The world's top two polluters, the U.S. and China, say they are not ready to commit to mandatory caps on greenhouse gases.
But that's not a worry to the organizers of the U.N. climate conference, who say they only want to jump-start the world's talks toward a new climate accord.
"This meeting is not about delivering a fully negotiated climate change deal, but it is to set the wheels in motion," the U.N. climate chief, Yvo de Boer, said.
Presidents, prime ministers and environmental ministers prepared to join discussions on how to head off the impacts of rising temperatures, from rising oceans to deadly droughts and diseases.
"Reaching a conclusion even in two years is going to be very ambitious, let alone trying to achieve that kind of result in two weeks," de Boer said.
The main negotiating text for the Dec. 3-14 meeting on the Indonesian island of Bali mentions targets for reducing the amount of pollutants pumped into the atmosphere, but in a nonbinding way.
Its preamble notes the widely accepted view that industrial nations' emissions should be cut by 25 percent to 40 percent below 1990 levels by 2020, and that global emissions must be slashed to half of 2000 levels by mid-century.
There is little chance those numbers will make it into the final document, de Boer said, but they will more than likely spark renewed debate at the Bali talks, which are meant to launch a two-year negotiation for a post-Kyoto Protocol agreement.
Delegates will, among other things, decide in the next week what issues to include in a "Bali roadmap," including likely references to the importance of helping the most vulnerable nations adapt, and the need to provide developing countries with the technical know-how they need to reduce emission.
As for mandatory caps, de Boer said, "I really hope that that is a discussion that will be taken up toward the end of that two years rather than here."
The Kyoto pact, which was rejected by the United States, commits three dozen industrial countries that signed on to cut emissions by an average of 5 percent below 1990 levels in the next five years.
One of the reasons Washington did not sign on was because the pact did not set targets for fast-developing countries like China. The two nations are the largest emitters of climate-changing gases, though scientists do not always agree which tops the list.
The chief U.S. negotiator said Washington would come up with its own plan to cut global-warming gases by mid-2008, and would not commit to mandatory caps in the coming days.
"We're not ready to do that here," said Harlan Watson, whose country favors a more voluntary approach to cuts.
That process of U.S.-led talks was inaugurated last September by President Bush, who invited 16 other "major economies" such as the Europeans, Japan, China and India, to Washington to discuss a future international program of cutbacks in carbon dioxide and other heat-trapping emissions.
Watson said the final decision would likely be announced at a "leaders" meeting in the middle of next year.
Environmentalists accuse the Bush administration of using those parallel talks to subvert the long-running U.N. negotiations and the spirit of the binding Kyoto Protocol.
China, which is increasingly turning to coal-powered electricity plants and factories to help fuel its booming economy, has also stood firm in saying it would not agree to binding targets. It says the West is responsible for rising temperatures, because it has been pumping climate-changing gases into the air for centuries.
"China is in the process of industrialization and there is a need for economic growth to meet the basic needs of the people and fight against poverty," said Su Wei, a top climate expert for the Chinese government and member of its Bali delegation.
Spain Electricity Prices surge to record highs as the wholesale market hits €339.84/MWh, driven by gas costs and CO2 permits, impacting PVPC regulated tariffs, free-market contracts, and household energy bills, OMIE data show.
Key Points
Rates in Spain's wholesale market that shape PVPC tariffs and free-market bills, moving with gas prices and CO2 costs.
✅ Record €339.84/MWh; peak 20:00-21:00; low 04:00-05:00 (OMIE).
✅ PVPC users and free-market contracts face higher bills.
✅ Drivers: high gas prices and rising CO2 emission rights.
Electricity in Spain's wholesale market will rise in price once more as European electricity prices continue to surge. Once again, it will set a historical record in Spain, reaching €339.84/MWh. With this figure, it is already the fifth time that the threshold of €300 has been exceeded.
This new high is a 6.32 per cent increase on today’s average price of €319.63/MWh, which is also a historic record, while Germany's power prices nearly doubled over the past year. Monday’s energy price will make it 682.65 per cent higher than the corresponding date in 2020, when the average was €43.42.
According to data published by the Iberian Energy Market Operator (OMIE), Monday’s maximum will be between the hours of 8pm and 9pm, reaching €375/MWh, a pattern echoed by markets where Electric Ireland price hikes reflect wholesale volatility. The cheapest will be from 4am to 5am, at €267.99.
The prices of the ‘pool’ have a direct effect on the regulated tariff – PVPC – to which almost 11 million consumers in the country are connected, and serve as a reference for the other 17 million who have contracted their supply in the free market, where rolling back prices is proving difficult across Europe.
These spiraling prices in recent months, which have fueled EU energy inflation, are being blamed on high gas prices in the markets, and carbon dioxide (CO2) emission rights, both of which reached record highs this year.
According to an analysis by Facua-Consumidores en Acción, if the same rates were maintained for the rest of the month, the last invoice of the year would reach €134.45 for the average user. That would be 94.1 per cent above the €69.28 for December 2020, while U.S. residential electricity bills rose about 5% in 2022 after inflation adjustments.
The average user’s bill so far this year has increased by 15.1 per cent compared to 2018, as US electricity prices posted their largest jump in 41 years. Thus, compared to the €77.18 of three years ago, the average monthly bill now reaches €90.87 euros. However, the Government continues to insist that this year households will end up paying the same as in 2018.
As Ruben Sanchez, the general secretary of Facua commented, “The electricity bill for December would have to be negative for President Sanchez, and Minister Ribera, to fulfill their promise that this year consumers will pay the same as in 2018 once the CPI has been discounted”.
Spring Storm Grid Risks highlight tornado outbreaks, flooding, power outages, and transmission disruptions, with NOAA flood outlooks, coal and barge delays, vulnerable nuclear sites, and distribution line damage demanding resilience, reliability, and emergency preparedness.
Key Points
Spring Storm Grid Risks show how tornadoes and floods disrupt power systems, fuel transport, and plants guide resilience.
✅ Tornado outbreaks and derechos damage distribution and transmission
✅ Flooding drives outages via treefall, substation and plant inundation
✅ Fuel logistics disrupted: rail coal, river barges, road access
The storm and tornado outbreak that recently barreled through the US Midwest, South and Mid-Atlantic was a devastating reminder of how much danger spring can deliver, despite it being the “milder” season compared to summer and winter.
Danger season is approaching, and the country is starting to see the impacts.
The event killed at least 32 people across seven states. The National Weather Service is still tallying up the number of confirmed tornadoes, which has already passed 100. Communities coping with tragedy are assessing the damage, which so far includes at least 72 destroyed homes in one Tennessee county alone, and dozens more homes elsewhere.
On Saturday, April 1–the day after the storm struck–there were 1.1 million US utility customers without power, even as EIA reported a January power generation surge earlier in the year. On Monday morning, April 3, there were still more than 80,000 customers in the dark, according to PowerOutage.us. The storm system brought disruptions to both distribution grids–those networks of local power lines you generally see running overhead to buildings–as well as the larger transmission grid in the Midwest, which is far less common than distribution-level issues.
While we don’t yet have a lot of granular details about this latest storm’s grid impacts, recent shifts in demand like New York City's pandemic power patterns show how operating conditions evolve, and it’s worth going through what else the country might be in for this spring, as well as in future springs. Moreover, there are steps policymakers can take to prepare for these spring weather phenomena and bolster the reliability and resilience of the US power system.
Heightened flood risk The National Oceanic Atmospheric Administration (NOAA) said in a recent outlook that about 44 percent of the United States is at risk of floods this spring, equating to about 146 million people. This includes most of the eastern half of the country, the federal agency said.
The agency also sees “major” flood risk potential in some parts of the Upper Mississippi River Basin, and relatively higher risk in the Sierra Nevada region, due in part to a historic snowpack in California.
Multiple components of the power system can be affected by spring floods.
Power lines – Floods can saturate soil and make trees more likely to uproot and fall onto power lines. This has been contributing to power outages during California’s recent heavy storms–called atmospheric rivers–that started over the winter. In other regions, soil moisture has even been used as a predictor of where power outages will occur due to hurricanes, so that utility companies are better prepared to send line repair crews to the right areas. Hurricanes are primarily a summer and fall phenomenon, and summer also brings grid stress from air conditioning demand in many states, so for now, during spring, they are less of a concern.
Fuel transport – Spring floods can hinder the transportation of fuels like coal. While it is a heavily polluting fossil fuel that is set to continue declining as a fuel source for US electricity generation, with the EIA summer outlook for wind and solar pointing to further shifts, coal still accounted for roughly 20 percent of the country’s generation in 2022.
About 70 percent of US coal is transported at least part of the way by trains. The rail infrastructure to transport coal from the Powder River Basin in Montana and Wyoming–the country’s primary coal source–was proven to be vulnerable to extreme floods in the spring of 2011, and even more extreme floods in the spring of 2019. The 2019 floods’ disruptions of coal shipments to power plants via rail persisted for months and into the summertime, also affecting river shipments of coal by barge. In June 2019, hundreds of barges were stalled in the Mississippi River, through which millions of tons of the fossil fuel are normally transported.
Power plants – Power plants themselves can also be at risk of flooding, since most of them are sited near a source of water that is used to create steam to spin the plants’ turbines, and conversely, low water levels can constrain hydropower as seen in Western Canada hydropower drought during recent reservoir shortfalls. Most US fossil fuel generating capacity from sources like methane gas, which recently set natural gas power records across the grid, and coal utilizes steam to generate electricity.
However, much of the attention paid to the flood risk of power plant sites has centered on nuclear plants, a key source of low-carbon electricity discussed in IAEA low-carbon electricity lessons that also require a water source for the creation of steam, as well as for keeping the plant cool in an emergency. To name a notable flood example here in the United States–both visually and substantively–in 2011, the Fort Calhoun nuclear plant in Nebraska was completely surrounded by water due to late-spring flooding along the Missouri River. This sparked a lot of concerns because it was just a few months after the March 2011 meltdown of the Fukushima Daiichi nuclear plant in Japan. The public was thankfully not harmed by the Nebraska incident, but this was unfortunately not an isolated incident in terms of flood risks posed to the US nuclear power fleet.
Canada Tidal Energy Investment drives Nova Scotia's PLAT-I floating tidal array at FORCE, advancing renewable energy, clean electricity, emissions reductions, and green jobs while delivering 9 MW of predictable ocean power to the provincial grid.
Key Points
Federal funding for a floating tidal array delivering 9 MW of clean power in Nova Scotia, cutting annual CO2 emissions.
✅ $28.5M for Sustainable Marine's PLAT-I floating array
✅ Delivers 9 MW to Nova Scotia's grid via FORCE
✅ Cuts 17,000 tonnes CO2 yearly and creates local jobs
Canada has an abundance of renewable energy sources that are helping power our country's clean growth future and the Government of Canada is investing in renewable energy and grid modernization to reduce emissions, create jobs and invigorate local economies in a post COVID-19 pandemic world.
The Honourable Seamus O'Regan, Canada's Minister of Natural Resources, today announced one of Canada's largest-ever investments in tidal energy development — $28.5 million to Sustainable Marine in Nova Scotia to deliver Canada's first floating tidal energy array.
Sustainable Marine developed an innovative floating tidal energy platform called PLAT-I as part of advances in ocean and river power technologies that has undergone rigorous testing on the waters of Grand Passage for nearly two years. A second platform is currently being assembled in Meteghan, Nova Scotia and will be launched in Grand Passage later this year for testing before relocation to the Fundy Ocean Research Centre for Energy (FORCE) in 2021. These platforms will make up the tidal energy array.
The objective of the project is to provide up to nine megawatts of predictable and clean renewable electricity to Nova Scotia's electrical grid infrastructure. This will reduce greenhouse gas emissions by 17,000 tonnes of carbon dioxide a year while creating new jobs in the province. The project will also demonstrate the ability to harness tides as a reliable source of renewable electricity to power homes, vehicles and businesses.
Tidal energy — a clean, renewable energy source generated by ocean tides and currents, alongside evolving offshore wind regulations that support marine renewables — has the potential to significantly reduce Canada's greenhouse gas emissions and improve local air quality by displacing electricity generated from fossil fuels.
Minister O'Regan made the announcement at the Marine Renewables Canada 2020 Fall Forum, which brings together its members and industry to identify opportunities and strategize a path forward for marine renewable energy sources.
Funding for the project comes from Natural Resources Canada's Emerging Renewables Power Program, part of Canada's more than $180-billion Investing in Canada infrastructure plan for public transit projects, green infrastructure, social infrastructure, trade and transportation routes and Canada's rural and northern communities, as Prairie provinces' renewable growth accelerates nationwide.
EDF Nuclear Power Price Deal sets a 70 euros/MWh reference price, adds consumer protection if wholesale electricity prices exceed 110 euros/MWh, and outlines taxation mechanisms to shield bills while funding nuclear investment.
Key Points
A government-EDF deal setting 70 euros/MWh with safeguards above 110 euros/MWh to protect consumers.
✅ Reference price fixed at 70 euros/MWh, near EDF costs.
✅ Consumer shield above 110 euros/MWh; up to 90% extra-revenue tax.
✅ Review clauses maintain 70 euros/MWh through market swings.
State-controlled power group EDF and the French government have reached a tentative deal on future nuclear power prices, echoing a new electricity pricing scheme France has floated, a source close to the government said on Monday, ending months of tense negotiations.
The two sides agreed on 70 euros per megawatt hour (MWH) as a reference level for power prices, aligning with EU plans for more fixed-price contracts for consumers, the source said, cautioning that details of the deal are still being finalised.
The negotiations aimed to find a compromise between EDF, which is eager to maximise revenues to fund investments, and the government, keen to keep electricity bills for French households and businesses as low as possible, amid ongoing EU electricity reform debates across the bloc.
EDF declined to comment.
The preliminary deal sets out mechanisms that would protect consumers if power market prices rise above 110 euros/MWH, similar to potential emergency electricity measures being weighed in Europe, the source said, adding that the deal also includes clauses that would provide a price guarantee for EDF.
The 70 euros/MWH agreed reference price level is close to EDF's nuclear production costs, as Europe moves to revamp its electricity market more broadly. The nuclear power produced by the company provides 70% of France's electricity.
The agreement would allow the government to tax EDF's extra revenues at 90% if prices surpass 110 euros/MWH, in order to offset the impact on consumers. It would also enable a review of conditions in case of market fluctuations to safeguard the 70 euro level for EDF, reflecting how rolling back electricity prices is tougher than it appears, the source said.
French wholesale electricity prices are still above 100 euros/MWH, after climbing to 1,200 euros during last year's energy crisis, even as diesel prices have returned to pre-conflict levels.
A final agreement should be officially announced on Tuesday after a meeting between Finance Minister Bruno Le Maire, Energy Transition Minister Agnes Pannier-Runacher and EDF chief Luc Remont.
That meeting will work out the final details on price thresholds and tax rates between the reference level and the upper limit, the source said.
Negotiations between the two sides were so fraught that at one stage they raised questions about the future of EDF chief Luc Remont, who was appointed by President Emmanuel Macron a year ago to turn around EDF.
The group ended 2022 with a 18 billion-euro loss and almost 65 billion euros of net debt, hurt by a record number of reactor outages that coincided with soaring energy prices in the wake of Russia's invasion of Ukraine.
With its output at a 30-year low, EDF was forced to buy electricity on the market to supply customers. The government, meanwhile, imposed a cap on electricity prices, leaving EDF selling power at a discount.
Germany Nuclear Debate Amid Energy Crisis highlights nuclear power vs coal and natural gas, renewables and hydropower limits, carbon emissions, energy security, and baseload reliability during Russia-related supply shocks and winter demand.
Key Points
Germany Nuclear Debate Amid Energy Crisis weighs reactor extensions vs coal revival to bolster security, curb emissions.
✅ Coal plants restarted; nuclear shutdown stays on schedule.
✅ Energy security prioritized amid Russian gas supply cuts.
Peel away the politics and the passion, the doomsaying and the denialism, and climate change largely boils down to this: energy. To avoid the chances of catastrophic climate change while ensuring the world can continue to grow — especially for poor people who live in chronically energy-starved areas — we’ll need to produce ever more energy from sources that emit little or no greenhouse gases.
It’s that simple — and, of course, that complicated.
Zero-carbon sources of renewable energy like wind and solar have seen tremendous increases in capacity and equally impressive decreases in price in recent years, while the decades-old technology of hydropower is still what the International Energy Agency calls the “forgotten giant of low-carbon electricity.”
And then there’s nuclear power. Viewed strictly through the lens of climate change, nuclear power can claim to be a green dream, even as Europe is losing nuclear power just when it really needs energy most.
Unlike coal or natural gas, nuclear plants do not produce direct carbon dioxide emissions when they generate electricity, and over the past 50 years they’ve reduced CO2 emissions by nearly 60 gigatonnes. Unlike solar or wind, nuclear plants aren’t intermittent, and they require significantly less land area per megawatt produced. Unlike hydropower — which has reached its natural limits in many developed countries, including the US — nuclear plants don’t require environmentally intensive dams.
As accidents at Chernobyl and Fukushima have shown, when nuclear power goes wrong, it can go really wrong. But newer plant designs reduce the risk of such catastrophes, which themselves tend to garner far more attention than the steady stream of deaths from climate change and air pollution linked to the normal operation of conventional power plants.
So you might imagine that those who see climate change as an unparalleled existential threat would cheer the development of new nuclear plants and support the extension of nuclear power already in service.
In practice, however, that’s often not the case, as recent events in Germany underline.
When is a Green not green? The Russian war in Ukraine has made a mess of global energy markets, but perhaps no country has proven more vulnerable than Germany, reigniting debate over a possible resurgence of nuclear energy in Germany among policymakers.
At the start of the year, Russian exports supplied more than half of Germany’s natural gas, along with significant portions of its oil and coal imports. Since the war began, Russia has severely curtailed the flow of gas to Germany, putting the country in a state of acute energy crisis, with fears growing as next winter looms.
With little natural gas supplies of the country’s own, and its heavily supported renewable sector unable to fully make up the shortfall, German leaders faced a dilemma. To maintain enough gas reserves to get the country through the winter, they could try to put off the closure of Germany’s last three remaining nuclear reactors temporarily, which were scheduled to shutter by the end of 2022 as part of Germany’s post-Fukushima turn against nuclear power, and even restart already closed reactors.
Or they could try to reactivate mothballed coal-fired power plants, and make up some of the electricity deficit with Germany’s still-ample coal reserves.
Based on carbon emissions alone, you’d presumably go for the nuclear option. Coal is by far the dirtiest of fossil fuels, responsible for a fifth of all global greenhouse gas emissions — more than any other single source — as well as a soup of conventional air pollutants. Nuclear power produces none of these.
German legislators saw it differently. Last week, the country’s parliament, with the backing of members of the Green Party in the coalition government, passed emergency legislation to reopen coal-powered plants, as well as further measures to boost the production of renewable energy. There would be no effort to restart closed nuclear power plants, or even consider a U-turn on the nuclear phaseout for the last active reactors.
“The gas storage tanks must be full by winter,” Robert Habeck, Germany’s economy minister and a member of the Green Party, said in June, echoing arguments that nuclear would do little to solve the gas issue for the coming winter.
Partially as a result of that prioritization, Germany — which has already seen carbon emissions rise over the past two years, missing its ambitious emissions targets — will emit even more carbon in 2022.
To be fair, restarting closed nuclear power plants is a far more complex undertaking than lighting up old coal plants. Plant operators had only bought enough uranium to make it to the end of 2022, so nuclear fuel supplies are set to run out regardless.
But that’s also the point. Germany, which views itself as a global leader on climate, is grasping at the most carbon-intensive fuel source in part because it made the decision in 2011 to fully turn its back on nuclear for good at the time, enshrining what had been a planned phase-out into law.
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.
