Missourians won't have to pay state sales tax for new, energy-efficient appliances if they wait to make their purchase until mid-April.
From April 19-25, the state is waiving its 4.225 percent sales tax on washing machines, refrigerators, freezers, dishwashers, water heaters, furnaces and air conditions if the new appliance is Energy Star-certified. The state tax break only applies to the first $1,500 for each appliance. Nine counties and just over 50 cities also plan to waive their sales taxes for that week.
In promoting the weeklong tax holiday that doesn't start for more than a month, state officials and the president of the Missouri Retailers Association surrounded themselves with refrigerators, washing machines and other appliances at a Jefferson City electronics store.
Revenue Department Director Karen Mitchell said the Show-Me Green Sales Tax Holiday makes it easier for consumers to use less electricity and needs to be promoted early because appliances aren't cheap.
"We know people do not make these types of decisions to purchase large items at the last minute," she said. "We hope people will begin thinking now about buying some of these appliances."
Lawmakers included the sales tax holiday in broader legislation last year that was designed to increase energy efficiency.
That law also allows income tax deductions of up to $1,000 for home energy audits and the implementation of their recommendations, beginning this year. It also lets the state treasurer provide incentives to businesses producing and selling fuel or power from alternative energy sources, such as the sun, wind or water.
Legislative staff in a cost estimate prepared last year for the sales tax holiday, estimated it would cost state government just over $1.1 million in lost collections.
Asked by reporters about the potential for a drop in state revenue, Missouri Retailers Association President David Overfelt said the affect likely would be minimal.
"This is not a budget-buster," he said.
Overfelt said his organization plans to work with lawmakers to expand the tax holiday for Energy Star-certified appliances to include television sets.
Cal ISO Flex Alert urges Southern California energy conservation as a Stage 2 emergency strains the power grid, with potential rolling blackouts during peak hours from 3 to 10 p.m., if demand exceeds supply.
Key Points
A statewide call to conserve power during high demand, issued by the grid operator to prevent rolling blackouts.
✅ Stage 2 emergency signals severe grid strain
✅ Peak Flex Alert hours: 3 to 10 p.m. statewide
✅ Set thermostats to 78 and avoid major appliances
Residents and businesses across Southern California were urged to conserve power Tuesday afternoon amid ongoing electricity inequities across the state as the manager of the state’s power grid warned rolling blackouts could be imminent for some power customers.
The California Independent System Operator (Cal ISO), which manages the state power grid, declared a Stage 2 emergency as of 2:30 p.m., indicating severe strain on the electrical system, similar to a recent grid alert in Alberta that relied on reserves.
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Rolling blackouts for some customers could occur in a Stage 3 emergency, distinct from the intentional shut-offs some utilities use to reduce wildfire risk.
Cal ISO issued a statewide Flex Alert in effect from 3 to 10 p.m. Tuesday and Wednesday, with conservation considered especially critical during those hours, a concern heightened by pandemic-era grid operations this year.
Officials told reporters rolling blackouts might be avoided Tuesday evening if residents repeat the level of conservation seen Monday.
“If we can get the same sort of response we got yesterday, we can minimize this, or perhaps avoid it altogether,” Cal-ISO President/CEO Steve Berberich said, noting that some operators have even planned staff lockdowns during COVID-19 to maintain reliability.
Cal-ISO controls roughly 80% of the state’s power grid through Southern California Edison, Pacific Gas and Electric Co., with the utility recently restoring power after shut-offs in affected communities, and San Diego Gas & Electric.
Residents are urged to set thermostats at 78 in the afternoon and evening hours and avoiding the use of air conditioning and major appliances during the Flex Alert hours, as utilities like PG&E prepare for winter storms to improve resilience.
✅ Renewables and storage can boost capacity and cut emissions
As heat ramps up ahead of what forecasters say will be a hotter than normal summer, electricity experts and officials are warning that states may not have enough power to meet demand in the coming months. And many of the nation's grid operators are also not taking climate change into account in their planning, despite available grid resilience guidance that could inform upgrades, even as extreme weather becomes more frequent and more severe.
Power operators in the Central US, in their summer readiness report, have already predicted "insufficient firm resources to cover summer peak forecasts." That assessment accounted for historical weather and the latest NOAA outlook that projects for more extreme weather this summer.
But energy experts say that some power grid operators are not considering how the climate crisis is changing our weather — including more frequent extreme events — and that is a problem if the intent is to build a reliable power grid while accelerating investing in carbon-free electricity across markets.
"The reality is the electricity system is old and a lot of the infrastructure was built before we started thinking about climate change," said Romany Webb, a researcher at Columbia University's Sabin Center for Climate Change Law. "It's not designed to withstand the impacts of climate change."
Webb says many power grid operators use historical weather to make investment decisions, rather than the more dire climate projections, simply because they want to avoid the possibility of financial loss, even as climate-related credit risks for nuclear plants are being flagged, for investing in what might happen versus what has already happened. She said it's the wrong approach and it makes the grid vulnerable.
"We have seen a reluctance on the part of many utilities to factor climate change into their planning processes because they say the science around climate change is too uncertain," Webb said. "The reality is we know climate change is happening, we know the impact it has in terms of more severe heatwaves, hurricanes, drought, with recent hydropower constraints in British Columbia illustrating the risks, and we know that all of those things affect the electricity system so ignoring those impacts just makes the problems worse."
An early heatwave knocked six power plants offline in Texas earlier this month. Residents were asked to limit electricity use, keeping thermostats at 78 degrees or higher and, as extreme heat boosts electricity bills for consumers, avoid using large appliances at peak times. The Electric Reliability Council of Texas, or ERCOT, in its seasonal reliability report, said the state's power grid is prepared for the summer and has "sufficient" power for "normal" summer conditions, based on average weather from 2006 to 2020.
But NOAA's recently released summer outlook forecasts above average temperatures for every county in the nation.
"We are continuing to design and site facilities based on historical weather patterns that we know in the age of climate change are not a good proxy for future conditions," Webb said.
When asked if the agency is creating a blind spot for itself by not accounting for extreme weather predictions, an ERCOT spokesperson said the report "uses a scenario approach to illustrate a range of resource adequacy outcomes based on extreme system conditions, including some extreme weather scenarios."
The North American Electric Reliability Corporation, or NERC — a regulating authority that oversees the health of the nation's electrical infrastructure — has a less optimistic projection.
In a recent seasonal reliability report, NERC placed Texas at "elevated risk" for blackouts this summer. It also reported that while much of the nation will have adequate electricity this summer, several markets are at risk of energy emergencies.
California grid operators, who recently avoided widespread rolling blackouts as heat strained the grid, in its summer reliability report also based its readiness analysis on "the most recent 20 years of historical weather data." The report also notes the assessment "does not fully reflect more extreme climate induced load and supply uncertainties."
Compounding the US power grid's supply and demand problem is drought: NERC says there's been a 2% loss of reliable hydropower from the nation's power-producing dams. Add to that the rapid retirement of many coal power plants — all while nearly everything from toothbrushes to cars are now electrified. Energy experts say adding more renewables into the mix will have the dual impact of cutting climate change inducing greenhouse gas emissions but also increasing the nation's power supply, aligning with efforts such as California's 100% carbon-free mandate that aim to speed the transition.
Coinmint Plattsburgh Dispute spotlights cryptocurrency mining, hydropower electricity rates, a $1M security deposit, Public Service Commission rulings, municipal utility policies, and seasonal migration to Massena data centers as Bitcoin price volatility pressures operations.
Key Points
Legal and energy-cost dispute over crypto mining, a $1,019,503 deposit, and operations in Plattsburgh and Massena.
✅ PSC allows higher rates and requires large security deposits.
✅ Winter electricity spikes drove a $1M deposit calculation.
✅ Coinmint shifted capacity to Massena data centers.
A few years ago, there was a lot of buzz about the North Country becoming the next Silicon Valley of cryptocurrency, even as Maine debated a 145-mile line that could reshape regional power flows. One of the companies to flock here was Coinmint. The cryptomining company set up shop in Plattsburgh in 2017 and declared its intentions to be a good citizen.
Today, Coinmint is fighting a legal battle to avoid paying the city’s electric utility more than $1 million owed for a security deposit. In addition to that dispute, a local property manager says the firm was evicted from one of its Plattsburgh locations.
Companies like Coinmint chose to come to the North Country because of the relatively low electricity prices here, thanks in large part to the hydropower dam on the St. Lawrence River in Massena, and regionally, projects such as the disputed electricity corridor have drawn attention to transmission costs and access. Coinmint operates its North Country Data Center facilities in Plattsburgh and Massena. In both locations, racks of computer servers perform complex calculations to generate cryptocurrency, such as bitcoin.
When cryptomining began to take off in Plattsburgh, the cost of one bitcoin was skyrocketing. That brought hype around the possibility of big business and job creation in the North Country. But cryptomininers like Coinmint were using massive amounts of energy in the winter of 2017-2018, and that season, electric bills of everyday Plattsburgh residents spiked.
Many cryptomining firms operate in a state of flux, beholden to the price of Bitcoin and other cryptocurrencies, even as the end to the 'war on coal' declaration did little to change utilities' choices. When the price of one bitcoin hit $20,000 in 2017, it fell by 30% just days later. That’s one reason why the price of electricity is so critical for companies like Coinmint to turn a profit.
Plattsburgh puts the brakes on “cryptocurrency mining” In early 2018, Plattsburgh passed a moratorium on cryptocurrency mining operations, after residents complained of higher-than-usual electric bills.
“Your electric bill’s $100, then it’s at $130. Why? It’s because these guys that are mining the bitcoins are riding into town, taking advantage of a situation,” said resident Andrew Golt during a 2018 public hearing.
Coinmint aimed to assuage the worries of residents and other businesses. “At the end of the day we want to be a good citizen in whatever communities we’re in,” Coinmint spokesman Kyle Carlton told NCPR at that 2018 meeting.
“We’re open to working with those communities to figure out whatever solutions are going to work.”
The ban was lifted in Feb. 2019. However, since it didn’t apply to companies that were already mining cryptocurrency in Plattsburgh, Coinmint has operated in the city all along.
Coinmint challenges attempt to protect ratepayers New rules passed by the New York Public Service Commission in March 2018 allow municipal power authorities including Plattsburgh’s to charge big energy users such as Coinmint higher electricity rates, amid customer backlash in other utility deals. The new rules also require them to put down a security deposit to ensure their bills get paid.
But Coinmint disputes that deposit charge. The company has been embroiled in a legal fight for nearly a year against Plattsburgh Municipal Lighting Department (PMLD) in an attempt to avoid paying the electric utility’s security deposit bill of $1,019,503. That bill is based on an estimate of what would cover two months of electricity use if a company were to leave town without paying its electric bills.
Coinmint would not discuss the dispute on the record with NCPR. Legal documents show the firm argues the deposit charge is inflated, based on a flawed calculation resulting in a charge hundreds of thousands of dollars higher than what it should be.
“Essentially they’re arguing that they should only have to put up some average of their monthly bills without accounting for the fact that winter bills are significantly higher than the average,” said Ken Podolny, an attorney representing the Plattsburgh utility.
The company took legal action in February 2019 against PMLD in the hopes New York’s energy regulator, the Public Service Commission, would agree with Coinmint that the deposit charge was too high. An informal commission hearing officer disagreed, and ruled in October the charge was calculated correctly.
Coinmint appealed the ruling in November and a hearing on the appeal could come as soon as February.
Less than a week after Coinmint lost its initial challenge of the deposit charge, the company made a splashy announcement trumpeting its plans to “migrate its Plattsburgh, New York infrastructure to its Massena, New York location for the 2019-2020 winter season.”
The announcement made no mention of the appeal or the recent ruling against Coinmint. The company attributed its new plan to “exceptionally-high” electricity rates in Plattsburgh, as hydropower transmission projects elsewhere in New England faced their own controversies.
"We recognize some in the Plattsburgh community have blamed our operation for pushing rates higher for everyone so, while we disagree with that assessment, we hope this seasonal migration will have a positive impact on rates for all our neighbors,” said Coinmint cofounder Prieur Leary in the press statement.
“In the event that doesn't happen, we trust the community will look for the real answers for these high costs." Prieur Leary has since been removed from the corporate team page on the company’s website.
The company still operates in Plattsburgh at one of its locations in the city. As for staff, while at least two Coinmint employees have moved from Plattsburgh to Massena, where the company operates a data center inside a former Alcoa aluminum plant, it is unclear how many people in total have made the move.
Coinmint left its second Plattsburgh location in 2019. The company would not discuss that move on the record, yet the circumstances of the departure are murky.
The local property manager of the industrial park site told NCPR, “I have no comment on our evicted tenant Coinmint.” The property owner, California’s Karex Property Management Services, also would not comment regarding the situation, noting that “all staff have been told to not discuss anything regarding our past tenant Coinmint.”
Today, Bitcoin and other cryptocurrencies are worth a fraction of what they were back in 2017 when Coinmint came to the North Country, and now, amid a debate over Bitcoin's electricity use shaping market sentiment, the future of the entire industry here remains uncertain.
The need to transition to clean energy is apparent, urgent and inescapable. We must limit Earth’s rising temperature to within 1.5 C to avoid the worst effects of climate change — an especially daunting challenge in the face of the steadily increasing global demand for energy and the need for reliable clean power, with concepts that can generate electricity at night now being explored worldwide.
Part of the answer is using energy more efficiently. More than 72 per cent of all energy produced worldwide is lost in the form of heat, and advances in turning thermal energy into electricity could recover some of it. For example, the engine in a car uses only about 30 per cent of the gasoline it burns to move the car. The remainder is dissipated as heat.
Recovering even a tiny fraction of that lost energy would have a tremendous impact on climate change. Thermoelectric materials, which convert wasted heat into useful electricity, can help, especially as researchers pursue low-cost heat-to-electricity materials for scalable deployment.
Until recently, the identification of these materials had been slow. My colleagues and I have used quantum computations — a computer-based modelling approach to predict materials’ properties — to speed up that process and identify more than 500 thermoelectric materials that could convert excess heat to electricity, and help improve energy efficiency.
Making great strides towards broad applications The transformation of heat into electrical energy by thermoelectric materials is based on the “Seebeck effect.” In 1826, German physicist Thomas Johann Seebeck observed that exposing the ends of joined pieces of dissimilar metals to different temperatures generated a magnetic field, which was later recognized to be caused by an electric current.
Shortly after his discovery, metallic thermoelectric generators were fabricated to convert heat from gas burners into an electric current. But, as it turned out, metals exhibit only a low Seebeck effect — they are not very efficient at converting heat into electricity.
In 1929, the Russian scientist Abraham Ioffe revolutionized the field of thermoelectricity. He observed that semiconductors — materials whose ability to conduct electricity falls between that of metals (like copper) and insulators (like glass) — exhibit a significantly higher Seebeck effect than metals, boosting thermoelectric efficiency 40-fold, from 0.1 per cent to four per cent.
This discovery led to the development of the first widely used thermoelectric generator, the Russian lamp — a kerosene lamp that heated a thermoelectric material to power a radio.
Are we there yet? Today, thermoelectric applications range from energy generation in space probes to cooling devices in portable refrigerators, and include emerging thin-film waste-heat harvesters for electronics as well. For example, space explorations are powered by radioisotope thermoelectric generators, converting the heat from naturally decaying plutonium into electricity. In the movie The Martian, for example, a box of plutonium saved the life of the character played by Matt Damon, by keeping him warm on Mars.
In the 2015 film, The Martian, astronaut Mark Watney (Matt Damon) digs up a buried thermoelectric generator to use the power source as a heater.
Despite this vast diversity of applications, wide-scale commercialization of thermoelectric materials is still limited by their low efficiency.
What’s holding them back? Two key factors must be considered: the conductive properties of the materials, and their ability to maintain a temperature difference, as seen in nighttime electricity from cold concepts, which makes it possible to generate electricity.
The best thermoelectric material would have the electronic properties of semiconductors and the poor heat conduction of glass. But this unique combination of properties is not found in naturally occurring materials. We have to engineer them, drawing on advances such as carbon nanotube energy harvesters to guide design choices.
Searching for a needle in a haystack In the past decade, new strategies to engineer thermoelectric materials have emerged due to an enhanced understanding of their underlying physics. In a recent study in Nature Materials, researchers from Seoul National University, Aachen University and Northwestern University reported they had engineered a material called tin selenide with the highest thermoelectric performance to date, nearly twice that of 20 years ago. But it took them nearly a decade to optimize it.
To speed up the discovery process, my colleagues and I have used quantum calculations to search for new thermoelectric candidates with high efficiencies. We searched a database containing thousands of materials to look for those that would have high electronic qualities and low levels of heat conduction, based on their chemical and physical properties. These insights helped us find the best materials to synthesize and test, and calculate their thermoelectric efficiency.
We are almost at the point where thermoelectric materials can be widely applied, but first we need to develop much more efficient materials. With so many possibilities and variables, finding the way forward is like searching for a tiny needle in an enormous haystack.
Just as a metal detector can zero in on a needle in a haystack, quantum computations can accelerate the discovery of efficient thermoelectric materials. Such calculations can accurately predict electron and heat conduction (including the Seebeck effect) for thousands of materials and unveil the previously hidden and highly complex interactions between those properties, which can influence a material’s efficiency.
Large-scale applications will require themoelectric materials that are inexpensive, non-toxic and abundant. Lead and tellurium are found in today’s thermoelectric materials, but their cost and negative environmental impact make them good targets for replacement.
Quantum calculations can be applied in a way to search for specific sets of materials using parameters such as scarcity, cost and efficiency, and insights can even inform exploratory devices that generate electricity out of thin air in parallel fields. Although those calculations can reveal optimum thermoelectric materials, synthesizing the materials with the desired properties remains a challenge.
A multi-institutional effort involving government-run laboratories and universities in the United States, Canada and Europe has revealed more than 500 previously unexplored materials with high predicted thermoelectric efficiency. My colleagues and I are currently investigating the thermoelectric performance of those materials in experiments, and have already discovered new sources of high thermoelectric efficiency.
Those initial results strongly suggest that further quantum computations can pinpoint the most efficient combinations of materials to make clean energy from wasted heat and the avert the catastrophe that looms over our planet.
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.
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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