A better budget will mean buried utility lines on Cumberland Avenue.
The city of Knoxville announced that it will put overhead electrical transmission lines underground, rather than moving them into the alleys bordering Cumberland, when it begins construction on the Cumberland Avenue Corridor Project.
"We were looking at relocating above ground in the alley because at the time it was the least expensive option that accomplished our goal of removing the poles and wires from Cumberland," said Anne Wallace, the city's Cumberland Avenue project manager. "We felt like the cost of burying the lines could be somewhat prohibitive."
Wallance added that the alleys already had overhead electrical lines.
Initially, the city estimated that it would cost $1.2 million more to bury the lines than to relocate them, but "we had more in the budget to move the utilities than we expected," Wallace said.
The design also includes a three-lane cross section of traffic with a shared eastbound bike/travel lane, a two-way left-turn lane and wider sidewalks without utility poles. Knoxville Utilities Board said it will make improvements to gas, sewer and water lines in conjunction with the project.
DOE RMUC Cybersecurity Program supports rural, municipal, and small investor-owned utilities with grants, technical assistance, grid resilience, incident response, workforce training, and threat intelligence sharing to harden energy systems and protect critical infrastructure.
Key Points
A $250M DOE program providing grants to boost rural and municipal utilities' cybersecurity and incident response.
✅ Grants and technical assistance for grid security
✅ Enhances incident response and threat intel sharing
✅ Builds cybersecurity workforce in rural utilities
The U.S. Department of Energy (DOE) today issued a Request for Information (RFI) seeking public input on a new $250 million program to strengthen the cybersecurity posture of rural, municipal, and small investor-owned electric utilities.
Funded by President Biden’s Bipartisan Infrastructure Law and broader clean energy funding initiatives, the Rural and Municipal Utility Advanced Cybersecurity Grant and Technical Assistance (RMUC) Program will help eligible utilities harden energy systems, processes, and assets; improve incident response capabilities; and increase cybersecurity skills in the utility workforce. Providing secure, reliable power to all Americans, with a focus on equity in electricity regulation across communities, will be a key focus on the pathway to achieving President Biden’s goal of a net-zero carbon economy by 2050.
“Rural and municipal utilities provide power for a large portion of low- and moderate-income families across the nation and play a critical role in ensuring the economic security of our nation’s energy supply,” said U.S. Secretary of Energy Jennifer M. Granholm. “This new program reflects the Biden Administration's commitment to improving energy reliability and connecting our nation’s rural communities to resilient energy infrastructure and the transformative benefits that come with it.”
Nearly one in six Americans live in a remote or rural community. Utilities in these communities face considerable obstacles, including difficulty recruiting top cybersecurity talent, inadequate infrastructure, as the aging U.S. power grid struggles to support new technologies, and lack of financial resources needed to modernize and harden their systems.
The RMUC Program will provide financial and technical assistance to help rural, municipal, and small investor-owned electric utilities improve operational capabilities, increase access to cybersecurity services, deploy advanced cyber security technologies, and increase participation of eligible entities in cybersecurity threat information sharing programs and coordination with federal partners initiatives. Priority will be given to eligible utilities that have limited cybersecurity resources, are critical to the reliability of the bulk power system, or those that support our national defense infrastructure.
The Office of Cybersecurity, Energy Security, and Emergency Response (CESER), which advances U.S. energy security objectives, will manage the RMUC Program, providing $250 million dollars in BIL funding over five years. To help inform Program implementation, DOE is seeking input from the cybersecurity community, including eligible utilities and representatives of third parties and organizations that support or interact with these utilities. The RFI seeks input on ways to improve cybersecurity incident preparedness, response, and threat information sharing; cybersecurity workforce challenges; risks associated with technologies deployed on the electric grid; national-scale initiatives to accelerate cybersecurity improvements in these utilities; opportunities to strengthen partnerships and energy security support efforts; the selection criteria and application process for funding awards; and more.
Pickering Nuclear False Alert Investigation probes Ontario's emergency alert system after a provincewide cellphone, radio, and TV warning, assessing human error, Pelmorex safeguards, Emergency Management Ontario oversight, and communication delays.
Key Points
An Ontario probe into the erroneous Pickering nuclear alert, focusing on human error, system safeguards, and oversight.
✅ Human error during routine testing suspected
✅ Pelmorex safeguards and EMO protocols under review
✅ Two-hour all-clear delay prompts communication fixes
An investigation into a mistaken Pickering alert warning of an incident at the Pickering Nuclear Generating Station will be completed fairly quickly, Ontario's solicitor general said.
Sylvia Jones tapped the chief of Emergency Management Ontario to investigate how the alert warning of an unspecified problem at the facility was sent in error to cellphones, radios and TVs across the province at about 7:30 a.m. Sunday.
"It's very important for me, for the people of Ontario, to know exactly what happened on Sunday morning," said Jones. "Having said that, I do not anticipate this is going to be a long, drawn-out investigation. I want to know what happened and equally important, I want some recommendations on insurances and changes we can make to the system to make sure it doesn't happen again."
Initial observations suggest human error was responsible for the alert that was sent out during routine tests of the emergency alert, Jones said.
"This has never happened in the history of the tests that they do every day, twice a day, but I do want to know exactly all of the issues related to it, whether it was one human error or whether it was a series of things."
Martin Belanger, the director of public alerting for Pelmorex, a company that operates the alert system, said there are a number of safeguards built in, including having two separate platforms for training and live alerts.
"The software has some steps and some features built in to minimize that risk and to make sure that users will be able to know whether or not they're sending an alert through the...training platform or whether they're accessing the live system in the case of a real emergency," he said.
Only authorized users have access to the system and the province manages that, Belanger said. Once in the live system, features make the user aware of which platform they are using, with various prompts and messages requiring the user's confirmation. There is a final step that also requires the user to confirm their intent of issuing an alert to cellphones, radio and TVs, Belanger said.
On Sunday, a follow-up alert was sent to cellphones nearly two hours after the original notification, and similar grid alerts in Alberta underscore timing and public expectations.
NDP energy critic Peter Tabuns is critical of that delay, noting that ongoing utility scam warnings can further erode public trust.
"That's a long time for people to be waiting to find out what's really going on," he said. "If people lose confidence in this system, the ability to use it when there is a real emergency will be impaired. That's dangerous."
Treasury Board President Peter Bethlenfalvy, who represents the riding of Pickering-Uxbridge, said getting that alert Sunday morning was "a shock to the system," and he too wants the investigation to address the reason for the all-clear delay.
"We all have a lot of questions," he said. "I think the public has every right to know exactly what went on and we feel exactly the same way."
People in the community know the facility is safe, Bethlenfalvy said.
"We have some of the safest nuclear assets in the world -- the safest -- at 60 per cent of Ontario's electricity," he said.
A poll released Monday found that 82 per cent of Canadians are concerned about spills from nuclear reactors contaminating drinking water and 77 per cent are concerned about neighbourhood safety and security risks for those living close to nuclear plants. Oraclepoll Research surveyed 2,094 people across the country on behalf of Friends of the Earth between Jan. 2 and 12, the day of the false alert. The have a margin of error of plus or minus 2.1 per cent, 19 times out of 20.
The wording of Sunday's alert caused much initial confusion, and events like a power outage in London show how morning disruptions can amplify concern, warning residents within 10 kilometres of the plant of "an incident," though there was no "abnormal" release of radioactivity and residents didn't need to take protective steps, but emergency crews were responding.
In the event of a real emergency, the wording would be different, Jones said.
"There are a number of different alerts that are already prepared and are ready to go," she said. "We have the ability to localize it to the communities that are impacted, but because this was a test, it went provincewide."
Jones said she expects the results of the probe to be made public.
The Pickering nuclear plant has been operating since 1971, and had been scheduled to be decommissioned this year, but the former Liberal government -- and the current Progressive Conservative government -- committed to keeping it open until 2024. Decommissioning is now set to start in 2028.
It operates six CANDU reactors, generates 14 per cent of Ontario's electricity and is responsible for 4,500 jobs across the region, according to OPG, and OPG's credit rating remains stable.
During the COVID-19 pandemic, Hydro One employees supported the Province of Ontario in the fight against COVID-19.
The Green party is calling on the province to use this opportunity to review its nuclear emergency response plan, including pandemic staffing contingencies, last updated in 2017 and subject to review every five years.
Toronto Mayor John Tory praised Ontario for swiftly launching an investigation, but said communication between city and provincial officials wasn't what it should have been under the circumstances.
"It was a poor showing and I think everybody involved knows that," he said. "We've got to make sure it's not repeated."
U.S. Energy Transition traces the shift from coal and oil to natural gas, nuclear power, and renewables like wind and solar, driven by efficiency, grid modernization, climate goals, and economic innovation.
Key Points
The U.S. Energy Transition is the shift from fossil fuels to cleaner power, driven by tech, policy, and markets.
✅ Shift from coal and oil to gas, nuclear, wind, and solar
✅ Enabled by grid modernization, storage, and efficiency
✅ Aims to cut emissions while ensuring reliability and affordability
The evolution of energy use in the United States is a dynamic narrative that reflects technological advancements, economic shifts, environmental awareness, and societal changes over time. From the nation's early reliance on wood and coal to the modern era dominated by oil, natural gas, and renewable sources, the story of energy consumption in the U.S. is a testament to innovation and adaptation.
Early Energy Sources: Wood and Coal
In the early days of U.S. history, energy needs were primarily met through renewable resources such as wood for heating and cooking. As industrialization took hold in the 19th century, coal emerged as a dominant energy source, fueling steam engines and powering factories, railways, and urban growth. The widespread availability of coal spurred economic development and shaped the nation's infrastructure.
The Rise of Petroleum and Natural Gas
The discovery and commercialization of petroleum in the late 19th century transformed the energy landscape once again. Oil quickly became a cornerstone of the U.S. economy, powering transportation, industry, and residential heating, and informing debates about U.S. energy security in policy circles. Concurrently, natural gas emerged as a significant energy source, particularly for heating and electricity generation, as pipelines expanded across the country.
Electricity Revolution
The 20th century witnessed a revolution in electricity generation and consumption, and understanding where electricity comes from helps contextualize how systems evolved. The development of hydroelectric power, spurred by projects like the Hoover Dam and Tennessee Valley Authority, provided clean and renewable energy to millions of Americans. The widespread electrification of rural areas and the proliferation of appliances in homes and businesses transformed daily life and spurred economic growth.
Nuclear Power and Energy Diversification
In the mid-20th century, nuclear power emerged as a promising alternative to fossil fuels, promising abundant energy with minimal greenhouse gas emissions. Despite concerns about safety and waste disposal, nuclear power plants became a significant part of the U.S. energy mix, providing a stable base load of electricity, even as the aging U.S. power grid complicates integration of variable renewables.
Renewable Energy Revolution
In recent decades, the U.S. has seen a growing emphasis on renewable energy sources such as wind, solar, and geothermal power, yet market shocks and high fuel prices alone have not guaranteed a rapid green revolution, prompting broader policy and investment responses. Advances in technology, declining costs, and environmental concerns have driven investments in clean energy infrastructure and policies promoting renewable energy adoption. States like California and Texas lead the nation in wind and solar energy production, demonstrating the feasibility and benefits of transitioning to sustainable energy sources.
Energy Efficiency and Conservation
Alongside shifts in energy sources, improvements in energy efficiency and conservation have played a crucial role in reducing per capita energy consumption and greenhouse gas emissions. Energy-efficient appliances, building codes, and transportation innovations have helped mitigate the environmental impact of energy use while reducing costs for consumers and businesses, and weather and economic factors also influence demand; for example, U.S. power demand fell in 2023 on milder weather, underscoring the interplay between efficiency and usage.
Challenges and Opportunities
Looking ahead, the U.S. faces both challenges and opportunities in its energy future, as recent energy crisis effects ripple across electricity, gas, and EVs alike. Addressing climate change requires further investments in renewable energy, grid modernization, and energy storage technologies. Balancing energy security, affordability, and environmental sustainability remains a complex task that requires collaboration between government, industry, and society.
Conclusion
The evolution of energy use throughout U.S. history reflects a continuous quest for innovation, economic growth, and environmental stewardship. From wood and coal to nuclear power and renewables, each era has brought new challenges and opportunities in meeting the nation's energy needs. As the U.S. transitions towards a cleaner and more sustainable energy future, leveraging technological advancements and embracing policy solutions, amid debates over U.S. energy dominance, will be essential in shaping the next chapter of America's energy story.
Ukraine Winter Energy Resilience focuses on energy security, grid repairs, renewable power, EU support, heating reliability, electricity imports, and conservation measures to stabilize infrastructure and protect households amid conflict and severe cold.
Key Points
A strategy to secure heat and power via repairs, renewables, imports, and conservation during wartime winter.
✅ Grid repairs and hardening of power plants and transmission lines
✅ Public conservation to cut peak demand and safeguard essential services
As winter approaches, Ukraine is bracing for a challenging season, especially in the energy sector amid global energy instability and price pressures, which has been heavily impacted by the ongoing conflict with Russia. With the weather forecast predicting colder temperatures, the Ukrainian government is ramping up efforts to secure energy supplies and bolster infrastructure, aiming to ensure that citizens have access to heating and electricity during the harsh months ahead.
The Energy Landscape in Ukraine
The conflict has severely disrupted Ukraine’s energy infrastructure, leading to widespread damage and inefficiencies. Key facilities, including power plants and transmission lines, have been targeted amid energy ceasefire violations reported by both sides, resulting in significant energy shortages. As a response, the government has implemented a series of measures aimed at stabilizing the energy sector, ensuring that the nation can withstand the winter months.
One of the primary strategies has been the repair and reinforcement of energy infrastructure. Officials have prioritized critical facilities that are essential for electricity generation and distribution. Emergency repairs and upgrades are being carried out to restore functionality and improve resilience against potential attacks.
In addition to repairing existing infrastructure, Ukraine is actively seeking to diversify its energy sources. This includes increasing reliance on renewable energy, such as wind and solar, which can be less susceptible to disruption. The shift toward renewables not only enhances energy security and supports moving away from fossil fuels in line with Ukraine's long-term environmental goals.
International Support and Collaboration
Ukraine's challenges have not gone unnoticed on the international stage. Countries and organizations around the world have pledged energy security support to help Ukraine fortify its energy sector. This assistance includes financial aid, technical expertise, and the provision of materials needed for infrastructure repairs.
The European Union, in particular, has been a key ally, providing both immediate and long-term support to Ukraine's energy efforts. The EU's commitment to helping Ukraine transition to a more sustainable energy model, including steps toward ENTSO-E synchronization to bolster grid stability, is reflected in various initiatives aimed at increasing energy efficiency and integrating renewable sources.
Furthermore, international organizations have mobilized resources to assist in the restoration of damaged infrastructure. This collaboration not only enhances Ukraine's energy capabilities but also strengthens ties with global partners, fostering a sense of solidarity amidst the ongoing conflict.
Preparing for Winter Challenges
As temperatures drop, the demand for heating will surge, putting additional pressure on an already strained energy system. To address this, the Ukrainian government is urging citizens to prepare for potential shortages. Officials are promoting energy conservation measures, encouraging households to reduce consumption and use energy more efficiently.
Public awareness campaigns are being launched to educate citizens about the importance of energy saving and the steps they can take to minimize their energy use and prevent outages during peak demand. These initiatives aim to foster a collective sense of responsibility as the nation braces for the winter ahead.
In addition to conservation efforts, the government is exploring alternative energy supplies. This includes negotiating with neighboring countries for electricity imports and enhancing domestic production where feasible. By securing a diverse range of energy sources, Ukraine aims to mitigate the risk of shortages and ensure that essential services remain operational.
The Role of Resilience and Innovation
Despite the challenges, the resilience of the Ukrainian people and their commitment to overcoming adversity shine through. Communities are coming together to support one another, sharing resources and information to help navigate the difficulties of winter.
Innovative solutions are also emerging as part of the response to the energy crisis. Local initiatives aimed at promoting energy efficiency and the use of alternative energy sources are gaining traction. From community-led solar projects to energy-efficient building practices, Ukrainians are finding ways to adapt and thrive even in the face of uncertainty.
Looking Ahead
As Ukraine prepares for the winter months, the focus remains on ensuring energy security and maintaining the functionality of critical infrastructure. While challenges loom, the collective efforts of the government, international partners, and citizens demonstrate a strong commitment to resilience and adaptation.
In conclusion, the upcoming winter presents significant challenges for Ukraine's energy sector, yet the nation's determination to secure its energy future remains unwavering. With ongoing repairs, international support, and community innovation, Ukraine is working diligently to navigate the complexities of this winter, aiming to emerge stronger and more resilient in the face of adversity. The resilience shown today will be crucial as the country continues to confront the ongoing impacts of conflict and seeks to build a sustainable future.
National Grid Cybersecurity Component Removal signals NCSC and GCHQ oversight of critical infrastructure, replacing NR Electric and Nari Technology grid control systems to mitigate supply chain risk, cyber threats, and blackout risk.
Key Points
A UK move to remove China-linked grid components after NCSC/GCHQ advice, reducing cyber and blackout risks.
✅ Aims to cut blackout risk and supply chain exposure
Britain's National Grid has started removing components supplied by a unit of China-backed Nari Technology's from the electricity transmission network over cybersecurity fears, reflecting a wider push on protecting the power grid across critical sectors.
The decision came in April after the utility sought advice from the National Cyber Security Center (NCSC), a branch of the nation's signals intelligence agency, Government Communications Headquarters (GCHQ), amid campaigns like the Dragonfly campaign documented by Symantec, the newspaper quoted a Whitehall official as saying.
National Grid declined to comment citing "confidential contractual matters." "We take the security of our infrastructure very seriously and have effective controls in place to protect our employees and critical assets, while preparing for an independent operator transition in Great Britain, to ensure we can continue to reliably, safely and securely transmit electricity," it said in a statement.
The report said an employee at the Nari subsidiary, NR Electric Company-U.K., had said the company no longer had access to sites where the components were installed, at a time when utilities worldwide have faced control-room intrusions by state-linked hackers, and that National Grid did not disclose a reason for terminating the contracts.
It quoted another person it did not name as saying the decision was based on NR Electric Company-U.K.'s components that help control and balance the grid, respond to work-from-home demand shifts, and minimize the risk of blackouts.
It was unclear whether the components remained in the electricity transmission network, the report said, amid reports of U.S. power plant breaches that have heightened vigilance.
NR Electric Company-U.K., GCHQ and the Chinese Embassy in London did not immediately respond to requests for comment outside of business hours.
Britain's Department for Energy Security and Net Zero said that it did not comment on the individual business decisions taken by private organizations. "As a government department we work closely with the private sector to safeguard our national security, and to support efforts to fast-track grid connections across the network," it said in a statement.
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.
