South Korea plans to address future power demand by going greener and lowering power consumption.
Having set a 2030 deadline to reduce emissions of greenhouse gases by 30, the country is in a state of flux. The government of South Korea is promoting the development of clean, alternative and renewable energies through a $36 billion, five-year plan that is already directly affecting domestic power policies.
New plans are pushing power companies to increase the number of district heating users between now and 2014. Combined heat and power CHP plants are common throughout South Korea and are generally associated with district heating. Not only do they help cut costs in terms of heating, but also supply electricity to local grids. Currently, about 13 of South Korea's 14 million households rely on district heating and CHP plants. The government is seeking to raise the number of households using district heating by at least one-third by 2014.
Korea District Heating Corporation KDHC serves almost 60 of all homes that use district heating in South Korea and plans to increase this customer base to 2 million by 2015. With plans to incorporate government-backed district-cooling research within the next few years, KDHC stands to benefit greatly from the increase in CHP plants.
Officials have mentioned that as South Korea looks to combat the looming electricity crunch, more and more existing power plants may be transformed into CHP plants. The majority of electricity costs are associated with the heating and cooling of homes. South Korea hopes to reduce the use of electricity for temperature control by directly supplying warm and cool air. The government is fully in support of district cooling research and hopes that it is incorporated into CHP plants the near future.
The call for more combined heat and power plants parallels South Korea's switch to natural gas in the country's coal-dominated market. Natural gas burns cleaner than coal and is generally the fuel of choice in CHP plants. A natural gas-fired CHP that is capable of supplying about 325 megawatts MW of electricity and more than 300 gigacalories per hour of steam to the local grid, such as the one KDHC is planning to construct in 2013, generally costs about $550 million. A coal-fired CHP plant, although capable of generating more electricity and steam for less money, emits twice as much carbon dioxide per unit of energy as a natural gas-fired plant.
Although the government is pushing for an increase in CHP plants, it is also demanding more renewable energy projects. KDHC will invest an additional $41 million in solar and wind power research in the coming years to prepare for the government's demands for increased renewable energy.
EU Solar Impact on Electricity Prices highlights how rising solar PV penetration drives negative pricing, shifts peak hours, pressures wholesale markets, and challenges grid balancing, interconnection, and flexibility amid changing demand and renewables growth.
Key Points
Explains how rising solar PV cuts wholesale prices, shifts negative-price hours, and strains grid flexibility.
✅ Negative pricing events surge with higher solar penetration.
✅ Grid balancing, interconnectors, and flexibility become critical.
The latest EU electricity market report has confirmed the affect deeper penetration of solar is having on wholesale electricity prices more broadly.
The Quarterly Report on European Electricity Markets for the final three months of last year noted the number of periods of negative electricity pricing doubled from 2019, to almost 1,600 such events, as global renewables set new records in deployment across markets.
Having experienced just three negative price events in 2019, the Netherlands recorded almost 100 last year “amid a dramatic increase in solar PV capacity,” in the nation, according to the report.
Whilst stressing the exceptional nature of the Covid-19 pandemic on power consumption patterns, the quarterly update also noted a shift in the hours during which negative electric pricing occurred in renewables poster child Germany. Previously such events were most common at night, during periods of high wind speed and low demand, but 2020 saw a switch to afternoon negative pricing. “Thus,” stated the report, “solar PV became the main driver behind prices falling into negative territory in the German market in 2020, as Germany's solar boost accelerated, and also put afternoon prices under pressure generally.”
The report also highlighted two instances of scarce electricity–in mid September and on December 9–as evidence of the problems associated with accommodating a rising proportion of intermittent clean energy capacity into the grid, and called for more joined-up cross-border power networks, amid pushback from Russian oil and gas across the continent.
Rising solar generation–along with higher gas output, year on year–also helped the Netherlands generate a net surplus of electricity last year, after being a net importer “for many years.” The EU report also noted a beneficial effect of rising solar generation capacity on Hungary‘s national electricity account, and cited a solar “boom” in that country and Poland, mirroring rapid solar PV growth in China in recent years.
With Covid-19 falls in demand helping renewables generate more of Europe's electricity (39%) than fossil fuels (36%) for the first time, as renewables surpassed fossil fuels across Europe, the market report observed the 5% of the bloc's power produced from solar closed in on the 6% accounted for by hard coal. In the final three months of the year, European solar output rose 12%, year on year, to 18 TWh and “the increase was almost single-handedly driven by Spain,” the study added.
With coal and lignite-fired power plunging 22% last year across the bloc, it is estimated the European power sector reduced its carbon footprint 14% as part of Europe's green surge although the quarterly report warned cold weather, lower wind speeds and rising gas prices in the opening months of this year are likely to see carbon emissions rebound.
There was good news on the transport front, though, with the report stating the scale of the European “electrically-charged vehicle” fleet doubled in 2020, to 2 million, with almost half a million of the new registrations arriving in the final months of the year. That meant cars with plug sockets accounted for a remarkable 17% of new purchases in Q4, twice the proportion seen in China and a slice of the pie six times bigger than such products claimed in the U.S.
Bruce Power Unit 6 refurbishment replaces major reactor components, shifting supply to hydroelectric and natural gas, sustaining Ontario jobs, extending plant life to 2064, and managing radioactive waste along Lake Huron, on-time and on-budget.
Key Points
A 4-year, $2.1B reactor overhaul within a 13-year, $13B program to extend plant life to 2064 and support Ontario jobs.
✅ Unit 6 offline 4 years; capacity shift to hydro and gas
✅ Part of 13-year, $13B program; extends life to 2064
✅ Creates jobs; manages radioactive waste at Lake Huron
The world’s largest nuclear fleet, became a little smaller Monday morning. Bruce Power has began the process to take Unit 6 offline to begin a $2.1 billion project, supported by manufacturing contracts with key suppliers, to replace all the major components of the reactor.
The reactor, which produces enough electricity to power 750,000 homes and reflects higher output after upgrades across the site, will be out of service for the next four years.
In its place, hydroelectric power and natural gas will be utilized more.
Taking Unit 6 offline is just the “official” beginning of a 13-year, $13-billion project to refurbish six of Bruce Power’s eight nuclear reactors, as Ontario advances the Pickering B refurbishment as well on its grid.
Work to extend the life of the nuclear plant started in 2016, and the company recently marked an operating record while supporting pandemic response, but the longest and hardest part of the project - the major component replacement - begins now.
“The Unit 6 project marks the next big step in a long campaign to revitalize this site,” says Mike Rencheck, Bruce Power’s president and CEO.
The overall project is expected to last until 2033, and mirrors life extensions at Pickering supporting Ontario’s zero-carbon goals, but will extend the life of the nuclear plant until 2064.
Extending the life of the Bruce Power nuclear plant will sustain 22,000 jobs in Ontario and add $4 billion a year in economic activity to the province, say Bruce Power officials.
About 2,000 skilled tradespeople will be required for each of the six reactor refurbishments - 4,200 people already work at the sprawling nuclear plant near Kincardine.
It will also mean tons of radioactive nuclear waste will be created that is currently stored in buildings on the Bruce Power site, along the shores of Lake Huron.
Bruce Power restarted two reactors back in 2012, and in later years doubled a PPE donation to support regional health partners. That project was $2-billion over-budget, and three years behind schedule.
Bruce Power officials say this refurbishment project is currently on-time and on-budget.
EasyPower Webinars deliver expert training on electrical power systems, covering arc flash, harmonics, grounding, overcurrent coordination, NEC and IEEE 1584 updates, with on-demand videos and email certificates for continuing education credits.
Key Points
EasyPower Webinars are expert-led power systems trainings with CE credit details and on-demand access.
✅ Arc flash, harmonics, and grounding fundamentals with live demos
✅ NEC 2020 and IEEE 1584 updates for compliance and safety
✅ CE credits with post-webinar email documentation
We've ramped up webinars to help your learning while you might be working from home, and similar live online fire alarm training options are widely available. As usual, you will receive an email the day after the webinar which will include the details most states need for you to earn continuing education credit, amid a broader grid warning during the pandemic from regulators.
EasyPower's well known webinar series covers a variety of topics regarding electrical power systems. Below you will see our webinars scheduled through the next few months, reflecting ongoing sector investments in the future of work across the electricity industry.
In addition, there are more than 150 videos that were recorded from past webinars in our EasyPower Video Library. The topics of these videos include arc flash training, short circuit, protective device coordination, power flow, harmonics, DC systems, grounding, and many others.
AUGUST WEBINARS
Active & Passive Harmonic Filters in EasyPower
By Tao Yang, Ph.D, PE, at EasyPower
In this webinar, Tao Yang, Ph.D, PE, from EasyPower provides a refresher course on fundamental concepts of harmonics study and the EasyPower Harmonics module. He describes the two major harmonics filters, both active and passive, and their implementation in the EasyPower Harmonics module. As passive filters are widely used in the industry, he covers four kinds of typical passive filters: notch, first order, second order, and C-type filters, including their implementation in EasyPower and their tuning processes. He uses live examples to demonstrate the modeling and parameter tuning for both active and passive filters using simple EasyPower cases.
The National Electrical Code (NEC) outlines several arc-flash mitigation options, aligning with broader arc flash training insights across the industry. This presentation, given by Mark Pollock at Littelfuse, reviews the arc-flash mitigation options from the NEC 2020, and some updates to the IEEE 1584-2018 standard. In addition to understanding the codes, we’ll discuss the return on investment for the various mitigation options and the importance of arc-flash assessments in your facility.
The PowerProtector™ module in EasyPower simplifies the process of coordinating protective devices. In this refresher webinar, Jim Chastain demonstrates the procedure to coordinate ground fault protection for both resistance-grounded and hard-grounded systems.
By James Onsager and Namrata Asarpota at S&C Electric
Coordination of overcurrent protective devices is necessary to limit interruptions to the smallest portion of the power system in the event of an overload or short-circuit. This webinar, given by James Onsager and Namrata Asarpota at S&C Electric, goes over the basics of Time Current Curves (TCCs), types of overcurrent protective devices (for both low-voltage and medium-voltage systems), and how to coordinate between them. Protection of common types of equipment such as transformers, cables and motors according the National Electrical Code (NFPA 70, NEC) is also discussed, alongside related fire alarm training online resources available to practitioners.
Static Discharge Awareness and Explosion Protection
By Christopher Coughlan at Newson Gale, a Hoerbiger Safety Solutions Company
For any person responsible for the safety of employees, colleagues, plant equipment and plant property, one of the most potentially confusing aspects of providing a safe operating environment is understanding and safeguarding again static discharge, with industry leadership in worker safety highlighting best practices. In this webinar given by Christopher Coughlan at Newson Gale, a Hoerbiger Safety Solutions Company, he discusses how to determine if your site’s manufacturing or handling processes have the potential to discharge static sparks into flammable or combustible atmospheres.
XGSLab New Feature - Seasonal Analysis For Grounding Systems
By David Lewis, P.E, Electrical Engineer, Grounding and Power Systems at EasyPower
In regions where the frost depth meets or exceeds the depth of a grounding system, the grounding system’s performance may be dramatically reduced, possibly creating hazardous conditions. The latest XGSLab release 9.5 provides a powerful new tool to analyze grounding system performance that considers the seasonal variation in soil characteristics. In this webinar, given by David Lewis, an electrical engineer at EasyPower, we describe the effect that seasonal variation can have on a grounding system and we step you through the use of the Seasonal Analysis tool.
Texas Power Grid Reliability faces record peak demand as ERCOT balances renewable energy, wind and solar variability, gas-fired generation, demand response, and transmission limits to prevent blackouts during heat waves and extreme weather.
Key Points
Texas Power Grid Reliability is ERCOT's capacity to meet peak demand with diverse resources while limiting outages.
✅ Record heat drives peak demand across ERCOT.
✅ Variable wind/solar need firm, flexible capacity.
✅ Demand response and reserves reduce blackout risk.
The electric power grid in Texas, which collapsed dramatically during the 2021 winter storm across the state, is being tested again as the state suffers unusually hot summer weather. Demand for electricity has reached new records at a time of rapid change in the mix of power sources as wind and solar ramp up. That’s feeding a debate about the dependability of the state’s power.
1. Why is the Texas grid under threat again?
Already the biggest power user in the nation, electricity use in the second most-populous state surged to record levels during heat waves this summer. The jump in demand comes as the state becomes more dependent on intermittent renewable power sources, raising concerns among some critics that more reliance on wind and solar will leave the grid more vulnerable to disruption. Green sources will produce almost 40% of the power in Texas this year, US Energy Information Administration data show. While that trails California’s 52%, Texas is a bigger market. It’s already No. 1 in wind, making it the largest clean energy market in the US.
2. How is Texas unique?
The spirit of defiance of the Lone Star State extends to its power grid as well. The Electric Reliability Council of Texas, or Ercot as the grid operator is known, serves about 90% of the state’s electricity needs and has very few high-voltage transmission lines connecting to nearby grids. It’s a deliberate move to avoid federal oversight of the power market. That means Texas has to be mainly self-reliant and cannot depend on neighbors during extreme conditions. That vulnerability is a dramatic twist for a state that’s also the energy capital of the US, thanks to vast oil and natural gas producing fields. Favorable regulations are also driving a wind and solar boom in Texas.
3. Why the worry?
The summer of 2023 will mark the first time all of the state’s needs cannot be met by traditional power plants, like nuclear, coal and gas. A sign of potential trouble came on June 20 when state officials urged residents to conserve power because of low supplies from wind farms and unexpected closures of fossil-fuel generators amid supply-chain constraints that limited availability. As of late July, the grid was holding up, thanks to the help of renewable sources. Solar generation has been coming in close to expected summer capacity, or exceeding it on most days. This has helped offset the hours in the middle of the day when wind speeds died down in West Texas.
4. Why didn’t the grid’s problems get fixed?
There is no easy fix. The Texas system allows the price of electricity to swing to match supply and demand. That means high prices — and high profits — drive the development of new power plants. At times spot power prices have been as low as $20-$50 a megawatt-hour versus more than $4,000 during periods of stress. The limitation of this pricing structure was laid bare by the 2021 winter blackouts. Since then, state lawmakers have passed market reforms that require weatherization of critical infrastructure and changed rules to put more money in the pockets of the owners of power generation.
5. What’s the big challenge?
There’s a real clash going on over what the grid of the future should look like in Texas and across the country, especially as severe heat raises blackout risks nationally. The challenge is to make sure nuclear and fossil fuel plants that are needed right now don’t retire too early and still allow newer, cleaner technologies to flourish. Some conservative Republicans have blamed renewable energy for destabilizing the grid and have pushed for more fossil-fuel powered generators. Lawmakers passed a controversial $10 billion program providing low-interest loans and grants to build new gas-fired plants using taxpayer money, but Texans ultimately have to vote on the subsidy.
6. Why do improvements take so long?
Figuring out how to keep the lights on without overburdening consumers is becoming a greater challenge amid more extreme weather fueled by climate change. As such, changing the rules is often a hotly contested process pitting utilities, generators, manufacturers, electricity retailers and other groups against one another. The process became more politicized after the storm in 2021 with Republican Gov. Greg Abbott and lawmakers ordering Ercot to make changes. Building more transmission lines and connecting to other states can help, but such projects are typically tied up for years in red tape.
7. What can be done?
The price cap for electricity was cut from $9,000/MWh to $5,000 to help avoid the punitive costs seen in the 2021 storm, though prices are allowed to spike more easily. Ercot is also contracting for more reserves to be online to help avoid supply shortfalls and improve reliability for customers, which added $1.7 billion in consumer costs alone last year. Another rule helps some gas generators pay for their fuel costs, while a more recent reform put in price floors when reserves fall to certain levels. Many power experts say that the easiest solution is to pay people to reduce their energy consumption during times of grid stress through so-called demand response programs. Factories, Bitcoin miners and other large users are already compensated to conserve during tight grid conditions.
Ukraine Electricity Exports resume as the EU grid links stabilize; ENTSO-E caps, megawatt capacity, renewables, and infrastructure repairs enable power flows to Moldova, Poland, Slovakia, and Romania despite ongoing Russian strikes.
Key Points
Resumed cross-border power sales showing grid stability under ENTSO-E limits and surplus generation.
✅ Exports restart to Moldova; Poland, Slovakia, Romania next.
✅ ENTSO-E cap limits to 400 MW; more capacity under negotiation.
✅ Revenues fund grid repairs after Russian strikes.
Ukraine began resuming electricity exports to European countries on Tuesday, its energy minister said, a dramatic turnaround from six months ago when fierce Russian bombardment of power stations plunged much of the country into darkness in a bid to demoralize the population.
The announcement by Energy Minister Herman Halushchenko that Ukraine was not only meeting domestic consumption demands but also ready to restart exports to its neighbors was a clear message that Moscow’s attempt to weaken Ukraine by targeting its infrastructure did not work.
Ukraine’s domestic energy demand is “100%” supplied, he told The Associated Press in an interview, and it has reserves to export due to the “titanic work” of its engineers and international partners.
Russia ramped up infrastructure attacks in September, when waves of missiles and exploding drones destroyed about half of Ukraine's energy system, even as it built lines to reactivate the Zaporizhzhia plant in occupied territory. Power cuts were common across the country as temperatures dropped below freezing and tens of millions struggled to keep warm.
Moscow said the strikes were aimed at weakening Ukraine’s ability to defend itself, and both sides have floated a possible agreement on power plant attacks amid mounting civilian harm, while Western officials said the blackouts that caused civilians to suffer amounted to war crimes. Ukrainians said the timing was designed to destroy their morale as the war marked its first anniversary.
Ukraine had to stop exporting electricity in October to meet domestic needs.
Engineers worked around the clock, often risking their lives to come into work at power plants and keep the electricity flowing. Kyiv’s allies also provided help. In December, U.S. Secretary of State Antony Blinken announced $53 million in bilateral aid to help the country acquire electricity grid equipment, on top of $55 million for energy sector support.
Much more work remains to be done, Halushchenko said. Ukraine needs funding to repair damaged generation and transmission lines, and revenue from electricity exports would be one way to do that.
The first country to receive Ukraine’s energy exports will be Moldova, he said.
Besides the heroic work by engineers and Western aid, warmer temperatures are enabling the resumption of exports by making domestic demand lower, and across Europe initiatives like virtual power plants for homes are helping balance grids. Nationwide consumption was already down at least 30% due to the war, Halushchenko said, with many industries having to operate with less power.
Renewables like solar and wind power also come into play as temperatures rise, taking some pressure off nuclear and coal-fired power plants.
But it’s unclear if Ukraine can keep up exports amid the constant threat of Russian bombardment.
“Unfortunately now a lot of things depend on the war,” Halushchenko said. “I would say we feel quite confident now until the next winter.”
Exports to Poland, Slovakia and Romania are also on schedule to resume, he said.
“Today we are starting with Moldova, and we are talking about Poland, we are talking about Slovakia and Romania,” Halushchenko added, noting that how much will depend on their needs.
“For Poland, we have only one line that allows us to export 200 megawatts, but I think this month we will finish another line which will increase this to an additional 400 MW, so these figures could change,” he said.
Export revenue will depend on fluctuating electricity prices in Europe, where stunted hydro and nuclear output may hobble recovery efforts. In 2022, while Ukraine was still able to export energy, Ukrainian companies averaged 40 million to 70 million euros a month depending on prices, Halushchenko said.
“Even if it’s 20 (million euros) it’s still good money. We need financial resources now to restore generation and transmission lines,” he said.
Ukraine has the ability to export more than the 400 megawatt capacity limit imposed by the European Network of Transmission System Operators for Electricity, or ENTSO-E, and rising EU wind and solar output is reshaping cross-border flows. “We are in negotiations to increase this cap because today we can export even more, we have the necessary reserves in the system,” the minister said.
The current capacity limit is in line with what Ukraine was exporting in September 2022 before Ukraine diverted resources to meet domestic needs amid the Russian onslaught.
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.
