A decision by the Ontario Power Authority to change the rules surrounding solar power production is drawing opposition from the solar energy industry.
On July 2, the authority quietly announced the rate being paid to some producers would be slashed from 80.2 cents to 58.8 cents per kilowatt hour.
Bill Murdoch, Progressive Conservative member of the legislature for Bruce-Grey-Owen Sound, says many farmers who have invested up to $100,000 in solar technology are going to be hurt by the reduction.
But Energy Minister Brad Duguid points out that those who already have contracts will continue to get the higher rate.
Mr. Duguid said that the new rate applies only to new ground-mounted systems and those planning roof-mounted installations will still get 80 cents per kilowatt hour under the microFIT program.
Mr. Duguid said microFIT would have become unsustainable if the original price structure had been maintained.
But John Verway of Copperhill Alternate Energy calls the proposed rate change counterproductive.
“Please do not allow a misguided and miscalculated change to destroy the progress so many have made so far,” Verway said in an open letter to Premier Dalton McGuinty.
“The jobs we have created will be lost and the confidence of manufacturers wanting to establish here will be irreparably damaged,” he said.
Due to the lower installation cost of ground-mounted systems, Mr. Duguid said profit margins under the 80.2-cent payment were in the 25 to 30 per cent range.
“A profit margin in the 10 to 11 per cent range... is what the program was based on,” he said.
Mr. Duguid said he doesn't anticipate the lower rate will discourage applications to the program.
“The rate of return is actually very generous even under the new proposed tariff.”
Mr. Verway disagrees.
“Customers are calling and cancelling orders, not changing to rooftop systems,” he said.
Mr. Murdoch said the rate reduction proves the Liberal government does not care about rural Ontario.
Mr. Duguid called Mr. Murdoch's comment “irresponsible” and said the change has “nothing to do with rural Ontario versus urban Ontario.”
Mr. Verway has started an advocacy group called Farmers for microFIT to lobby government members to “honour their commitment” to those who have responded to the program.
California income-based utility charges face bipartisan pushback as the PUC weighs fixed fees for PG&E, SDG&E, and Southern California Edison, reshaping rate design, electricity affordability, energy equity, and privacy amid proposed per-kWh reductions.
Key Points
PUC-approved fixed fees tied to household income for PG&E, SDG&E, and SCE, offset by lower per-kWh rates.
✅ Critics warn admin, privacy, legal risks and higher bills for savers
✅ Backers say lower-income pay less; kWh rates cut ~33% in PG&E area
Efforts are being made across California's political landscape to derail a legislative initiative that introduced income-based utility charges for customers of Southern California Edison and other major utilities.
Legislators from both the Democratic and Republican parties have proposed bills aimed at nullifying the 2022 legislation that established a sliding scale for utility charges based on customer income, a decision made in a late-hour session and subsequently endorsed by Governor Gavin Newsom.
The plan, pending final approval from the state Public Utilities Commission (PUC) — all of whose current members were appointed by Governor Newsom — would enable utilities like Southern California Edison, San Diego Gas & Electric, and PG&E to apply new income-based charges as early as this July.
Among the state legislators pushing back against the income-based charge scheme are Democrats Jacqui Irwin and Marc Berman, along with Republicans Janet Nguyen, Kelly Seyarto, Rosilicie Ochoa Bogh, Scott Wilk, Brian Dahle, Shannon Grove, and Roger Niello.
A cadre of specialists, including economist Ahmad Faruqui who has advised all three utilities implicated in the fee proposal, have outlined several concerns regarding the PUC's pending decision.
Faruqui and his colleagues argue that the proposed charges are excessively high in comparison to national standards, reflecting soaring electricity prices across the state, potentially leading to administrative challenges, legal disputes, and negative unintended outcomes, such as penalizing energy-conservative consumers.
Advocates for the income-based fee model, including The Utility Reform Network (TURN) and the National Resources Defense Council, argue it would result in higher charges for wealthier consumers and reduced fees for those with lower incomes. They also believe that the utilities plan to decrease per kilowatt-hour rates as part of a broader rate structure review to balance out the new fees.
However, even supporters like TURN and the Natural Resources Defense Council acknowledge that the income-based fee model is not a comprehensive solution to making soaring electricity bills more affordable.
If implemented, California would have the highest income-based utility fees in the country, with averages far surpassing the national average of $11.15, as reported by EQ Research:
Southern California Edison would charge $51.
San Diego Gas & Electric would levy $73.31.
PG&E would set fees at $50.92.
The proposal has raised concerns among state legislators about the additional financial burden on Californians already struggling with high electricity costs.
Critics highlight several practical challenges, including the PUC's task of assessing customers' income levels, a process fraught with privacy concerns, potential errors, and constitutional questions regarding access to tax information.
Economists have pointed out further complications, such as the difficulty in accurately assessing incomes for out-of-state property owners and the variability of customers' incomes over time.
The proposed income-based charges would differ by income bracket within the PG&E service area, for example, with lower-income households facing lower fixed charges and higher-income households facing higher charges, alongside a proposed 33% reduction in electricity rates to help mitigate the fixed charge impact.
Yet, the economists warn that most customers, particularly low-usage customers, could end up paying more, essentially rewarding higher consumption and penalizing efficiency.
This legislative approach, they caution, could inadvertently increase costs for moderate users across all income brackets, a sign of major changes to electric bills that could emerge, challenging the very goals it aims to achieve by promoting energy inefficiency.
Arc One Electric Speedboat delivers zero-emission performance, quiet operation, and reduced maintenance, leveraging battery propulsion, aerospace engineering, and venture-backed innovation to cut noise pollution, fuel costs, and water contamination in high-performance marine recreation.
Key Points
Arc One Electric Speedboat is a battery-powered, zero-emission craft offering quiet, high-performance marine cruising.
✅ 475 hp, 24 ft hull, about 40 mph top speed
✅ Cuts noise, fumes, and water contamination vs gas boats
✅ Backed by Andreessen Horowitz; ex-SpaceX engineers
A team of former SpaceX rocket engineers have joined the race to build the first commercial electric speedboat.
The Arc Boat company announced it had raised $4.25m (£3m) in seed funding to start work on a 24ft 475-horsepower craft that will cost about $300,000.
The LA-based company, which is backed by venture capital firm Andreessen Horowitz (an early backer of Facebook and Airbnb), said the first model of the Arc One boat would be available for sale by the end of the year.
Mitch Lee, Arc’s chief executive, said he wanted to build electric boats because of the impact conventional petrol- or diesel-powered boats have on the environment.
“They not only get just two miles to the gallon, they also pump a lot of those fumes into the water,” Lee said. “In addition, there is the huge noise pollution factor [of conventional boats] and that is awful for the marine life. With gas-powered boats it’s not just carbon emissions into the air, it’s also polluting the water and causing noise pollution. Electric boats, like electric ships clearing the air on the B.C. coast, eliminate all that.”
Lee said electric vessels would also reduce the hassle of boat ownership. “I love being out on the water, being on a boat is so much fun, but owning a boat is so awful,” he said. “I have always believed that electric boats make sense. They will be quicker, quieter and way cheaper and easier to operate and maintain, with access options like an electric boat club in Seattle lowering barriers for newcomers.”
While the first models will be very expensive, Lee said the cost was mostly in developing the technology and cheaper versions would be available in the future, mirroring advances in electric aviation seen across the industry. “It is very much the Tesla approach – we are starting up market and using that income to finance research and development and work our way down market,” he said.
Lee said the technology could be applied to larger craft, and even ferries could run on electricity in the future, as projects for battery-electric high-speed ferries begin to scale.
“We started in February with no team, no money and no warehouse,” he said. “By December we are going to be selling the Arc One, and we are hiring aggressively because we want to accelerate the adoption of electric boats across a whole range of craft, including an electric-ready ferry on Kootenay Lake.”
Lee founded the company with fellow mechanical engineer Ryan Cook. Cook, the company’s chief technology officer, was previously the lead mechanical engineer at Elon Musk’s space exploration company SpaceX where he worked on the Falcon 9 rocket, the world’s first orbital class reusable rocket. In parallel, Harbour Air's electric aircraft highlights cross-sector electrification. Apart from Lee, all of Arc’s employees have some experience working at SpaceX.
The Arc boat, which would have a top speed of 40 mph, joins a number of startups rushing to make the first large-scale production of electric-powered speedboats, while a Vancouver seaplane airline demonstrates complementary progress with a prototype electric aircraft. The Monaco Yacht Club this month held a competition for electric boat prototypes to “instigate a new vision and promote all positive approaches to bring yachting into line” with global carbon dioxide emission reduction targets. Sweden’s Candela C-7 hydrofoil boat was crowned the fastest electric vessel.
NECEC Clean Energy Connect advances with Maine DEP permits, Hydro-Québec contracts, and rigorous transmission line mitigation, including tapered vegetation, culvert upgrades, and forest conservation, delivering low-carbon power, broadband fiber, and projected ratepayer savings.
Key Points
A Maine transmission project delivering Hydro-Québec power with strict DEP mitigation, lower bills, and added broadband.
✅ DEP permits mandate tapered vegetation, culvert upgrades, land conservation
✅ Hydro-Québec to supply 9.55 TWh/yr via MA contracts; bill savings 2-4%
✅ Added broadband fiber in Somerset and Franklin; local tax benefits
The Maine DEP reviewed the Clean Energy Connect project for more than two years, while regional interest in cross-border transmission continued to grow, before issuing permits that included additional environmental mitigation elements.
"Collectively, the requirements of the permit require an unprecedented level of environmental protection and compensatory land conservation for the construction of a transmission line in the state of Maine," DEP said in a May 11 statement.
Requirements include limits on transmission corridor width, forest preservation, culvert replacement and vegetation management projects, while broader grid programs like vehicle-to-grid integration enhance clean energy utilization across the region.
"In our original proposal we worked hard to develop a project that provided robust mitigation measures to protect the environment," NECEC Transmission CEO Thorn Dickinson said in a statement. "And through this permitting process, we now have made an exceedingly good project even better for Maine."
NECEC will be built on land owned or controlled by Central Maine Power. The 53 miles of new corridor on working forest land will use a new clearing technique for tapered vegetation, while the remainder of the project follows existing power lines.
Environmentalists said they agreed with the decision, and the mitigation measures state regulators took, noting similar momentum behind new wind investments in other parts of Canada.
"Building new ways to deliver low-carbon energy to our region is a critical piece of tackling the climate crisis," CLF Senior Attorney Phelps Turner said in a statement. "DEP was absolutely right to impose significant environmental conditions on this project and ensure that it does not harm critical wildlife areas."
Once complete, Turner said the transmission line will allow the region "to retire dirty fossil fuel plants in the coming years, which is a win for our health and our climate."
The Massachusetts Department of Public Utilities in June 2019 advanced the project by approving contracts for the state's utilities to purchase 9,554,940 MWh annually from Hydro-Quebec. Officials said the project is expected to provide approximately 2% to 4% savings on monthly energy bills.
Total net benefits to Massachusetts ratepayers over the 20-year contract, including both direct and indirect benefits, are expected to be approximately $4 billion, according to the state's estimates.
NECEC "will also deliver significant economic benefits to Maine and the region, including lower electricity prices, increased local real estate taxes and reduced energy costs with examples like battery-backed community microgrids demonstrating local resilience, expanded fiber optic cable for broadband service in Somerset and Franklin counties and funding of economic development for Western Maine," project developers said in a statement.
Bay of Fundy Tidal Energy advances as Nova Scotia permits Jupiter Hydro to test floating barge platforms with helical turbines in Minas Passage, supporting renewable power, grid-ready pilots, and green jobs in rural communities.
Key Points
A Nova Scotia tidal energy project using helical turbines to generate clean power and create local jobs.
✅ Permits enable 1-2 MW prototypes near Minas Passage
✅ Floating barge platforms with patented helical turbines
✅ PPA at $0.50/kWh with Nova Scotia Power
An Alberta-based company has been granted permission to try to harness electricity from the powerful tides of the Bay of Fundy.
Nova Scotia has issued two renewable energy permits to Jupiter Hydro.
Backers have long touted the massive energy potential of Fundy's tides -- they are among the world's most powerful -- but large-scale commercial efforts to harness them have borne little fruit so far, even as a Scottish tidal project recently generated enough power to supply nearly 4,000 homes elsewhere.
The Jupiter application says it will use three "floating barge type platforms" carrying its patented technology. The company says it uses helical turbines mounted as if they were outboard motors.
"Having another company test their technology in the Bay of Fundy shows that this early-stage industry continues to grow and create green jobs in our rural communities," Energy and Mines Minister Derek Mombourquette said in a statement.
The first permit allows the company to test a one-megawatt prototype that is not connected to the electricity grid.
The second -- a five-year permit for up to two megawatts -- is renewable if the company meets performance standards, environmental requirements and community engagement conditions.
Mombourquette also authorized a power purchase agreement that allows the company to sell the electricity it generates to the Nova Scotia grid through Nova Scotia Power for 50 cents per kilowatt hour.
On its web site, Jupiter says it believes its approach "will prove to be the most cost effective marine energy conversion technology in the world," even as other regional utilities consider initiatives like NB Power's Belledune concept for turning seawater into electricity.
The one megawatt unit would have screws which are about 5.5 metres in diameter.
The project is required to obtain all other necessary approvals, permits and authorizations.
It will be located near the Fundy Ocean Research Center for Energy in the Minas Passage and will use existing electricity grid connections.
A study commissioned by the Offshore Energy Research Association of Nova Scotia says by 2040, the tidal energy industry could contribute up to $1.7 billion to Nova Scotia's gross domestic product and create up to 22,000 full-time jobs, a transition that some argue should be planned by an independent body to ensure reliability.
Last month, Nova Scotia Power said it now generates 30 per cent of its power from renewables, as the province moves to increase wind and solar projects after abandoning the Atlantic Loop.
The utility says 18 per cent came from wind turbines, nine per cent from hydroelectric and tidal turbines and three per cent by burning biomass across its fleet.
However, over half of the province's electrical generation still comes from the burning of coal or petroleum coke, even as environmental advocates push to reduce biomass use in the mix. Another 13 per cent come from burning natural gas and five per cent from imports.
AIDAsol shore power Rostock-Warnem fcnde delivers cold ironing for cruise ships, up to 20 MVA at berths P7 and P8, cutting port emissions during berthing and advancing AIDA's green cruising strategy across European ports.
Key Points
Rostock-Warnem fcnde shore power supplies two cruise ships up to 20 MVA, enabling cold ironing and cutting emissions.
✅ Up to 20 MVA; powers two cruise ships at berths P7 and P8
✅ Enables cold ironing for AIDA fleet to reduce berth emissions
✅ Part of AIDA green cruising with fuel cells and batteries
In a ceremony held in Rostock-Warnemünde yesterday during Germany’s 12th National Maritime Conference, the 2,174-passenger cruise ship AIDAsol inaugurated Europe’s largest shore power plants for ships.
The power plant has been established under a joint agreement between AIDA Cruises, a unit of Carnival Corporation & plc (NYSE/LSE: CCL; NYSE: CUK), the state government of Mecklenburg-Western Pomerania, the city of Rostock and the Port of Rostock.
“With our green cruising strategy, we have been investing in a sustainable cruise market for many years,” said AIDA Cruises President Felix Eichhorn. “The shore power plant in Rostock-Warnemünde is another important step — after the facility in Hamburg — on our way to an emission-neutral cruise that we want to achieve with our fleet. I would like to thank the state government of Mecklenburg-Western Pomerania and all partners involved for the good and trusting cooperation. Together, we are sending out an important signal, not just in Germany, but throughout Europe.”
CAN POWER TWO CRUISE SHIPS AT A TIME The shore power plant, which was completed in summer 2020, is currently the largest in Europe and aligns with port electrification efforts such as the all-electric berth at London Gateway in the UK. With an output of up to 20 megavolt amperes (MVA), two cruise ships can be supplied with electricity at the same time at berths P7 and P8 in Warnemünde.
In regular passenger operation AIDAsol needs up to 4.5 megawatts per hour (MWh) of electricity.
The use of shore power to supply ships with energy is a decisive step in AIDA Cruises’ plans to reduce local emissions to zero during berthing, complementing recent progress with electric ships on the B.C. coast, as a cruise ship typically stays in port around 40% of its operating time.
As early as 2004, when the order for the construction of AIDAdiva was placed, and for all other ships put into service in subsequent years, the company has considered the use of shore power as an option for environmentally friendly ship operation.
Since 2017, AIDA Cruises has been using Europe’s first shore power plant in Hamburg-Altona, where AIDAsol is in regular operation, while operators like BC Ferries add hybrid ferries to expand low-emission service in Canada. Currently, 10 ships in the AIDA fleet can either use shore power where available or are technically prepared for it.
The aim is to convert all ships built from 2000 onwards, supporting future solutions like offshore charging with wind power.
With AIDA Cruises starting a cruise season from Kiel, Germany, on May 22, AIDAsol will also be the first cruise ship to complete the final tests on a newly built shore power plant there, as innovations such as Berlin’s electric flying ferry highlight the broader shift toward electrified waterways. Construction of that plant is the result of a joint initiative by the state government of Schleswig-Holstein, the city and the port of Kiel and AIDA Cruises. AIDAsol is scheduled to arrive in Kiel on the afternoon of May 13.
As part of its green cruising strategy, AIDA Cruises has been investing in a sustainable cruise operation for many years, paralleling urban shifts toward zero-emission bus fleets in Berlin. Other steps on the path to the zero emission ship of the future are already in preparation. This year, AIDAnova will receive the first fuel cell to be used on an ocean-going cruise ship. In 2022, the largest battery storage system to date in cruise shipping will go into operation on board an AIDA ship, similar to advances in battery-electric ferries in the U.S. In addition, the company is already addressing the question of how renewable fuels can be used on board cruise ships in the future.
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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