Wal-Mart Canada stores across the country began reducing lighting by one-third for the summer in 240 of its stores, a strategy aimed at helping the company meet its plan to lower carbon emissions by at least 19,000 tons this year. As a result, Wal-Mart Canada expects to slash carbon emissions by over 4,500 tons, help control summer smog conditions, and aid the stability of provincial power grids.
Other energy conservation programs adopted by the company include the ongoing retrofit of stores with more efficient lighting, heating, air conditioning and ventilation systems, and an alternative energy plan that is expected to make the retailer Canada's single largest commercial buyer of alternative energy.
The reduced summer-lighting program was piloted in Wal-Mart stores across Ontario in the summers during 2005 and 2006, originally implemented in response to continuing summer energy concerns in the province. The Canada-wide expansion of the program is a result of the company's sustainability goals and its recently introduced "For the Greener Good" program.
Participating locations have posted door-front notices explaining the change and its environmental benefit to shoppers.
"Our customers have told us to be creative and to act boldly when it comes to sustainability," said Wal-Mart Canada Corp. President and CEO Mario Pilozzi in a statement. "We have been amazed at the positive response and the positive results already."
Wal-Mart Canada now has 13 internal networks looking into opportunities to effect sustainable change in such areas as product availability, shipping, packaging, materials, store construction and design, and greenhouse gas reduction.
"We have found that there is a great marriage between environmental sustainability and business sustainability," said Pilozzi. "There are many ways we can benefit our environment while benefiting our business. The effect of our lighting reductions is a great example: less lighting means we save more than a million dollars in energy costs while also taking the equivalent of 500 cars off the road for the year."
Wal-Mart's three long-term sustainability goals worldwide and in Canada are to produce zero waste, to be powered 100 percent by renewable energy, and to make more environmentally preferable products available to shopper.
Wal-Mart Canada operates 277 discount stores, seven Wal-Mart Supercentres, and six Sam's Club membership warehouse operations.
Cerro Dominador CSP Plant delivers 110MW concentrated solar power in Chile's Atacama Desert, with 10,600 heliostats, 17.5-hour molten salt storage, and 24/7 dispatchable energy; built by Acciona and Abengoa within a 210MW complex.
Key Points
A 110MW CSP solar-thermal plant in Chile with heliostats and 17.5h molten salt storage, delivering 24/7 dispatchable clean power.
✅ 110MW CSP with 17.5h molten salt for 24/7 dispatch
✅ 10,600 heliostats; part of a 210MW hybrid CSP+PV complex
✅ Built by Acciona and Abengoa; first of its kind in LatAm
A consortium formed by Spanish groups Abengoa and Acciona, as Spain's renewable sector expands with Enel's 90MW wind build activity, has signed a contract to complete the construction of the 110MW Cerro Dominador concentrated solar power (CSP) plant in Chile.
The consortium received notice to proceed to build the solar-thermal plant, which is part of the 210MW Cerro Dominador solar complex.
Under the contract, Acciona, which has 51% stake in the consortium and recently launched a 280 MW Alberta wind farm, will be responsible for building the plant while Abengoa will act as the technological partner.
Expected to be the first of its kind in Latin America upon completion, the plant is owned by Cerro Dominador, which in turn is owned by funds managed by EIG Global Energy Partners.
The project will add to a Abengoa-built 100MW PV plant, comparable to California solar projects in scope, which was commissioned in February 2018, to form a 210MW combined CSP and PV complex.
Spread across an area of 146 hectares, the project will feature 10,600 heliostats and will have capacity to generate clean and dispatachable energy for 24 hours a day using its 17.5 hours of molten salt storage technology, a field complemented by battery storage advances.
Expected to prevent 640,000 tons of CO2 emission, the plant is located in the commune of María Elena, in the Atacama Desert, in the Antofagasta Region.
“In total, the complex will avoid 870,000 tons of carbon dioxide emissions into the atmosphere every year and, in parallel with Enel's 450 MW U.S. wind operations, will deliver clean energy through 15-year energy purchase agreements with distribution companies, signed in 2014.
“The construction of the solarthermal plant of Cerro Dominador will have an important impact on local development, with the creation of more than 1,000 jobs in the area during its construction peak, and that will be priority for the neighbors of the communes of the region,” Acciona said in a statement.
The Cerro Dominador plant represents Acciona’s fifth solar thermal plant being built outside of Spain. The firm has constructed 10 solarthermal plants with total installed capacity of 624MW.
Acciona has been operating in Chile since 1993. The company, through its Infrastructure division, executed various construction projects for highways, hospitals, hydroelectric plants and infrastructures for the mining sector.
Downed Power Line Vehicle Safety: Follow stay-in-the-car protocol, call 911, avoid live wires and utility poles, and use the bunny hop to escape only for fire. Electrical hazards demand emergency response caution.
Key Points
Stay in the car, call 911, and use a bunny hop escape only if fire threatens during downed power line incidents.
✅ Stay in vehicle; tell bystanders to keep back and call 911.
✅ Exit only for fire; jump clear and bunny hop away.
✅ Treat all downed lines as live; avoid paths to ground.
Ameren Illinois and Safe Electricity are urging the public to stay in their cars and call 911 in the event of an accident involving a power pole that brings down power lines on or around the car.
In a media simulation Tuesday at the Ameren facility on West Lafayette Avenue, Ameren Illinois employees demonstrated the proper way to react if a power line has fallen on or around a vehicle, as some utilities consider on-site staffing measures during outbreaks. Although the situation might seem rare, Illinois motorists alone hit 3,000 power poles each year, said Krista Lisser, communications director for Safe Energy.
“We want to get the word out that, if you hit a utility pole and a live wire falls on your vehicle, stay in your car,” Lisser said. “Our first reaction is we panic and think we need to get out, a sign of the electrical knowledge gap many people have. That’s not the case, you need to stay in because, when that live wire comes down, electricity is all around you. You may not see it, it may not arc, it may not flash, you may not know if there’s electricity there.”
Should someoneinvolved in such an accident see a good Samaritan attempting to help, he should try to tell the would-be rescuer to stay back to prevent injury to the Samaritan, Ameren Illinois Communications Executive Brian Bretsch said.
“We have seen instances where someone comes up and wants to help you,” Bretsch said. “You want to yell, ‘Please stay away from the vehicle. Everyone is OK. Please stay away.’ You’ll see … instances every now and then where the Samaritan will come up, create that path to ground and get injured, and there are also climbers seeking social media glory who put themselves at risk.”
The only instance in which one should exit a car in the vicinity of a downed wire is if the vehicle is on fire and there is no choice but to exit. In that situation, those in the car should “bunny hop” out of the car by jumping from the car without touching the car and the ground at the same time, Bretsch and Lisser said.
After the initial jump, those escaping the vehicle should continue jumping with both feet together and hands tucked in and away from danger until they are safely clear of the downed wire.
It’s important for everyone to be informed, because an encounter with a live wire could easily result in serious injury, as in the Hydro One worker injury case, or death, Lisser said.
“They’re so close to our roads, especially in our rural communities, that it’s quite a common occurrence,” Lisser said. “Just stay away from (downed lines), especially after storms and amid grid oversight warnings that highlight reliability risks … Always treat a downed line as a live wire. Never assume the line is dead.”
Amur-Heihe ETL Power Supply Tripling will expand Russia-China electricity exports, extending 750 MW DC full-load hours to stabilize northeast China grids amid coal shortages, peak demand spikes, and cross-border energy security concerns.
Key Points
Russia will triple electricity via Amur-Heihe ETL, boosting 750 MW DC operations to relieve shortages in northeast China.
✅ 500 kV converter station increases full-load hours from 5 to 16
✅ Supports Heilongjiang, Liaoning, and Jilin grids amid coal shortfall
✅ Cross-border 750 MW DC link enhances reliability, peak demand coverage
Russia will triple electricity supplies via the Amur-Heihe electric transmission line (ETL) starting October 1, China Central Television has reported, a move seen within broader shifts in China's electricity sector by observers.
"Starting October 1, the overhead convertor substation of 500 kW (750 MW DC) will increase its daily time of operation with full loading from 5 to 16 hours per day," the TV channel said.
"This measure will make it possible to dramatically ease the situation with the electricity supply," the report said. Electricity from this converting station is used in three northeastern provinces of China - Heilongjiang, Liaoning and Jilin, while regional markets are strained as India rations coal supplies amid surging demand today. In 29 years, Russia supplied over 30 bln kilowatt hours of electricity, according to the channel.
The Amur-Heihe overhead transnational power line was constructed for increasing electricity exports to China, where projections see electricity to meet 60% of energy use by 2060 according to Shell. It was commissioned in 2012. Its maximum capacity is 750 MW.
China’s Jiemian News reported on September 27 that, amid nationwide power cuts affecting grids, 20 regions were limited in electricity supplies to a various extent due to the ongoing coal deficit. In particular, in China’s northeastern provinces, restrictions on power consumption were imposed not only on industrial enterprises, but also on households, as well as on office premises, raising concerns for U.S. solar supply chains among downstream manufacturers.
Later, China’s financial media Zhongxin Jingwei noted that the coal deficit had been triggered by price hikes brought on by tightened national environmental standards and efforts to reduce coal power production across the country. Reduced coal imports amid disruptions in the work of foreign suppliers due to the coronavirus pandemic was an additional reason, and earlier power demand drops as factories shuttered compounded imbalances.
US power grid modernization addresses aging infrastructure, climate resilience, extreme weather, EV demand, and clean energy integration, using AI, transmission upgrades, and resilient substations to improve reliability, reduce outages, and enable rapid recovery.
Key Points
US power grid modernization strengthens infrastructure for resilience, reliability, and clean energy under rising demand.
✅ Hardening substations, lines, and transformers against extreme weather
✅ Integrating EV load, DERs, and renewables into transmission and distribution
✅ Using AI, sensors, and automation to cut outages and speed restoration
The power grid in the U.S. is aging and already struggling to meet current demand, with dangerous vulnerabilities documented across the system today. It faces a future with more people — people who drive more electric cars and heat homes with more electric furnaces.
Alice Hill says that's not even the biggest problem the country's electricity infrastructure faces.
"Everything that we've built, including the electric grid, assumed a stable climate," she says. "It looked to the extremes of the past — how high the seas got, how high the winds got, the heat."
Hill is an energy and environment expert at the Council on Foreign Relations. She served on the National Security Council staff during the Obama administration, where she led the effort to develop climate resilience. She says past weather extremes can no longer safely guide future electricity planning.
"It's a little like we're building the plane as we're flying because the climate is changing right now, and it's picking up speed as it changes," Hill says.
The newly passed infrastructure package dedicates billions of dollars to updating the energy grid with smarter electricity infrastructure programs that aim to modernize operations. Hill says utility companies and public planners around the country are already having to adapt. She points to the storm surge of Hurricane Sandy in 2012.
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"They thought the maximum would be 12 feet," she says. "That storm surge came in close to 14 feet. It overcame the barriers at the tip of Manhattan, and then the electric grid — a substation blew out. The city that never sleeps [was] plunged into darkness."
Hill noted that Con Edison, the utility company providing New York City with energy, responded with upgrades to its grid: It buried power lines, introduced artificial intelligence, upgraded software to detect failures. But upgrading the way humans assess risk, she says, is harder.
"What happens is that some people tend to think, well, that last storm that we just had, that'll be the worst, right?" Hill says. "No, there is a worse storm ahead. And then, probably, that will be exceeded."
In 2021, the U.S. saw electricity outages for millions of people as a result of historic winter storms in Texas, a heatwave in the Pacific Northwest and Hurricane Ida along the Gulf Coast. Climate change will only make extreme weather more likely and more intense, driving longer, more frequent outages for utilities and customers.
In the West, California's grid reliability remains under scrutiny as the state navigates an ambitious clean energy shift.
And that has forced utility companies and other entities to grapple with the question: How can we prepare for blackouts and broader system stress we've never experienced before?
A modern power station in Maryland is built for the future In the town of Edgemere, Md., the Fitzell substation of Baltimore Gas and Electric delivers electricity to homes and businesses. The facility is only a year or so old, and Laura Wright, the director of transmission and substation engineering, says it's been built with the future in mind.
She says the four transformers on site are plenty for now. And to counter the anticipated demand of population growth and a future reliance on electric cars, she says the substation has been designed for an easy upgrade.
"They're not projecting to need that additional capacity for a while, but we designed this station to be able to take that transformer out and put in a larger one," Wright says.
Slopes were designed to insulate the substation from sea level rise. And should the substation experience something like a catastrophic flooding event or deadly tornado, there's a plan for that too.
"If we were to have a failure of a transformer," Wright says, "we can bring one of those mobile transformers into the substation, park it in the substation, connect it up in place of that transformer. And we can do that in two to three days."
The Fitzell substation is a new, modern complex. Older sites can be knocked down for weeks.
That raises the question: Can the amount of money dedicated to the power grid in the new infrastructure legislation actually make meaningful changes to the energy system across the country, where studies find more blackouts than other developed nations persist?
"The infrastructure bill, unfortunately, only scratches the surface," says Daniel Cohan, an associate professor in civil and environmental engineering at Rice University.
Though the White House says $65 billion of the infrastructure legislation is dedicated to power infrastructure, a World Resources Institute analysis noted that only $27 billion would go to the electric grid — a figure that Cohan also used.
"If you drill down into how much is there for the power grid, it's only about $27 billion or so, and mainly for research and demonstration projects and some ways to get started," he says.
Cohan, who is also author of the forthcoming book Confronting Climate Gridlock, says federal taxpayer dollars can be significant but that most of the needed investment will eventually come from the private sector — from utility companies and other businesses spending "many hundreds of billions of dollars per decade," even as grid modernization affordability remains a concern. He also says the infrastructure package "misses some opportunities" to initiate that private-sector action through mandates.
"It's better than nothing, but, you know, with such momentous challenges that we face, this isn't really up to the magnitude of that challenge," Cohan says.
Cohan argues that thinking big, and not incrementally, can pay off. He believes a complete transition from fossil fuels to clean energy by 2035 is realistic and attainable — a goal the Biden administration holds — and could lead to more than just environmental benefit.
"It also can lead to more affordable electricity, more reliable electricity, a power supply that bounces back more quickly when these extreme events come through," he says. "So we're not just doing it to be green or to protect our air and climate, but we can actually have a much better, more reliable energy supply in the future."
Siwash Creek Hydroelectric Project faces downsizing under a BC Hydro power purchase agreement, with run-of-river generation, high grid interconnection costs, First Nations partnership, and surplus electricity from Site C reshaping clean energy procurement.
Key Points
A downsized run-of-river plant in BC, co-owned by Kanaka Bar and Green Valley, selling power via a BC Hydro PPA.
✅ Approved at 500 kW under a BC Hydro clean-energy program
✅ Grid interconnection initially quoted at $2.1M
✅ Joint venture: Kanaka Bar and Green Valley Power
A small run-of-river hydroelectric project recently selected by B.C. Hydro for a power purchase agreement may no longer be financially viable.
The Siwash Creek project was originally conceived as a two-megawatt power plant by the original proponent Chad Peterson, who holds a 50-per-cent stake through Green Valley Power, with the Kanaka Bar Indian Band holding the other half.
The partners were asked by B.C. Hydro to trim the capacity back to one megawatt, but by the time the Crown corporation announced its approval, it agreed to only half that — 500 kilowatts — under its Standing Order clean-energy program.
“Hydro wanted to charge us $2.1 million to connect to the grid, but then they said they could reduce it if we took a little trim on the project,” said Kanaka Bar Chief Patrick Michell.
The revenue stream for the band and Green Valley Power has been halved to about $250,000 a year. The original cost of running the $3.7-million plant, including financing, was projected to be $273,000 a year, according to the Kanaka Bar economic development plan.
“By our initial forecast, we will have to subsidize the loan for 20 years,” said Michell. “It doesn’t make any sense.”
The Kanaka Band has already invested $450,000 in feasibility, hydrology and engineering studies, with a similar investment from Green Valley.
B.C. Hydro announced it would pursue five purchase agreements last March with five First Nations projects — including Siwash Creek — including hydro, solar and wind energy projects, as two new generating stations were being commissioned at the time. A purchase agreement allows proponents to sell electricity to B.C. Hydro at a set price.
However, at least ten other “shovel-ready” clean energy projects may be doomed while B.C. Hydro completes a review of its own operations and its place in the energy sector, where legal outcomes like the Squamish power project ruling add uncertainty, including B.C.’s future power needs.
With the 1,100-megawatt Site C Dam planned for completion in 2024, and LNG demand cited to justify it, B.C. Hydro now projects it will have a surplus of electricity until the early 2030s.
Even if British Columbians put 300,000 electric vehicles on the road over the next 12 years, amid BC Hydro’s first call for power, they will require only 300 megawatts of new capacity, the company said.
A long-term surplus could effectively halt all small-scale clean energy development, according to Clean Energy B.C., even as Hydro One’s U.S. coal plant remains online in the region.
“(B.C. Hydro) dropped their offer down to 500 kilowatts right around the time they announced their review,” said Michell. “So we filled out the paperwork at 500 kilowatts and (B.C. Hydro) got to make its announcement of five projects.”
In the new few weeks, Kanaka and Green Valley will discuss whether they can move forward with a new financial model or shelve the project, he said.
B.C. Hydro declined to comment on the rationale for downsizing Siwash Creek’s power purchase agreement.
The Kanaka Bar Band successfully operates a 49.9-megawatt run-of-river plant on Kwoiek Creek with partners Innergex Renewable Energy.
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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