The Public Utility Commission of Texas PUCT in late March 2014 unanimously approved an application by Electric Transmission Texas, LLC ETT and Sharyland Utilities, L.P. Sharyland to build a 345-kilovolt kV transmission line from a substation northwest of the city of Edinburg to a substation located east of the city of Brownsville. The cost of the project is estimated to total $309 million and is expected to be completed during the summer of 2016.
The PUCT commissioners approved construction of the new approximately 96-mile line that would extend from the existing AEP Texas Central Company North Edinburg Substation to the existing Brownsville Public Utilities Board Loma Alta Substation located near the Brownsville Ship Channel. The western half of the line will be constructed, owned and operated by ETT, while the eastern half will be constructed and operated by Sharyland Utilities, L.P. The midpoint is approximately one mile east of the Hidalgo/Cameron county line.
The approved route runs generally east from the North Edinburg Substation and, after approximately 7.5 miles, turns south continuing past the city of Donna. Approximately 2 miles north of U.S. Highway 281, the route turns east, roughly paralleling the north side of U.S. Highway 281 until the city of Rangerville, where it turns north-northeast toward the city of San Benito. It then continues east around the northern and eastern sides of Brownsville, ultimately terminating at the Loma Alta Substation.
“When we first filed our joint application in July 2013, we emphasized that this transmission line is needed to ensure continued reliable electric service for the Lower Rio Grande Valley, which is forecast to have continued electrical demand growth,” said ETT President Calvin Crowder. “The need has grown since that time, and the Electric Reliability Council of Texas ERCOT has determined this project is critical for the reliability of the ERCOT system and, specifically, the Brownsville area.”
“This project will not only improve both the reliability and stability of the grid in the Lower Rio Grande Valley, it also will provide a real engine for economic growth in communities throughout the region,” said Sharyland President Mark Caskey. “A reliable, large-scale source of electric power is absolutely critical in attracting new investment and economic development, especially for communities like Brownsville.”
ERCOT endorsed the project in January 2012. Since that time, ETT and Sharyland have worked with an experienced routing consultant to perform an environmental assessment and routing analysis for the proposed transmission line. In addition, public input was gathered at jointly hosted public open houses in October 2012 and February 2013.
The application was filed in July 2013 under PUCT Docket No. 41606 – Joint Application of Electric Transmission Texas, LLC and Sharyland Utilities, L.P. to Amend Their Certificates of Convenience and Necessity for the Proposed North Edinburg to Loma Alta Double-Circuit 345 kV Transmission Line in Hidalgo and Cameron Counties, Texas.
Pennsylvania Electric Rate Increases hit Peco, PPL, and Pike County, driven by natural gas costs and wholesale power markets; default rate changes, price to compare shifts, and time-of-use plans affect residential bills.
Key Points
Electric default rates are rising across Pennsylvania as natural gas costs climb, affecting Peco, PPL, and Pike customers.
✅ PPL, Peco, and Pike raising default rates Dec. 1
✅ Natural gas costs driving wholesale power prices
✅ Consider standard offer, TOU rates, and efficiency
Energy costs for electric customers are going up by as much as 50% across Pennsylvania next week, the latest manifestation of US electricity price increases impacting gasoline, heating oil, propane, and natural gas.
Eight Pennsylvania electric utilities are set to increase their energy prices on Dec. 1, reflecting the higher cost to produce electricity. Peco Energy, which serves Philadelphia and its suburbs, will boost its energy charge by 6.4% on Dec. 1, from 6.6 cents per kilowatt hour to about 7 cents per kWh. Energy charges account for about half of a residential bill.
PPL Electric Utilities, the Allentown company that serves a large swath of Pennsylvania including parts of Bucks, Montgomery, and Chester Counties, will impose a 26% increase on residential energy costs on Dec. 1, from about 7.5 cents per kWh to 9.5 cents per kWh. That’s an increase of $40 a month for an electric heating customer who uses 2,000 kWh a month.
Pike County Light & Power, which serves about 4,800 customers in Northeast Pennsylvania, will increase energy charges by 50%, according to the Pennsylvania Public Utility Commission.
“All electric distribution companies face the same market forces as PPL Electric Utilities,” PPL said in a statement. Each Pennsylvania utility follows a different PUC-regulated plan for procuring energy from power generators, and those forces can include rising nuclear power costs in some regions, which explains why some customers are absorbing the hit sooner rather than later, it said.
There are ways customers can mitigate the impact. Utilities offer a host of programs and grants to support low-income customers, and some states are exploring income-based fixed charges to address affordability, and they encourage anyone struggling to pay their bills to call the utility for help. Customers can also control their costs by conserving energy. It may be time to put on a sweater and weatherize the house.
Peco recently introduced time-of-use rates — as seen when Ontario ended fixed pricing — that include steep discounts for customers who can shift electric usage to late night hours — that’s you, electric vehicle owners.
There’s also a clever opportunity available for many Pennsylvania customers called the “standard offer” that might save you some real money, but you need to act before the new charges take effect on Dec. 1 to lock in the best rates.
Why are the price hikes happening? But first, how did we get here?
Energy charges are rising for a simple reason: Fuel prices for power generators are increasing, and that’s driven mostly by natural gas. It’s pushing up electricity prices in wholesale power markets and has lifted typical residential bills in recent years.
“It’s all market forces right now,” said Nils Hagen-Frederiksen, PUC spokesperson. Energy charges are strictly a pass-through cost for utilities. Utilities aren’t allowed to mark them up.
The increase in utility energy charges does not affect customers who buy their energy from competitive power suppliers in deregulated electricity markets. About 27% of Pennsylvania’s 5.9 million electric customers who shop for electricity from third-party suppliers either pay fixed rates, whose price remains stable, or are on a variable-rate plan tied to market prices. The variable-rate electric bills have probably already increased to reflect the higher cost of generating power.
Most New Jersey electric customers are shielded for now from rising energy costs. New Jersey sets annual energy prices for customers who don’t shop for power. Those rates go into effect on June 1 and stay in place for 12 months. The current energy market fluctuations will be reflected in new rates that take effect next summer, said Lauren Ugorji, a spokesperson for Public Service Electric & Gas Co., New Jersey’s largest utility.
For each utility, its own plan Pennsylvania has a different system for setting utility energy charges, which are also known as the “default rate,” because that’s the price a customer gets by default if they don’t shop for power. The default rate is also the same thing as the “price to compare,” a term the PUC has adopted so consumers can make an apples-to-apples comparison between a utility’s energy charge and the price offered by a competitive supplier.
Each of the state’s 11 PUC-regulated electric utilities prepares its own “default service plan,” that governs the method by which they procure power on wholesale markets. Electric distribution companies like Peco are required to buy the lowest priced power. They typically buy power in blind auctions conducted by independent agents, so that there’s no favoritism for affiliated power generators
Some utilities adjust charges quarterly, and others do it semi-annually. “This means that each [utility’s] resulting price to compare will vary as the market changes, some taking longer to reflect price changes, both up and down,” PPL said in a statement. PPL conducted its semi-annual auction in October, when energy prices were rising sharply.
Most utilities buy power from suppliers under contracts of varying durations, both long-term and short-term. The contracts are staggered so market price fluctuations are smoothed out. One utility, Pike County Power & Light, buys all its power on the spot market, which explains why its energy charge will surge by 50% on Dec. 1. Pike County’s energy charge will also be quicker to decline when wholesale prices subside, as they are expected to next year.
Peco adjusts its energy charge quarterly, but it conducts power auctions semi-annually. It buys about 40% of its power in one-year contracts, and 60% in two-year contracts, and does not buy any power on spot markets, said Richard G. Webster Jr., Peco’s vice president of regulatory policy and strategy.
“At any given time, we’re replacing about a third of our supplied portfolio,” he said.
The utility’s energy charge affects only part of the monthly bill. For a Peco residential electric customer who uses 700 kWh per month, the Dec. 1 energy charge increase will boost monthly bills by $2.94 per month, or 2.9%. For an electric heating customer who uses about 2,000 kWh per month, the change will boost bills $8.40 a month, or about 3.5%, said Greg Smore, a Peco spokesperson.
Duke Energy Carolinas Solar RFP draws 3.9 GW of utility-scale bids, oversubscribed in DEP and DEC, below avoided cost rates, minimal battery storage, strict PPA terms, and interconnection challenges across North and South Carolina.
Key Points
Utility-scale solar procurement in DEC and DEP, evaluated against avoided cost, with few storage bids and PPA terms.
✅ 3.9 GW bids for 680 MW; DEP most oversubscribed
✅ Most projects 7-80 MWac; few include battery storage
✅ Bids must price below 20-year avoided cost estimate
Last week the independent administrator for Duke’s 680 MW solar solicitation revealed data about the projects which have bid in response to the offer, showing a massive amount of interest in the opportunity.
Overall, 18 individuals submitted bids for projects in Duke Energy Carolinas (DEC) territory and 10 in Duke Energy Progress (DEP), with a total of more than 3.9 GW of proposals – more nearly 6x the available volume. DEP was relatively more over-subscribed, with 1.2 GWac of projects vying for only 80 MW of available capacity.
This is despite a requirement that such projects come in below the estimate of Duke’s avoided cost for the next 20 years, and amid changes in solar compensation that could affect project economics. Individual projects varied in capacity from 7-80 MWac, with most coming within the upper portion of that range.
These bids will be evaluated in the spring of 2019, and as Duke Energy Renewables continues to expand its portfolio, Duke Energy Communications Manager Randy Wheeless says he expects the plants to come online in a year or two.
Lack of storage
Despite recent trends in affordable batteries, of the 78 bids that came in only four included integrated battery storage. Tyler Norris, Cypress Creek Renewables’ market lead for North Carolina, says that this reflects that the methodology used is not properly valuing storage.
“The lack of storage in these bids is a missed opportunity for the state, and it reflects a poorly designed avoided cost rate structure that improperly values storage resources, commercially unreasonable PPA provisions, and unfavorable interconnection treatment toward independent storage,” Norris told pv magazine.
“We’re hopeful that these issues will be addressed in the second RFP tranche and in the current regulatory proceedings on avoided cost and state interconnection standards and grid upgrades across the region.”
Limited volume for North Carolina?
Another curious feature of the bids is that nearly the same volume of solar has been proposed for South Carolina as North Carolina – despite this solicitation being in response to a North Carolina law and ongoing legal disputes such as a church solar case that challenged the state’s monopoly model.
National Grid Demand Flexibility Service helps stabilise the UK grid during tight supply, offering discounts for smart meter users who shift peak-time electricity use, reducing power cut risks amid low wind and import constraints.
Key Points
A National Grid scheme paying smart homes to cut peak-time use, easing supply pressure and avoiding power cuts.
✅ Pays volunteers with smart meters to reduce peak demand.
✅ Credits discounts for shifting use to off-peak windows.
✅ Manages tight margins and helps avert UK power cuts.
National Grid has decided not to activate a scheme on Tuesday to help the UK avoid power cuts after being poised to do so.
It would have seen some households offered discounts on their electricity bills if they cut peak-time use.
National Grid had been ready to trigger the scheme following a warning that Britain's energy supplies were looking tighter than usual this week.
However, it decided that the measure was not required.
Alerts are sent out automatically when expected supplies drop below a certain level. But they do not mean that blackouts are likely, or that the situation is critical.
National Grid said it was "confident" it would be able to manage margins and "demand is not at risk".
Discounts Earlier on Monday, the grid operator said it was considering whether to pay households across Britain to reduce their energy use to help out on Tuesday evening.
Under the Demand Flexibility Service (DFS), announced earlier this month, customers that have signed up could get discounts on their bills if they use less electricity in a given window of time.
That could mean delaying the use of a tumble-dryer or washing machine, or cooking dinner in the microwave rather than the oven.
Major suppliers such as Octopus and British Gas are taking part, but only customers that have an electricity smart meter and that have volunteered are eligible. About 14 million UK homes have an electricity smart meter.
The DFS has already been tested twice but has not yet run live.
Octopus, the supplier with the most customers signed up, said that some households had earned more than £4 during the hour-long tests, while the average saving was "well over £1".
It came after forecasts projected a large drop in the amount of power that Britain will be able to import from French nuclear power stations on Monday and Tuesday evenings.
The lack of strong winds to power turbines has also affected how much power can be generated within the UK, and efforts to fast-track grid connections aim to ease constraints.
Such warnings are not unusual - around 12 have been issued and cancelled without issue in the last six years, and other regions such as Canada are seeing grids strained by harsh weather as well.
However, they have become more common this year due to the energy crisis, and the most recent notice was sent out last week.
The situation means that the UK will have to import electricity from other sources on Monday and Tuesday evening.
Supplies are also expected be tight in France, forecasters say.
France has been facing months of problems with its nuclear power plants, which generate around three-quarters of the country's electricity.
More than half of the nuclear reactors run by state energy company EDF have closed due to maintenance problems and technical issues.
It has added to a massive energy crisis in Europe which is facing a winter without gas supplies from Russia.
Ontario Global Adjustment Deferral offers COVID-19 electricity bill relief to industrial and commercial consumers not on the RPP, aligning GA to March levels for Class A and Class B manufacturers to improve cash flow.
Key Points
A temporary GA deferral easing electricity costs for Ontario industrial and commercial users not on the RPP.
✅ Sets Class B GA at $115/MWh; Class A gets equal percentage cut.
✅ Applies April-June 2020; automatic bill adjustments and credits.
✅ Deferred charges repaid over 12 months starting January 2021.
"Manufacturers are pleased the government listened to Canadian Manufacturers & Exporters (CME) member recommendations and is taking action to reduce Ontario electricity bills immediately," said Dennis Darby, President & CEO of CME.
"The majority of manufacturers have identified cash flow as their top concern during the crisis, "added Darby. "The GA system would have caused a nearly $2 billion cost surge to Ontario manufacturers this year. This new initiative by the government is on top of the billions in support already provided to help manufacturers weather this unprecedented storm, while other provinces accelerate British Columbia's clean energy shift to drive long-term competitiveness. All these measures are a great start in helping businesses of all sizes stay afloat during the crisis and, keeping Ontarians employed."
"We call on the Ontario government to continue to consider the impact of electricity costs on the manufacturing sector, even after the COVID-19 crisis is resolved," stated Darby. "High prices are putting Ontario manufacturers at a significant competitive disadvantage and, discourages investments." A recent report from London Economics International (LEI) found that when compared to jurisdictions with similar manufacturing industries, Ontario's electricity prices can be up to 75% more expensive, underscoring the importance of planning for Toronto's growing electricity needs to maintain affordability.
To provide companies with temporary immediate relief on their electricity bills, the Ontario government is deferring a portion of Global Adjustment (GA) charges for industrial and commercial electricity consumers that do not participate in the Regulated Price Plan (RPP), starting from April 2020, as some regions saw reduced electricity demand from widespread remote work during the pandemic. The GA rate for smaller industrial and commercial consumers (i.e., Class B) has been set at $115 per megawatt-hour, which is roughly in line with the March 2020 value. Large industrial and commercial consumers (i.e., Class A) will receive the same percentage reduction in GA charges as Class B consumers.
The Ontario government intends to keep this relief in place through the end of June 2020, alongside investments like smart grid technology in Sault Ste. Marie to support reliability, subject to necessary extensions and approvals to implement this initiative.
Industrial and commercial electricity consumers will automatically see this relief reflected on their bills. Consumers who have already received their April bill should see an adjustment on a future bill.
The government intends to bring forward subsequent amendments that would, if approved, recover the deferred GA charges (excluding interest) from industrial and commercial electricity consumers, as Toronto prepares for a surge in electricity demand amid continued growth, over a 12-month period beginning in January 2021.
IAEA Nuclear Security Mission in China reviews regulatory frameworks, physical protection, and compliance at nuclear power plants, endorsing CAEA efforts, IPPAS guidance, and capacity building to strengthen safeguards, risk management, and global cooperation.
Key Points
An IAEA advisory visit assessing China's nuclear security, physical protection, and regulatory frameworks.
✅ Reviews laws, regulations, and physical protection measures
✅ Endorses CAEA, COE, and IPPAS-aligned best practices
✅ Recommends accelerated rulemaking for expanding reactors
The International Atomic Energy Agency commended China's efforts and accomplishments in nuclear security after conducting its first nuclear security advisory mission to the nation, according to the China Atomic Energy Authority.
The two-week International Physical Protection Advisory Service mission, from Aug 28to Saturday, reviewed the legislative and regulatory framework for nuclear security as well as the physical protection of nuclear material and facilities, including worker safety protocols during health emergencies.
An eight-member expert team led by Joseph Sandoval of the United States' Sandia National Laboratories visited Fangjiashan Nuclear Power Plant, part of the Qinshan Nuclear Power Station in Zhejiang province, to examine security arrangements and observe physical protection measures, where recognized safety culture practices can reinforce performance.
The experts also met with officials from several Chinese government bodies involved in nuclear security such as the China Atomic Energy Authority, National Nuclear Safety Administration and Ministry of Public Security.
The international agency has carried out 78 of the protection missions in 48 member states since 1995. This was the first in China, it said.
The China Atomic Energy Authority said on Tuesday that a report by the experts highly approves of the Chinese government's continuous efforts to strengthen nuclear safety, to boost the sustainable development of the nuclear power industry and to help establish a global nuclear security system.
The report identifies the positive roles played by the State Nuclear Security Technology Center and its subsidiary, the Center of Excellence on Nuclear Security, in enhancing China's nuclear security capability and supporting regional and global cooperation in the field, such as bilateral cooperation agreements that advance research and standards, officials at the China Atomic Energy Authority said.
"A strong commitment to nuclear security is a must for any state that uses nuclear power for electricity generation and that is planning to significantly expand this capacity by constructing new power reactors," said Muhammad Khaliq, head of the international agency's nuclear security of materials and facilities section. "China'sexample in applying IAEA nuclear security guidance and using IAEA advisory services demonstrates its strong commitment to nuclear security and its enhancement worldwide."
The report notes that along with the rapid growth of China's nuclear power sector, challenges have emerged when it comes to the country's nuclear security mechanism and management, as highlighted by grid reliability warnings during pandemics in other markets.
It suggests that the Chinese government accelerate the making of laws and regulations to better govern this sector.
Deng Ge, director of the State Nuclear Security Technology Center, said the IAEAmission would help China strengthen its nuclear security since the nation could learn from other countries' successful experience, including on-site staffing measures to maintain critical operations, and find out its weaknesses for rectification.
Deng added that the mission's report can help the international community understand China's contributions to the global nuclear security system and also offer China's best practices to other nations.
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.
