Ontario's electricity transmission giant is launching the largest expansion to the province's transmission system in 20 years that will give it access to enough electricity to power about 1.5 million homes by 2011.
Hydro One said it will spend $600 million to expand the transmission system between the Bruce power plant and a switching station in Milton.
Energy Minister Dwight Duncan said today that the expansion will help boost the province's accessible renewable and nuclear electricity supply from the Bruce region by 3,000 megawatts.
The new line will help the province tap into renewable energy projects underway in the region, as well as into two nuclear reactors at Bruce Power which are scheduled to go online in 2009.
"It gives us a real opportunity for a lot more cleaner, greener power that will be emissions-free," he said. "This is the largest transmission project we've done in 20 years."
The 180-kilometre expansion, which is still subject to environmental assessments and the approval of the Ontario Energy Board, is expected to be completed by December 2011.
The plan also affects about 400 properties along the 180-kilometre corridor but Duncan said only 30 of those are impacted in a "profound way."
"It's already along an existing hydro corridor," he said, adding consultations with landowners will begin shortly.
Shawn-Patrick Stensil, energy campaigner with Greenpeace, said the province has left itself little wiggle room to complete the transmission line.
According to documents obtained by Stensil under a freedom of information request, the government signed a deal with Bruce Power which could leave taxpayers on the hook for $1 billion in penalties.
"The government signed this deal... knowing they didn't have enough transmission capacity," he said. "There is no saying they're going to do it in time."
With tight deadlines, Stensil said the government will likely skimp on much-needed public consultations.
The government said the new transmission lines will carry clean, renewable energy, but Stensil said it will primarily transmit nuclear-generated power to the Toronto area.
Acting CEO Laura Formusa said in a statement that Hydro One "is sensitive to concerns of property owners, aboriginal communities, local municipalities and stakeholders impacted by the project."
"(We) will work to ensure that we manage their concerns in a manner that is fair and responsible," she said.
The announcement comes the same day as the Ontario Power Authority recommended Hydro One move forward with the expansion.
In a report last fall, the authority said a new line was required to tap into the increased energy production from the Bruce region.
Canada Tariffs on U.S. Energy and Minerals signal retaliatory tariffs amid trade tensions, targeting energy exports and critical minerals, reflecting sovereignty concerns and shifting consumer behavior, reduced U.S. purchases, and demand for Canadian-made goods.
Key Points
They are proposed retaliatory tariffs on energy exports and critical minerals to counter U.S. trade pressures.
✅ 75% support tariffs; 70% back dollar-for-dollar retaliation
✅ Consumer shift: fewer U.S. purchases, more Canadian-made goods
✅ Concerns over sovereignty and U.S. trade tactics intensify
A recent survey has revealed that a significant majority of Canadians—approximately 75%—support the implementation of tariffs on energy exports and critical minerals in response to electricity exports at risk amid trade tensions with the United States. This finding underscores the nation's readiness to adopt assertive measures to protect its economic interests amid escalating trade disputes.
Background on Trade Tensions
The trade relationship between Canada and the United States has experienced fluctuations in recent years, with both nations navigating complex issues related to tariffs and energy tariffs and trade tensions as well as trade agreements and economic policies. The introduction of tariffs has been a contentious strategy, often leading to reciprocal measures and impacting various sectors of the economy.
Public Sentiment Towards Retaliatory Tariffs
The survey, conducted by Leger between February 14 and 17, 2025, sampled 1,500 Canadians and found that 70% favored implementing dollar-for-dollar retaliatory tariffs against the U.S. Notably, 45% of respondents were strongly in favor, while 25% were somewhat in favor. This strong support reflects widespread dissatisfaction with U.S. trade policies and growing support for Canadian energy projects among voters, alongside a collective sentiment favoring decisive action.
Concerns Over U.S. Economic Strategies
The survey also highlighted that 81% of Canadians are apprehensive about potential U.S. economic tactics aimed at drawing Canada into a closer political union. These concerns are fueled by statements from U.S. President Donald Trump, who has suggested annexation and employed tariffs that could spike NY energy prices to influence Canadian sovereignty. Such sentiments have heightened fears about the erosion of Canada's political autonomy under economic duress.
Impact on Consumer Behavior
In response to these trade tensions, including reports that Ford threatened to cut U.S. electricity exports, many Canadians have adjusted their purchasing habits. The survey indicated that 63% of respondents are buying fewer American products in stores, and 62% are reducing online purchases from U.S. retailers. Specific declines include a 52% reduction in Amazon purchases, a 50% drop in fast-food consumption from American chains, and a 43% decrease in spending at U.S.-based retail stores. Additionally, 30% of Canadians have canceled planned trips to the United States, while 68% have increased their purchases of Canadian-made products. These shifts demonstrate a tangible impact on consumer behavior driven by nationalistic sentiments and support for retaliatory measures.
Economic and Political Implications
The widespread support for retaliatory tariffs and the corresponding changes in consumer behavior have significant economic and political implications. Economically, while tariffs can serve as a tool for asserting national interests, they also risk triggering trade wars that can harm various sectors, including agriculture, manufacturing, and technology, with experts cautioning against cutting Quebec's energy exports in response. Politically, the situation presents a challenge for Canadian leadership to balance assertiveness in defending national interests with the necessity of maintaining a stable and mutually beneficial relationship with the U.S., Canada's largest trading partner.
As Canada approaches its federal elections, trade policy is emerging as a pivotal issue. Voters are keenly interested in how political parties propose to navigate the complexities of international trade, particularly with the United States and how a potential U.S. administration's stance, such as Biden's approach to the energy sector could shape outcomes. The electorate's strong stance on retaliatory tariffs may influence party platforms and campaign strategies, emphasizing the need for clear and effective policies that address both the immediate concerns of trade disputes and the long-term goal of sustaining positive international relations.
The survey results reflect a nation deeply engaged with its trade dynamics and protective of its sovereignty. While support for retaliatory tariffs is robust, it is essential for policymakers to carefully consider the broader consequences of such actions. Striking a balance between defending national interests and fostering constructive international relationships will be crucial as Canada navigates these complex trade challenges in the coming years.
Bruce Power Capacity Uprate boosts nuclear output through generator stator upgrades, turbine and transformer enhancements, and cooling pump improvements at Bruce A and B, unlocking megawatts and efficiency gains from legacy heavy water design capacity.
Key Points
Upgrades that raise Bruce Power capacity via stator, turbine, transformer, and cooling enhancements.
Bruce Power’s Unit 3 nuclear reactor will squeeze out an extra 22 megawatts of electricity, thanks to upgrades during its recent planned outage for refurbishment.
Similar gains are anticipated at its three sister reactors at Bruce A generating station, which presents the opportunity for the biggest efficiency gains and broader economic benefits for Ontario, due to a design difference over Bruce B’s four reactors, Bruce Power spokesman John Peevers said.
Bruce A reactor efficiency gains stem mainly from the fact Bruce A’s non-nuclear side, including turbines and the generator, was sized at 88 per cent of the nuclear capacity, Peevers said, while early Bruce C exploration work advances.
This allowed 12 per cent of the energy, in the form of steam, to be used for heavy water production, which was discontinued at the plant years ago. Heavy water, or deuterium, is used to moderate the reactors.
That design difference left a potential excess capacity that Bruce Power is making use of through various non-nuclear enhancements. But the nuclear operator, which also made major PPE donations during the pandemic, will be looking at enhancements at Bruce B as well, Peevers said.
Bruce Power’s efficiency gain came from “technology advancements,” including a “generator-stator improvement project that was integral to the uprate,” and contributed to an operating record at the site, a Bruce Power news release said July 11.
Peevers said the stationary coils and the associated iron cores inside the generator are referred to as the stator. The stator acts as a conductor for the main generator current, while the turbine provides the mechanical torque on the shaft of the generator.
“Some of the other things we’re working on are transformer replacement and cooling pump enhancements, backed by recent manufacturing contracts, which also help efficiency and contribute to greater megawatt output,” Peevers said.
The added efficiency improvements raised the nuclear operator’s peak generating capacity to 6,430 MW, as projects like Pickering life extensions continue across Ontario.
EU Power Market Overhaul targets soaring electricity prices by decoupling gas from power, boosting renewables, refining price caps, and stabilizing grids amid inflation, supply shocks, droughts, nuclear outages, and intermittent wind and solar.
Key Points
EU plan to redesign electricity pricing, curb gas-driven costs, boost renewables, and protect consumers from volatility.
✅ Decouples power prices from marginal gas generation
✅ Caps non-gas revenues to fund consumer relief
✅ Supports grid stability with storage, demand response, LNG
While energy prices are soaring around the world, Europe is in a particularly tight spot. Its heavy dependence on Russian gas -- on top of droughts, heat waves, an unreliable fleet of French nuclear reactors and a continent-wide shift to greener but more intermittent sources like solar and wind -- has been driving electricity bills up and feeding the highest inflation in decades. As Europe stands on the brink of a recession, and with the winter heating season approaching, officials are considering a major overhaul of the region’s power market to reflect the ongoing shift from fossil fuels to renewables.
1. How is electricity priced? Unlike oil or natural gas, there’s no efficient way to save lots of electricity to use in the future, though projects to store electricity in gas pipes are emerging. Commercial use of large-scale batteries is still years away. So power prices have been set by the availability at any given moment. When it’s really windy or sunny, for example, then more is produced relatively cheaply and prices are lower. If that supply shrinks, then prices rise because more generators are brought online to help meet demand -- fueled by more expensive sources. The way the market has long worked is that it is that final technology, or type of plant, needed to meet the last unit of consumption that sets the price for everyone. In Europe this year, that has usually meant natural gas.
2. What is the relationship between power and gas? Very close. Across western Europe, gas plants have been a vital part of the energy infrastructure for decades, with Irish price spikes highlighting dispatchable power risks, fed in large part by supplies piped in from Siberia. Gas-fired plants were relatively quick to build and the technology straightforward, at least compared with nuclear plants and burns cleaner than coal. About 18% of Europe’s electricity was generated at gas plants last year; in 2020 about 43% of the imported gas came from Russia. Even during the depths of the Cold War, there’d never been a serious supply problem -- until the relationship with Russia deteriorated this year after it invaded Ukraine. Diversifying away from Russia, such as by increasing imports of liquefied natural gas, requires new infrastructure that takes a lot of time and money.
3. Why does it work this way? In theory, the relationship isn’t different from that with coal, for example. But production hiccups and heatwave curbs on plants from nuclear in France to hydro in Spain and Norway significantly changed the generation picture this year, and power hit records as plants buckled in the heat. Since coal-fired and nuclear plants are generally running all the time anyway, gas plants were being called upon more often -- at times just to keep the lights on as summer temperatures hit records. And with the war in Ukraine resulting in record gas prices, that pushed up overall production costs. It’s that relationship that has made the surging gas price the driver for electricity prices. And since the continent is all connected, it has pushed up prices across the region. The value of the European power market jumped threefold last year, to a record 836 billion euros ($827 billion today).
4. What’s being considered? With large parts of European industry on its knees and households facing jumps in energy bills of several hundred percent, as record electricity prices ripple through markets, the pressure on governments and the European Union to intervene has never been higher. One major proposal is to impose a price cap on electricity from non-gas producers, with the difference between that and the market price channeled to relief for consumers. While it sounds simple, any such changes would rip up a market design that’s worked for decades and could threaten future investments because of unintended consequences.
5. How did this market evolve? The Nordic region and the British market were front-runners in the 1990s, then Germany followed and is now the largest by far. A trader can buy and sell electricity delivered later on same day in blocks of an hour or even down to 15-minute periods, to meet sudden demand or take advantage of price differentials. The price for these contracts is decided entirely by the supply and demand, how much the wind is blowing or which coal plants are operating, for example. Demand tends to surge early in the morning and late afternoon. This system was designed when fossil fuels provided the bulk of power. Now there are more renewables, which are less predictable, with wind and solar surpassing gas in EU generation last year, and the proposed changes reflect that shift.
6. What else have governments done? There are also traders who focus on longer-dated contracts covering periods several years ahead, where broader factors such as expected economic output and the extent to which renewables are crowding out gas help drive prices. This year’s wild price swings have prompted countries including Germany, Sweden and Finland to earmark billions of euros in emergency liquidity loans to backstop utilities hit with sudden margin calls on their trading.
Illinois Zero Emission Credits support nuclear plants via tradable credits tied to wholesale electricity prices, carbon costs, created by the Future Energy Jobs Bill to avert Exelon closures and sustain low-carbon power.
Key Points
State credits that value nuclear power's zero-carbon output, priced by market and carbon metrics to keep plants running.
✅ Pegged to wholesale prices, carbon costs, and state averages.
✅ Created by Future Energy Jobs Bill to prevent plant retirements.
✅ Supports Exelon Quad Cities and Clinton nuclear facilities.
Nuclear plants have produced over half of Illinois electricity generation since 2010, but the states two largest plants would have been retired amid the debate over saving nuclear plants if the state had not created a zero emission credit (ZEC) mechanism to support the facilities.
The two plants, Quad Cities and Clinton, collectively delivered more than 12 percent of the states electricity generation over the past several years. In May 2016, however, Exelon, the owner of the plants, announced that they had together lost over $800 million dollars over the previous six years and revealed plans to retire them in 2017 and 2018, similar to the Three Mile Island closure later announced for 2019 by its owner.
In December 2016, Illinois passed the Future Energy Jobs Bill, which established a zero emission credit (ZEC) mechanism
to support the plants financially. Exelon then cancelled its plans to retire the two facilities.
The ZEC is a tradable credit that represents the environmental attributes of one megawatt-hour of energy produced from the states nuclear plants. Its price is based on a number of factors that include wholesale electricity market prices, nuclear generation costs, state average market prices, and estimated costs of the long-term effects of carbon dioxide emissions.
The bill is set to take effect in June, but faces multiple court challenges as some utilities have expressed concerns that the ZEC violates the commerce clause and affects federal authority to regulate wholesale energy prices, amid gas-fired competition in nearby markets that shapes the revenue outlook.
Illinois ranks first in the United States for both generating capacity and net electricity generation from nuclear power, a resource many see as essential for net-zero emissions goals, and accounts for approximately one-eighth of the nuclear power generation in the nation.
UK Wind and Tidal Power Auction signals strong CfD support for offshore wind, tidal stream projects, investor certainty, and clean electricity, accelerating the net-zero transition, boosting jobs, and strengthening UK energy security and grid integration.
Key Points
A CfD auction awarding contracts for wind and tidal projects to scale clean power and advance UK net-zero.
✅ Jobs, investment, and grid integration accelerate
In a significant development for the UK’s renewable energy sector, the latest auction for renewable energy contracts has underscored a transformative shift towards wind and tidal power. As reported by The Guardian, the auction results reveal a strong commitment to expanding these technologies, with new contracts adding 10 GW to the UK grid, marking a pivotal moment in the UK’s transition to cleaner energy sources.
The Auction’s Impact
The renewable energy auction, which took place recently, has allocated contracts for a substantial increase in wind and tidal power projects. This auction, part of the UK’s Contracts for Difference (CfD) scheme, is designed to support the development of low-carbon energy technologies by providing financial certainty to investors. By offering fixed prices for the electricity generated by these projects, the CfD scheme aims to stimulate investment and accelerate the deployment of renewable energy sources.
The latest results are particularly notable for the significant share of contracts awarded to offshore wind farms and tidal power projects, highlighting how offshore wind is powering up the UK as policy and investment priorities continue to shift. This marks a shift from previous auctions, where solar power and onshore wind were the dominant technologies. The move towards supporting offshore wind and tidal power reflects the UK’s strategic focus on harnessing its abundant natural resources to drive the transition to a low-carbon energy system.
Offshore Wind Power: A Major Contributor
Offshore wind power has emerged as a major player in the UK’s renewable energy landscape, within a global market projected to become a $1 trillion business over the coming decades. The recent auction results highlight the continued growth and investment in this sector.
The UK has been a global leader in offshore wind development, with several large-scale projects already operational and more in the pipeline. The auction has further cemented this position, underscoring what the U.S. can learn from the U.K. in scaling offshore wind capacity, with new projects set to contribute significantly to the country’s renewable energy capacity. These projects are expected to deliver substantial amounts of clean electricity, supporting the UK’s goal of achieving net-zero emissions by 2050.
Tidal Power: An Emerging Frontier
Tidal power, although less developed compared to wind and solar, is gaining momentum as a promising renewable energy source, with companies harnessing oceans and rivers to demonstrate practical potential. The auction results have allocated contracts to several tidal power projects, signaling growing recognition of the potential of this technology.
Tidal power harnesses the energy from tidal movements and currents, which are highly predictable and consistent, and a market outlook for wave and tidal energy points to emerging growth drivers and investment. This makes it a reliable complement to intermittent sources like wind and solar power. The inclusion of tidal power projects in the auction reflects the UK’s commitment to diversifying its renewable energy portfolio and exploring all available options for achieving energy security and sustainability.
Economic and Environmental Benefits
The expansion of wind and tidal power projects through the recent auction offers numerous economic and environmental benefits. From an economic perspective, these projects are expected to create thousands of jobs in construction, maintenance, and manufacturing. They also stimulate investment in local economies and support the growth of the green technology sector.
Environmentally, the increased deployment of wind and tidal power contributes to significant reductions in greenhouse gas emissions. Offshore wind farms and tidal power projects produce clean electricity with minimal environmental impact, helping to mitigate the effects of climate change and improve air quality.
Challenges and Future Outlook
Despite the positive outcomes of the auction, there are challenges to address. Offshore wind farms and tidal power projects require substantial upfront investment and face technical and logistical challenges. Issues such as grid integration, environmental impact assessments, and supply chain constraints need to be carefully managed to ensure the successful deployment of these projects.
Looking ahead, the UK’s renewable energy strategy will continue to evolve as new technologies and innovations emerge, and growth despite Covid-19 underscores sector resilience. The success of the latest auction demonstrates the growing confidence in wind and tidal power and sets the stage for further advancements in renewable energy.
The UK government’s commitment to supporting these technologies through initiatives like the CfD scheme is crucial for achieving long-term energy and climate goals. As the country progresses towards its net-zero target, the continued expansion of wind and tidal power will play a key role in shaping a sustainable and resilient energy future.
Conclusion
The latest renewable energy auction represents a significant milestone in the UK’s transition to a low-carbon energy system. By awarding contracts to wind and tidal power projects, the auction underscores the country’s commitment to harnessing diverse and reliable sources of renewable energy. The expansion of offshore wind and the emerging role of tidal power highlight the UK’s strategic approach to achieving energy security, reducing emissions, and driving economic growth. As the renewable energy sector continues to evolve, the UK remains at the forefront of global efforts to build a sustainable and clean energy future.
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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