Texas regulators added two cost-related caveats to a final order approving American Electric Power Co's plan to build a coal-fired power plant in Arkansas while regulators in that state delayed action on the unit's air permit.
In its final order the Texas Public Utility Commission said Texas customers of AEP's Southwestern Electric Power Co (SWEPCO) unit will pay no more their share of the $1.52 billion price tag to build the 600-megawatt John W Turk Jr. coal-fired plant in Fulton, Arkansas.
"This cap on the capital cost of the Turk plant limits the financial risk to Texas ratepayers," the order said.
Texas regulators, who voted last month to approve the plant, also limited the amount of future carbon-mitigation costs than can be passed to Texas ratepayers at $28 per ton through 2030.
Estimated costs for carbon mitigation ranged from $13 to $70 per ton, with the average between $30-$45, the order said.
SWEPCO spokesman Scott McCloud said the utility is evaluating the final order and had no comment on whether the company would file an appeal.
Commissioner Julie Parsley, who voted against SWEPCO's plan, said both stipulations "are not legally enforceable" on future commissions.
Meanwhile, issuance of an air permit for Turk, tentatively approved by the air division of the Arkansas Department of Environmental Quality, will be delayed from the third quarter, McCloud said, after that agency scheduled a second public hearing to allow comment on SWEPCO's plan to control mercury emissions.
While not required, the agency decided to hold a hearing next month on the mercury issue after a federal court ruling halted implementation of the Clean Air Mercury Rule.
AEP revised its Turk application to comply with Arkansas mercury emission rules leading to a need for additional public input. No permit can be issued until response to public comments are completed, an agency spokesman said.
Rising construction costs and climate-change worry have led utilities to cancel dozens of proposed coal-fired units in the past two years. Even so, more coal plants are being built in the U.S. now than two decades, according to a government report.
About 29 coal plants with a capacity exceeding 15,000 MW are under construction. Another 20 projects have permits or are near construction. Operation of the Turk plant is expected in the second half of 2012.
Louisiana Grid Rebuild After Hurricane Laura will overhaul transmission lines and distribution networks in Lake Charles, as Entergy restores power after catastrophic outages, replacing poles, transformers, and spans to stabilize critical electric infrastructure.
Key Points
Entergy's project replacing transmission and distribution in Lake Charles to restore power after the Cat 4 storm
✅ 1,000+ transmission structures and 6,637 poles damaged
✅ Entergy targets first energized line into Lake Charles in 2 weeks
✅ Full rebuild of Calcasieu and Cameron lines will take weeks
The main power utility for southwest Louisiana will need to "rebuild" the region's grid after Hurricane Laura blasted the region with 150 mph winds last week, top officials said.
The Category 4 hurricane made landfall last Thursday just south of Lake Charles near Cameron, damaging or destroying thousands of electric poles as well as leaving "catastrophic damages" to the transmission system for southwest Louisiana, similar to impacts seen during Typhoon Mangkhut outages in Hong Kong that left many without electricity.
“This is not a restoration," Entergy Louisiana president and CEO Phillip May said in a statement. "It’s almost a complete rebuild of our transmission and distribution system that serves Calcasieu and Cameron parishes.”
According to Entergy, all nine transmission lines that deliver power into the Lake Charles area are currently out service due to storm damage to multiple structures and spans of wire.
The transmission system is a critical component in the delivery of power to customers’ homes, and failures at substations can trigger large outages, as seen in Los Angeles station fire outage reported recently, according to the company.
Of those structures impacted, many were damaged "beyond repair" and require complete replacement.
Broken electrical poles are seen in Holly Beach, La., in the aftermath of Hurricane Laura, Saturday, Aug. 29, 2020. (AP Photo/Gerald Herbert)
Entergy said the damage in southwest Louisiana includes 1,000 transmission structures, 6,637 broken poles, 2,926 transformers and 338 miles of downed distribution wire, highlighting why proactive reliability investments in Hamilton are being pursued by other utilities.
Some 8,300 workers are now in the area working to rebuild the transmission lines, but Entergy said that it will be about two to three weeks before power is available to customers in the Lake Charles area, a timeline similar to Tennessee outages after severe storms reported recently in other states.
"Restoring power will take longer to customers in inaccessible areas of the region," the company said. "While not impacting the expected restoration of service to residential customers, initial estimates are it will take weeks to rebuild all transmission lines in Calcasieu and Cameron parishes."
Entergy Louisiana expects to energize the first of its transmission lines into Lake Charles in two weeks.
“We understand going without power for this extended period will be challenging, and this is not the news customers want to hear. But we have thousands of workers dedicated to rebuilding our grid as quickly as they safely can to return some normalcy to our customers’ lives,” May said.
According to power outage tracking website poweroutage.us, over 164,000 customers remain without service in Louisiana as of Thursday morning, while a Carolinas outage update shows hundreds of thousands affected there as well.
On Wednesday, the Edison Electric Institute, the association of investor-owned electric companies in the U.S., said in a statement to FOX Business that electricity has been restored to approximately 737,000 customers, or 75% of those impacted by the storm across Louisiana, eastern Texas, Mississippi, and Arkansas, even as utilities adapt to climate change to improve resilience.
At least 29,000 workers from 29 states, the District of Columbia and Canada are working to restore power in the region, according to the Electricity Subsector Coordinating Council (ESCC), which is coordinating efforts from government and power industry.
“The transmission loss in Louisiana is significant, with more than 1,000 transmission structures damaged or destroyed by the storm," Department of Energy (DOE) Deputy Secretary Mark Menezes said in a statement. Rebuilding the transmission system is essential to the overall restoration effort and will take weeks given the massive scale and complexity of the work. We will continue to coordinate closely to ensure the full capabilities of the industry and government are marshaled to rebuild this critical infrastructure as quickly as possible.”
At least 17 deaths in Louisiana have been attributed to the storm; more than half of those killed by carbon monoxide poisoning from the unsafe operation of generators, and residents are urged to follow generator safety tips to reduce these risks. Two additional deaths were verified on Wednesday in Beauregard Parish, which health officials said were due to heat-related illness following the storm.
Puerto Rico Earthquakes continue as a seismic swarm with aftershocks, landslides near Pe f1uelas, damage in Ponce and Guayanilla, grid outages from Costa Sur Plant, PREPA recovery, vulnerable buildings post-Hurricane Maria raising safety concerns.
Key Points
Recurring seismic events impacting Puerto Rico, causing damage, aftershocks, outages, and displacement.
✅ Seismic swarm with 6.4 and 5.9 magnitude quakes and ongoing aftershocks
✅ Costa Sur Plant offline; PREPA urges conservation amid grid repairs
✅ Older, code-deficient buildings and landslides raise safety risks
Some in Puerto Rico are beginning to fear the ground will never stop shaking. The island has been pummeled by hundreds of earthquakes in recent weeks, including the recent 5.9 magnitude temblor, where there were reports of landslides in the town of Peñuelas along the southern coast, rattling residents already on edge from the massive 6.4 magnitude quake, and raising wider concerns about climate risks to the grid in disaster-prone regions.
That was the largest to strike the island in more than a century causing hundreds of structures to crumble, forcing thousands from their homes and leaving millions without power, a scenario echoed by Texas power outages during winter storms too. One person was killed and several others injured.
Utility says 99% of customers have electricity
Puerto Rico's public utility, PREPA, tweeted some welcome news Monday: that nearly all of the homes and businesses it serves have had electric power restored. Still it is urging customers to conserve energy amid utility supply-chain shortages that can slow critical repairs.
Reporting from the port city of Ponce, NPR's Adrian Florido said the Costa Sur Plant, which produces more than 40% of Puerto Rico's electricity, was badly damaged in last week's quake. It remains offline indefinitely, even as grid operators elsewhere have faced California blackout warnings during extreme heat.
He also reports many residents are still reeling from the devastation caused by Hurricane Maria, a deadly Category 4 storm that battered the island in September 2017. The storm exposed the fact that buildings across the island were not up to code, similar to how aging systems have contributed to PG&E power line fires in California. The series of earthquakes are only amplifying fears that structures have been further weakened.
"People aren't coping terribly well," Florido said on NPR's Morning Edition Monday, noting that households elsewhere have endured pandemic power shutoffs and burdensome bills.
Many earthquake victims sleeping outdoors
Florido spoke to one displaced resident, Leticia Espada, who said more than 50 homes in her town of Guayanilla, about an hour drive east of the port city of Ponce, had collapsed.
After sleeping outside for days on her patio following Tuesday's quake, she eventually came to her town's baseball stadium where she's been sleeping on one of hundreds of government-issued cots.
She's like so many others sleeping in open-air shelters, many unwilling to go back to their homes until they've been deemed safe, while even far from disaster zones, brief events like a Northeast D.C. outage show how fragile service can be.
"Thousands of people across several towns sleeping in tents or under tarps, or out in the open, protected by nothing but the shade of a tree with no sense of when these quakes are going to stop," Florido reports.
US energy mix shows how the electric grid blends renewables, fossil fuels, nuclear, and hydro, varying by ISO/RTO markets, utilities, and state policies, affecting carbon emissions, pricing, reliability, and access.
Key Points
The US energy mix is the grid's source breakdown by region: fossil fuels, renewables, nuclear, and hydro.
✅ Check ISO or RTO dashboards for real-time generation by fuel source.
✅ Utilities may offer green power plans or RECs at modest premiums.
✅ Energy mix shifts with policy, pricing, and grid reliability needs.
There are few resources more important than energy. Sure, you may die if you don't eat for days. But your phone will die if you go too long without charging it. Energy feeds tech, the internet, city infrastructure, refrigerators, lights, and has evolved throughout U.S. history in profound ways. You get the idea. Yet unlike our other common needs, such as food, energy sources aren't exactly front of mind for most people.
"I think a lot of people don't put a lot of bandwidth into thinking about this part of their lives," said Richard McMahon, the SVP of energy supply and finance at Edison Electric Institute, a trade group that represents investor-owned electric companies in the US.
It makes sense. For most Americans, electricity is always there, and in many locations, there's not much of a choice involved, even as electricity demand is flat across the U.S. today. You sign up with a utility when you move into a new residence and pay your bills when they're due.
But there's an important reality that indifference eschews: In 2018, a third of the energy-related carbon-dioxide emissions in the US came from the electric power sector, according to the US Energy Information Administration (EIA).
A good chunk of that is from the residential sector, which consistently uses more energy than commercial customers, per EIA data.
Just as many people exercise choice when they eat, you typically also have a choice when it comes to your energy supply. That's not to say your current offering isn't what you want, or that switching will be easy or affordable, but "if you're a customer and want power with a certain attribute," McMahon said, "you can pretty much get it wherever you are."
But first, you need to know the energy mix you have right now. As it turns out, it's not so straightforward. At all.
This brief guide may help.
For some utility providers, you can find out if it publishes the energy mix online. Dominion Energy, which serves Idaho, North Carolina, Ohio, South Carolina, Utah, Virginia, West Virginia, and Wyoming, provides this information in a colored graphic.
"Once you figure out who your utility is you can figure out what mix of resources they use," said Heidi Ratz, an electricity markets researcher at the World Resources Institute.
But not all utilities publish this information.
It has to do with their role in the grid and reflects utility industry trends in structure and markets. Some utility companies are vertically integrated; they generate power through nuclear plants or wind farms and distribute those electrons directly to their customers. Other utilities just distribute the power that different companies produce.
Consider Consolidated Edison, or Con Ed, which distributes energy to parts of New York City. While reporting this story, Business Insider could not find information about the utility's energy mix online. When reached for comment, a spokesperson said, "we're indifferent to where it comes from."
That's because, in New York, distribution utilities like Con Ed often buy energy through a wholesale marketplace.
Take a look at this map. If you live in one of the colored regions, your electricity is sold on a wholesale market regulated by an organization called a regional transmission organization (RTO) or independent system operator (ISO). Distribution utilities like Con Ed often buy their energy through these markets, based on availability and cost, while raising questions about future utility revenue models as prices shift.
Still, it's pretty easy to figure out where your energy comes from. Just look up the ISO or RTO website (such as NYISO or CAISO). Usually, these organizations will provide energy supply information in near-real time.
That's exactly what Con Edison (which buys energy on the NYISO marketplace) suggested. As of Friday morning, roughly 40% of the energy on the market place was natural gas or other fossil fuels, 34% was nuclear, and about 22% was hydro.
If you live in another region governed by an ISO or RTO, such as in most of California, you can do the same thing. Like NYISO, CAISO has a dashboard that shows (again, as of Friday morning) about 36% of the energy on the market comes from natural gas and more than 20% comes from renewables.
In the map linked above, you'll notice that some of the ISOs and RTOs like MISO encompass enormous regions. That means that even if you figure out where the energy in your market comes from, it's not going to be geographically specific. But there are a couple of ways to drill down even further.
The Environmental Protection Agency has a straightforward tool called Power Profiler. You can enter your zip code to see the fuel mix in your area. But it's not perfect. The data are from 2016 and, in some regions of the country like the upper Midwest, they aren't much more localized, and some import dirty electricity due to regional trading.
The World Resources Institute also has a tool that allows you to see the electricity mix by state, based on 2017 data from EIA. These numbers represent power generation, not the electricity actually flowing into your sockets, but they offer a rough idea of what energy resources are operating in your state.
One option is to check with your utility to see if it has a "green power" offering. Over 600 utilities across the country have one, according to the Climate Reality Project, though they often come at a slightly higher cost. It's typically on the scale of just a few more cents per kilowatt-hour.
There are also independent, consumer-facing companies like Arcadia and Green Mountain Energy that allow you to source renewable energy, by virtually connecting you to community solar projects or purchasing Renewable Energy Certificates, or RECs, on your behalf, as America goes electric and more options emerge.
"RECs measure an investment in a clean energy resource," Ratz said, in an email. "The goal of putting that resource on the grid is to push out the need for dirtier resources."
The good news: Even if you do nothing, your energy mix will get cleaner. Coal production has fallen to lows not seen since the 1980s, amid disruptions in coal and nuclear sectors that affect reliability and costs, while renewable electricity generation has doubled since 2008. So whether you like it or not, you'll be roped into the clean energy boom one way or another.
FERC DER Aggregation advances debates over distributed energy resources as Congress presses action on Order 841, grid resilience, and wholesale market access, including rooftop solar, storage, and virtual power plant participation across PJM and ISO-NE.
Key Points
FERC DER Aggregation enables grouped distributed resources to join wholesale markets, providing capacity and flexibility.
? Opens wholesale market access for aggregated DER portfolios
? Aligns with Order 841, storage, and grid resilience goals
? Raises jurisdictional questions between FERC and state regulators
The Monday letter from Congressional Democrats illustrates growing frustration in Washington over the lack of FERC action on multiple power sector issues, including the aging U.S. grid and related challenges.
Last May, after the FERC technical conference, 16 Democratic Senators wrote to then-Chairman Kevin McIntyre urging him to develop guidance for grid operators on aggregated DERs.
In July, McIntyre responded, saying that FERC was "diligently reviewing the record," but the commission has taken no action since.
Since then, "DER adoption and renewable energy aggregation have continued to grow," House and Senate lawmakers wrote in their identical Monday letters, "driven not only by state and federal policies, but consumer interest in choosing cost-competitive technologies such as rooftop solar, smart thermostats and customer-sited energy generation and storage, reflecting key utility trends in the sector."
The lawmakers wrote they were "encouraged" by FERC Chairman Neil Chatterjee's comments in June 2018, writing that he "specifically cited the role DERs will play in our continued grid transition."
In that speech at the S&P Global Platts 2018 Transmission Planning and Development Conference, Chatterjee noted "growing interest" in non-transmission alternatives, including "DERs and storage."
"How the Commission treats filings associated with those first-of-kind projects could prove an important factor in investors’ assessments of whether similar non-traditional projects are bankable or not — and more broadly signal whether FERC is open to innovation in the transmission sector,” he said.
In addition to the DER order and rehearing decision on Order 841, FERC has multiple other power sector initiatives that have not seen official action in months, even as major changes to electricity pricing are debated by stakeholders.
The highest profile is its open proceeding on grid resilience, set up last January after FERC rejected a coal and nuclear bailout proposal from the Department of Energy. In October, the CEO of the PJM Interconnection, the nation’s largest wholesale power market, urged FERC to issue a final order in the docket, calling for "leadership" from the commission.
Chatterjee, however, has not indicated when FERC could decide on the case. In December, Commissioner Rich Glick told a Washington audience he is "not entirely sure where the chairman wants to go with that proceeding yet."
Outside of resilience, FERC also has open reviews of both its pipeline certificate policy and implementation of the Public Utilities Regulatory Policy Act, a key law supporting renewable energy. McIntrye set those reviews in motion during his tenure as chairman, but after his death in January the timing of both remains unclear.
In recent months, Chatterjee has also delayed FERC votes on major export facilities for liquefied natural gas and a political spending case involving PJM after impasses between Republicans and Democrats on FERC.
Two members from each party currently sit on the commission. That allows Democrats to deadlock commission votes on natural gas facilities and other issues — a partisan divide on display this week when they clashed with the chairman over offshore wind.
As the commission considers final guidance on DERs, the boundaries of federal jurisdiction are likely to be a key issue. At the technical conference, states from the Midcontinent ISO argued FERC should allow them to choose whether to let aggregated DERs participate in retail and wholesale markets. Other states argued the value proposition of distributed resources may rely on that sort of dual participation.
Despite the lack of action from FERC, some grid operators are moving forward with aggregated distributed resources in New England market reform efforts and elsewhere, demonstrating momentum. Last week, a residential solar-plus-storage aggregation cleared the ISO-NE capacity auction for the first time, committing to provide 20 MW of capacity beginning in 2022.
On the Senate side, Sens. Sheldon Whitehouse, R.I., and Ed Markey, Mass., led the letter to FERC. In the House, Reps. Peter Welch, Vt., and Mike Levin, Calif., led the signatories.
Automaker EV Fast-Charging Network will deploy 30,000 DC fast chargers across US and Canada, supporting CCS and NACS, integrating Tesla compatibility, easing range anxiety, and expanding highway and urban charging infrastructure with amenities and uptime.
Key Points
A $1B joint venture by seven automakers to build 30,000 DC fast chargers with CCS and NACS across the US and Canada.
✅ 30,000 DC fast chargers by 2030 across US and Canada
✅ Supports CCS and NACS; Tesla compatibility planned
✅ Launching mid-2024; focus on highways, urban hubs, amenities
Seven major automakers announced a plan on Wednesday to nearly double the number of fast chargers in the United States in an effort to address one of the main reasons that people hesitate to buy electric cars, even as the age of electric cars accelerates.
The carmakers — BMW Group, General Motors, Honda, Hyundai, Kia, Mercedes-Benz Group and Stellantis — will initially invest at least $1 billion in a joint venture that will build 30,000 charging ports on major highways and other locations in the United States and Canada.
The United States and Canada have about 36,000 fast chargers — those that can replenish a drained battery in 30 minutes or less. In some sparsely populated areas, such chargers can be hundreds of miles apart. Surveys show that fear about not being able to find a charger during longer journeys is a major reason that some car buyers are reluctant to buy electric vehicles.
Sales of electric vehicles have risen quickly in the United States as the market hits an inflection point, but there are signs that demand is softening. As a result, Tesla, Ford and other carmakers have cut prices in recent months and are offering incentives. Popular models that had long waiting lists last year are now available in a few days or weeks.
Major carmakers are investing billions of dollars to manufacture electric vehicles and batteries and to establish supplier networks. Having staked their futures on the technology, they have a strong incentive to ensure that electric vehicles catch on with car buyers, even as gas-electric hybrids help bridge the transition.
The chargers installed by the joint venture will have plugs designed for the connections used by most carmakers other than Tesla, as well as the standard developed by Tesla, amid fights for control over charging, that Ford, G.M. and other companies have said they intend to switch to in 2025.
“The better experience people have, the faster E.V. adoption will grow,” Mary T. Barra, the chief executive of General Motors, said in a statement.
The seven automakers plan to formalize the joint venture and announce its name by the end of the year, Chris Martin, a Honda spokesman, said. The first chargers will begin operating around the middle of 2024, he said, with all 30,000 in place by the end of the decade.
The joint venture is open to adding other partners, he said. Among major automakers, Ford was a notable absence from the announcement on Wednesday. The company said in a statement on Wednesday that it would continue to iThe partnership also does not include Volkswagen. The company is a majority shareholder of Electrify America, one of the largest fast-charging providers.
Tesla accounts for more than half the fast chargers in the United States and has said it will open its networks to other car brands, though, so far, it has only made fewer than 100 ports available. Owners of Ford and G.M. vehicles, among others, will be able to connect to 12,000 Tesla fast chargers using an adapter beginning next year. In 2025, Ford and G.M. plan to make models designed to take the Tesla plug without an adapter.
The decision by the seven carmakers to form the joint venture is an indication that they do not intend to rely solely on Tesla, which dominates sales of electric vehicles, for charging.
The chargers being built by the joint venture will be concentrated in urban areas and along major highways, especially those used most heavily by vacationers and other travelers, the companies said in a joint statement. Charging stations will be close to restrooms, restaurants and other amenities. The partners said they would try to take advantage of federal and state funds available for charging infrastructure amid questions about whether the U.S. has the power to charge it at scale.
Most electric vehicle owners charge at home and rarely need to use public chargers. Home chargers typically replenish batteries overnight. Most public chargers, about 125,000 in the United States and Canada, also operate relatively slowly — taking four to 10 hours to do the job.nvest in its own network, which allows Ford owners to charge from a variety of providers with one mobile phone app.
Boeing 787 More-Electric Architecture replaces pneumatics with bleedless pressurization, VFSG starter-generators, electric brakes, and heated wing anti-ice, leveraging APU, RAT, batteries, and airport ground power for efficient, redundant electrical power distribution.
Key Points
An integrated, bleedless electrical system powering start, pressurization, brakes, and anti-ice via VFSGs, APU and RAT.
✅ VFSGs start engines, then generate 235Vac variable-frequency power
✅ Bleedless pressurization, electric anti-ice improve fuel efficiency
✅ Electric brakes cut hydraulic weight and simplify maintenance
The 787 Dreamliner is different to most commercial aircraft flying the skies today. On the surface it may seem pretty similar to the likes of the 777 and A350, but get under the skin and it’s a whole different aircraft.
When Boeing designed the 787, in order to make it as fuel efficient as possible, it had to completely shake up the way some of the normal aircraft systems operated. Traditionally, systems such as the pressurization, engine start and wing anti-ice were powered by pneumatics. The wheel brakes were powered by the hydraulics. These essential systems required a lot of physical architecture and with that comes weight and maintenance. This got engineers thinking.
What if the brakes didn’t need the hydraulics? What if the engines could be started without the pneumatic system? What if the pressurisation system didn’t need bleed air from the engines? Imagine if all these systems could be powered electrically… so that’s what they did.
Power sources
The 787 uses a lot of electricity. Therefore, to keep up with the demand, it has a number of sources of power, much as grid operators track supply on the GB energy dashboard to balance loads. Depending on whether the aircraft is on the ground with its engines off or in the air with both engines running, different combinations of the power sources are used.
Engine starter/generators
The main source of power comes from four 235Vac variable frequency engine starter/generators (VFSGs). There are two of these in each engine. These function as electrically powered starter motors for the engine start, and once the engine is running, then act as engine driven generators.
The generators in the left engine are designated as L1 and L2, the two in the right engine are R1 and R2. They are connected to their respective engine gearbox to generate electrical power directly proportional to the engine speed. With the engines running, the generators provide electrical power to all the aircraft systems.
APU starter/generators
In the tail of most commercial aircraft sits a small engine, the Auxiliary Power Unit (APU). While this does not provide any power for aircraft propulsion, it does provide electrics for when the engines are not running.
The APU of the 787 has the same generators as each of the engines — two 235Vac VFSGs, designated L and R. They act as starter motors to get the APU going and once running, then act as generators. The power generated is once again directly proportional to the APU speed.
The APU not only provides power to the aircraft on the ground when the engines are switched off, but it can also provide power in flight should there be a problem with one of the engine generators.
Battery power
The aircraft has one main battery and one APU battery. The latter is quite basic, providing power to start the APU and for some of the external aircraft lighting.
The main battery is there to power the aircraft up when everything has been switched off and also in cases of extreme electrical failure in flight, and in the grid context, alternatives such as gravity power storage are being explored for long-duration resilience. It provides power to start the APU, acts as a back-up for the brakes and also feeds the captain’s flight instruments until the Ram Air Turbine deploys.
Ram air turbine (RAT) generator
When you need this, you’re really not having a great day. The RAT is a small propeller which automatically drops out of the underside of the aircraft in the event of a double engine failure (or when all three hydraulics system pressures are low). It can also be deployed manually by pressing a switch in the flight deck.
Once deployed into the airflow, the RAT spins up and turns the RAT generator. This provides enough electrical power to operate the captain’s flight instruments and other essentials items for communication, navigation and flight controls.
External power
Using the APU on the ground for electrics is fine, but they do tend to be quite noisy. Not great for airports wishing to keep their noise footprint down. To enable aircraft to be powered without the APU, most big airports will have a ground power system drawing from national grids, including output from facilities such as Barakah Unit 1 as part of the mix. Large cables from the airport power supply connect 115Vac to the aircraft and allow pilots to shut down the APU. This not only keeps the noise down but also saves on the fuel which the APU would use.
The 787 has three external power inputs — two at the front and one at the rear. The forward system is used to power systems required for ground operations such as lighting, cargo door operation and some cabin systems. If only one forward power source is connected, only very limited functions will be available.
The aft external power is only used when the ground power is required for engine start.
Circuit breakers
Most flight decks you visit will have the back wall covered in circuit breakers — CBs. If there is a problem with a system, the circuit breaker may “pop” to preserve the aircraft electrical system. If a particular system is not working, part of the engineers procedure may require them to pull and “collar” a CB — placing a small ring around the CB to stop it from being pushed back in. However, on the 787 there are no physical circuit breakers. You’ve guessed it, they’re electric.
Within the Multi Function Display screen is the Circuit Breaker Indication and Control (CBIC). From here, engineers and pilots are able to access all the “CBs” which would normally be on the back wall of the flight deck. If an operational procedure requires it, engineers are able to electrically pull and collar a CB giving the same result as a conventional CB.
Not only does this mean that the there are no physical CBs which may need replacing, it also creates space behind the flight deck which can be utilised for the galley area and cabin.
A normal flight
While it’s useful to have all these systems, they are never all used at the same time, and, as the power sector’s COVID-19 mitigation strategies showed, resilience planning matters across operations. Depending on the stage of the flight, different power sources will be used, sometimes in conjunction with others, to supply the required power.
On the ground
When we arrive at the aircraft, more often than not the aircraft is plugged into the external power with the APU off. Electricity is the blood of the 787 and it doesn’t like to be without a good supply constantly pumping through its system, and, as seen in NYC electric rhythms during COVID-19, demand patterns can shift quickly. Ground staff will connect two forward external power sources, as this enables us to operate the maximum number of systems as we prepare the aircraft for departure.
Whilst connected to the external source, there is not enough power to run the air conditioning system. As a result, whilst the APU is off, air conditioning is provided by Preconditioned Air (PCA) units on the ground. These connect to the aircraft by a pipe and pump cool air into the cabin to keep the temperature at a comfortable level.
APU start
As we near departure time, we need to start making some changes to the configuration of the electrical system. Before we can push back , the external power needs to be disconnected — the airports don’t take too kindly to us taking their cables with us — and since that supply ultimately comes from the grid, projects like the Bruce Power upgrade increase available capacity during peaks, but we need to generate our own power before we start the engines so to do this, we use the APU.
The APU, like any engine, takes a little time to start up, around 90 seconds or so. If you remember from before, the external power only supplies 115Vac whereas the two VFSGs in the APU each provide 235Vac. As a result, as soon as the APU is running, it automatically takes over the running of the electrical systems. The ground staff are then clear to disconnect the ground power.
If you read my article on how the 787 is pressurised, you’ll know that it’s powered by the electrical system. As soon as the APU is supplying the electricity, there is enough power to run the aircraft air conditioning. The PCA can then be removed.
Engine start
Once all doors and hatches are closed, external cables and pipes have been removed and the APU is running, we’re ready to push back from the gate and start our engines. Both engines are normally started at the same time, unless the outside air temperature is below 5°C.
On other aircraft types, the engines require high pressure air from the APU to turn the starter in the engine. This requires a lot of power from the APU and is also quite noisy. On the 787, the engine start is entirely electrical.
Power is drawn from the APU and feeds the VFSGs in the engines. If you remember from earlier, these fist act as starter motors. The starter motor starts the turn the turbines in the middle of the engine. These in turn start to turn the forward stages of the engine. Once there is enough airflow through the engine, and the fuel is igniting, there is enough energy to continue running itself.
After start
Once the engine is running, the VFSGs stop acting as starter motors and revert to acting as generators. As these generators are the preferred power source, they automatically take over the running of the electrical systems from the APU, which can then be switched off. The aircraft is now in the desired configuration for flight, with the 4 VFSGs in both engines providing all the power the aircraft needs.
As the aircraft moves away towards the runway, another electrically powered system is used — the brakes. On other aircraft types, the brakes are powered by the hydraulics system. This requires extra pipe work and the associated weight that goes with that. Hydraulically powered brake units can also be time consuming to replace.
By having electric brakes, the 787 is able to reduce the weight of the hydraulics system and it also makes it easier to change brake units. “Plug in and play” brakes are far quicker to change, keeping maintenance costs down and reducing flight delays.
In-flight
Another system which is powered electrically on the 787 is the anti-ice system. As aircraft fly though clouds in cold temperatures, ice can build up along the leading edge of the wing. As this reduces the efficiency of the the wing, we need to get rid of this.
Other aircraft types use hot air from the engines to melt it. On the 787, we have electrically powered pads along the leading edge which heat up to melt the ice.
Not only does this keep more power in the engines, but it also reduces the drag created as the hot air leaves the structure of the wing. A double win for fuel savings.
Once on the ground at the destination, it’s time to start thinking about the electrical configuration again. As we make our way to the gate, we start the APU in preparation for the engine shut down. However, because the engine generators have a high priority than the APU generators, the APU does not automatically take over. Instead, an indication on the EICAS shows APU RUNNING, to inform us that the APU is ready to take the electrical load.
Shutdown
With the park brake set, it’s time to shut the engines down. A final check that the APU is indeed running is made before moving the engine control switches to shut off. Plunging the cabin into darkness isn’t a smooth move. As the engines are shut down, the APU automatically takes over the power supply for the aircraft. Once the ground staff have connected the external power, we then have the option to also shut down the APU.
However, before doing this, we consider the cabin environment. If there is no PCA available and it’s hot outside, without the APU the cabin temperature will rise pretty quickly. In situations like this we’ll wait until all the passengers are off the aircraft until we shut down the APU.
Once on external power, the full flight cycle is complete. The aircraft can now be cleaned and catered, ready for the next crew to take over.
Bottom line
Electricity is a fundamental part of operating the 787. Even when there are no passengers on board, some power is required to keep the systems running, ready for the arrival of the next crew. As we prepare the aircraft for departure and start the engines, various methods of powering the aircraft are used.
The aircraft has six electrical generators, of which only four are used in normal flights. Should one fail, there are back-ups available. Should these back-ups fail, there are back-ups for the back-ups in the form of the battery. Should this back-up fail, there is yet another layer of contingency in the form of the RAT. A highly unlikely event.
The 787 was built around improving efficiency and lowering carbon emissions whilst ensuring unrivalled levels safety, and, in the wider energy landscape, perspectives like nuclear beyond electricity highlight complementary paths to decarbonization — a mission it’s able to achieve on hundreds of flights every single day.
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