PJM Interconnection, the electricity grid operator for more than 51 million people in 13 states and the District of Columbia, has canceled the voltage reduction it ordered at 3:55 p.m. August 8.
PJM had ordered utilities in the East to reduce voltage to meet the extremely high demand for electricity during the heat wave. PJM also has canceled its request to consumers to reduce their use of electricity.
The voltage reduction had applied to the Mid-Atlantic region. It affected the service territories of Atlantic City Electric; Baltimore Gas & Electric Co.; Delmarva Power; Jersey Central Power & Light Co. (JCP&L); Metropolitan Edison Co. (Met-Ed); PECO, an Exelon Company; Pepco; Pennsylvania Electric Co. (Penelec); PPL Electric Utilities; PSE&G; and UGI Utilities, Inc.
The 5 percent voltage reduction ended at 5:11 p.m. (EDT) for most of the region and at 6:14 p.m. (EDT) for the Baltimore and Washington areas.
PJM thanked consumers for their conservation of electricity and added that wise use of energy was always prudent. PJM said conservation had been important in meeting power supply needs.
2019 Global CO2 Emissions stayed flat, IEA reports, as renewable energy growth, wind and solar deployment, nuclear output, and coal-to-gas switching in advanced economies offset increases elsewhere, supporting climate goals and clean energy transitions.
Key Points
33 gigatonnes, unchanged YoY, as advanced economies cut power emissions via renewables, gas, and nuclear.
✅ IEA reports emissions flat at 33 Gt despite 2.9% GDP growth
✅ Advanced economies cut power-sector CO2 via wind, solar, gas
✅ Nuclear restarts and mild weather aided reductions
Despite widespread expectations of another increase, global energy-related CO2 emissions stopped growing in 2019, according to International Energy Agency (IEA) data released today. After two years of growth, global emissions were unchanged at 33 gigatonnes in 2019, a notable marker in the global energy transition narrative even as the world economy expanded by 2.9%.
This was primarily due to declining emissions from electricity generation in advanced economies, thanks to the expanding role of renewable sources (mainly wind and solar across many markets), fuel switching from coal to natural gas, and higher nuclear power generation, the Paris-based organisation says in the report.
"We now need to work hard to make sure that 2019 is remembered as a definitive peak in global emissions, not just another pause in growth," said Fatih Birol, the IEA's executive director. "We have the energy technologies to do this, and we have to make use of them all."
Higher nuclear power generation in advanced economies, particularly in Japan and South Korea, avoided over 50 Mt of CO2 emissions. Other factors included milder weather in several countries, and slower economic growth in some emerging markets. In China, emissions rose but were tempered by slower economic growth and higher output from low-carbon sources of electricity. Renewables continued to expand in China, and 2019 was also the first full year of operation for seven large-scale nuclear reactors in the country.
A significant decrease in emissions in advanced economies in 2019 offset continued growth elsewhere. The USA recorded the largest emissions decline on a country basis, with a fall of 140 million tonnes, or 2.9%. US emissions are now down by almost 1 gigatonne from their peak in 2000. Emissions in the European Union fell by 160 million tonnes, or 5%, in 2019 driven by reductions in the power sector as electricity producers move away from coal in the generation mix. Japan’s emissions fell by 45 million tonnes, or around 4%, the fastest pace of decline since 2009, as output from recently restarted nuclear reactors increased.
Emissions in the rest of the world grew by close to 400 million tonnes in 2019, with almost 80% of the increase coming from countries in Asia where coal-fired power generation continued to rise, and in Australia emissions rose 2% due to electricity and transport. Coal-fired power generation in advanced economies declined by nearly 15%, reflecting a sharp fall in coal-fired electricity across multiple markets, as a result of growth in renewables, coal-to-gas switching, a rise in nuclear power and weaker electricity demand.
The IEA will publish a World Energy Outlook Special Report in June that will map out how to cut global energy-related carbon emissions by one-third by 2030 and put the world on track for longer-term climate goals, a pathway that, in Canada, will require more electricity to hit net-zero. It will also hold an IEA Clean Energy Transitions Summit in Paris on 9 July, bringing together key government ministers, CEOs, investors and other major stakeholders.
Birol will discuss the results published today tomorrow at an IEA Speaker Series event at its headquarters with energy and climate ministers from Poland, which hosted COP24 in Katowice; Spain, which hosted COP25 in Madrid; and the UK, which will host COP26 in Glasgow this year, as greenhouse gas concentrations continue to break records worldwide.
Solar ITC Impact on U.S. Wind frames how a 30% solar investment tax credit could undercut wind PTC economics, shift corporate procurement, and, without transmission and storage, slow onshore builds despite offshore wind momentum.
Key Points
It is how a solar ITC extension may curb U.S. wind growth absent PTC parity, transmission, storage, and offshore backing.
✅ ITC at 30% risks shifting corporate procurement to solar.
✅ Post-PTC wind faces grid, transmission, and curtailment headwinds.
✅ Offshore wind, storage pairing, TOU demand could offset.
The booming U.S. wind industry, amid a wind power surge, faces an uncertain future in the 2020s. Few factors are more important than the fate of the solar ITC.
An extension of the solar investment tax credit (ITC) at its 30 percent value would be “devastating” to the future U.S. wind market, according to a new Wood Mackenzie report.
The U.S. is on track to add a record 14.6 gigawatts of new wind capacity in 2020, despite Covid-19 impacts, and nearly 39 gigawatts during a three-year installation boom from 2019 to 2021, according to Wood Mackenzie’s 2019 North America Wind Power Outlook.
But the market’s trajectory begins to look highly uncertain from the early 2020s onward, and solar is one of the main reasons why.
Since the dawn of the modern American renewables market, the wind and solar sectors have largely been allies on the national stage, benefiting from many of the same favorable government plans and sharing big-picture goals. Until recently, wind and solar companies rarely found themselves in direct competition.
But the picture is changing as solar catches up to wind on cost and the grid penetration of renewables surges. What was once a vague alliance between the two fastest growing renewables technologies could morph into a serious rivalry.
While many project developers are now active in both sectors, including NextEra Energy Resources, Invenergy and EDF, the country’s thriving base of wind manufacturers could face tougher days ahead.
The ITC's inherent advantage
At this point, wind remains solar’s bigger sibling in many ways.
The U.S. has nearly 100 gigawatts of installed wind capacity today, compared to around 67 gigawatts of solar. With their substantially higher capacity factors, wind farms generated four times more power for the U.S. grid last year than utility-scale solar plants, for a combined wind-solar share of 8.2 percent, according to government figures, even as renewables are projected to reach one-fourth of U.S. electricity generation. (Distributed PV systems further add to solar’s contribution.)
But it's long been clear that wind would lose its edge at some point. The annual solar market now regularly tops wind. The cost of solar energy is falling more rapidly, and appears to have more runway for further reduction. Solar’s inherent generation pattern is more valuable in many markets, delivering power during peak-demand hours, while the wind often blows strongest at night.
And then there’s the matter of the solar ITC.
In 2015, both wind and solar secured historic multi-year extensions to their main federal subsidies. The extensions gave both industries the longest period of policy clarity they’ve ever enjoyed, setting in motion a tidal wave of installations set to crest over the next few years.
Even back in 2015, however, it was clear that solar got the better deal in Washington, D.C.
While the wind production tax credit (PTC) began phasing down for new projects almost immediately, solar developers were given until the end of 2019 to qualify projects for the full ITC.
And critically, while the wind PTC drops to nothing after its sunset, commercially owned solar projects will remain eligible for a 10 percent ITC forever, based on the existing legislation. Over time, that amounts to a huge advantage for solar.
In another twist, the solar industry is now openly fighting for an extension of the 30 percent ITC, while the wind industry seemingly remains cooler on the prospect of pushing for a similar prolongation — having said the current PTC extension would be the last.
Plenty of tailwinds, too
Wood Mackenzie's report catalogues multiple factors that could work for or against the wind market in the "uncharted" post-PTC years, many of them, including the Covid-19 crisis, beyond the industry’s direct control.
If things go well, annual installations could bounce back to near-record levels by 2027 after a mid-decade contraction, the report says. But if they go badly, installations could remain depressed at 4 gigawatts or below from 2022 through most of the coming decade, and that includes an anticipated uplift from the offshore market.
An extension of the solar ITC without additional wind support would “severely compound” the wind market’s struggle to rebound in the 2020s, the report says. The already-evident shift in corporate renewables procurement from wind to solar could intensify dramatically.
The other big challenge for wind in the 2020s is the lack of progress on transmission infrastructure that would connect potentially massive low-cost wind farms in interior states with bigger population centers. A hoped-for national infrastructure package that might address the issue has not materialized.
Even so, many in the wind business remain cautiously optimistic about the post-PTC years, with a wind jobs forecast bolstering sentiment, and developers continue to build out longer-term project pipelines.
Turbine technology continues to improve. And an extension of the solar ITC is far from assured.
Other factors that could work in wind’s favor in the years ahead include:
The nascent offshore sector, which despite lingering regulatory uncertainty at the federal level looks set to blossom into a multi-gigawatt annual market by the mid-2020s, in line with an offshore wind forecast that highlights substantial growth potential. Lobbying efforts for an offshore wind ITC extension are gearing up, offering a potential area for cooperation between wind and solar.
The potential linkage of policy support for energy storage to wind projects, building on the current linkage with solar.
Growing electric vehicle sales and a shift toward time-of-use retail electricity billing, which could boost power demand during off-peak hours when wind generation is strong.
The land-use advantages wind farms have over solar in some agricultural regions.
BC Hydro Asset Management Audit confirms disciplined oversight of dams, generators, power lines, substations, and transformers, with robust lifecycle planning, reliability metrics, and capital investment sustaining aging infrastructure and near full-capacity performance.
Key Points
Audit confirming BC Hydro's asset governance and lifecycle planning, ensuring safe, reliable grid infrastructure.
✅ $25B in assets; many facilities operating near full capacity.
✅ 80% of assets are dams, generators, lines, poles, substations, transformers.
✅ $2.5B invested in renewal, repair, and replacement in fiscal 2018.
A report by B.C.’s auditor-general says B.C. Hydro is doing a good job managing the province’s dams, generating stations and power lines, including storm response during severe weather events.
Carol Bellringer says in the audit that B.C. Hydro’s assets are valued at more than $25 billion and even though some generating facilities are more than 85 years old they continue to operate near full-capacity and can accommodate holiday demand peaks when needed.
The report says about 80 per cent of Hydro’s assets are dams, generators, power lines, poles, substations and transformers that are used to provide electrical service to B.C., where residential electricity use shifted during the pandemic.
The audit says Hydro invested almost $2.5 billion to renew, repair or replace the assets it manages during the last fiscal year, ending March 31, 2018, and, in a broader context, bill relief has been offered to only part of the province.
Bellringer’s audit doesn’t examine the $10.7 billion Site C dam project, which is currently under construction in northeast B.C. and not slated for completion until 2024.
She says the audit examined whether B.C. Hydro has the information, practices, processes and systems needed to support good asset management, at a time when other utilities are dealing with pandemic impacts on operations.
U.S. Climate Change Donation Survey reveals Americans' willingness to fund sustainability via government incentives, electrification, and renewable energy. Public opinion favors wind, solar, and decarbonization, highlighting policy support post-pandemic amid economic recovery efforts.
Key Points
A 2020 U.S. poll on climate attitudes: donation willingness, renewable support, and views on government incentives.
✅ 70% would donate income; 31% would donate nothing.
✅ 59% prefer government incentives; 47% support taxes, conservation.
✅ 85% land wind, 83% offshore wind, 90% solar support.
A new study of American consumers' attitudes toward climate change finds that more than two-thirds of respondents (70%) indicate their willingness to give or donate a percentage of their personal income to support the fight against climate change and the path to net-zero electricity emissions by mid-century.
Twenty-eight percent indicated they were willing to provide less than 1% of their income; 33% said they would be willing to contribute 1-5% of their income; 6% said they would give between 6-10% of their income; and 3% indicated they would contribute more than 10% of their income. Just under one-third (31%) of those surveyed indicated they were unwilling to give or donate any percentage of their income to support the fight against climate change.
The U.S. findings are part of a series of surveys commissioned by Nexans in the U.S., UK and France, in order to determine public opinion on climate change and related issues in the wake of the COVID-19 pandemic. The U.S. study was conducted online by Researchscape from August 20 – 24, 2020. It had 1,013 respondents, ages 18 or older, with the results weighted to be representative of the overall population (variables available upon request).
Nexans, is headquartered in Paris with a major offshore wind cable manufacturing facility in Charleston, S.C. and an industrial cable manufacturing facility in El Dorado, Ark. The company is fully committed to fighting climate change and is helping to make sustainable electrification possible. The survey was developed as part of its celebration of the first Climate Day in Paris which included a roundtable event with world-renowned experts, the release of an unprecedented global study by Roland Berger on the challenges raised by the electrification of the world, the question of whether the global energy transition is on track, and Nexans' own commitment to be carbon neutral by 2030.
Paying the Tab to Address Climate Change
Participants were given the opportunity to choose from seven multiple responses to the question "How should the fight against climate change be paid for?" The majority (59%) replied it should be paid for by "government incentives for both businesses and consumers." It was followed by "federal, state and/or local taxes" and "conservation programs" (tied at 47%); "business investments" (42%), such as carbon-free electricity initiatives, and "consumer-driven purchases" (33%). Just 9% selected none of the above and 2% selected other.
"Through the organization of this Climate Day, Nexans is asserting itself not only as an actor but also a thought leader of the energy transition for a sustainable electrification of the world. This electrification raises a number of challenges and paradoxes that must be overcome. And it will only happen with the direct involvement of the populations concerned. These surveys provide a better understanding of the level of information and disinformation, including climate change denial, in public opinion as well as their level of acceptability of these lifestyle changes," said Christopher Guérin, CEO, Nexans.
Among other findings, 44% are dissatisfied with the job that federal and state governments are doing to address climate change, while utilities like Duke Energy face investor pressure to release climate reports, 35% are somewhat satisfied and 21% are either very satisfied or completed satisfied with government's role.
Americans expressed overwhelmingly favorable views of wind and solar renewable energy proposals, as carbon emissions fall when electricity producers move away from coal. Specifically, 85% stated being in favor of wind turbines on land (15% against), 83% in favor of wind turbines off the coast (17% against) and 90% in support of solar panel farms (10% opposed).
Those surveyed were asked about their current and changing priorities towards climate change as influenced by the coronavirus pandemic and impacts like extreme heat on electricity bills. Thirty-nine percent indicated that climate change was no more and no less a priority due to the current health emergency; just under a third (31%) indicated that climate change is more of a priority while 30% said it was less of a priority.
In similar research conducted by Nexans in the United Kingdom, nearly two thirds (65.8%) of UK respondents said they would be willing to donate part of their salary to fight climate change. Furthermore, nearly a third (29%) of the UK's consumers believe that combating climate change has become more of a priority in light of the coronavirus pandemic. The UK research was conducted online by Savanta from August 21 – 24, 2020. A total of 2210 respondents, aged 16 and above, representative of the UK population took part.
Philippsburg Demolition Delay: EnBW postpones controlled cooling-tower blasts amid the coronavirus pandemic, affecting decommissioning timelines in Baden-Wurttemberg and grid expansion for a transformer station to route renewable power and secure supply in southern Germany.
Key Points
EnBW's COVID-19 delay of Philippsburg cooling-tower blasts, affecting decommissioning and grid plans.
✅ Controlled detonation shifted to mid-May at earliest
✅ Demolition links to transformer station for north-south grid
✅ Supports security of supply in southern Germany
German energy company EnBW said the coronavirus outbreak has impacted plans to dismantle its Philippsburg nuclear power plant in Baden-Wurttemberg, southwest Germany, amid plans to phase out coal and nuclear nationally.
The controlled detonation of Phillipsburg's cooling towers will now take place in mid-May at the earliest, subject to coordination as Germany debates whether to reconsider its nuclear phaseout in light of supply needs.
However, EnBW said the exact demolition date depends on many factors - including the further development in the coronavirus pandemic and ongoing climate policy debates about energy choices.
Philippsburg 2, a 1402MWe pressurised water reactor unit permanently shut down on 31 December 2019, as part of Germany's broader effort to shut down its remaining reactors over time.
At the end of 2019, the Ministry of the Environment gave basic approval for decommissioning and dismantling of unit 2 of the Philippsburg nuclear power plant, inluding explosive demolition of the colling towers. Since then EnBW has worked intensively on getting all the necessary formal steps on the way and performing technical and logistical preparatory work, even as discussions about a potential nuclear resurgence continue nationwide.
“The demolition of the cooling towers is directly related to future security of supply in southern Germany. We therefore feel obliged to drive this project forward," said Jörg Michels head of the EnBW nuclear power division.
The timely removal of the cooling towers is important as the area currently occupied by nuclear plant components is needed for a transformer station for long-distance power lines, an issue underscored during the energy crisis when Germany temporarily extended nuclear power to bolster supply. These will transport electricity from renewable sources in the north to industrial centres in the south.
As of early 2020, there six nuclear reactors in operation in Germany, even as the country turned its back on nuclear in subsequent years. According to research institute Fraunhofer ISE, nuclear power provided about 14% of Germany's net electricity in 2019, less than half of the figure for 2000.
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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