OwnerJuly 2015 to presentEl Cerrito

Finding best available technologies for meeting energy needs today and tomorrow: energy efficiency, demand response,, solar, wind, electric vehicles, biofuels and smart grid. It’s all the innovations that make the energy we use more secure, clean, and affordable. The energy world's best hopes lie in what's happening in the digital realm, especially in data analytics.

Tuesday, March 29, 2011

Direct Load Control (DLC)

A utility or system operator remotely shuts down or cycles a customer’s electrical equipment on short notice to address system or local reliability contingencies. In exchange, the customer receives an incentive payment or bill credit.
Commercial and Residential AC Represents a big opportunity for Direct Load Control in California

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Back to Load Shifting Index
1. Background

2. Acronyms/Definitions
3. Business Case
4. Benefits
5. Risks/Issues
6. Success Criteria
7. Links

  • On February 26, 2008, a cold front moved through west Texas, and winds died in the evening just as electricity demand was peaking. Over a 2 hour period the generation from wind power in the region plummeted rapidly from 1.7 GW to only 300 MW, while the power demand rose to a peak of 35612 MW from 31200 MW. The sudden loss of wind power and the lack of alternative electricity supply to ramp up as quickly forced the Electric Reliability Council of Texas (ERCOT)to curtail 1100 MW demand from industrial customers within 10 minutes and grid stability was restored within 3 hours.
  • DLC is the most widely deployed technology today in the mass markets in the US and has been around for 50 years. Under direct load control (DLC), a utility or system operator remotely shuts down or cycles a customer’s electrical equipment on short notice to address system or local reliability contingencies. In exchange, the customer receives an incentive payment or bill credit.
  • Certain applications are identified as “deferrable”, to run later in the day, after the peak. These applications will vary by region, but common loads include residential electric hot-water heaters, air conditioners, pool pumps, crop-irrigation pumps, etc. In a distribution network outfitted with load control, these devices are outfitted with communicating controllers that can run a program that limits the duty cycle of the equipment under control. The utility only exercises the equipment when necessary. The consumer is usually rewarded for participating in the optional load control program by paying a reduced rate for energy.
  • Operation of DLC typically occurs during times of high peak demand. However, it can also be operated when economic to avoid high on-peak electricity purchases. The traditional DLC option is implemented as follows. During a DR event, DLC participants have their appliances turned off for the full duration of an event or for various fractions of an hour (e.g., a common duty cycle is 15 minutes off during an hour). A one-way remote switch is connected to the condensing unit of an air conditioner or to the immersion element in a water heater. The operation of the switch is controlled through radio signals (for older systems) or through digital paging (for newer systems). Most switches also contain multiple relays so that air conditioners and water heaters can be controlled by the same switch with independent control strategies for each relay.
  • More recent DLC programs involve installation of programmable communicating thermostats for customers. Smart thermostats allow remote adjustment of temperature settings, so the utility can remotely adjust the temperature upward to reduce demand. After an event, the temperature setting is readjusted to the pre-event, customer-selected level.

2. Acronyms/Definitions
  1. DLC – Direct Load Control
  2. DBP - Demand Bidding Program - Provides incentive payments of up to $0.50/kWh for day-ahead curtailment commitments and $0.60/kWh for day-of commitments Participants place bids online the day before the event for the amount of power they are willing to reduce, in increments of 2 hours or more. DBP events usually take place from noon to 8:00 p.m. and can occur on any weekday excluding holidays
    1. SCE DBP
    2. PG&E DBP
  3. BIP - Base Interruptible Program - Allows participants to nominate a level of "firm" service (the amount of electricity necessary to meet operational requirements during an interruption) that is below their historic average maximum demand. They receive a monthly incentive payment based on the size of the remaining, curtailable portion of their load, in return for committing to reduce to the firm level when called upon by the utility. The incentives are typically about $7 per committed kW per month for curtailment of 15% of load when called by the utility with 30-minute notice. There is a minimum drop of 100 kW per event. PG&E and SDG&E, however, offer a longer, 3-hour, notice in exchange for a lower incentive option ($3/kW). Curtailment requests cannot exceed one per day (of up to four hours), ten per month, or 120 hours per year (90 hours for the lower incentive options).

    Penalties apply for customers that fail to reduce load as requested—the amount depends on the utility and the incentive option. All three utilities have now contracted with numerous third-party aggregators who recruit customers to participate in BIP and manage their participation process. By serving as an intermediary, the aggregators can handle many of the details on customers' behalf and help them develop load reduction strategies. The aggregators may also offer innovative program features—for example, by assuming the risk of non-compliance penalties or by allowing customers to participate who might otherwise be too small to enroll directly in the utility's program.
    1. SCE TOU-BIP
    2. PG&E BIP
    3. SDG&E BIP
  4. CBP - Capacity Bidding Program - Participants receive a monthly incentive to reduce their energy use to a pre-determined amount once a CBP event is called by the utility. Customers also have the option to directly enroll or go through a third-party aggregator to join the CBP.
    1. SCE CBP
    2. PG&E CBP
    3. SDG&E CBP
  5. Optional Binding Mandatory Curtailment Program – Offered by PG&E and SCE - Provides customers with exemption from rotating outages if they can reduce their circuit load during Stage 3 Emergencies. Participants must reduce their power consumption by 5-15% for the duration of every rotating outage event. The penalty for failure to reduce as requested is $6.00 per kWh for energy use that exceeds an established baseline.
  6. PeakChoice Program - PG&E recently launched its new "cafeteria-style" PeakChoice Program, which is open to any customer that can provide a load reduction of at least 10 kW. The unique feature of the program is that it offers participants a high degree of flexibility in customizing the terms of their participation. (Video)
  7. Smart AC Program - Offered by PG&E
  8. Summer Air Conditioning Cycling Program Offered by SCE and SDG&E to their commercial customers through SCE's Summer Discount Plan and SDG&E's Summer Saver program. These programs provide a credit on participants' summer season electric bills in return for allowing the utility to cycle air conditioners when needed during the months of May to September. Customers can choose among several options regarding the frequency and duration of curtailments, each with corresponding remuneration levels.

3. Business Case
  • A Smart Grid will facilitate the implementation of all types of load control programs beyond just demand response, due to its advanced control features. The smart grid concept also includes traditional load control programs used by many utilities to cycle water heating and air conditioning equipment during peak demand periods. Results of several dozen utility experiments show that a combination of equipment control and price feedback technologies often doubles the impacts of load controls. Most residential and commercial programs consist of a relatively small number of participants, relative to utility populations.
  • The advanced control capabilities of devices operating within a Smart Grid will make it easier for utilities to implement other types of load control technologies such as load-limiting devices that may yield more permanent peak demand reductions, as distinguished from demand response programs that yield temporary peak load reductions.
  • Smart grid technologies can provide traditional load control functions, cycling air conditioning, water heating and swimming pool pumps, while more advanced options provide individual equipment control to these and additional end uses through programmable devices accessible by both the utility and the utility customer. These technologies permit households to respond to a price signal to lower thermostat setting and schedule major electric appliances.

Residential Air Conditioning in California represents a great opportunity for DLC

4. Benefits
  • Energy Savings – Load control programs implemented in the U.S. in 2005 yielded peak demand reductions of 10,359 MW and energy savings of 1.01 billion kWh. The programs resulted in energy savings of 97 kWh for each kW of peak load reduction. The average ratio observed over the last ten years of peak load management programs tracked by the U.S. Energy Information Administration is 113 kWh of energy savings for each kW of peak load reduction, which is considerably is higher than the 65 kWh/kW ratio observed for recent Auto- DR programs. The variance may be due in part to the more permanent nature of some of the non-demand- response load control efforts.

    Although actual reductions vary by size of the appliance, customer usage patterns and climate, in one pilot, the demand reductions for each central air conditioner is about 1 kW and for water heaters about 0.6 kW1. Typically, DLC programs limit the number of times or hours that the customer’s appliance can be turned off per year or season. DLC participants usually receive a fixed monthly incentive payment. The payment amount may depend on the load commitment level
  • Dispatchabilty - Load reduction associated with DLC takes place instantaneously and there is no notification time.

5. Risks/Issues
  • Lack of Feedback - The idea of one-way load control systems, where you just turn things on and off, seems to be receding. In its place is coming a next generation product that offer a much more collaborative process of allowing consumers to opt in and opt out.
  • Aging DLC Infrastructure - In many parts of the country DLC switches are aging. In many cases people have said that only 70 percent of the switches actually work.
  • Payments - There are concerns about how much do you have to pay in order to get that reduction in load. And there are people who are trying to cut back the amount of payments they make because they feel they have too many free riders.
  • Economic Development Rates - Curtailable and interruptible rates were developed for a particular objective in mind and in many parts of the country they have actually morphed into becoming economic development rates. And so people didn't expect to be interrupted, they were just getting a discount. And so when the interruption suddenly arrived there was a lot of concern as to what was going on.
  • Operations/Maintenance Cost - Once a utility installs control device; they “own” most calls regarding failed appliances. Often incur control equipment removal cost 2, 5, even 15 years later. With direct load control, the utility owns the risk for failure of control equipment or communication signal.
  • Residential Feedback - What we have today is that conventional air conditioner load control switches, that generally will sell for about $75 to $100 apiece. They are in wide use by lots of utilities, including California utilities. They are subject to a lot of factors that affect their performance. Although one of the factors is that because of the nature of that device the utilities, once they install them, really have no idea whether they are still working or even in place. And because air conditioners have a useful life of maybe 13 to 15 years, a certain percentage of air conditioners and their switches wind up in a landfill somewhere every year, unbeknownst to the utility.
  • Kickback - the increased energy consumption seen in demand control programs that occurs post-curtailment as equipment comes back to its normal operating state

6. Success Criteria
  • Studies indicate that customers want to know when direct load control measures are in effect. The DR solution shall provide the ability to manage direct load control programs. It accomplishes this by managing the transmission of direct load control actions to direct-load-control-enabled devices, shown as device, HAN device, and smart appliances. This solution will also provide interactions with customers to convey direct load control information.

7. Links
  • Peak Load Management Alliance - Market Potential Study for Water Heater Demand Management Rebecca Farrell Troutfetter, Frontier Associates LLC, Austin, TX - Water heating represents between 13 and 17 percent of residential energy consumption nationwide. Based on the 2007 Census data, roughly 42 percent of all homes in the U.S. have electric water heating; this equates to over 53 million homes. With such a high saturation of electric water heating nationwide, direct load control for water heaters has high potential for reducing peak demand, especially to help offset summer peaking driven by electric air conditioning use.

    If a 25% participation rate was reached nationwide, as suggested by the FERC study (for air conditioning), the resulting savings would be about 5,300 MW of peak demand reduction, which equates to about $424 million in utility savings due to reduced on-peak generation needs
  • Energy Information Administration – Official Energy Statistics from the US Government - Demand-Side Management Actual Peak Load Reductions by Program Category

Friday, March 25, 2011

Building Systems Basics

Commercial and residential buildings account for 39% of total energy consumption in the US. Smart Building has the capacity for greatly increasing building system operating efficiency, reducing greenhouse gas emissions and improving comfort and performance of occupants

Building automation can control 66% of energy in homes and building and since buildings consume 40% of all energy, building automation can control over a quarter of all the energy used in the United States.

1. Background
2. Acronyms/Definitions
3. Business Case
4. Benefits
5. Risks/Issues
6. Success Factors
7. Links

Commercial and residential buildings account for 40% of total energy consumption in the US. Same for CO2 production. HVAC and Lighting account for 60% of commercial building electric energy usage According to Amory Levins, ~75% is wasted.

Smart buildings and green buildings have a lot in common but are not the same thing:
  1. Green Building
    • Sustainable Sites
    • Water Efficiency
    • Energy & Atmposhere
    • Materials and Resources
    • Indoor Environmental Quality
    • Innovation and Design Process

  2. Smart Buildings
    • Data Network
    • VOIP
    • Video Distribution
    • A/V Systems
    • Video Surveilance
    • Access Control
    • HVAC Control
    • Power Management
    • Programmable Lighting Controls
    • Facilities Management
    • Cabling Infrastructure
    • Wireless Systems

  3. Smart and Green
    • Optimize Energy Performance
    • Additonal Commissioning
    • Measurement & Verification
    • Carbon Dioxide(Co2) Monitoring
    • Controlability of Systems
    • Perforamnce Monitoring Systems
    • Innovation in Design

2. Acronyms/Definitions
  1. ACH - Air Changes per Hour - The number of times per hour that the volume of a specific room or building is supplied or removed from that space by mechanical and natural ventilation. Air changes in a confined space are important for a variety of reasons, mainly though, we need fresh air to live. Without sufficient fresh air exchange, moisture is trapped in a room/home/building, molds can feed, and other allergens and excessive dangerous gases (e.g. Carbon monoxide, Carbon Dioxide, urea formaldehyde), can remain in the home. A new focus on energy efficiency is resulting in buildings more sealed from air transfer in and out making fresh air intake very important.
  2. AHU - Air Handling Units - - A device used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system. An air handler is usually a large metal box containing a blower, heating or cooling elements, filter racks or chambers, sound attenuators, and dampers. Air handlers usually connect to ductwork that distributes the conditioned air through the building and returns it to the AHU.

    Small air handlers, for local use, are called terminal units, and may only include an air filter, coil, and blower; these simple terminal units are called blower coils or fan coil units. A larger air handler that conditions 100% outside air, and no recirculated air, is known as a makeup air unit (MAU). An air handler designed for outdoor use, typically on roofs, is known as a packaged unit (PU) or rooftop unit (RTU).
  3. Boiler – provides hot water or steam for heating the building or for process needs. Types include, Fire Tube, Water Tube and Modular
  4. Chiller – A machine that removes heat from a liquid via a vapor-compression or absorption refrigeration cycle. This liquid can then be circulated through a heat exchanger to cool air or equipment as required. Provides chilled water for cooling the building or for process needs. Types include: Centrifugal, Screw, Reciprocating and Absorption Moving water around a building is much easier than Freon. Controllable through demand limit.
  5. Coil - Equipment that performs heat transfer when mounted inside an Air Handling unit or ductwork. It is heated or cooled by electrical means or by circulating liquid or steam within it. Air flowing across it is heated or cooled.
  6. Condenser - A a device or unit used to condense a substance from its gaseous to its liquid state, typically by cooling it. In so doing, the latent heat is given up by the substance, and will transfer to the condenser coolant. - A component in the basic refrigeration cycle that ejects or removes heat from the system. The condenser is the hot side of an air conditioner or heat pump. Condensers are heat exchangers, and can transfer heat to air or to an intermediate fluid (such as water or an aqueous solution of ethylene glycol) to carry heat to a distant sink, such as ground (earth sink), a body of water, or air (as with cooling towers).
  7. Cooling Tower - moves heat from the process water that was extracted from the building or process out of the building or process
  8. Air-Side Economizer - Air damper that can save energy in buildings by using cool outside air as a means of cooling the indoor space when the outside air is both sufficiently cool and sufficiently dry. When no additional conditioning of it is needed; this portion of the air-side economizer control scheme is called free cooling. With the appropriate electronic controls, economizers can be used in climates which experience various weather systems. However, because they are generally not tuned, 50% in US cost more than they provide. Good controls, and valves or dampers, as well as maintenance, are needed to ensure proper operation of the air- and water-side economizers.
  9. ESCO - Energy Service Company - A business providing a broad range of comprehensive energy solutions including designs and implementation of energy savings projects, energy conservation, energy infrastructure outsourcing, power generation and energy supply, and risk management. The ESCO performs an in-depth analysis of the property, designs an energy efficient solution, installs the required elements, and maintains the system to ensure energy savings during the payback period. Everything you need to know about ESCO’s is at the National Association of ESCO’s
  10. HVAC – Heating, Ventilating and Air-Conditioning
  11. Packaged System - Air Handling Units that have been packaged for sale based on industry demand. Types include: Roof Top Units, Split Systems, Unit Ventilators and Heat Pumps. Still see VAV systems downstream from packaged systems
  12. Plug Load - Devices that plug into a buildings’ electrical system and include appliances, TVs, VCRs, pop machines, drinking fountains, and office equipment such as fax machines, computers, printers, and copiers. In short, plug loads consist of any electrical
    equipment that is plugged into a wall outlet or electrical plug
  13. Setpoint - the target value that an automatic control system will aim to reach. For example, a boiler control system might have a temperature setpoint, that is a temperature the control system aims to attain.
  14. VAV – Variable Air Volume – Technique for controlling the capacity of a HVAC system. The simplest VAV system incorporates one supply duct that, when in cooling mode, distributes approximately 55 °F supply air. Because the supply air temperature, in this simplest of VAV systems, is constant, the air flow rate must vary to meet the rising and falling heat gains or losses within the thermal zone served. The fan capacity control, especially with modern electronic variable speed drives, reduces the energy consumed by fans which can be a substantial part of the total cooling energy requirements of a building. Dehumidification is greater with VAV systems than it is with constant volume systems which modulate the discharge air temperature to attain part load cooling capacity.

    Control of the system's fan capacity is critical in VAV systems. Without proper and rapid flow rate control, the system's ductwork, or its sealing, can easily be damaged by over-pressurization. Includes reheat coil, fan. Without a remote fan powered box, a centralized 100 HP Air Handler would have to be used.
  15. VAV Box - (aka VAV Terminal Unit) - Sheet metal box + controller
    The zone-level flow control device. It is basically a quality, calibrated air damper with an automatic actuator. The VAV terminal unit is connected to either a local or a central control system
    Advantages of VAV systems:
    • Ability to control temperatures in interior and exterior zones without under or overcooling
    • Capability of taking advantage of varying loads as a result of the sun's diversity
    • Low installed first cost
    • Readily adaptable to night set back and compatibility with energy management systems
    • Economical to operate since the amount of air being moved is only that required to satisfy the load
    • Suitable for partial operation of a building such as overtime or weekend usage of a particular area
  1. VFD - Variable Frequency Drive - A system for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor. Widely used in ventilations systems for large buildings, variable-frequency motors on fans save energy by allowing the volume of air moved to match the system demand. Variable frequency drives are also used on pumps, conveyor and machine tool drives. Big energy savings are often possible when the loads (for example pumps and fans) can be run at a lower speed when the maximum output is not required. Controllable by reducing speed.
3. Business Case
  • Poor building performance is crippling the future of the current industry. Smart Building has the capacity for greatly increasing building system operating efficiency, improving comfort and performance of occupants and reducing greenhouse gas emissions. For example, computer systems embedded during construction will use CO2 sensors to track a building’s occupants at all times, precisely targeting heating and cooling
  • A crash program to improve the energy efficiency of American homes, offices, and factories could slash energy consumption by 23 percent by 2020 and produce $1.2 trillion in savings, according to a report by the McKinsey consulting firm. McKinsey said that taking steps such as better insulating buildings, replacing old appliances, and sealing ducts is the fastest and best way to cut the country’s energy consumption. The firm recommended an investment of $520 billion in energy efficiency programs over the next 10 years, an amount that dwarfs the $10 billion to $15 billion included in the Obama administration’s economic stimulus package.

3. Benefits
  • An efficiency improvement of 50% reduces the size of needed supply by half, or doubles the amount of functionality that a backup supply can support. In this context, rapid improvements in the electrical efficiency of facilities have value far greater than the economic value of its reduced consumption.

5. Risks/Issues
  • Balancing air quality (CO2 levels) with efficiency
  • Simultaneous Heating and Cooling - Occurs frequently in HVAC systems and represents a large opportunity for energy reduction. In systems with primary and terminal level temperature control the lack of coordination between control settings creates waste. Automatic control valves ‘told to close’ don’t always comply. Certain automatic control routines, even with DDC controls, can allow overlap on a transient or continuous basis.
  • Some engineers hate ice storage because it is "less efficient" than stand-alone chillers. In the small picture, this is correct. An ice storage system will use 7% to 8% more kWh than a chiller-only system yet, overall, using ice reduces CO2 emissions and fuel use, not to mention save tons of money. According to the California Energy Commission, during the summer daytime peak, the electric power system is up to 15% less efficient mechanically (peaker plants vs. baseload plants) and thermodynamically (cooling towers and transmission and distribution are less efficient because of high temperatures). In terms of emissions, the on-peak system emits 40 percent more CO2 per megawatt-hour than off-peak. Thus, in spite of consuming more kWh, ice storage is a strong environmental and economic strategy.
  • SEER Deficiencies - SEER is not a reliable predictor of energy performance in California or of demand reduction. PG&E states that the CEC report cited by TURN for the increase in SEER ratings is replete with statements about the inadequacy of SEER ratings in California. For instance, the CEC report states: Current HVAC appliance performance testing is conducted to national standards. Standard ratings for the seasonal energy efficiency ratio (SEER) are conducted at a maximum temperature of 82ยบ Fahrenheit and treat dehumidification as equal to sensible cooling. In the hot dry climates of California, outside air temperatures over 95° Fahrenheit with 35% relative humidity is common. The current standards provide inaccurate assessments of energy requirements during peak periods in California and the Southwest.

6. Success Factors
  • All new residential construction in California will be zero net energy by 2020
  • All new commercial construction in California will be zero net energy by 2030

7. Links
  1. Commercial Buildings Energy Consumption Survey (CBECS) A sample survey of US commercial buildings energy characteristics that is published every 4 years by the Energy Information Administration. The survey includes data on buildings’ energy consumption, energy expenditures, end-use equipment, and energy sources
  2. DOE Zero Energy Buildings Database - This database features profiles of eight zero energy commercial buildings. Each profile contains an overview and information about the process, financing, land use, site, energy use, materials, indoor environment, ratings, and lessons learned
  3. More about commercial buildings research at Berkeley Lab:

Thursday, March 17, 2011

Distribution Network

Current distribution networks were not designed for two way power flow. We need monitoring and control in the distribution world like we have in the transmission world

Navigate this Report
Back to Distribution Index
1. Background

2. Acronyms/Definitions
3. Business Case
4. Benefits
5. Risks/Issues
6. Success Criteria
7. Links

  • The distribution system is the most equipment and maintenance intensive portion of the bulk power system. The design of the distribution system is not a true “grid”; with multiple power delivery paths for a single load. Instead, each load is usually clearly paired with a generation source, typically a substation delivery point.
  • A centralized grid can be inefficient and costly. Only a third of the fuel energy burnt in power plants ends up as electricity, with half lost as waste heat, and a further 8% lost along long-distance transmission lines. The grid is often congested because it relies on a few high-traffic arteries. The congestion amplifies the inefficiency because if the utility cannot redirect power from efficient sources, they have to turn to costlier, dirtier and more inefficient sources to meet peak demand.
  • A more distributed grid, by its very architecture, can improve efficiency by matching local supply with demand. With multiple decentralized energy sources, electricity can be generated close to the point of use, avoiding the losses and congestion that result from long-distance transmission. Some of the most efficient energy sources are small turbines powered by natural gas, or biogas, which use waste heat to provide heat and hot water to the local area, and convert energy with 70–85% efficiency.
  • In a paradigm shift, the distinction between transmission and distribution blurs when energy flow becomes bidirectional. For example, distribution grids in rural areas might generate more energy than they use turning the local smart grid into a virtual power plant, or a city's fleet of one million vehicles could be used to trim peaks in transmission supply by integrating them to the smart grid using vehicle to grid technology.
Today's Hierarchical Power System compared to a fully networked Smart Grid illustrating the shift from a one-to-many paradigm to a many-to-many arrangement. In the first, we see today’s hierarchical power system, which looks much like an organizational chart with the large generator at the top and consumers at the bottom. The second diagram shows a network structure characteristic of a fully implemented smart grid.

2. Acronyms/Definitions
  1. Distribution Network – “the Wooden Pole System”
    Carries electricity from the transmission system and delivers it to consumers. Typically includes medium-voltage (less than 69 kV) power lines, electrical substations and pole-mounted transformers, low-voltage (less than 1000 V) distribution wiring and sometimes electricity meters. Distribution represents 85% of the T&D investment and is responsible for 90% of outages
  2. Bus –Shortened from the word busbar meaning a node in an electrical network where one or more elements are connected together. Substation structure used to connect two or more substation devices including transmission lines and transformers
  3. Circuit Breaker –A switching devices connected to the end of a transmission line capable of opening or closing the circuit in response to a command, usually from a relay. Open/close circuit when there is an overload or a fault condition as well as routine switching
  4. DA - Distribution Automation - The extension of intelligent control over electrical power grid functions to the distribution level and beyond. Normally, electric utilities with SCADA systems have extensive control over transmission-level equipment, and increasing control over distribution-level equipment via distribution automation. However, they often are unable to control smaller entities such as Distributed energy resources, buildings, and homes.
  5. DER - Distributed Energy Resource - (also called DG – Distributed Generation, on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy) Physical, capital assets on the distribution network that generate, store, or consume electric power. Among these are demand response, distributed generation, and electricity storage. Systems are small-scale power generation technologies (typically in the range of 3 kW to 10,000 kW) used to provide an alternative to or an enhancement of the traditional electric power system. DER’s are not broadly deployed as grid assets at present.

    Includes solar, micro-wind, micro-hydro, fuel cells, and combined heat and power. This generation can help to support local power grids in the presence of blackouts, and ease the load on long-distance transmission lines, but it can also destabilize the grid if not managed correctly". Usually, utility control centers are unable to manage distributed generators directly, and this may be a valuable capability in the future.
  6. Disconnect Switch – Open/close circuits under no load conditions for isolating equipment
  7. Field Capacitor Banks – Capacitive devices located on distribution circuits that raise voltage and provide VAR support
  8. IEC 61850 - a standard for the design of electrical substation automation. The abstract data models defined in IEC 61850 can be mapped to a number of protocols. Current mappings in the standard are to MMS (Manufacturing Message Specification), GOOSE, SMV, and soon to Web Services. These protocols can run over TCP/IP networks and/or substation LANs using high speed switched Ethernet to obtain the necessary response times of < 4 ms for protective relaying.
  9. Interconnected Network is generally found in more urban areas and will have multiple connections to other points of supply. These points of connection are normally open but allow various configurations by the operating utility by closing and opening switches. Operation of these switches may be by remote control from a control centre or by a lineman. The benefit of the interconnected model is that in the event of a fault or required maintenance a small area of network can be isolated and the remainder kept on supply
  10. Radial Network - leaves the station and passes through the network area with no normal connection to any other supply. This is typical of long rural lines with isolated load areas. Radial distribution systems are not designed for 2-way power flows or multiple supply inputs into a single circuit
  11. Recloser - a circuit breaker equipped with a mechanism that can automatically close the breaker after it has been opened due to a fault. Autoreclosers are used in coordinated protection schemes for overhead line power distribution circuits. These circuits are prone to transitory faults such as nearby lightning strikes, wind-borne debris,and animals climbing the insulators. With a conventional circuit breaker, a transient fault would open the breaker, disabling the line until a technician could manually close the circuit breaker or replace the blown fuse. But an autorecloser will make several pre-programmed attempts to reenergize the line. If the transient fault has cleared, the autorecloser's circuit breaker will remain closed and normal operation of the power line will resume. If the fault is permanent (downed wires, tree branches lying on the wires, etc.) the autorecloser will exhaust its pre-programmed attempts to re-energize the line and remain tripped off until manually commanded to try again. About 90% of faults on overhead power lines are transient and can be cured by autoreclosing.
  12. Relay An electrically operated switch. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. Relays controls the opening and subsequent reclosing of circuit breakers. Relays take measurements from local current and voltage transformers and from communication channels connected to the remove end of the lines.
  13. Substation - Transform voltage from high to low, or the reverse, or perform any of several other important functions. Electric power may flow through several substations between generating plant and consumer, and its voltage may change in several steps. The word substation comes from the days before the distribution system became a grid. The first substations were connected to only one power station, where the generators were housed, and were subsidiaries of that power station.

    Substations generally have switching, protection and control equipment and one or more transformers. In a large substation, circuit breakers are used to interrupt any short circuits or overload currents that may occur on the network. Smaller distribution stations may use recloser circuit breakers or fuses for protection of distribution circuits. Other devices such as capacitors and voltage regulators may also be located at a substation. Functions include: switching, voltage transformation, and voltage control. Equipment used includes transformers, circuit breakers, relays, and disconnect switches
  14. Switchgear - The combination of electrical disconnects, fuses and/or circuit breakers used to isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream.
  15. Transformer – A device that is used to change one value of voltage and current to another value of voltage and current (e.g. 12kV to 120/240 volts) A substation that has a step-up transformer increases the voltage while decreasing the current, while a step-down transformer decreases the voltage while increasing the current for domestic and commercial distribution.

3. Business Case
  • 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. Smart Grid technology can enable distributed generation through voltage regulation, reserve power flow and power fluctuation (frequency regulation)
  • With the growth of dynamic generation sources, the needs of the distribution system will need to be dynamically managed. Dynamically controlling a complex distribution system will require new smart grid tools and systems.
  • The smart grid will seamlessly integrate all types and sizes of electrical generation and storage and simplify interconnection processes analogous to “plug and play.”

4. Benefits

  • According to a Navigant research report, a smart distribution network will simplify interconnection of PV and improve its economics, increasing the projected installed capacity by over 60% by 2020.
  • Defers capital expansion
  • Serves isolated remote load
  • Improves power quality and reliability
  • Supports Low carbon future
  • Provides system protection that we currently have in the transmission network (within cycles – milliseconds) will be available at the edge of grid as well

5. Risks/Issues

  • Modeling - Utilities don’t know what level of PV penetration will create problems in the distribution network. PG&E currently has more than 30,000 solar customers with 300 MW and so far there have been overloads and high voltage situations in subdivisions and groups of homes with a high penetration of PV.
  • Reverse power flow can occur when the load is low
  • Frequency Regulation As a cloud comes over, PV production is spiky, coming s on and turning off very fast resulting in fluctuation in frequency
  • Transformers for solar subdivisions need to be rated higher than if there was simply distribution load there. This will increase cost without smart grid technology to manage flows.
  • Voltage Regulation - Inverters we have today on individual PV systems are not designed to regulate overall voltage. They don’t necessarily think about how to operate the grid. When everyone’s PV’s are on we see high voltage. Coordinated control of PV inverters will help optimize the grid.
  • Safety
    1. Protection when power line comes down.
    2. Adaptive protective systems
    3. Bi-directional flow protection
    4. Unauthorized DER energizing distribution lines endanger worker and public safety
  • Poor Information and Visibility of DER on the network
    1. 30,000 PV units on PGE today. Don’t know how operating
    2. Generation Status
    3. Forecasting
  • New electric transportation loads may create overloading at points on distribution
  • Proliferation of DER may create significant power quality issues from voltage variations harmonics and loss of reactive power control
  • Distributed Generation is currently a parallel universe.
  • Interconnection rules vary widely. utility to utility
  • Technical standards (e.g., IEEE 1547) do not allow PV inverters to provide gird support

6. Success Criteria
  • Mandatory, strict power distribution reliability standards
  • Coordinate DER and demand response to ensure reliability of distribution systems
  • Develop technical standards for interoperability

7. Links
  1. EEI - Electricity Distribution - The nation's electric distribution systems deliver power along millions of miles of lines to neighborhoods, businesses, and consumers.
  2. Electric Power Distribution Handbook.pdf (11.3 MB)
  3. Electric Power Distribution Systems Operations, Naval Facilities Engineering Command, Alexandria, Virginia

Tuesday, March 8, 2011

Super Grids

Within 6 Hours deserts receive more energy from the sun than humankind consumes in a year. HVDC Transmission lines can transport that energy to the cities where people live

Conceptual 765 kV backbone system for wind resource integration

1. Background
2. Acronyms/Definitions
3. Business Case
4. Benefits
5. Risks/Issues6. Next Steps
7. Companies
8. Links

  • A super grid is a wide area transmission network that makes it possible to trade high volumes of electricity across great distances. The Super Grid is highly coordinated from a macro level spanning nations and continents, all the way down to the micro level scheduling low priority loads like water heater and refrigeration. In the European SuperSmart Grid proposal and the US Unified Smart Grid concept, such super grids have intelligence features in the wide area transmission layer which integrate the local smart grids into a single wide area super grid. This is similar to how the internet bound together small networks into single ubiquitous network.

2. Acronyms/Definitions
  1. CSP – Concentrating Solar Power- Systems that use lenses or mirrors to concentrate a large area of sunlight, or solar thermal energy, onto a small area. Electrical power is produced when the concentrated light is converted to heat which drives a heat engine (usually a steam turbine) connected to an electrical power generator
  2. CPV - Concentrated Photovoltaics - Similar to CSP, sunlight is concentrated onto a small area using lenses or mirrors. Unlike CSP, solar power is directly converted to electricity without the use of steam turbines by concentrating the sunlight onto photovoltaic surfaces. CPV systems can be less expensive to produce than standard photovoltaic systems, because the concentration allows for the production of a much smaller area of solar cells
  3. Desertec - (Wikipedia) - A concept to generate electricity from renewable sources in deserts where solar power ismost abundant. A high-voltage direct current grid carries the electricity generated from renewables over long distances with a minimum loss of power, making it available wherever it is needed. Thanks to heat storage tanks, solar thermal power plants in deserts can supply electricity day and night, ideally supplementing electricity grids that rely on fluctuating energy sources such as photovoltaic and wind power. Under the proposal, solar thermal energy collectors (not solar cells) would be located in the deserts of North Africa, and would provide Europe with one sixth of its electricity. It could take 30 years to build, and cost more than £200 billion. The high solar radiation in the deserts of the Middle East and North Africa outweighs the 10-15% transmission losses between the desert regions and Europe. This means that solar thermal power plants in the desert regions are more economic than the same kinds of plants in southern Europe. The German Aerospace Center has calculated that, if solar thermal power plants were to be constructed in large numbers in the coming years, the estimated cost would come down from 0.09-0.22 Euro/kWh to about 0.04-0.05 Euro/kWh
  4. EHV - Extra High Voltage

  5. ENTSO-E - European Network of Transmission System Operators for Electricity - As of July 2009, the work of ATSOI, BALTSO, ETSO, NORDEL, UCTE and UKTSOA has been fully integrated into ENTSO-E. Set up as part of the 3rd EC package combines 42 TSO’s from 34 countries and replaces all six European TSO associations
  6. EUMENA - Europe, the Middle East, North Africa Region

  7. HVDC – High Voltage Direct Current – See my HVDC Blog Article for how it works

  8. IPS/UPS - A wide area synchronous transmission grid of the CIS countries with a common mode of operation and centralized supervisory control. It has an installed generation capacity of 300 gigawatts, and produces 1200 terawatt-hours annually for 280 million customers. The Russian portion of the interconnection is known as Unified power system of Russia (UPS). The Integrated Power System (IPS) portion of the network includes the national networks of Ukraine, Kazakhstan, Kyrgyzstan, Belarus, Azerbaijan, Tajikistan, Uzbekistan, Georgia, Moldova and Mongolia.|

  9. Mega Grid – Another name for Super Grid

  10. SSG - SuperSmart Grid - A hypothetical wide area electricity network connecting Europe with northern Africa, the Middle East, Turkey and the IPS/UPS system of CIS countries. The system would unify super grid and smart grid capabilities into a comprehensive network. There is no planned locations for infrastructure or schedule explicitly for the SSG; the name is used to discuss the economic and technological feasibility of such a thru network and ways that it might gain political support
    DESERTEC's conceptual plan of a super grid linking renewable sources across North Africa, the Middle East and Europe.

  11. Super Grid - A wide area transmission network that makes it possible to trade high volumes of electricity across great distances. (aka Mega Grid)
  12. TREC - Trans-Mediterranean Renewable Energy Cooperation – A voluntary association formed in 2003 as an initiative of the German association of the Club of Rome and the Hamburg Climate Protection Foundation. TREC promotes an increase of Europe's energy supply and a reduction of its CO2 emissions by campaigning for renewable non-polluting electric power transmission to Europe via high-voltage direct current (HVDC) lines from solar and wind power stations in the deserts of the Middle East and North Africa
  13. TSO – Transmission System Operator - An entity entrusted with transporting electrical power on a national or regional level, using fixed infrastructure. Due to the cost of establishing a transmission infrastructure, such as main power lines s and associated connection points, a TSO is usually a natural monopoly, and as such is often subjected to regulation
  14. UCTE - Union for the Co-ordination of Transmission of Electricity - Operates the European synchronous grid and is an association of electricity distribution network operators in Continental Europe. Its interconnected network is a single phase-locked 50 Hz mains frequency electricity grid that supplies over 400 million customers in 22 countries, including most European Union members
    Wide area synchronous grids in Europe.

  15. Unified National Smart Grid - A proposal for a United States wide area grid that is a national interconnected network relying on a high capacity backbone of electric power transmission lines linking all the nation's local electrical networks that have been upgraded to smart grids.
  16. Wide Area Synchronous Grid (aka Interconnection) - A power grid at a regional scale or greater that operates at a synchronized frequency and is electrically tied together during normal system conditions.
  17. VFT - Variable Frequency Transformer- Used to transmit electricity between two asynchronous alternating current domains. The VFT is a relatively recent development (first deployed in 2004). Most grid interties use high-voltage direct current converters.

3. Business Case
  • A super grid is a possible solution is to utilize the enormous potential for solar and wind power in the world’s deserts and move the power to temperate load centers. For example, renewable electricity from North Africa would be sufficient to satisfy the electricity needs of the Mediterranean and the rest of Europe many times over. However, the electricity would have to be transported over vast distances from North Africa to European load centers. Due to high transmission losses, long-distance transport is not feasible with the current AC system, even if the interconnection capacities were sufficient, which they are not. HVDC technology to transport electricity efficiently over vast distances has been available for decades. European electricity market could be integrated in an HVDC grid, known in Europe as a SuperSmartGrid (SSG), and connected to neighboring regions, such as North Africa, and their vast renewable energy resources. The SSG would operate “on top” of the current HVAC grid—only handling long-distance transmission—and existing AC grids would still distribute electricity over shorter domestic distances.
  • As an engineering matter, putting PV in North Africa and bring the power to Europe over efficient high-voltage DC lines is quite feasible — not very different in scale from piping in gas across continents and beneath seas, as is already done.
  • A series of detailed modeling studies by Dr. Gregor Czisch, which looked at the European wide adoption of renewable energy and interlinking power grids using HVDC cables, indicates that the entire European power usage could come from renewables, with 70% total energy from wind at the same sort of costs or lower than at present.
Desertec Concept
4. Benefits
  • US Wind Integration - A new grid system could carry electricity from the wind-rich Midwest to New York, Washington DC, Atlanta, and other eastern cities.
  • Offshore Wind Integration - Longer term, wind turbines off the Atlantic coast could generate wind energy that would flow in the other direction, from east to west.
  • Improved Load Balancing of Intermittent Power Sources - One advantage of such a geographically dispersed and dynamically balanced system is that the need for base load generation is significantly reduced since intermittency of some sources such as ocean, solar and wind can be smoothed.
  • Opens Up Markets - In the same way that freeways revolutionized interstate transport and the internet revolutionized online commerce when comprehensive high capacity networks for them were built, it is argued that a high capacity super grid will provide a distribution network so comprehensive and with such available capacity that energy trading is only limited by how much electricity that entrepreneurs can bring to market.

5. Risks/Issues
  • Political Risk – Those fretful about buying power from Russia or the more unsavory Gulf oil producers might be equally unhappy to buy it from Libya or Algeria. Implementation of DESERTEC would require cooperation between the states of Europe and the states of the Middle East and North Africa. The European importation of electricity from the Middle East and North Africa could entail political risks if the proportion of total energy supply exceeded a certain level. This is especially because the sites might be vulnerable from terrorism (although it would be spread over different sites, with around 20 power cables transmitting) and there are no military forces defined to protect it.
  • Long Planning Horizon - it takes a very long time to get the appropriate authorizations ( 7 to 10 years ) to build new transmission lines, longer than the time required to build new power plants ( 3 – 4 years for wind farms or combined cycle gas turbines – CCGT ) Most of the transmission investments will not be driven by demand, in other words not driven by higher volumes of transmitted electricity; consequently the unit cost of transmitted electricity will increase. This tariff impact needs public and political acceptance before such investments will take place.
  • Cost - Transmitting energy long distances has been criticized, with questions raised over the cost of cabling compared to energy generation, and electricity losses. Investment may also be required within Europe in a ‘Supergrid’. In response one proposal is to cascade power between neighboring states so that states draw on the power generation of neighboring states rather than from desert sites.
  • Financing - Venture capital is currently unlikely to be interested given cheap oil and gas prices make the proposals more costly than fossil fuel alternatives. One key question will be the cultural aspect, as Middle Eastern and African nations may need assurance that they will own the project rather than it being imposed from Europe.
  • Market Silos - There is a need for a single market in electricity throughout the EUMENA region so that, for example, any customer in Germany or the UK may buy electricity directly from any supplier in North Africa or the Middle East.

6. Next Steps
  • With some modest upgrading of the existing grid to remove bottlenecks, the trading of electricity throughout EUMENA may begin quite soon. As volumes increase, transmission capacities may be increased by converting HVAC lines to HVDC, by building new HVDC lines, and by the installation of smart electronics.

7. Companies
  1. Desertex Foundation - The mission of DESERTEC Foundation is the fast global implementation of the DESERTEC Concept. Desertec Project - a sound alternative to Russian gas pipelines?

  2. GCC Grid - Gulf Cooperation Council Interconnection Authority (GCCIA) - A joint stock company subscribed by the six (6) Gulf States. Saudi Arabia will be able to give and receive 1,200 megawatts, the UAE 900 megawatts and Qatar 750 megawatts. Nations are now negotiating to sell power to each other starting from next year. By facilitating sharing, the huge grid project will reduce electricity costs by making it possible to share the lowest cost generation on the grid.

    Phase two of the long-planned GCC Grid was inaugurated in May 2011. When all four sections are complete it will unite the six Gulf nations on one unified electric grid, making it much easier to build and share power from renewable energy sources, and realize the gains in energy efficiency that come from sharing a wider grid. The cost savings could amount to Dh$18.4b – in US dollars, about $5 billion.

    An analysis by Richard Tabor at Charles River Associates found a compelling economic case for the huge interconnected grid that, once complete, will link the power systems of the six Gulf countries. But the economic benefits are skewed. Saudi Arabia and Oman would be the clear winners, and Kuwait and Bahrain would come out even, while Qatar and the UAE might be negatively affected with higher energy costs.

    The GCC Interconnection Project will connect the grids of the six Gulf states with both overhead electric lines and an underwater cable in the Arabian Gulf, at a cost of more than $1.4 billion. It will make it possible to create a common energy market and help grow sustainable energy supplies from solar projects and wind farms.

  3. Super Smart Grid - The SuperSmart Grid project is a collaborative effort between a number of individuals who divide their time between the European Climate Forum and the Potsdam Institute for Climate Impact Research.

8. Links
  1. HVDC Transmission Projects
  2. Gerry Wolff, TREC-UK coordinator, talks about the July 13, 2009, meeting in Munich, Germany, that created the Desertec Industrial Initiative to implement a network of concentrating solar collectors in North Africa for the generation of green electricity for local and European use, recorded from Wales, UK, July 16, 2009
  3. Study TRANS-CSP on an Intercontinental Transfer of Solar Energy – A DLR Study for the BMU 2006 . The TRANS-CSP study focuses on the interconnection of the electricity grid of Europe, the Middle East and North Africa (EUMENA) with the purpose of supplying about 15% of the European electricity demand by solar energy imports from the South by the year 2050.