Dominion Virginia Power has chosen ElsterÂ’s EnergyAxis System Smart Grid Solution for use in the utilityÂ’s recently announced energy conservation plans.
In 2009, Dominion plans to deploy 200,000 smart meters as part of a large demonstration program of smart grid technology in urban and rural areas of DominionÂ’s service territory. Dominion expects to improve customer service and business operations through advanced system control, real-time outage notification, and power quality monitoring.
As part of this program, Dominion is deploying a number of smart thermostats with the EnergyAxis System for a residential critical peak pricing pilot this summer. Dominion will measure customer responsiveness to changing energy prices and the impact on energy demand during peak usage periods.
DominionÂ’s plans for using the EnergyAxis System strengthen a long-standing relationship between Dominion and Elster.
“Dominion is an industry leader, providing its customers with state-of-the-art, cost-effective, energy conservation programs,” said Ivo Steklac, global vice president, Elster Integrated Solutions. “We are excited that our EnergyAxis System will provide Dominion with a solid foundation to help meet its business and energy conservation goals.”
Meaford Pumped Storage Project aims to balance the grid with hydro-electric generation, a hilltop reservoir, and transmission lines near Georgian Bay, pending environmental assessment, permitting, and federal review of impacts on fish and drinking water.
Key Points
TC Energy proposal to pump water uphill off-peak and generate 1,000 MW at peak, pending studies and approvals.
✅ Balances grid by storing off-peak energy and generating at peak.
✅ Environmental studies and federal review underway before approvals.
Plans for a $3.3 billion hydro-electric project in Meaford are still in the early study stages, but some residents have concerns about what it might mean for the environment, as past Site C stability issues have illustrated for large hydro projects.
A one-year permit was granted for TC Energy Corporation (TC Energy) to begin studies on the proposed location back in May, and cross-border projects like the New England Clean Power Link require federal permits as well to proceed. Local municipalities were informed of the project in June.
TC Energy is proposing to have a pumped storage project at the 4th Canadian Division Training (4CDTC) Meaford property, which is on federal lands.
A letter sent to local municipalities explains that the plan is to balance supply and demand on the electrical grid by pumping water uphill during off-peak hours. It would then release the water back into Georgian Bay during peak periods, generating up to 1,000 megawatts of electricity.
The project is expected to create 800 jobs over four years of construction, in addition to long-term operational positions.
According to the company's website, the proposed pump station would require a large reservoir on the military base, a generating station, transmission lines infrastructure, and a break wall 850 metres from shore.
Some residents fear the project will threaten the bay and the fish, echoing Site C dam concerns shared with northerners, and the region's drinking water.
Meaford's mayor says the town has no jurisdiction on federal lands, but that a list of concerns has been forwarded to the company, while Ontario First Nations have urged government action on urgent transmission needs elsewhere.
TC Energy will tackle preliminary engineering and environmental studies to determine the feasibility of the proposed location, which could take up to two years.
Once the assessments are done, they need to be presented to the government for further review and approval, as seen when Ottawa's Site C stance left work paused pending a treaty rights challenge.
TC Energy's website states that the company anticipates construction to begin in 2022 if it gets all the go-ahead, with the plant to begin operations four years later.
Input from residents is being collected until April 2020, similar to when the National Energy Board heard oral traditional evidence on the Manitoba-Minnesota transmission line.
AWS Renewable Energy Projects deliver new wind power for AWS data centers in Ireland, Sweden, and the US, adding 229 MW and 670,000 MWh annually, supporting 100% renewable targets and global cloud sustainability.
Key Points
AWS projects add wind power in Ireland, Sweden, and the US to supply clean energy for AWS data centers.
✅ 229 MW new wind capacity; 670,000 MWh annual generation
✅ Advances 100% renewable goal for global AWS infrastructure
Amazon has announced three new clean energy projects as part of its long-term goal to power all Amazon Web Services (AWS) global infrastructure with renewable energy. These projects – one in Ireland, one in Sweden, and one in the United States – will deliver wind-generated energy that will total over 229 megawatts (MW) of power, with expected generation of over 670,000 megawatt hours (MWh) of renewable energy annually. The new projects are part of AWS’s long-term commitment to achieve 100 percent renewable energy for its global infrastructure. In 2018, AWS exceeded 50 percent renewable energy for its global infrastructure.
Once complete, these projects, combined with AWS’s previous nine renewable energy projects, reflect how renewable power developers benefit from diversified sources and are expected to generate more than 2,700,000 MWh of renewable energy annually – equivalent to the annual electricity consumption of over 262,000 US homes, which is approximately the size of the city of Nashville, Tennessee.
“Each of these projects brings us closer to our long-term commitment to use 100 percent renewable energy to power our global AWS infrastructure,” said Peter DeSantis, Vice President of Global Infrastructure and Customer Support, Amazon Web Services. “These projects are well-positioned to serve AWS data centers in Ireland, Sweden, and the US. We expect more projects in 2019 as we continue toward our goal of powering all AWS global infrastructure with renewable energy.”
Amazon has committed to buying the energy from a new wind project in Ireland, a 91.2 MW wind farm in Donegal. The Donegal wind farm project is expected to deliver clean energy no later than the end of 2021.
“AWS’s investment in renewable projects in Ireland illustrates their continued commitment to adding clean energy to the grid and it will make a positive contribution to Ireland’s renewable energy goals,” said Leo Varadkar, An Taoiseach of Ireland. “As a significant employer in Ireland, it is very encouraging to see Amazon taking a lead on this issue. We look forward to continuing to work with Amazon as we strive to make Ireland a leader on renewable energy.”
Amazon will also purchase 91 MW of power from a new wind farm in Bäckhammar, Sweden, which is expected to deliver renewable energy by the end of 2020.
“Sweden has long been known for ambitious renewable energy goals, and this new wind farm showcases both our country’s leadership and AWS’s commitment to renewable energy,” said Anders Ygeman, Sweden’s Minister for Energy and Digital Development. “This is a significant step in Sweden’s renewable energy production as we work toward our target of 100 percent renewable energy by 2040.”
California leads the United States in renewable electricity generation from non-hydroelectric sources, as US solar and wind growth accelerates, and the state’s Tehachapi Mountains, where AWS’s wind farm will be located, contain some of the largest wind farms in the country. The wind farm project in Tehachapi is expected to bring up to 47 MW of new renewable energy capacity by the end of 2020.
“This announcement from AWS is great news, not just for California, but for the entire country, as it reaffirms our role as a leader in renewable energy and allows us to take an important step forward on deploying the clean energy we need to respond to climate change,” said California State Senator Jerry Hill, San Mateo and Santa Clara Counties, a member of the Senate Standing Committee on Energy, Utilities and Communications.
Beyond the sustainability initiatives focused on powering the AWS global infrastructure, Amazon recently announced Shipment Zero, which is Amazon’s vision to make all Amazon shipments net zero carbon, with 50 percent of all shipments net zero by 2030. Additional sustainability programs across the company include Amazon Wind Farm Texas, which adds more than 1 million MWh of clean energy each year, alongside Amazon Wind Farm US East that is now fully operational, demonstrating scale. In total, Amazon has enabled 53 wind and solar projects worldwide, which produce more than 1,016 MW and are expected to deliver over 3,075,636 million MWh of energy annually, while peers like Arvato's solar power plant underscore broader momentum across the industry. These projects support hundreds of jobs, while providing tens of millions of dollars of investment in local communities, with Iowa wind power offering a strong example. Amazon has also set a goal to host solar energy systems at 50 fulfillment centers by 2020. This deployment of rooftop solar systems, aided by cheap batteries that enhance storage, is part of a long-term initiative that will start in North America and spread across the globe. Amazon also implemented the District Energy Project that uses recycled energy for heating Amazon offices in Seattle. For more information on Amazon’s sustainability initiatives, visit www.amazon.com/sustainability.
Central Asia power shortages strain grids across Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, and Turkmenistan, driven by drought-hit hydropower, aging coal and gas plants, rising demand, cryptomining loads, and winter peak consumption risks.
Key Points
Regionwide blackouts from drought, aging plants and grids, rising demand, and winter peaks stressing Central Asia.
✅ Drought slashes hydropower in Kyrgyzstan, Tajikistan, Uzbekistan
✅ Aging coal and gas TPPs and weak grids cause frequent outages
✅ Cryptomining loads and winter heating spike demand and stress supply
Central Asians from western Kazakhstan to southern Tajikistan are suffering from power and energy shortages that have caused hardship and emergency situations affecting the lives of millions of people.
On October 14, several units at three power plants in northeastern Kazakhstan were shut down in an emergency that resulted in a loss of more than 1,000 megawatts (MW) of electricity.
It serves as an example of the kind of power failures that plague the region 30 years after the Central Asian countries gained independence and despite hundreds of millions of dollars being invested in energy infrastructure and power grids, and echo risks seen in other advanced markets such as Japan's near-blackouts during recent cold snaps.
Some of the reasons for these problems are clear, but with all the money these countries have allocated to their energy sectors and financial help they have received from international financial institutions, it is curious the situation is already so desperate with winter officially still weeks away.
The Current Problems Three power plants were affected in the October 14 shutdowns of units: Ekibastuz-1, Ekibastuz-2, and the Aksu power plant.
Ekibastuz-1 is the largest power plant in Kazakhstan, capable of generating some 4,000 MW, roughly 13 percent of Kazakhstan’s total power output.
The Kazakhstan Electricity Grid Operating Company (KEGOC) explained the problems resulted partially from malfunctions and repair work, but also from overuse of the system that the government would later say was due to cryptominers, a large number of whom have moved to Kazakhstan recently from China after Beijing banned the mining needed by Bitcoin and other cryptocurrencies, amid its own China's power cuts across several provinces in 2021.
But between November 8 and 9, rolling blackouts were reported in the East Kazakhstan, North Kazakhstan, and Kyzylorda provinces, as well as the area around Almaty, Kazakhstan’s biggest city, and Shymkent, its third largest city.
People in Uzbekistan say they, too, are facing blackouts that the Energy Ministry described as “short-term outages,” even as authorities have looked to export electricity to Afghanistan to support regional demand, though it has been clear for several weeks that the country will have problems with natural gas supplies this winter.
Power lines in Uzbekistan Kyrgyz President Sadyr Japarov continues to say there won't be any power rationing in Kyrgyzstan this winter, but at the end of September the National Energy Holding Company ordered “restrictions on the lighting of secondary streets, advertisements, and facades of shops, cafes, and other nonresidential customers.”
Many parts of Tajikistan are already experiencing intermittent supplies of electricity.
Even in Turkmenistan, a country with the fourth-largest reserves of natural gas in the world, there were reports of problems with electricity and heating in the capital, Ashgabat.
What Is Going On? The causes of some of these problems are easy to see.
The population of the region has grown significantly, with the population of Central Asia when the Soviet Union collapsed in late 1991 being some 50 million and today about 75 million.
Kyrgyzstan and Tajikistan are mountainous countries that have long been touted for their hydropower potential and some 90 percent of Kyrgyzstan’s domestically produced electricity and 98 percent of Tajikistan’s come from hydropower.
But a severe drought that struck Central Asia this year has resulted in less hydropower and, in general, less energy for the region, similar to constraints seen in Europe's reduced hydro and nuclear output this year.
Tajik authorities have not reported how low the water in the country’s key reservoirs is, but Kyrgyzstan has reported the water level in the reservoir at its Toktogul hydropower plant (HPP) is 11.8 billion cubic meters (bcm), the lowest level in years and far less than the 14.7 bcm of water it had in November 2020.
The Toktogul HPP, with an installed capacity of 1,200 MW, provides some 40 percent of the country's domestically produced electricity, but operating the HPP this winter to generate desperately needed energy brings the risk of leaving water levels at the reservoir critically low next spring and summer when the water is also needed for agricultural purposes.
This year’s drought is something Kyrgyzstan and Tajikistan will have to take into consideration as they plan how to provide power for their growing populations in the future. Hydropower is a desirable option but may be less reliable with the onset of climate change, prompting interest in alternatives such as Ukraine's wind power to diversify generation.
Uzbekistan is also feeling the effects of this year’s drought, and, like the South Caucasus where Georgia's electricity imports have increased, supply shortfalls are testing grids.
According to the International Energy Agency, HPPs account for some 12 percent of Uzbekistan’s generating capacity.
Uzbekistan’s Energy Ministry attributed low water levels at HPPs that have caused a 23 percent decrease in hydropower generation this year.
A reservoir in Kyrgyzstan Kazakhstan and Uzbekistan are the most populous Central Asian countries, and both depend on thermal power plants (TPP) for generating most of their electricity.
Most of the TPPs in Kazakhstan are coal-fired, while most of the TPPs in Uzbekistan are gas-fired.
Kazakhstan has 68 power plants, 80 percent of which are coal-fired TPPs, and most are in the northern part of the country where the largest deposits of coal are located. Kazakhstan has the world's 10th largest reserves of coal.
About 88 percent of Uzbekistan’s electricity comes from TTPs, most of which use natural gas.
Uzbekistan’s proven reserves are some 800 billion cubic meters, but gas production in Uzbekistan has been decreasing.
In December 2020, Uzbek President Shavkat Mirziyoev ordered a halt to the country’s gas exports and instructed that gas to be redirected for domestic use. Mirziyoev has already given similar instructions for this coming winter.
How Did It Come To This? The biggest problem with the energy infrastructure in Central Asia is that it is generally very old. Nearly all of its power plants date back to the Soviet era -- and some well back into the Soviet period.
The use of power plants and transmission lines that some describe as “obsolete” and a few call “decrepit” has unfortunately been a necessity in Central Asia, even as regional players pursue new interconnections like Iran's plan to transmit electricity to Europe as a power hub.
Reporting on Kazakhstan in September 2016, the Asian Development Bank (ADB) said, “70 percent of the power generation infrastructure is in need of rehabilitation.”
The Ekibastuz-1 TPP is relatively new by the power-plant standards of Central Asia. The first unit of the eight units of the TPP was commissioned in 1980.
The first unit at the AKSU TPP was commissioned in 1968, and the first unit of the gas- and fuel-fired TPP in southern Kazakhstan’s Zhambyl Province was commissioned in 1967.
Rio Tinto waste heat-to-electricity initiative captures underground mining thermal energy at Resolution Copper, Arizona, converting it to renewable power for cooling systems and microgrids, advancing decarbonization, energy efficiency, and the miner's 2050 carbon-neutral goal.
Key Points
A program converting underground thermal energy into on-site electricity to cut emissions and support mine cooling.
✅ Captures low-grade heat from rock and geothermal water.
✅ Generates electricity for ventilation, refrigeration, microgrids.
✅ Scalable, safe, and grid- or storage-ready for peak demand.
The world’s second-largest miner, Rio Tinto announced that it is accepting proposals for solutions that transform waste heat into electricity for reuse from its underground operations.
In a press release, the company said this initiative is aimed at drastically reducing greenhouse gas emissions, even as energy-intensive projects like bitcoin mining operations expand, so that it can achieve its goal of becoming carbon neutral by 2050.
Initially, the project would be implemented at the Resolution copper mine in Arizona, which Rio owns together with BHP (ASX, LON: BHP). At this site, massive electrically-driven refrigeration and ventilation systems, aligned with broader electrified mining practices, are in charge of cooling the work environment because of the latent heat from the underground rock and groundwater.
THE INITIATIVE IS AIMED AT REDUCING GREENHOUSE GAS EMISSIONS SO THAT RIO CAN ACHIEVE ITS GOAL OF BECOMING CARBON NEUTRAL BY 2050
“When operating, the Resolution copper mine will be a deep underground block cave mine some 7,000 feet (~2 kilometres) deep, with ambient air temperatures ranging between 168°F to 180°F (76°C to 82°C), conditions that, during heat waves, when bitcoin mining power demand can strain local grids, further heighten cooling needs, and underground water at approximately 194°F (90°C),” the media brief states.
“Rio Tinto is seeking solutions to capture and reuse the heat from underground, contributing towards powering the equipment needed to cool the operations. The solution to capture and convert this thermal energy into electrical energy, such as emerging thin-film thermoelectrics, should be safe, environmentally friendly and cost-effective.”
The miner also said that, besides capturing heat for reuse, the solution should generate electrical energy from low range temperatures below the virgin rock temperature and/or from the high thermal water coming from the underground rock, similar to using transformer waste heat for heating in the power sector.
At the same time, the solution should be scalable and easily transported through the many miles of underground tunnels that will be built to ventilate, extract and move copper ore to the surface.
Rio requires proposals to offer the possibility of distributing the electrical energy generated back into the electrical grid from the mining operation or stored and used at a later stage when energy is required during peak use periods, especially as jurisdictions aim to use more electricity for heat in colder seasons.
India spot electricity prices surged on Q3 demand, lifting power tariffs in the spot market as discoms scrambled for supply; Sembcorp SGPL boosted PLF and short-term PPA realizations, benefiting from INR per kWh peaks.
Key Points
India spot electricity prices hit Q3 records amid demand spikes, lifting tariffs and aiding Sembcorp SGPL via PLF gains.
✅ Record 10.6 cents/kWh average; 15-minute peak 20.7 cents/kWh
✅ SGPL shifted output to short-term PPA at 7.3 cents/kWh
✅ PLF ramped above 90%, cutting core losses by 30-40%
Electricity prices in India, now the third-largest electricity producer globally, bolted to a record high of 10.6 cents/kWh (INR5.1/kWh) in Q3.
A jolt in Indian spot electricity prices could save Sembcorp Industries' Indian business from further losses, even though demand has occasionally slumped in recent years, UOB Kay Hian said.
The firm said spot electricity prices in India bolted to a record high of 10.6 cents/kWh (INR5.1/kWh) in Q3 and even hit a 15-minute peak of 20.7 cents/kWh (9.9/kWh). The spike was due to a power supply crunch on higher electricity demand from power distribution companies, alongside higher imported coal volumes as domestic supplies shrank.
As an effect, Sembcorp Industries' Sembcorp Gayatri Power Limited's (SGPL) losses of $26m in Q1 and $29m in Q2 could narrow down by as much as 30-40%.
On a net basis, SGPL will recognise a significantly higher electricity tariff in 3Q17. By tactically shutting down its Unit #3 for maintenance, Unit #4 effectively had its generation contracted out at the higher short-term PPA tariff of around 7.3 cents/kWh (Rs3.5/kWh).
SGPL also capitalised on the price spike in 3Q17 as it ramped up its plant load factor (PLF) to more than 90%.
“On the back of this, coupled with the effects of reduced finance costs, we expect SGPL’s 3Q17 quarterly core loss to shrink by 30-40% from previous quarters,” UOB Kay Hian said.
Whilst electricity prices have corrected to 7.1 cents/kWh (INR3.4/kWh), the firm said it could still remain elevated on structural factors, even as coal and electricity shortages ease nationwide.
Sembcorp Industries' India operations brought in a robust performance for Q3. PLF for Thermal Powertech Corporation India Limited (TPCIL) hit 91%, whilst it reached 73% for SGPL, echoing the broader trend of thermal PLF up across the sector.
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.
