricity being used on Connecticut’s electric system (i.e., the current demand), today's forecasted demand and past seasonal peak demand.

Does the Graph reflect system reliability?

No. The Graph is meant to educate consumers about how peak electric demand can impact cost and the environment. While peak demand can affect reliability, you must refer to the CT Power Update Map, the System Reliability tab, for this information.

What is peak demand and how does it affect the cost of electricity?

Peak demand is the highest point of real‑time customer demand. The size or capacity of Connecticut’s electric system must be built to meet annual peak demand. So, although annual peak demands only occurs a few times each year, additional system-wide costs are incurred to meet this demand for electricity.

What is Current Demand?

Current Demand (the green dot and value) is the real-time amount of electricity that Connecticut's homes, businesses, schools, government, etc. are using, measured in megawatts. The green line shows the actual demand that occured throughout the day.

What is Forecasted Demand?

Forecasted Demand is an estimate of the demand that will occur throughout the day. The forecast is provided by ISO New England and is represented by the grey line.

What does the red line represent?

The red line is an average of past seasonal peak demands. The goal is to keep the current system demand below the red line to help control overall electric costs in Connecticut.

How do I interpret the Connecticut Power Update Graph?

The Graph compares Connecticut's current electric demand to the daily forecasted peak demand. It also shows past seasonal peak demands. The goal is to keep current demand below past peak levels to help control future electric costs. Success will be indicated whenever actual demand (green line) remains below the historical peak (red line).

Historical peak demand is used to set a portion of our future costs. So, exceeding the historical peak, (green line crosses the red line) can increase costs in the future. However, if we can keep current demand below past levels we can control costs going forward.

When does Connecticut’s peak demand occur?

Connecticut’s peak demand—the highest coincident use of electricity—occurs between noon and 8 p.m. on weekdays. The highest peaks typically occur on hot, humid summer days and are driven largely by air conditioning. However, other appliances, such as pool pumps, dehumidifiers, dishwashers and clothes washers and dryers also contribute to peak demand.

What's the difference between seasonal peak demand and Connecticut's annual peak demand?

The highest demand for electricity, CT's annual peak, typically occurs weekdays between noon and 8 pm, during the summer months of June through September; the summer seasonal peak. The non-summer peak demand that occurs during fall, winter and spring, is generally lower than the summer peak. We show seasonal peak values to remind consumers year-round about the benefits of reducing our peak use. Learn more about seasonal peak demand.

What actions can I take to reduce peak demand?

You can lessen peak demand by reducing “discretionary” electric use during Connecticut's peak hours, weekday between noon and 8 pm. Appliances and devices that can lessen peak demand include pool pumps, dehumidifiers, dishwashers and clothes washers and dryers. Consumers are encouraged to avoid the use of these items generally during the peak hours of noon to 8 p.m. The reminder here is to “Wait 'til 8” to use major appliances.

Note that while limiting the use of major appliances takes a big chunk out of discretionary usage, reducing the use of other, smaller devices adds up as well. Any reduction in unnecessary use of electricity will help relieve system demand.

Why do I need to be informed about the demand on our electric system?

Controlling peak demand and being energy efficient in general provide economic, environmental and societal benefits, as follows.

Economic benefits. Current electric costs are partially driven by past years' annual peak demands. So, controlling peak demand today helps control future system‑wide costs. High peak demand affects the wholesale price of electricity and can require higher costs associated with investments in transmission lines and generators to keep Connecticut's electric system reliable.

Environmental benefits. Many peak generating plants in service today are older, less efficient units that produce more harmful emissions. So, reducing peak demand can help improve air quality by requiring these plants to run less frequently.

Societal benefits. When the electric system becomes strained by high demand, Connecticut becomes vulnerable to power disruptions. These disruptions are commonly referred to as rolling brownouts (i.e., voltage reductions) and rolling blackouts (i.e., shutting off power for up to two hours) in varying sections of the state.

These benefits can be summarized as follows: “Taking actions to reduce peak demand can help control overall costs for everyone, lower harmful emissions and reduce the strain on Connecticut's electric system to maintain reliability.”

What is the Connecticut electric system?

The Connecticut electric system, sometimes referred to as the state power grid, consists of hundreds of miles of high-voltage electric transmission lines that carry electricity from generating plants in Connecticut and across New England to local distribution systems operated by The Connecticut Light and Power Company, The United Illuminating Company and several municipal electric systems.

What is a megawatt?

One megawatt is equal to one million watts of electricity and provides enough electricity to power approximately 200 homes during periods of peak summer demand. The number of homes whose needs can be met by one megawatt varies by season, time of day and each homes' power demand. One megawatt can serve more homes in the middle of the night or during the spring and fall when the demand of each home is lower.

System Reliability - FAQ

What is the CT Power Update Map?

The CT Power Update Map uses real-time data to display the reliability of Connecticut’s electric system i.e., the ability of the electric system to handle the current demand for electricity.

Why is the Map divided into two zones?

A large percentage of Connecticut's overall electric demand is concentrated in Southwest Connecticut (SWCT). As a result, ISO New England, New England’s regional electric system operator, treats SWCT as a separate region for electric system planning and operation purposes.

Why is the Map color-coded?

The Map is divided into two zones — Southwest Connecticut (SWCT) and the remainder of the state. Each zone is color-coded to reflect the Power Advisories issued in each zone by ISO New England through the Connecticut Valley Electric Exchange (CONVEX).

What do the colors mean?

The colors correspond to Power Advisories issued by the Connecticut Valley Electric Exchange (CONVEX). Power Advisories, which reflect the level of reliability of Connecticut's electric system, are defined below.

Status	Color	Definition
Normal	Green	The available supply of electricity is sufficient to meet demand at this time, and the power system is operating normally.
Power Caution	Yellow	Electricity reserves are lower than normal. However, there is still sufficient power to meet the needs of customers.
Power Watch	Orange	Additional steps to manage electric capacity could affect the public and customers should reduce unnecessary power usage.
Power Warning	Red	Immediate reduction in power usage is necessary to avert an overload of the electrical system.

How can I help maintain the reliability of the electric system?

Each of us can lessen peak demand by reducing “discretionary” electric use during peak hours of noon to 8 pm, weekdays.

Appliances and devices that can help lessen peak demand include pool pumps, dehumidifiers, dishwashers and clothes washers and dryers. Consumers are encouraged to avoid their use during the peak hours of noon to 8 pm, weekdays. The reminder here is to “Wait ’til 8” to use major appliances.

Please note that while limiting the use of major appliances takes a big chunk out of discretionary usage, reducing the use of other, smaller devices adds up as well. Any reduction in the unnecessary use of electricity will help relieve system demand.

Air conditioning typically drives Connecticut’s peak demand. However, many of us do not view the use of air conditioning as discretionary. During periods of high demand or when immediate action is requested, the state and your electric utility may ask you to reduce air conditioning load. This can be done by increasing the temperature of your air conditioner by just 3 to 5 degrees. This reduces the use of air conditioners’ compressors (the largest electric draw in an AC system), but still keeps the temperature in a home or business comfortable.

In addition, you can visit Onethingct.com to learn about other simple steps you can take to use energy wisely.

Which towns are in Southwest Connecticut?

You may think Southwest Connecticut (SWCT) is Fairfield County. For purposes of the electric system, SWCT stretches across New Milford, Woodbury, Watertown, Waterbury and Southington to the North; and Meriden, Wallingford, and Branford to the East.

Below is a list of the 54 cities and towns within SWCT:

Ansonia, Beacon Falls, Bethany, Bethel, Branford, Bridgeport, Bridgewater, Brookfield, Cheshire, Danbury, Darien, Derby, East Haven, Easton, Fairfield, Greenwich, Hamden, Meriden, Middlebury, Milford, Monroe, Naugatuck, New Canaan, New Fairfield, New Haven, New Milford, Newtown, North Branford, North Haven, Norwalk, Orange, Oxford, Prospect, Redding, Ridgefield, Roxbury, Seymour, Shelton, Sherman, Southbury, Southington, Stamford, Stratford, Trumbull, Wallingford, Waterbury, Watertown, West Haven, Weston, Westport, Wilton, Wolcott, Woodbridge, Woodbury.

What is the Connecticut electric system?

The Connecticut electric system, sometimes referred to a the state power grid, consists of hundreds of miles of high-voltage electric transmission lines that carry electricity from generating plants in Connecticut and across New England to local distribution systems operated by The Connecticut Light and Power Company, The United Illuminating Company, and several municipal electric systems.

For more information on Connecticut's electric power grid, see ISO-New England's key

facts at www.iso-ne.com/nwsiss/grid_mkts/key_facts/connecticut.pdf

and the Connecticut Siting Council's annual Forecast of Loads and Resources at

www.ct.gov/csc/lib/csc/f2007/csc_forecast_07.pdf.

For more information on how electricity flows, visit

www.iso-ne.com/nwsiss/grid_mkts/elec_works/index.html.