Energy Secretary Steven Chu announced plans to restart the FutureGen clean coal power project, which was scrapped by the previous Bush administration as too expensive.
An agreement was reached between the Energy Department and the FutureGen Alliance, a nonprofit global consortium of coal producers and users, for a clean coal plant in Mattoon, Illinois.
The plant would be the first U.S. commercial scale carbon capture and storage project.
"Not only does this research have the potential to reduce harmful greenhouse gas emissions in the U.S., but it also could eventually result in lower emissions around the world," Chu said.
FutureGen's $1.8 billion coal-fired power plant with the technology to cut greenhouse gas emissions was scrapped by the Bush administration due to a ballooning price tag.
But a congressional report released in March revealed that the prior administration's cost estimates for the project were flawed, with the intent of killing the project.
President Barack Obama has expressed support for the project, which would be built in his home state.
The new agreement calls for a restart of preliminary design activities and an updated cost estimate, the department said.
Once these activities and others are completed in early 2010, the department and the alliance will decide whether to continue with the project.
The Energy Department expects to spend about $1.073 billion on the project, with $1 billion from the American Recovery and Reinvestment Act.
Offshore wind power accelerates low-carbon electrification, leveraging floating turbines, high capacity factors, HVDC transmission, and hydrogen production to decarbonize grids, cut CO2, and deliver competitive, reliable renewable energy near demand centers.
Key Points
Offshore wind power uses offshore turbines to deliver low-carbon electricity with high capacity factors and falling costs.
✅ Sea-based wind farms with 40-50% capacity factors
✅ Enables hydrogen production and strengthens grid reliability
The need for affordable low-carbon technologies is greater than ever
Global energy-related CO2 emissions reached a historic high in 2018, driven by an increase in coal use in the power sector. Despite impressive gains for renewables, fossil fuels still account for nearly two-thirds of electricity generation, the same share as 20 years ago. There are signs of a shift, with increasing pledges to decarbonise economies and tackle air pollution, and with World Bank support helping developing countries scale wind, but action needs to accelerate to meet sustainable energy goals. As electrification of the global energy system continues, the need for clean and affordable low-carbon technologies to produce this electricity is more pressing than ever. This World Energy Outlook special report offers a deep dive on a technology that today has a total capacity of 23 GW (80% of it in Europe) and accounts for only 0.3% of global electricity generation, but has the potential to become a mainstay of the world's power supply. The report provides the most comprehensive analysis to date of the global outlook for offshore wind, its contributions to electricity systems and its role in clean energy transitions.
The offshore wind market has been gaining momentum
The global offshore wind market grew nearly 30% per year between 2010 and 2018, benefitting from rapid technology improvements. Over the next five years, about 150 new offshore wind projects are scheduled to be completed around the world, pointing to an increasing role for offshore wind in power supplies. Europe has fostered the technology's development, led by the UK offshore wind sector alongside Germany and Denmark. The United Kingdom and Germany currently have the largest offshore wind capacity in operation, while Denmark produced 15% of its electricity from offshore wind in 2018. China added more capacity than any other country in 2018.
The untapped potential of offshore wind is vast
The best offshore wind sites could supply more than the total amount of electricity consumed worldwide today. And that would involve tapping only the sites close to shores. The IEA initiated a new geospatial analysis for this report to assess offshore wind technical potential country by country. The analysis was based on the latest global weather data on wind speed and quality while factoring in the newest turbine designs. Offshore wind's technical potential is 36 000 TWh per year for installations in water less than 60 metres deep and within 60 km from shore. Global electricity demand is currently 23 000 TWh. Moving further from shore and into deeper waters, floating turbines could unlock enough potential to meet the world's total electricity demand 11 times over in 2040. Our new geospatial analysis indicates that offshore wind alone could meet several times electricity demand in a number of countries, including in Europe, the United States and Japan. The industry is adapting various floating foundation technologies that have already been proven in the oil and gas sector. The first projects are under development and look to prove the feasibility and cost-effectiveness of floating offshore wind technologies.
Offshore wind's attributes are very promising for power systems
New offshore wind projects have capacity factors of 40-50%, as larger turbines and other technology improvements are helping to make the most of available wind resources. At these levels, offshore wind matches the capacity factors of gas- and coal-fired power plants in some regions – though offshore wind is not available at all times. Its capacity factors exceed those of onshore wind and are about double those of solar PV. Offshore wind output varies according to the strength of the wind, but its hourly variability is lower than that of solar PV. Offshore wind typically fluctuates within a narrower band, up to 20% from hour to hour, than solar PV, which varies up to 40%.
Offshore wind's high capacity factors and lower variability make its system value comparable to baseload technologies, placing it in a category of its own – a variable baseload technology. Offshore wind can generate electricity during all hours of the day and tends to produce more electricity in winter months in Europe, the United States and China, as well as during the monsoon season in India. These characteristics mean that offshore wind's system value is generally higher than that of its onshore counterpart and more stable over time than that of solar PV. Offshore wind also contributes to electricity security, with its high availability and seasonality patterns it is able to make a stronger contribution to system needs than other variable renewables. In doing so, offshore wind contributes to reducing CO2 and air pollutant emissions while also lowering the need for investment in dispatchable power plants. Offshore wind also has the advantage of avoiding many land use and social acceptance issues that other variable renewables are facing.
Offshore wind is on track to be a competitive source of electricity
Offshore wind is set to be competitive with fossil fuels within the next decade, as well as with other renewables including solar PV. The cost of offshore wind is declining and is set to fall further. Financing costs account for 35% to 50% of overall generation cost, and supportive policy frameworks are now enabling projects to secure low cost financing in Europe, with zero-subsidy tenders being awarded. Technology costs are also falling. The levelised cost of electricity produced by offshore wind is projected to decline by nearly 60% by 2040. Combined with its relatively high value to the system, this will make offshore wind one of the most competitive sources of electricity. In Europe, recent auctions indicate that offshore wind will soon beat new natural gas-fired capacity on cost and be on a par with solar PV and onshore wind. In China, offshore wind is set to become competitive with new coal-fired capacity around 2030 and be on par with solar PV and onshore wind. In the United States, recent project proposals indicate that offshore wind will soon be an affordable option, even as the 1 GW timeline continues to evolve, with potential to serve demand centres along the country's east coast.
Innovation is delivering deep cost reductions in offshore wind, and transmission costs will become increasingly important. The average upfront cost to build a 1 gigawatt offshore wind project, including transmission, was over $4 billion in 2018, but the cost is set to drop by more than 40% over the next decade. This overall decline is driven by a 60% reduction in the costs of turbines, foundations and their installation. Transmission accounts for around one-quarter of total offshore wind costs today, but its share in total costs is set to increase to about one-half as new projects move further from shore. Innovation in transmission, for example through work to expand the limits of direct current technologies, will be essential to support new projects without raising their overall costs.
Offshore wind is set to become a $1 trillion business
Offshore wind power capacity is set to increase by at least 15-fold worldwide by 2040, becoming a $1 trillion business. Under current investment plans and policies, the global offshore wind market is set to expand by 13% per year, reflecting its growth despite Covid-19 in recent years, passing 20 GW of additions per year by 2030. This will require capital spending of $840 billion over the next two decades, almost matching that for natural gas-fired or coal-fired capacity. Achieving global climate and sustainability goals would require faster growth: capacity additions would need to approach 40 GW per year in the 2030s, pushing cumulative investment to over $1.2 trillion.
The promising outlook for offshore wind is underpinned by policy support in an increasing number of regions. Several European North Seas countries – including the United Kingdom, Germany, the Netherlands and Denmark – have policy targets supporting offshore wind. Although a relative newcomer to the technology, China is quickly building up its offshore wind industry, aiming to develop a project pipeline of 10 GW by 2020. In the United States, state-level targets and federal incentives are set to kick-start the U.S. offshore wind surge in the coming years. Additionally, policy targets are in place and projects under development in Korea, Japan, Chinese Taipei and Viet Nam.
The synergies between offshore wind and offshore oil and gas activities provide new market opportunities. Since offshore energy operations share technologies and elements of their supply chains, oil and gas companies started investing in offshore wind projects many years ago. We estimate that about 40% of the full lifetime costs of an offshore wind project, including construction and maintenance, have significant synergies with the offshore oil and gas sector. That translates into a market opportunity of $400 billion or more in Europe and China over the next two decades. The construction of foundations and subsea structures offers potential crossover business, as do practices related to the maintenance and inspection of platforms. In addition to these opportunities, offshore oil and gas platforms require electricity that is often supplied by gas turbines or diesel engines, but that could be provided by nearby wind farms, thereby reducing CO2 emissions, air pollutants and costs.
Offshore wind can accelerate clean energy transitions
Offshore wind can help drive energy transitions by decarbonising electricity and by producing low-carbon fuels. Over the next two decades, its expansion could avoid between 5 billion and 7 billion tonnes of CO2 emissions from the power sector globally, while also reducing air pollution and enhancing energy security by reducing reliance on imported fuels. The European Union is poised to continue leading the wind energy at sea in Europe industry in support of its climate goals: its offshore wind capacity is set to increase by at least fourfold by 2030. This growth puts offshore wind on track to become the European Union's largest source of electricity in the 2040s. Beyond electricity, offshore wind's high capacity factors and falling costs makes it a good match to produce low-carbon hydrogen, a versatile product that could help decarbonise the buildings sector and some of the hardest to abate activities in industry and transport. For example, a 1 gigawatt offshore wind project could produce enough low-carbon hydrogen to heat about 250 000 homes. Rising demand for low-carbon hydrogen could also dramatically increase the market potential for offshore wind. Europe is looking to develop offshore "hubs" for producing electricity and clean hydrogen from offshore wind.
It's not all smooth sailing
Offshore wind faces several challenges that could slow its growth in established and emerging markets, but policy makers and regulators can clear the path ahead. Developing efficient supply chains is crucial for the offshore wind industry to deliver low-cost projects. Doing so is likely to call for multibillion-dollar investments in ever-larger support vessels and construction equipment. Such investment is especially difficult in the face of uncertainty. Governments can facilitate investment of this kind by establishing a long-term vision for offshore wind and by drawing on U.K. policy lessons to define the measures to be taken to help make that vision a reality. Long-term clarity would also enable effective system integration of offshore wind, including system planning to ensure reliability during periods of low wind availability.
The success of offshore wind depends on developing onshore grid infrastructure. Whether the responsibility for developing offshore transmission lies with project developers or transmission system operators, regulations should encourage efficient planning and design practices that support the long-term vision for offshore wind. Those regulations should recognise that the development of onshore grid infrastructure is essential to the efficient integration of power production from offshore wind. Without appropriate grid reinforcements and expansion, there is a risk of large amounts of offshore wind power going unused, and opportunities for further expansion could be stifled. Development could also be slowed by marine planning practices, regulations for awarding development rights and public acceptance issues.
The future of offshore wind looks bright but hinges on the right policies
The outlook for offshore wind is very positive as efforts to decarbonise and reduce local pollution accelerate. While offshore wind provides just 0.3% of global electricity supply today, it has vast potential around the world and an important role to play in the broader energy system. Offshore wind can drive down CO2 emissions and air pollutants from electricity generation. It can also do so in other sectors through the production of clean hydrogen and related fuels. The high system value of offshore wind offers advantages that make a strong case for its role alongside other renewables and low-carbon technologies. Government policies will continue to play a critical role in the future of offshore wind and the overall pace of clean energy transitions around the world.
Advanced Traffic Light System for Geothermal Safety models fracture growth and friction with rock physics, geophones, and supercomputers to predict induced seismicity during hydraulic stimulation, enabling real-time risk control for ETH Zurich and SED.
Key Points
ATLS uses rock physics, geophones, and HPC to forecast induced seismicity in real time during geothermal stimulation.
✅ Real-time seismic risk forecasts during hydraulic stimulation
✅ Uses rock physics, friction, and fracture modeling on HPC
✅ Supports ETH Zurich and SED field tests in Iceland and Bedretto
The Swiss Earthquake Service and ETH Zurich want to make geothermal energy safer, so news piece from Switzerland earlier this month. This is to be made possible by new software, including machine learning, and the computing power of supercomputers. The first geothermal tests have already been carried out in Iceland, and more will follow in the Bedretto laboratory.
In areas with volcanic activity, the conditions for operating geothermal plants are ideal. In Iceland, the Hellisheidi power plant makes an important contribution to sustainable energy use, alongside innovations like electricity from snow in cold regions.
Deep geothermal energy still has potential. This is the basis of the 2050 energy strategy. While the inexhaustible source of energy in volcanically active areas along fault zones of the earth’s crust can be tapped with comparatively little effort and, where viable, HVDC transmission used to move power to demand centers, access on the continents is often much more difficult and risky. Because the geology of Switzerland creates conditions that are more difficult for sustainable energy production.
Improve the water permeability of the rock
On one hand, you have to drill four to five kilometers deep to reach the correspondingly heated layers of earth in Switzerland. It is only at this depth that temperatures between 160 and 180 degrees Celsius can be reached, which is necessary for an economically usable water cycle. On the other hand, the problem of low permeability arises with rock at these depths. “We need a permeability of at least 10 millidarcy, but you can typically only find a thousandth of this value at a depth of four to five kilometers,” says Thomas Driesner, professor at the Institute of Geochemistry and Petrology at ETH Zurich.
In order to improve the permeability, water is pumped into the subsurface using the so-called “fracture”. The water acts against friction, any fracture surfaces shift against each other and tensions are released. This hydraulic stimulation expands fractures in the rock so that the water can circulate in the hot crust. The fractures in the earth’s crust originate from tectonic tensions, caused in Switzerland by the Adriatic plate, which moves northwards and presses against the Eurasian plate.
In addition to geothermal energy, the “Advanced Traffic Light System” could also be used in underground construction or in construction projects for the storage of carbon dioxide.
Quake due to water injection
The disadvantage of such hydraulic stimulations are vibrations, which are often so weak or cannot be perceived without measuring instruments. But that was not the case with the geothermal projects in St. Gallen 2013 and Basel 2016. A total of around 11,000 cubic meters of water were pumped into the borehole in Basel, causing the pressure to rise. Using statistical surveys, the magnitudes 2.4 and 2.9 defined two limit values ??for the maximum permitted magnitude of the earthquakes generated. If these are reached, the water supply is stopped.
In Basel, however, there was a series of vibrations after a loud bang, with a time delay there were stronger earthquakes, which startled the residents. In both cities, earthquakes with a magnitude greater than 3 have been recorded. Since then it has been clear that reaching threshold values ??determines the stop of the water discharge, but this does not guarantee safety during the actual drilling process.
Simulation during stimulation
The Swiss Seismological Service SED and the ETH Zurich are now pursuing a new approach that can be used to predict in real time, building on advances by electricity prediction specialists in Europe, during a hydraulic stimulation whether noticeable earthquakes are expected in the further course. This is to be made possible by the so-called “Advanced Traffic Light System” based on rock physics, a software developed by the SED, which carries out the analysis on a high-performance computer.
Geophones measure the ground vibrations around the borehole, which serve as indicators for the probability of noticeable earthquakes. The supercomputer then runs through millions of possible scenarios, similar to algorithms to prevent power blackouts during ransomware attacks, based on the number and type of fractures to be expected, the friction and tensions in the rock. Finally, you can filter out the scenario that best reflects the underground.
Further tests in the mountain
However, research is currently still lacking any real test facility for the system, because incorrect measurements must be eliminated and a certain data format adhered to before the calculations on the supercomputer. The first tests were carried out in Iceland last year, with more to follow in the Bedretto geothermal laboratory in late summer, where reliable backup power from fuel cell solutions can keep instrumentation running. An optimum can now be found between increasing the permeability of rock layers and an adequate water supply.
The new approach could make geothermal energy safer and ultimately help this energy source to become more accepted, while grid upgrades like superconducting cables improve efficiency. Research also sees areas of application wherever artificially caused earthquakes can occur, such as in underground mining or in the storage of carbon dioxide underground.
Ontario-Quebec Electricity Trade Agreement ends as Ontario pivots to IESO procurement, hydropower alternatives, natural gas capacity, and energy auctions, impacting grid reliability, power imports, and GHG emissions across both provincial markets.
Key Points
A seven-year power import pact; Ontario will end it, shifting to IESO procurement and gas capacity.
✅ Seasonal hydropower exchange of 2.3 TWh annually.
✅ IESO projects Quebec supply constraints by decade end.
The Ontario government does not plan to renew the Ontario-Quebec electricity trade agreement, Radio-Canada is reporting.
The seven-year contract, which expires next year, aims to reduce Ontario's greenhouse gas (GHG) emissions by buying 2.3 Terawatt-hours of electricity from Quebec annually — that corresponds to about seven per cent of Hydro-Quebec's average annual exports.
The announcement comes as the provincially owned Quebec utility continues its legal battle over a plan to export power to Massachusetts.
The Ontario agreement has guaranteed a seasonal exchange of energy, since Quebec has a power surplus in summer, and the province's electricity needs increase in the winter. Ontario plans on exercising its last and only option in the summer of 2026, for a block of 500 megawatts.
The office of the Ontario Minister of Energy Todd Smith says the province will save money by relying "on a competitive procurement process" instead, amid debates over clean, affordable electricity policy in Ontario. And, the Independent Electricity System Operator (IESO), the equivalent of Hydro-Quebec in Ontario, added that, at any rate, Quebec is expected to "run out of electricity in the middle or at the end of the decade."
During the Quebec election campaign, Premier Francois Legault said his province needed to increase hydroelectricity production because he is expecting demand for hydroelectricity to increase by an additional 100 terawatt-hours in the coming decades — half of Hydro-Quebec's current annual output.
Coalition Avenir Quebec pitches more hydro dams to Quebec voters The provinces will still continue to buy and sell power, reaching deals through annual energy auctions.
Eloise Edom, an associate researcher at Polytechnique Montreal's Institut de l'energie Trottier, says the announcement came as somewhat of a surprise because "we're still talking about a lot of energy."
Hydro-Quebec refused to comment on "the SIERE [Independent Electricity System Operator]'s intentions for the agreement, which ends next year," said company spokesperson Lynn St-Laurent.
No green options Yet Ontario is running out of electricity, even as questions persist about whether it is embracing clean power to meet demand, in part because of plans to refurbish nuclear reactors at the Bruce and Darlington generator stations.
Windsor has already lost out on a $2.5-billion factory because the region is short of electricity for new industrial loads. And by 2025, Toronto will run out of power for the electrification of its transit system, according to the latest estimates from the IESO.
The Ford government recently announced that it hopes to extend the life of the Pickering nuclear station amid ongoing debate. It is also evaluating the possibility of increasing hydroelectricity production at its existing dams.
For now, Ontario is banking on its natural gas plants to meet demand, which have won most recent IESO tenders for contracts running until 2026. Last Friday, the province announced that it was going to buy an additional 1,500 megawatts by 2027.
"The [Ontario energy] minister's expectations may be that the increase in natural gas prices is temporary and that it will fade," energy economist Jean-Thomas Bernard said. "With this in mind, he probably does not want to sign a long-term contract [with Hydro-Quebec] and prefers to buy electricity on a day-to-day basis and through calls for tenders."
If the Quebec deal expires, Ontario, Canada's second highest GHG emitter, would have to increase its emissions for the sector, at least in the medium term, with electricity getting dirtier as gas fills the gap.
Last year, the IESO found that it would be very difficult to set a moratorium on natural gas before 2030. The IESO must produce a final report on the subject for the energy minister by the end of November.
Wind And Solar Energy Growth is reshaping the global power mix, accelerating grid decarbonization as coal declines; boosted by pandemic demand drops, renewables now supply near 10% of electricity, advancing climate targets toward net-zero trajectories.
Key Points
It is the rise in wind and solar's share of electricity, driving decarbonization and displacing coal globally.
✅ Share doubled in five years across 83% of global electricity
✅ Coal's share fell; renewables neared 10% in H1 2020
✅ Growth still insufficient for 1.5 C; needs ~13% coal cuts yearly
Wind and solar energy doubled its share of the global power mix over the last five years, with renewable power records underscoring the trend, moving the world closer to a path that would limit the worst effects of global warming.
The sources of renewable energy made up nearly 10% of power in most parts of the world in the first half of this year, according to analysis from U.K. environmental group Ember, while globally over 30% of electricity is renewable in broader assessments.
That decarbonization of the power grid was boosted this year as shutdowns to contain the coronavirus reduced demand overall, leaving renewables to pick up the slack.
Ember analyzed generation in 48 countries that represent 83% of global electricity. The data showed wind and solar power increased 14% in the first half of 2020 compared with the same period last year while global demand fell 3% because of the impact of the coronavirus.
At the same time that wind turbines and solar panels have proliferated, coal’s share of the mix has fallen around the world. In some, mainly western European countries, where renewables surpassed fossil fuels, coal has been all but eliminated from electricity generation.
China relied on the dirtiest fossil fuel for 68% of its power five years ago, and solar PV growth in China has accelerated since then. That share dipped to 62% this year and renewables made up 10% of all electricity generated.
Still, the growth of renewables may not be going fast enough for the world to hit its climate goals, even as the U.S. is projected to have one-fourth of electricity from renewables soon, and coal is still being burnt for power in many parts of the world.
Coal use needs to fall by about 79% by 2030 from last year’s levels - a fall of 13% every year throughout the decade to come, and in the U.S. renewable electricity surpassed coal in 2022, Ember said.
New installations of wind farms are set to hold more or less steady in the next five years, according to data from BloombergNEF on deployment trends. That will make it difficult to realize a sustained pace of doubling renewable power every five years.
“If your expectations are that we need to be on target for 1.5 degrees, clearly we’re not going fast enough,” said Dave Jones, an analyst at Ember. “We’re not on a trajectory where we’re reducing coal emissions fast enough.”
Black Hills Energy Corriedale Wind Farm Expansion earns regulatory approval in Wyoming, boosting capacity to over 52MW near Cheyenne with five turbines, supporting Renewable Ready customers and wind power goals under PUC and PSC oversight.
Key Points
An approved Wyoming wind project upgrade to over 52MW, adding five turbines to serve Renewable Ready customers.
✅ Adds 12.5MW via five new wind turbines near Cheyenne
✅ Cost increases to $79m; prior estimate $57m
✅ Approved by SD PUC after Wyoming PSC review
US company Black Hills Energy has received regulatory approval to increase the size of its Corriedale wind farm in Wyoming, where Wyoming wind exports to California are advancing, to over 52MW from 40MW previously.
The South Dakota Public Utilities Commission approved the additional 12.5MW capacity after the Wyoming Public Service Commission determined the boost was within commission rules, as federal initiatives like DOE wind energy awards continue to support the sector.
Black Hills Energy will install five additional turbines, raising the project cost to $79m from $57m, amid growing heartland wind investment across the region. Corriedale will be built near Cheyenne and is expected to be placed in service in late 2020.
Black Hills said that during the initial subscription period for its Renewable Ready program, applications of interest from eligible commercial, industrial and governmental agency customers were received in excess of the program's 40MW, underscoring the view that more energy sources can make stronger projects.
Black Hills Corporations chief executive and president Linden Evans said: “We are pleased with the opportunity to expand our Renewable Ready program, allowing us to meet our customers’ interest in renewable wind energy, which co-op members increasingly support.
“This innovative program expands our clean energy portfolio while meeting our customers’ evolving needs, particularly around cleaner and more sustainable energy, as projects like new energy generation coming online demonstrate.”
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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