Texas regulators added two cost-related caveats to a final order approving American Electric Power Co's plan to build a coal-fired power plant in Arkansas while regulators in that state delayed action on the unit's air permit.
In its final order the Texas Public Utility Commission said Texas customers of AEP's Southwestern Electric Power Co (SWEPCO) unit will pay no more their share of the $1.52 billion price tag to build the 600-megawatt John W Turk Jr. coal-fired plant in Fulton, Arkansas.
"This cap on the capital cost of the Turk plant limits the financial risk to Texas ratepayers," the order said.
Texas regulators, who voted last month to approve the plant, also limited the amount of future carbon-mitigation costs than can be passed to Texas ratepayers at $28 per ton through 2030.
Estimated costs for carbon mitigation ranged from $13 to $70 per ton, with the average between $30-$45, the order said.
SWEPCO spokesman Scott McCloud said the utility is evaluating the final order and had no comment on whether the company would file an appeal.
Commissioner Julie Parsley, who voted against SWEPCO's plan, said both stipulations "are not legally enforceable" on future commissions.
Meanwhile, issuance of an air permit for Turk, tentatively approved by the air division of the Arkansas Department of Environmental Quality, will be delayed from the third quarter, McCloud said, after that agency scheduled a second public hearing to allow comment on SWEPCO's plan to control mercury emissions.
While not required, the agency decided to hold a hearing next month on the mercury issue after a federal court ruling halted implementation of the Clean Air Mercury Rule.
AEP revised its Turk application to comply with Arkansas mercury emission rules leading to a need for additional public input. No permit can be issued until response to public comments are completed, an agency spokesman said.
Rising construction costs and climate-change worry have led utilities to cancel dozens of proposed coal-fired units in the past two years. Even so, more coal plants are being built in the U.S. now than two decades, according to a government report.
About 29 coal plants with a capacity exceeding 15,000 MW are under construction. Another 20 projects have permits or are near construction. Operation of the Turk plant is expected in the second half of 2012.
UK Renewables Surpass Nuclear Milestone as wind farms and solar panels outpace atomic output, cutting greenhouse gas emissions. BEIS data show low-carbon power generation rising while onshore wind subsidies and auction timelines face policy debate.
Key Points
It is the quarter when UK wind and solar generated more electricity than nuclear, signaling cleaner, low-carbon growth.
✅ BEIS reports wind and solar at 18.33 TWh vs nuclear 16.69 TWh
✅ Energy sector emissions fell 8% as coal use dropped
✅ Calls grow to reopen onshore wind support via CFD auctions
Wind farms and solar panels, with wind leading the power mix during key periods, produced more electricity than the UK’s eight nuclear power stations for the first time at the end of last year, official figures show.
Britain’s greenhouse gas emissions also continued to fall, dropping 3% in 2017, as coal use fell and the use of renewables climbed, though low-carbon generation stalled in 2019 according to later data.
Energy experienced the biggest drop in emissions of any UK sector, of 8%, while pollution from transport and businesses stayed flat.
Energy industry chiefs said the figures showed that the government should rethink its ban on onshore wind subsidies, a move that ministers have hinted could happen soon.
Lawrence Slade, chief executive of the big six lobby group Energy UK, said: “We need to keep up the pace ... by ensuring that the lowest cost renewables are no longer excluded from the market.”
Across the whole year, low-carbon sources of power – wind, solar, biomass and nuclear – provided a record 50.4% of electricity, up from 45.7% in 2016, when wind beat coal for the first time.
But in the fourth quarter of 2017, high wind speeds, new renewables installations and lower nuclear output saw wind and solar becoming the second biggest source of power for the first time.
Wind and solar generated 18.33 terawatt hours (TWh), with nuclear on 16.69TWh, and the UK later set a new record for wind power during 2019, the figures published by the Department for Business, Energy and Industrial Strategy show.
But renewables still have a long way to go to catch up with gas, the UK’s top source of electricity at 36.12TWh, which saw its share of generation fall slightly, though at times wind became the main source as capacity expanded.
Greenpeace said the figures showed the government should capitalise on its lead in renewables and “stop wasting time and money propping up nuclear power”.
Horizon Nuclear Power, a subsidiary of the Japanese conglomerate Hitachi, is in talks with Whitehall officials for a financial support package from the government, which it says it needs by midsummer.
By contrast, large-scale solar and onshore wind projects are not eligible for support, after the Conservative government cut subsidies in 2015.
However the energy minister, Claire Perry, recently told House Magazine that “we will have another auction that brings forward wind and solar, we just haven’t yet said when”.
Germany's Coal Reliance reflects an energy crisis, soaring natural gas prices, and a nuclear phase-out, as Destatis data show higher coal-fired electricity despite growing wind and solar generation, impacting grid stability and emissions.
Key Points
Germany's coal reliance is more coal power due to gas spikes and a nuclear phase-out, despite wind and solar growth.
✅ Coal share near one-third of electricity, per Destatis
✅ Gas-fired output falls as prices soar after Russia's invasion
✅ Wind and solar rise; grid stability and recession risks persist
Germany is relying on highly-polluting coal for almost a third of its electricity, as the impact of government policies, reflecting an energy balancing act for the power sector, and the war in Ukraine leads producers in Europe’s largest economy to use less gas and nuclear energy.
In the first six months of the year, Germany generated 82.6 kWh of electricity from coal, up 17 per cent from the same period last year, according to data from Destatis, the national statistics office, published on Wednesday. The leap means almost one-third of German electricity generation now comes from coal-fired plants, up from 27 per cent last year. Production from natural gas, which has tripled in price to €235 per megawatt hour since Russia’s invasion in late February, fell 18 per cent to only 11.7 per cent of total generation.
Destatis said that the shift from gas to coal was sharper in the second quarter. Coal-fired electricity increased by an annual rate of 23 per cent in the three months to June, while electricity generation from natural gas fell 19 per cent.
The figures highlight the challenge facing European governments in meeting clean energy goals after the Kremlin announced this week that the Nordstream 1 pipeline that takes Russian gas to Germany would remain closed until Europe removed sanctions on the country’s oil.
Germany has been trying to reduce its reliance on coal, which releases almost twice as many emissions as gas and more than 60 times those of nuclear energy, according to estimates from the Intergovernmental Panel on Climate Change, though grid expansion challenges have slowed renewable build-out in recent years.
Chancellor Olaf Scholz said the opposition CDU bore “complete responsibility” for the exit from coal and nuclear power that formed part of his predecessor Angela Merkel’s Energiewende policies, amid a continuing nuclear option debate in climate policy, which in turn raised reliance on Russian gas. At the beginning of this year, more than 50 per cent of Germany’s gas imports came from Russia, a figure that fell slightly over the opening half of 2022.
But CDU leader Friedrich Merz accused the government of “madness” over its decision to idle the country’s three remaining nuclear power stations from the end of this year, though officials have argued that nuclear would do little to solve the gas issue in the short term.
Electricity generation from nuclear energy has already halved after three of the six nuclear power plants that were still in operation at the end of 2021 were closed during the first half of this year. Berlin said on Monday it would keep on standby two of its remaining three nuclear power stations, a move to extend nuclear power during the energy crisis, which were all due to close at the end of the year.
The German government has warned of the risk of electricity shortages this winter. “We cannot be sure that, in the event of grid bottlenecks in neighbouring countries, there will be enough power plants available to help stabilise our electricity grid in the short term,” said German economy minister Robert Habeck on Monday.
However Scholz said that, after raising gas storage levels to 86 per cent of capacity, Germany would “probably get through this winter, despite all the tension”.
One bright spot from the data was the increase in use of renewable energy, highlighting a recent renewables milestone in Germany. The proportion of electricity generated from wind power generation rose by 18 per cent to 25 per cent of all electricity generation, while solar energy production increased 20 per cent.
Ángel Talavera, head of Europe economics at the consultancy Oxford Economics, said that the success in moving away from gas towards other energy sources “means that the risks of hard energy rationing over the winter are less severe now, even with little to no Russian gas flows”.
However, economists still expect a recession in the eurozone’s largest economy, amid a deteriorating German economy outlook over the near term, as a large part of the impact comes via higher prices and because industries and households still rely on gas for heating.
Separate official data also published on Wednesday showed that German industrial production slid 0.3 per cent between June and July. Production at Germany’s most energy intensive industries fell almost 7 per cent in the five months after Russia’s invasion of Ukraine.
“The demand destruction caused by the surge in prices will still send the German economy into recession over the winter,” said Talavera.
Ontario Electricity Transition faces surging demand, GHG targets, and federal regulations, balancing natural gas, renewables, battery storage, and grid reliability while pursuing net-zero by 2035 and cost-effective decarbonization for industry, EVs, and growing populations.
Key Points
Ontario Electricity Transition is the province's shift to a reliable, low-GHG grid via renewables, storage, and policy.
✅ Demand up 75% by 2050; procurement adds 4,000 MW capacity.
✅ Gas use rises to 25% by 2030, challenging GHG goals.
✅ Tripling wind and solar with storage can cut costs and emissions.
Ontario's electricity sector stands at a pivotal crossroads. Once a leader in clean energy, the province now faces the dual challenge of meeting surging demand while adhering to stringent greenhouse gas (GHG) reduction targets. Recent developments, including the expansion of natural gas infrastructure and proposed federal regulations, have intensified debates about the future of Ontario's energy landscape, as this analysis explains in detail.
Rising Demand and the Need for Expansion
Ontario's electricity demand is projected to increase by 75% by 2050, equivalent to adding four and a half cities the size of Toronto to the grid. This surge is driven by factors such as industrial electrification, population growth, and the transition to electric vehicles. In response, as Ontario confronts a looming shortfall in the coming years, the provincial government has initiated its most ambitious energy procurement plan to date, aiming to secure an additional 4,000 megawatts of capacity by 2030. This includes investments in battery storage and natural gas generation to ensure grid reliability during peak demand periods.
The Role of Natural Gas: A Controversial Bridge
Natural gas has become a cornerstone of Ontario's strategy to meet immediate energy needs. However, this reliance comes with environmental costs. The Independent Electricity System Operator (IESO) projects that by 2030, natural gas will account for 25% of Ontario's electricity supply, up from 4% in 2017. This shift raises concerns about the province's ability to meet its GHG reduction targets and to embrace clean power in practice.
The expansion of gas-fired plants, including broader plans for new gas capacity, such as the Portlands Energy Centre in Toronto, has sparked public outcry. Environmental groups argue that these expansions could undermine local emissions reduction goals and exacerbate health issues related to air quality. For instance, emissions from the Portlands plant have surged from 188,000 tonnes in 2017 to over 600,000 tonnes in 2021, with projections indicating a potential increase to 1.65 million tonnes if the expansion proceeds as planned.
Federal Regulations and Economic Implications
The federal government's proposed clean electricity regulations aim to achieve a net-zero electricity sector by 2035. However, Ontario's government has expressed concerns that these regulations could impose significant financial burdens. An analysis by the IESO suggests that complying with the new rules would require doubling the province's electricity generation capacity, potentially adding $35 billion in costs by 2050, while other estimates suggest that greening Ontario's grid could cost $400 billion over time. This could result in higher residential electricity bills, ranging from $132 to $168 annually starting in 2033.
Pathways to a Sustainable Future
Experts advocate for a diversified approach to decarbonization that balances environmental goals with economic feasibility. Investments in renewable energy sources, such as new wind and solar resources, along with advancements in energy storage technologies, are seen as critical components of a sustainable energy strategy. Additionally, implementing energy efficiency measures and modernizing grid infrastructure can enhance system resilience and reduce emissions.
The Ontario Clean Air Alliance proposes phasing out gas power by 2035 through a combination of tripling wind and solar capacity and investing in energy efficiency and storage solutions. This approach not only aims to reduce emissions but also offers potential cost savings compared to continued reliance on gas-fired generation.
Ontario's journey toward a decarbonized electricity grid is fraught with challenges, including balancing reliability, clean, affordable electricity, and environmental sustainability. While natural gas currently plays a significant role in meeting the province's energy needs, its long-term viability as a bridge fuel remains contentious. The path forward will require careful consideration of technological innovations, regulatory frameworks, and public engagement to ensure a clean, reliable, and economically viable energy future for all Ontarians.
COP24 Climate Talks in Poland gather nearly 200 nations to finalize the Paris Agreement rulebook, advance the Talanoa Dialogue, strengthen emissions reporting and transparency, and align finance, technology transfer, and IPCC science for urgent mitigation.
Key Points
UNFCCC summit in Katowice to finalize Paris rules, enhance transparency, and drive stronger emissions cuts.
✅ Paris rulebook on reporting, transparency, markets, and timelines
✅ Talanoa Dialogue to assess gaps and raise ambition by 2020
✅ Finance and tech transfer for developing countries under UNFCCC
Delegates from nearly 200 countries have assembled this month in Katowice, Poland — the heart of coal country — to try to move the ball forward on battling climate change.
It’s now the 24th annual meeting, or “COP” — conference of the parties — under the landmark U.N. Framework Convention on Climate Change, which the United States signed under then-President George H.W. Bush in 1992. More significantly, it’s the third such meeting since nations adopted the Paris climate agreement in 2015, widely seen at the time as a landmark moment in which, at last, developed and developing countries would share a path toward cutting greenhouse gas emissions, as Obama's clean energy push sought to lock in momentum.
But the surge of optimism that came with Paris has faded lately. The United States, the second largest greenhouse gas emitter, said it would withdraw from the agreement, though it has not formally done so yet. Many other countries are off target when it comes to meeting their initial round of Paris promises — promises that are widely acknowledged to be too weak to begin with. And emissions have begun to rise after a brief hiatus that had lent some hope of progress.
The latest science, meanwhile, is pointing toward increasingly dire outcomes. The amount of global warming that the world already has seen — 1 degree Celsius, 1.8 degrees Fahrenheit — has upended the Arctic, is killing coral reefs and may have begun to destabilize a massive part of Antarctica. A new report from the U.N.'s Intergovernmental Panel on Climate Change (IPCC), requested by the countries that assembled in Paris to be timed for this year’s meeting, finds a variety of increasingly severe effects as soon as a rise of 1.5 degrees Celsius arrives — an outcome that can’t be avoided without emissions cuts so steep that they would require societal transformations without any known historical parallel, the panel found.
It’s in this context that countries are meeting in Poland, with expectations and stakes high.
So what’s on the agenda in Poland?
The answer starts with the Paris agreement, which was negotiated three years ago, has been signed by 197 countries and is a mere 27 pages long. It covers a lot, laying out a huge new regime not only for the world as a whole to cut its greenhouse gas emissions, but for each individual country to regularly make new emissions-cutting pledges, strengthen them over time, report emissions to the rest of the world and much more. It also addresses financial obligations that developed countries have to developing countries, including how to achieve clean and universal electricity at scale, and how technologies will be transferred to help that.
But those 27 pages leave open to interpretation many fine points for how it will all work. So in Poland, countries are performing a detailed annotation of the Paris agreement, drafting a “rule book” that will span hundreds of pages.
That may sound bureaucratic, but it’s key to addressing many of the flash points. For instance, it will be hard for countries to trust that their fellow nations are cutting emissions without clear standards for reporting and vetting. Not everybody is ready to accept a process like the one followed in the United States, which not only publishes its emissions totals but also has an independent review of the findings.
“A number of the developing countries are resisting that kind of model for themselves. They see it as an intrusion on their sovereignty,” said Alden Meyer, director of strategy and policy at the Union of Concerned Scientists and one of the many participants in Poland this week. “That’s going to be a pretty tough issue at the end of the day.”
It’s hardly the only one. Also unclear is what countries will do after the time frames on their current emissions-cutting promises are up, which for many is 2025 or 2030. Will all countries then start reporting newer and more ambitious promises every five years? Every 10 years?
That really matters when five years of greenhouse gas emissions — currently about 40 billion tons of carbon dioxide annually — are capable of directly affecting the planet’s temperature.
What can we expect each day?
The conference is in its second week, when higher-level players — basically, the equivalent of cabinet-level leaders in the United States — are in Katowice to advance the negotiations.
As this happens, several big events are on the agenda. On Tuesday and Wednesday is the “Talanoa Dialogue,” which will bring together world leaders in a series of group meetings to discuss these key questions: “Where are we? Where do we want to go? How do we get there?”
Friday is the last day of the conference, but pros know these events tend to run long. On Friday — or after — we will be waiting for an overall statement or decision from the meeting which may signal how much has been achieved.
What is the “Talanoa Dialogue”?
“Talanoa” is a word used in Fiji and in many other Pacific islands to refer to “the sharing of ideas, skills and experience through storytelling.” This is the process that organizers settled on to fulfill a plan formed in Paris in 2015.
That year, along with signing the Paris agreement, nations released a decision that in 2018 there should be a “facilitative dialogue" among the countries “to take stock” of where their efforts stood to reduce greenhouse gas emissions. This was important because going into that Paris meeting, it was already clear that countries' promises were not strong enough to hold global warming below a rise of 2 degrees Celsius (3.6 degrees Fahrenheit) above preindustrial temperatures.
This dialogue, in the Talanoa process, was meant to prompt reflection and maybe even soul searching about what more would have to be done. Throughout the year, “inputs” to the Talanoa dialogue — most prominently, the recent report by the United Nations' Intergovernmental Panel on Climate Change on the meaning and consequences of 1.5 degrees Celsius of warming —have been compiled and synthesized. Now, over two days in Poland, countries' ministers will assemble to share stories in small groups about what is working and what is not and to assess where the world as a whole is on achieving the required greenhouse gas emissions reductions.
What remains to be seen is whether this process will culminate in any kind of product or statement that calls clearly for immediate, strong ramping up of climate change promises across the world.
With the clock ticking, will countries do anything to increase their ambition at this meeting?
If negotiating the Paris rule book sounds disappointingly technical, well, you’re not the only one feeling that way. Pressure is mounting for countries to accomplish something more than that in Poland — to at minimum give a strong signal that they understand that the science is looking worse and worse, and the world’s progress on the global energy transition isn’t matching that outlook.
“The bigger issue is how we’re going to get to an outcome on greater ambition,” said Lou Leonard, senior vice president for climate and energy at the World Wildlife Fund, who is in Poland observing the talks. “And I think the first week was not kind on moving that part of the agenda forward.”
Most countries are not likely to make new emissions-cutting promises this week. But there are two ways that the meeting could give a strong statement that countries should — or will — come up with new promises at least by 2020. That’s when extremely dramatic emissions cuts would have to start, including progress toward net-zero electricity by mid-century, according to the recent report on 1.5 degrees Celsius of warming.
The first is the aforementioned “Talanoa dialogue” (see above). It’s possible that the outcome of the dialogue could be a statement acknowledging that the world isn’t nearly far enough along and calling for much stronger steps.
There will also be a decision text released for the meeting as a whole, which could potentially send a signal. Leonard said he hopes that would include details for the next steps that will put the world on a better course.
“We have to create milestones, and the politics around it that will pressure countries to do something that quite frankly they don’t want to do,” he said. “It’s not going to be easy. That’s why we need a process that will help make it happen. And make the most of the IPCC report that was designed to come out right now so it could do this for us. That’s why we have it, and it needs to serve that role.”
The United States says it will withdraw from the agreement, so what role is it playing in Poland?
Despite President Trump’s pledge to withdraw, the United States remains in the Paris agreement (for now) and has sent a delegation of 44 people to Poland, largely from the State Department but also from the Environmental Protection Agency, Energy Department and even the White House, while domestically a historic U.S. climate law has recently passed to accelerate clean energy. Many of these career government officials remain deeply engaged in hashing out details of the agreement.
Still, the country as a whole is being cast in an antagonistic role in the talks.
Germany energy liquidity crisis is straining municipal utilities as gas and power prices surge, margin calls rise, and Russian supply cuts bite, forcing state support, interventions, and emergency financing to stabilize households and businesses.
Key Points
A cash squeeze on German municipal utilities as soaring gas and power prices trigger margin calls and funding gaps.
✅ Margin calls and spot-market purchases strain cash flow
✅ State liquidity lines and EU collateral support proposed
Germany’s fears that soaring power prices and gas prices could trigger a deeper crisis is starting to get real.
Several hundred local utilities are coming under strain and need support, according to the head of Germany’s largest energy lobby group. The companies, generally owned by municipalities, supply households and small businesses directly and are a key part of the country’s power and gas network.
“The next step from the government and federal states must be to secure liquidity for these municipal companies,” Kerstin Andreae, chairwoman of the German Association of Energy and Water Industries, told Bloomberg in Berlin. “Prices are rising, and they have no more money to pay the suppliers. This is a big problem.”
Germany’s energy crunch intensified over the weekend after Russia’s Gazprom PJSC halted its key gas pipeline indefinitely, a stark wake-up call for policymakers to reduce fossil fuel dependence. European energy prices have surged again amid concerns over shortages this winter and fears of a worst-case energy scenario across the bloc.
Many utilities are running into financial issues as they’re forced to cover missing Russian deliveries with expensive supplies on the spot market. German energy giant Uniper SE, which supplies local utilities, warned it will likely burn through a 7 billion-euro ($7 billion) government safety net and will need more help already this month.
Some German local utilities have already sought help, according to a government official, who asked not to be identified in line with briefing rules.
With Europe’s largest economy already bracing for recession, Chancellor Olaf Scholz’s administration is battling on several fronts, testing the government’s financial capacity. The ruling coalition agreed Sunday on a relief plan worth about 65 billion euros -- part of an emerging energy shield package to contain the fallout of surging costs for households and businesses.
Starting in October, local utilities will have to pay a levy for the gas acquired, which will further increase their financial burden, Andreae said.
Margin Calls European gas prices are more than four times higher than usual for this time of year, underscoring why rolling back electricity prices is tougher than it appears for policymakers, as Russia cuts supplies in retaliation for sanctions related to its invasion of Ukraine. When prices peak, energy companies have to pay margin calls, extra collateral required to back their trades.
Read more: Energy Trade Risks Collapsing Over Margin Calls of $1.5 Trillion
The problem has hit local utilities in other countries as well. In Austria, the government approved a 2 billion-euro loan for Vienna’s municipal utility last month.
The European Union is also planning help, floating gas price cap strategies among other tools. The bloc’s emergency measures will include support for electricity producers struggling to find enough cash to guarantee trades, according to European Commission President Ursula von der Leyen.
The situation has worsened in Germany as some of the country’s big gas importers are reluctant to sell more supplies to some of municipal companies amid fears they could default on payments, Andreae said.
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.
