AT THE edge of Dar es Salaam, TanzaniaÂ’s commercial capital, in a space roughly the size of a football field, stands hope for AfricaÂ’s industrial future: the Ubungo power plant. Gleaming pipes emerge from the ground five modern generators hum quietly. This was where, in 2013, Barack Obama announced his Power Africa plan to electrify the continent.
The trouble with plants such as Ubungo is that there are not enough of them. Opposite the power plant, young men sell charcoal to burn for cooking and heat. At night in the city centre the streetlights are turned off. South of the Sahara there are only seven countries—Cameroon, Gabon, Ghana, Ivory Coast, Namibia, Senegal and South Africa—in which more than 50 of people have access to electricity. In a typical year the whole region generates less electrical power than Canada, and half of that supply is in South Africa.
Generating power in Africa ought to be a good business. Africans tend to pay extraordinary prices for electricity. Businesses rely on dirty and expensive diesel generators. Tanzanian mines are powered by generators burning diesel that has been trucked across the country a kilowatt-hour can cost as much as $1. Grid power at an American mine, by way of comparison, costs less than a tenth as much.
So there ought to be a rush to invest in African power plants. But there is not. Tanzania, a country of 50m people with substantial recent discoveries of natural gas, illustrates some of the bottlenecks.
Tanzania has about 1,500MW of installed electricity-generation capacity—about as much as a small American city. More than a third comes from hydroelectric power stations. Because of drought in recent years, these rarely run at full capacity. In early October, at the end of the dry season, the country had to shut down all its hydroelectric plants. Tanzania is not alone in relying heavily on hydropower. In Malawi and Zambia almost all power comes from water, when it flows.
Tanzania wants to build new gas-fired plants, connected via a new pipeline from a newly discovered gasfield in the south. Plants such as the one at Ubungo ought to generate lots of extra power cheaply. But that is not happening as quickly as it should. The Ubungo plant, which is owned by an American firm, Symbion, did not begin running at full capacity on local gas until last September. Before that, shortages meant that production often relied on imported liquid fuels such as kerosene.
Gas is relatively clean, reliable and inexpensive. Indeed, the Ubungo power station could easily add capacity, says Magesvaran Subramaniam, SymbionÂ’s local boss. It is just a matter of buying more mobile generators. The trouble is neither a lack of gas to power the plant nor a shortage of demand for the juice it sends down the wire it is that the only customer does not pay its bills on time. Tanesco, which has a monopoly on distributing power in Tanzania, is severely cash-strapped. Its outgoings are inflated by the need to buy expensive emergency backup fuel to keep the lights on when the supply from dams falters. In practice, payments to independent power producers such as Symbion often come last on its list.
On December 2nd SonGas, a private-equity owned firm that runs another gas-powered plant in Dar es Salaam, and which contributes as much as 20 of Tanzania’s grid power, threatened to stop generating electricity unless it is paid money is it owed by Tanesco. SonGas, like other firms investing in power plants across Africa, has a guarantee from Tanzania’s government that it will be paid—something financial backers generally insist on before investing in private power producers. But this does not help its short-term cashflow. Tanesco’s arrears do not mean that SonGas can refuse to pay for the gas it buys.
For many, then, the best hope of getting the lights on is to bypass the grid entirely. M-Kopa, a Kenyan firm, is expanding across east Africa selling its solar-powered battery systems, which contain a torch and a mobile-phone charger. Customers are effectively given loans to buy them repayments are made through mobile money.
Generating power at home may transform life in rural areas for the better, but factories, mines and mills need a reliable, large-scale power supply. If Africa is to industrialise, it needs power plants. These will not be built unless customers start paying their electricity bills.
Clean Energy Industry Support includes tax credits, refundability, safe harbor extensions, EV incentives, and stimulus measures to stabilize renewable energy projects, protect the workforce, and ensure financing continuity during economic recovery.
Key Points
Policies and funding to stabilize renewables, protect jobs, and extend tax incentives for workforce continuity.
✅ Extend PTC/ITC and remove phase-outs to sustain projects
✅ Enable direct pay or refundability to unlock financing
✅ Preserve safe harbor timelines disrupted by supply chains
U.S. Senator Catherine Cortez Masto (D-Nev.) led 17 Senate colleagues, as the Senate moves to modernize public-land renewables, in sending a letter calling on Congress to include support for the United States' clean energy industry and workforce in any economic aid packages.
"As Congress takes steps to ensure that our nation's workforce is prepared to emerge stronger from the coronavirus health and economic crisis, we must act to shore up clean energy businesses and workers who are uniquely impacted by the crisis, echoing a power-sector call for action from industry groups," said the senators. "This action, which has precedent in prior financial recovery efforts, could take several forms, including tax credit extensions or removal of the current phase-out schedule, direct payment or refundability, or extensions of safe harbor continuity."
"We need to make sure that any package protects workers and helps families stay afloat in these challenging times. Providing support to the clean energy industry will give much-needed certainty and confidence, as the sector targets a market majority, for those workers that they will be able to keep their paychecks and their jobs in this critical industry," the senators also said.
In addition to Senator Cortez Masto, the letter was also signed by Senators Ed Markey (D-Mass.), Martin Heinrich (D-N.M), Sheldon Whitehouse (D-R.I.), Debbie Stabenow (D-Mich.), Tina Smith (D-Minn.), Jack Reed (D-R.I.), Cory Booker (D-N.J.), Richard Blumenthal (D-Conn.), Amy Klobuchar (D-Minn.), Chris Van Hollen (D-Md.), Dianne Feinstein (D-Calif.), Jacky Rosen (D-Nev.), Tammy Duckworth (D-Ill.), Chris Coons (D-Del.), Mazie Hirono (D-Hawaii), Dick Durbin (D-Ill.), and Kyrsten Sinema (D-Ariz.).
Dear Leader McConnell, Leader Schumer, Chairman Grassley, Ranking Member Wyden:
As Congress takes steps to ensure that our nation's workforce is prepared to emerge stronger from the coronavirus health and economic crisis, we must act to shore up clean energy businesses and workers who are uniquely impacted by the crisis, with wind investments at risk amid the pandemic. This action, which has precedent in prior financial recovery efforts, could take several forms, including tax credit extensions or removal of the current phase-out schedule, direct payment or refundability, or extensions of safe harbor continuity.
First and foremost, we need to take care of workers' health and immediate needs to stay in their homes and provide for their families, and the Families First Coronavirus Response Act is a critical down payment. Now, we must make sure the workforce has jobs to return to and that employers remain able to pay for critical benefits like paid sick and family leave, healthcare, and Unemployment Insurance.
The renewable energy industry employs over 800,000 people across every state in the United States. This industry and its workers could suffer significant harms as a result of the coronavirus emergency and resulting financial impact. Renewable energy businesses are already seeing project cancellations or delays, as the Covid-19 crisis hits solar and wind across the sector, with the solar industry reporting delays of 30 percent. Likewise, the energy efficiency sector is susceptible to similar impacts. As the coronavirus pandemic intensifies in the United States, that rate of delay or cancellations will only continue to skyrocket. Global and domestic supply chains are already facing chaotic changes, with equipment delays of three to four months for parts of the industry. A major collapse in financing is all but certain as investment firms' profits turn to losses and capital is suddenly unavailable for large labor-intensive investments.
To ensure that we do not lose years of progress on clean energy and the source of employment for tens of thousands of renewable energy workers, Congress should look to previous relief packages as an example for how to support this sector and the broader American economy. The American Recovery and Reinvestment Act of 2009 (also known as the Recovery Act or ARRA) provided over $90 billion in funding for clean energy and grid modernization, along with emergency relief programs. Specifically, ARRA provided immediate funding streams like the 1603 Cash Grant program for renewables and the 30 percent clean energy manufacturing tax credit to give immediate relief for the clean energy industry. As Congress develops this new package, it should consider these immediate relief programs for the renewable and clean energy industry, especially as analyses suggest green energy could drive Covid-19 recovery at scale. This could include direct payment or refundability, extensions of safe harbor continuity, tax credit extensions, electric vehicle credit expansion, or removal of the current phase-out schedules for the clean energy industry.
We need to make sure that any package protects workers and helps families stay afloat in these challenging times. Providing support to the clean energy industry will give much-needed certainty and confidence for those workers that they will be able to keep their paychecks and their jobs in this critical industry.
These strategies to provide assistance to the clean energy industry must be included in any financial recovery discussions, particularly if the Trump Administration continues its push to aid the oil industry, even as some advocate a total fossil fuel lockdown to accelerate climate action. We appreciate your consideration and collaboration as we do everything in our power to quickly recover from this health and economic emergency.
COVID-19 Solar Job Losses are erasing five years of workforce growth, SEIA reports, with U.S. installations and capacity down, layoffs accelerating, 3 GW expected in Q2, and policy support key for economic recovery.
Key Points
COVID-19 Solar Job Losses describe the pandemic-driven decline in U.S. solar employment, installations, and capacity.
✅ SEIA reports a 38% national drop in solar jobs
✅ Q2 installs projected at 3 GW, below forecasts
✅ Layoffs outpace U.S. economy without swift policy aid
Job losses associated with the COVID-19 crisis have wiped out the past five years of workforce growth in the solar energy field, according to a new industry analysis.
The expected June 2020 solar workforce of 188,000 people across the United States is 114,000 below the pre-pandemic forecast of 302,000 workers, a shortfall tied to the solar construction slowdown according to the Solar Energy Industries Association, which said in a statement Monday that the solar industry is now losing jobs at a faster rate than the U.S. economy.
In Massachusetts, the loss of 4,284 solar jobs represents a 52 percent decline from previous projections, according to the association’s analysis.
The national 38 percent drop in solar jobs coincides with a 37 percent decrease in expected solar installations in the second quarter of 2020, and similar pressures have put wind investments at risk across the sector, the association stated. The U.S. is now on track to install 3 gigawatts of new capacity this quarter, though subsequent forecasts anticipated solar and storage growth as investments returned, and the association said the decrease from the expected capacity is equivalent to the electricity needed to power 288,000 homes.
“Thousands of solar workers are being laid off each week, but with swift action from Congress, we know that solar can be a crucial part of our economic recovery,” with proposals such as the Biden solar plan offering a potential policy path, SEIA President and CEO Abigail Ross Hopper said in a statement, as recent analyses point to US solar and wind growth under supportive policies.
Birtle Transmission Line connects Manitoba Hydro to SaskPower, enabling 215 MW of clean hydroelectricity, improving grid reliability, supporting affordable rates, and advancing Green Infrastructure goals under the Investing in Canada Plan across Manitoba and Saskatchewan.
Key Points
A 46 km line moving up to 215 MW from Manitoba Hydro to SaskPower, improving reliability and supplying cleaner power.
✅ Enables interprovincial grid tie between Manitoba and Saskatchewan
✅ Delivers up to 215 MW of renewable hydroelectricity
✅ Supports affordable rates and lower GHG emissions
The federal government announced funding for the Birtle Transmission Line Monday morning.
The project will help Manitoba Hydro build a transmission line from Birtle South Station in the Municipality of Prairie View to the Manitoba–Saskatchewan border 46 kilometres northwest. Once completed, the new line will allow up to 215 megawatts of hydroelectricity to flow from the Manitoba Hydro power grid to the SaskPower power grid, similar to the Great Northern Transmission Line connecting Manitoba and Minnesota today.
The government said the transmission line would create a more stable energy supply, keep energy rates affordable and help Saskatchewan's efforts to reduce cumulative greenhouse-gas emissions in that province.
"The Government of Canada is proud to be working with Manitoba to support projects that create jobs and improve people's lives across the province. The Birtle Transmission Line will provide the region with reliable and greener energy, as seen with Canadian hydropower to New York projects, that will help protect our environment while laying the groundwork for clean economic growth," said Jim Carr, member of Parliament for Winnipeg South Centre, on behalf of Catherine McKenna, minister of infrastructure and communities.
The Government of Canada is investing more than $18.7 million, and the government of Manitoba is contributing more than $42 million in this project through the Green Infrastructure Stream of the Investing in Canada Plan, which also supports Atlantic grid improvements nationwide.
"The Province of Manitoba has one of the cleanest electricity grids in Canada and the world with over 99 per cent of our electricity generated from clean, renewable sources, rooted in Manitoba's hydro history," said Central Services Minister Reg Helwer. "The Made-in-Manitoba Climate and Green Plan is good not only for Manitoba but for Canada and globally."
Jay Grewal, president, and CEO of Manitoba Hydro said the funding is a great example of co-operation between the provincial and federal governments, including investments in smart grid technology that modernize local networks.
"We are very pleased that Manitoba Hydro's Birtle Transmission Project is among the first projects to receive funding under the Canada Infrastructure Program, and we would like to thank both levels of governments for recognizing the importance of the project as we strengthen ties with our neighbours in Saskatchewan, as U.S.-Canada transmission approvals advance elsewhere," said Grewal.
A spokesperson for Manitoba Hydro said it’s too early to say how many jobs will be created during construction, as final contracts have not yet been awarded.
USDA Rural Energy Infrastructure Funding boosts renewable energy, BESS, and transmission upgrades, delivering grid modernization, resilience, and clean power to rural cooperatives through loans and grants aligned with climate goals, decarbonization, and energy independence.
Key Points
USDA Rural Energy Infrastructure Funding is a $4.37B program advancing renewables, BESS, and grid upgrades for rural power.
✅ Loans and grants for cooperatives modernizing rural grids.
✅ Prioritizes BESS to integrate wind and solar reliably.
✅ Upgrades transmission to cut losses and boost grid stability.
The U.S. Department of Agriculture (USDA) has announced a major investment of $4.37 billion aimed at upgrading rural electric cooperatives across the nation. This funding will focus on advancing renewable energy projects, enhancing battery energy storage systems (BESS), and upgrading transmission infrastructure to support a grid overhaul for renewables nationwide.
The USDA’s Rural Development initiative will provide loans and grants to cooperatives, supporting efforts to transition to cleaner energy sources that help rural America thrive, improve energy resilience, and modernize electrical grids in rural areas. These upgrades are expected to bolster the reliability and efficiency of energy systems, making rural communities more resilient to extreme weather events and fostering the expansion of renewable energy.
The funding will primarily support energy storage technologies, such as BESS, which allow excess energy from renewable sources like wind energy, solar, and hydropower technology to be stored and used during periods of high demand or when renewable generation is low. These systems are critical for integrating more renewable energy into the grid, ensuring a stable and sustainable power supply.
In addition to energy storage, the USDA’s investment will go toward enhancing the transmission networks that carry electricity across rural regions, aligning with a recent rule to boost renewable transmission across the U.S. By upgrading these systems, the USDA aims to reduce energy losses, improve grid stability, and ensure that rural communities have reliable access to power, particularly in remote and underserved areas.
This investment aligns with the Biden administration’s broader climate and clean energy goals, focusing on reducing greenhouse gas emissions and fostering sustainable energy practices, including next-generation building upgrades that lower demand. The USDA's support will also promote energy independence in rural areas, enabling local cooperatives to meet the energy demands of their communities while decreasing reliance on fossil fuels.
The funding is expected to have a far-reaching impact, not only reducing carbon footprints but also creating jobs in the renewable energy and construction sectors. By modernizing energy infrastructure, rural electric cooperatives can expand access to clean, affordable energy while contributing to the nationwide shift toward a more sustainable energy future.
The USDA’s commitment to supporting rural electric cooperatives marks a significant step in the transition to a more resilient and sustainable energy grid, mirroring grid modernization projects in Canada seen in recent years. By investing in renewables and modernizing transmission and storage systems, the government aims to improve energy access and reliability in rural communities, ultimately driving the growth of a cleaner, more energy-efficient economy.
As part of the initiative, the USDA has also highlighted its commitment to helping rural cooperatives navigate the challenges of implementing new technologies and infrastructure. The agency has pledged to provide technical assistance, ensuring that cooperatives have the resources and expertise needed to successfully complete these projects.
In conclusion, the USDA’s $4.37 billion investment represents a significant effort to improve the energy landscape of rural America. By supporting the development of renewable energy, energy storage, and transmission upgrades, the USDA is not only fostering a cleaner energy future but also enhancing the resilience of rural communities. This initiative will contribute to the nationwide transition toward a sustainable, low-carbon economy, ensuring that rural areas are not left behind in the global push for renewable energy.
Canadian Clean Hydrogen is surging, driven by net-zero goals, tax credits, and exports. Fuel cells, electrolysis, and low-emissions power and transport signal growth, though current production is largely fossil-based and needs decarbonization.
Key Points
Canadian Clean Hydrogen is the shift to make and use low-emissions hydrogen for energy and industry to reach net-zero.
✅ $17B tax credits through 2035 to scale electrolyzers and hubs
✅ Export MOUs with Germany and the Netherlands target 2025 shipments
✅ IEA: 99% of hydrogen from fossil fuels; deep decarbonization needed
As the world races to find effective climate solutions, and toward an electric planet vision, hydrogen is earning buzz as a potentially low-emitting alternative fuel source.
The promise of hydrogen as a clean fuel source is nothing new — as far back as the 1970s hydrogen was being promised as a "potential pollution-free fuel for our cars."
While hydrogen hasn't yet taken off as the fuel of the future — a 2023 report from McKinsey & Company and the Hydrogen Council estimates that there is a grand total of eight hydrogen vehicle fuelling stations in Canada — many still hope that will change.
The hope is hydrogen will play a significant role in combating climate change, serving as a low-emissions substitute for fossil fuels in power generation, home heating and transportation, where cleaning up electricity remains critical, and today, interest in a Canadian clean hydrogen industry may be starting to bubble over.
"People are super excited about hydrogen because of the opportunity to use it as a clean chemical fuel. So, as a displacement for natural gas, diesel, gasoline, jet fuel," said Andrew Gillis, CEO of Canadian hydrogen company Aurora Hydrogen.
Plans for low or zero-emissions hydrogen projects are beginning to take shape across the country. But, at the moment, hydrogen is far from a low-emissions fuel, which is why some experts suggest expectations for the resource should be tempered.
The IEA report indicates that in 2021, global hydrogen production emitted 900 million tonnes of carbon dioxide — roughly 180 million more than the aviation industry — as roughly 99 per cent of hydrogen production came from fossil fuel sources.
"There is a concern that the role of hydrogen in the process of decarbonization is being very greatly overstated," said Mark Winfield, professor of environmental and urban change at York University.
A growing excitement
In 2020, the government released a hydrogen strategy, aiming to "cement hydrogen as a tool to achieve our goal of net-zero emissions by 2050 and position Canada as a global, industrial leader of clean renewable fuels."
The latest budget includes over $17 billion in tax credits between now and 2035 to help fund clean hydrogen projects.
Today, the most common application for hydrogen in Canada is as a material in industrial activities such as oil refining and ammonia, methanol and steel production, according to Natural Resources Canada.
But, the buzz around hydrogen isn't exactly over its industrial applications, said Aurora Hydrogen's Gillis.
"All these sorts of things where we currently have emitting gaseous or liquid chemical fuels, hydrogen's an opportunity to replace those and access the energy without creating emissions at the point of us," Gillis said.
When used in a fuel cell, hydrogen can produce electricity for transportation, heating and power generation without producing common harmful emissions like nitrogen oxide, hydrocarbons and particulate matter — BloombergNEF estimates that hydrogen could meet 24 per cent of global energy demand by 2050.
A growing industry
Canada's hydrogen strategy aims to have 30 per cent of end-use energy be from clean hydrogen by 2050. According to the strategy, Canada produces an estimated three million tonnes of hydrogen per year from natural gas today, but the strategy doesn't indicate how much hydrogen is produced from low-emissions sources.
In recent years, the Canadian clean hydrogen industry has earned international interest, especially as Germany's hydrogen strategy anticipates significant imports.
In 2021, Canada signed a memorandum of understanding with the Netherlands to help develop "export-import corridors for clean hydrogen" between the two countries. Canada also recently inked a deal with Germany to start exporting the resource there by 2025.
But while a low-emissions hydrogen plant went online in Becancour, Que., in 2021, the rest of Canada's clean-hydrogen industry seems to be in the early stages.
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.
