State regulators gave the go-ahead to Xcel Energy's plans for a green makeover: shutting down two coal-fired power plants in the state and building one of the world's largest utility-scale solar power plants.
After days of deliberations, the Colorado Public Utilities Commission approved Xcel's voluntary decision to shutter electricity generating stations in Denver and Grand Junction - making it the first utility in the nation to do so in order to reduce pollution emissions.
The commission also approved the utility's request for a 200-megawatt solar plant using concentrated solar technology that not only helps generate electricity from the sun, but also allows energy to be stored for later use.
The commission approved, too, Xcel's request to add 850 megawatts of wind energy to its system.
"That's great news," said Harriet Moyer Aptekar, development manager of Ausra, a Silicon Valley company supported by venture firm Kleiner Perkins and Sun Microsystems co-founder Vinod Khosla. "We will be very interested when Xcel seeks bids and we'll be competing for it."
Spanish company Abengoa Solar, with U.S. headquarters in Lakewood, BrightSourceEnergy and Ausra are among the solar companies that have established a presence in Colorado to tap into its growing market. Abengoa, which is building a 280-megawatt solar plant in Arizona, has indicated it will compete for Xcel's project.
The proposed solar and wind projects would catapult the utility into compliance with state laws that require larger utilities to receive 20 percent of their electricity from solar, wind or biomass sources by 2020.
Commission spokesman Terry Bote said a written decision likely will be issued by mid-September, clearing the way for Xcel to proceed with its plan.
"Based on the approved framework, Xcel Energy will then solicit bids consistent with the approved plan and submit its recommended choices to the PUC," he said. "An independent evaluator will also review the bids and make recommendations."
Xcel spokesman Mark Stutz said he couldn't say how soon the utility would seek bids for the solar and wind projects.
"We are generally pleased, however, that the commission essentially has agreed with our final plan concerning additional wind and solar power, and our plans to close two of our power plants," Stutz said. "The additional wind and solar provides benefits to the environment, and we look forward to those additions to our system by 2015.
"Gov. (Bill) Ritter last year called for a 20 percent reduction in carbon dioxide emission by 2020," he added. "The plant closures will help us reduce our carbon emissions and put us well on the way toward meeting the governor's goal."
In November, Xcel offered to shut down two coal-fired plants, the Arapahoe at 2601 S. Platte River Drive, and the Cameo in Grand Junction.
To replace the 229 megawatts the plants provide, Xcel initially said it would build a 480-megawatt natural gas-fired plant at the Arapahoe site but later withdrew its proposal in the face of criticism.
The Cameo plant is scheduled to close by December 2010, while units at the Arapahoe will be shut down in 2012.
Cloud Data Centers Environmental Impact highlights massive electricity use, carbon emissions, and cooling demands, with coal-heavy grids in China; big tech shifts to renewable energy, green data centers, and cooler climates to boost sustainability.
Key Points
Energy use, emissions, and cooling load of cloud systems, and shifts to renewables to reduce climate impact.
✅ Global data centers use 3-5% of electricity, akin to airlines
✅ Cooling drives energy demand; siting in cool climates saves power
✅ Shift from coal to renewables lowers CO2 and improves PUE
A hidden environmental price makes storing data in the cloud a costly convenience.
Between 3 to 5% of all electricity used globally comes from data centers that house massive computer systems, with computing power forecasts warning consumption could climb, an amount comparable to the airline industry, says Ben Brock Johnson, Here & Now’s tech analyst.
Instead of stashing information locally on our own personal devices, the cloud allows users to free up storage space by sending photos and files to data centers via the internet.
The cloud can also use large data sets to solve problems and host innovative technologies that make cities and homes smarter, but storing information at data centers uses energy — a lot of it.
"Ironically, the phrase 'moving everything to the cloud' is a problem for our actual climate right now," Johnson says.
A new study from Greenpeace and North China Electric Power University reports that in five years, China's data centers alone will consume as much power as the total amount used in Australia in 2018. The industry's electricity consumption is set to increase by 66% over that time.
Buildings storing data produced 99 million metric tons of carbon last year in China, the study finds, with SF6 in electrical equipment compounding warming impacts, which is equivalent to 21 million cars.
The amount of electricity required to run a data center is a global problem, but in China, 73% of these data centers run on coal, even as coal-fired electricity is projected to fall globally this year.
The Chinese government started a pilot program for green data centers in 2015, which Johnson says signals the country is thinking about the environmental consequences of the cloud.
"Beijing’s environmental awareness in the last decade has really come from a visible impact of its reliance on fossil fuels," he says. "The smog of Chinese cities is now legendary and super dangerous."
The country's solar power innovations have allowed the country to surpass the U.S. in cleantech, he says.
Chinese conglomerate Alibaba Group has launched data centers powered by solar and hydroelectric power.
"While I don't know how committed the government is necessarily to making data centers run on clean technology," Johnson says. "I do think it is possible that a larger evolution of the government's feelings on environmental responsibility might impact this newer tech sector."
In the U.S., there has been a big push to make data centers more sustainable amid warnings that the electric grid is not designed for mounting climate impacts.
Canada has made notable progress decarbonizing power, with nationwide electricity gains supporting cleaner data workloads.
Apple now says all of its data centers use clean energy. Microsoft is aiming for 70% renewable energy by 2023, aligning with declining power-sector emissions as producers move away from coal.
Amazon is behind the curve, for once, with about 50%, Johnson says. Around 1,000 employees are planning to walk out on Sept. 20 in protest of the company’s failure to address environmental issues.
"Environmental responsibility fits the brand identities these companies want to project," he says. "And as large tech companies become more competitive with each other, as Apple becomes more of a service company and Google becomes a device company, they want to convince users more and more to think of them as somehow different even if they aren't."
Google and Facebook are talking about building data centers in cooler places like Finland and Sweden instead of hot deserts like Nevada, he says.
In Canada, cleaning up electricity is critical to meeting climate pledges, according to recent analysis.
Computer systems heat up and need to be cooled down by air conditioning units, so putting a data center in a warm climate will require greater cooling efforts and use more energy.
In China, 40% of the electricity used at data centers goes toward cooling equipment, according to the study.
The more data centers consolidate, Johnson says they can rely on fewer servers and focus on larger cooling efforts.
But storing data in the cloud isn't the only way tech users are unknowingly using large amounts of energy: One Google search requires an amount of electricity equivalent to powering a 60-watt light bulb for 17 seconds, magazine Yale Environment 360 reports.
"In some ways, we're making strides even as we are creating a bigger problem," he says. "Which is like, humanity's MO, I guess."
Washington State Hybrid-Electric Ferries advance green maritime transit with battery-diesel propulsion, lower emissions, and fleet modernization, integrating charging infrastructure and reliable operations across WSF routes to meet climate goals and reduce fuel consumption.
Key Points
New WSF vessels using diesel-battery propulsion to cut emissions, improve efficiency, and sustain reliable ferry service.
✅ Hybrid diesel-battery propulsion reduces fuel use and CO2
✅ Larger vessels with efficient batteries and charging upgrades
✅ Compatible with WSF docks, maintenance, and safety standards
Washington State is embarking on an ambitious update to its ferry fleet, introducing hybrid-electric boats that represent a significant leap toward greener and more sustainable transportation. The state’s updated plans reflect a commitment to reducing carbon emissions and enhancing environmental stewardship while maintaining the efficiency and reliability of its vital ferry services.
The Washington State Ferries (WSF) system, one of the largest in the world, has long been a critical component of the state’s transportation network, linking various islands and coastal communities with the mainland. Traditionally powered by diesel engines, the ferries are responsible for significant greenhouse gas emissions. In response to growing environmental concerns and legislative pressure, WSF is now turning to hybrid-electric technology similar to battery-electric high-speed ferries seen elsewhere to modernize its fleet and reduce its carbon footprint.
The updated plans for the hybrid-electric boats build on earlier efforts to introduce cleaner technologies into the ferry system. The new designs incorporate advanced hybrid-electric propulsion systems that combine traditional diesel engines with electric batteries. This hybrid approach allows the ferries to operate on electric power during certain segments of their routes, reducing reliance on diesel fuel and cutting emissions as electric ships on the B.C. coast have demonstrated during similar operations.
One of the key features of the updated plans is the inclusion of larger and more capable hybrid-electric ferries, echoing BC Ferries hybrid ships now entering service in the region. These vessels are designed to handle the demanding operational requirements of the Washington State Ferries system while significantly reducing environmental impact. The new boats will be equipped with state-of-the-art battery systems that can store and utilize electric power more efficiently, leading to improved fuel economy and lower overall emissions.
The transition to hybrid-electric ferries is driven by both environmental and economic considerations. On the environmental side, the move aligns with Washington State’s broader goals to combat climate change and reduce greenhouse gas emissions, including programs like electric vehicle rebate program that encourage cleaner travel across the state. The state has set ambitious targets for reducing carbon emissions across various sectors, and upgrading the ferry fleet is a crucial component of achieving these goals.
From an economic perspective, hybrid-electric ferries offer the potential for long-term cost savings. Although the initial investment in new technology can be substantial, with financing models like CIB support for B.C. electric ferries helping spur adoption and reduce barriers for agencies, the reduced fuel consumption and lower maintenance costs associated with hybrid-electric systems are expected to lead to significant savings over the lifespan of the vessels. Additionally, the introduction of greener technology aligns with public expectations for more sustainable transportation options.
The updated plans also emphasize the importance of integrating hybrid-electric technology with existing infrastructure. Washington State Ferries is working to ensure that the new vessels are compatible with current docking facilities and maintenance practices. This involves updating docking systems, as seen with Kootenay Lake electric-ready ferry preparations, to accommodate the specific needs of hybrid-electric ferries and training personnel to handle the new technology.
Public response to the hybrid-electric ferry initiative has been largely positive, with many residents and environmental advocates expressing support for the move towards greener transportation. The new boats are seen as a tangible step toward reducing the environmental impact of one of the state’s most iconic transportation services. The project also highlights Washington State’s commitment to innovation and leadership in sustainable transportation, alongside global examples like Berlin's electric flying ferry that push the envelope in maritime transit.
However, the transition to hybrid-electric ferries is not without its challenges. Implementing new technology requires careful planning and coordination, including addressing potential technical issues and ensuring that the vessels meet all safety and operational standards. Additionally, there may be logistical challenges associated with integrating the new ferries into the existing fleet and managing the transition without disrupting service.
Despite these challenges, the updated plans for hybrid-electric boats represent a significant advancement in Washington State’s efforts to modernize its transportation system. The initiative reflects a growing trend among transportation agencies to embrace sustainable technologies and address the environmental impact of traditional transportation methods.
In summary, Washington State’s updated plans for hybrid-electric ferries mark a crucial step towards a more sustainable and environmentally friendly transportation network. By incorporating advanced hybrid-electric technology, the state aims to reduce carbon emissions, improve fuel efficiency, and align with its broader climate goals. While challenges remain, the initiative demonstrates a commitment to innovation and underscores the importance of transitioning to greener technologies in the quest for a more sustainable future.
Berkshire Hathaway Energy Wind Power drives cheap electricity rates in Iowa via utility-scale wind turbines, integrated transmission, battery storage, and grid management, delivering renewable energy, stable pricing, and long-term rate freezes through 2028.
Key Points
A vertically integrated wind utility lowering Iowa rates via owned generation, transmission, and advanced grid control.
✅ Owned wind assets meet Iowa residential demand
✅ Integrated transmission lowers costs and losses
✅ Rate freeze through 2028 sustains cheap power
In his latest letter to Berkshire Hathaway shareholders, Warren Buffett used the 20th anniversary of Berkshire Hathaway Energy to tout its cheap electricity bills for customers.
When Berkshire purchased the majority share of BHE in 2000, the cost of electricity for its residential customers in Iowa was 8.8 cents per kilowatt-hour (kWh) on average. Since then, these electricity rates have risen at a paltry <1% per year, with a freeze on rate hikes through 2028. As anyone who pays an electricity bill knows, that is an incredible deal.
As Buffett himself notes with alacrity, “Last year, the rates [BHE’s competitor in Iowa] charged its residential customers were 61% higher than BHE’s. Recently, that utility received a rate increase that will widen the gap to 70%.”
The Winning Strategy
So, what’s Buffett’s secret to cheap electricity? Wind power.
“The extraordinary differential between our rates and theirs is largely the result of our huge accomplishments in converting wind into electricity,” Buffett explains.
Wind turbines in Iowa that BHE owns and operates are expected to generate about 25.2 million megawatt-hours (MWh) of electricity for its customers, as projects like Building Energy operations begin to contribute. By Buffett’s estimations, that will be enough to power all of its residential customers’ electricity needs in Iowa.
The company has plans to increase its renewable energy generation in other regions as well. This year, BHE Canada is expected to start construction on a 117.6MW wind farm in Alberta, Canada with its partner, Renewable Energy Systems, that will provide electricity to 79,000 homes in Canada’s oil country.
But I would argue that the secret to BHE’s success perhaps goes deeper than transitioning to sources of renewable energy. There are plenty of other utility companies that have adopted wind and solar power as an energy source. In the U.S., where renewable electricity surpassed coal in 2022, at least 50% of electricity customers have the option to buy renewable electricity from their power supplier, according to the Department of Energy. And some states, such as New York, have gone so far as to allow customers to pick from providers who generate their electricity.
What differentiates BHE from a lot of the competition in the utility space is that it owns the means to generate, store, transmit and supply renewable power to its customers across the U.S., U.K. and Canada, with lessons from the U.K. about wind power informing policy.
In its financial filings for 2019, the company reported that it owns 33,600MW of generation capacity and has 33,400 miles of transmission lines, as well as a 50% interest in Electric Transmission Texas (ETT) that has approximately 1,200 miles of transmission lines. This scale and integration enables BHE to be efficient in the distribution and sale of electricity, including selling renewable energy across regions.
BHE is certainly not alone in building renewable-energy fueled electricity dominions. Its largest competitor, NextEra, built 15GW of wind capacity and has started to expand its utility-scale solar installations. Duke Energy owns and operates 2,900 MW of renewable energy, including wind and solar. Exelon operates 40 wind turbine sites across the U.S. that generate 1,500 MW.
Integrated Utilities Power Ahead
It’s easy to see why utility companies see wind as a competitive source of electricity compared to fossil fuels. As I explained in my previous post, Trump’s Wrong About Wind, the cost of building and generating wind energy have fallen significantly over the past decade. Meanwhile, improvements in battery storage and power management through new technological advancements have made it more reliable (Warren Buffett bet on that one too).
But what is also striking is that integrated power and transmission enables these utility companies to make those decisions; both in terms of sourcing power from renewable energy, as well as the pricing of the final product. Until wind and solar power are widespread, these utility companies are going to have an edge of the more fragmented ends of the industry who can’t make these purchasing or pricing decisions independently.
Warren Buffett very rarely misses a beat. He’s not the Oracle of Omaha for nothing. Berkshire Hathaway’s ownership of BHE has been immensely profitable for its shareholders. In the year ended December 31, 2019, BHE and its subsidiaries reported net income attributable to BHE shareholders of $2.95 billion.
There’s no question that renewable energy will transform the utility industry over the next decade. That change will be led by the likes of BHE, who have the power to invest, control and manage their own energy generation assets.
NEIMA advances NRC regulatory modernization, creating a licensing framework for advanced reactors, improving uranium permitting, capping reactor fees, and mandating DOE planning for excess uranium, boosting transparency, accountability, and innovation across the US nuclear sector.
Key Points
NEIMA is a US law modernizing NRC rules and enabling advanced reactor licensing while reforming fees.
✅ Modernizes NRC licensing for advanced reactors
✅ Caps annual reactor fees and boosts transparency
✅ Streamlines uranium permitting; directs DOE plans
Bipartisan legislation modernising US nuclear regulation and supporting the establishment of a licensing framework for next-generation advanced reactors has been signed by US President Donald Trump, whose order boosting U.S. uranium and nuclear energy underscored the administration's focus on the sector.
The Nuclear Energy Innovation and Modernisation Act (NEIMA) became law on 14 January.
As well as directing the Nuclear Regulatory Commission (NRC) to modify the licensing process for commercial advanced nuclear reactor facilities, the bill establishes new transparency and accountability measures to the regulator's budget and fee programmes, and caps fees for existing reactors. It also directs the NRC to look at ways of improving the efficiency of uranium licensing, including investigating the safety and feasibility of extending uranium recovery licences from ten to 20 years' duration, and directs the Department of Energy, which oversees nuclear cleanup and related projects, to issue at least every ten years a long-term plan detailing the management of its excess uranium inventories.
Maria Korsnick, president and CEO of the US Nuclear Energy Institute, described NEIMA as a "significant, positive step" toward the reform of the NRC's fee collection process. "This legislation establishes a more equitable and transparent funding structure which will benefit all operating reactors and future licensees," she said. "The bill also reaffirms Congress’s support for nuclear innovation by working to establish an efficient and stable regulatory structure that is prepared to license the advanced reactors of the future."
Marilyn Kray, president-elect of the American Nuclear Society, said the passage of the legislation was a "big win" for the nation and its nuclear community. "By reforming outdated laws, NRC will now be able to invest more freely in advanced nuclear R&D and licensing activities. This in turn will accelerate deployment of cutting-edge American nuclear systems and better prepare the next generation of nuclear engineers and technologists," she said.
The bill was introduced in 2017 by Senator John Barrasso of Wyoming. It was approved by Congress on 21 December by 361 votes to 10, having been passed by the Senate the previous day, even as later Biden's climate law developments produced mixed results.
NEIMA is one of several bipartisan bills that support advanced nuclear innovation considered by the 115th US Congress, which ended on 2 January. These are: the Nuclear Energy Innovation Capabilities Act (NEICA); the Nuclear Energy Leadership Act; the Nuclear Utilisation of Keynote Energy Act; the Advanced Nuclear Fuel Availability Act, a focus sharpened by the U.S. ban on Russian uranium in the fuel market; and legislation to expedite so-called part 810 approvals, which are needed for the export of technology, equipment and components. NEICA, which supports the deployment of advanced reactors and also directs the DOE to develop a reactor-based fast neutron source for the testing of advanced reactor fuels and materials, was signed into law in October.
High-Temperature Superconducting Cables enable lossless, high-voltage, underground transmission for grid modernization, linking renewable energy to cities with liquid nitrogen cooling, boosting efficiency, cutting emissions, reducing land use, and improving resilience against disasters and extreme weather.
Key Points
Liquid-nitrogen-cooled power cables delivering electricity with near-zero losses, lower voltage, and greater resilience.
✅ Near-lossless transmission links renewables to cities efficiently
✅ Operate at lower voltage, reducing substation size and cost
✅ Underground, compact, and resilient to extreme weather events
For most of us, transmitting power is an invisible part of modern life. You flick the switch and the light goes on.
But the way we transport electricity is vital. For us to quit fossil fuels, we will need a better grid, with macrogrid planning connecting renewable energy in the regions with cities.
Electricity grids are big, complex systems. Building new high-voltage transmission lines often spurs backlash from communities, as seen in Hydro-Qu e9bec power line opposition over aesthetics and land use, worried about the visual impact of the towers. And our 20th century grid loses around 10% of the power generated as heat.
One solution? Use superconducting cables for key sections of the grid. A single 17-centimeter cable can carry the entire output of several nuclear plants. Cities and regions around the world have done this to cut emissions, increase efficiency, protect key infrastructure against disasters and run powerlines underground. As Australia prepares to modernize its grid, it should follow suit with smarter electricity infrastructure initiatives seen elsewhere. It's a once-in-a-generation opportunity.
What's wrong with our tried-and-true technology? Plenty.
The main advantage of high voltage transmission lines is they're relatively cheap.
But cheap to build comes with hidden costs later. A survey of 140 countries found the electricity currently wasted in transmission accounts for a staggering half-billion tons of carbon dioxide—each year.
These unnecessary emissions are higher than the exhaust from all the world's trucks, or from all the methane burned off at oil rigs.
Inefficient power transmission also means countries have to build extra power plants to compensate for losses on the grid.
Labor has pledged A$20 billion to make the grid ready for clean energy, and international moves such as US-Canada cross-border approvals show the scale of ambition needed. This includes an extra 10,000 kilometers of transmission lines. But what type of lines? At present, the plans are for the conventional high voltage overhead cables you see dotting the countryside.
System planning by Australia's energy market operator shows many grid-modernizing projects will use last century's technologies, the conventional high voltage overhead cables, even as Europe's HVDC expansion gathers pace across its network. If these plans proceed without considering superconductors, it will be a huge missed opportunity.
How could superconducting cables help? Superconduction is where electrons can flow without resistance or loss. Built into power cables, it holds out the promise of lossless electricity transfer, over both long and short distances. That's important, given Australia's remarkable wind and solar resources are often located far from energy users in the cities.
High voltage superconducting cables would allow us to deliver power with minimal losses from heat or electrical resistance and with footprints at least 100 times smaller than a conventional copper cable for the same power output.
And they are far more resilient to disasters and extreme weather, as they are located underground.
Even more important, a typical superconducting cable can deliver the same or greater power at a much lower voltage than a conventional transmission cable. That means the space needed for transformers and grid connections falls from the size of a large gym to only a double garage.
Bringing these technologies into our power grid offers social, environmental, commercial and efficiency dividends.
Unfortunately, while superconductors are commonplace in Australia's medical community (where they are routinely used in MRI machines and diagnostic instruments) they have not yet found their home in our power sector.
One reason is that superconductors must be cooled to work. But rapid progress in cryogenics means you no longer have to lower their temperature almost to absolute zero (-273℃). Modern "high temperature" superconductors only need to be cooled to -200℃, which can be done with liquid nitrogen—a cheap, readily available substance.
Overseas, however, they are proving themselves daily. Perhaps the most well-known example to date is in Germany's city of Essen. In 2014, engineers installed a 10 kilovolt (kV) superconducting cable in the dense city center. Even though it was only one kilometer long, it avoided the higher cost of building a third substation in an area where there was very limited space for infrastructure. Essen's cable is unobtrusive in a meter-wide easement and only 70cm below ground.
Superconducting cables can be laid underground with a minimal footprint and cost-effectively. They need vastly less land.
A conventional high voltage overhead cable requires an easement of about 130 meters wide, with pylons up to 80 meters high to allow for safety. By contrast, an underground superconducting cable would take up an easement of six meters wide, and up to 2 meters deep.
This has another benefit: overcoming community skepticism. At present, many locals are concerned about the vulnerability of high voltage overhead cables in bushfire-prone and environmentally sensitive regions, as well as the visual impact of the large towers and lines. Communities and farmers in some regions are vocally against plans for new 85-meter high towers and power lines running through or near their land.
Climate extremes, unprecedented windstorms, excessive rainfall and lightning strikes can disrupt power supply networks, as the Victorian town of Moorabool discovered in 2021.
What about cost? This is hard to pin down, as it depends on the scale, nature and complexity of the task. But consider this—the Essen cable cost around $20m in 2014. Replacing the six 500kV towers destroyed by windstorms near Moorabool in January 2020 cost $26 million.
While superconducting cables will cost more up front, you save by avoiding large easements, requiring fewer substations (as the power is at a lower voltage), and streamlining approvals.
Where would superconductors have most effect? Queensland. The sunshine state is planning four new high-voltage transmission projects, to be built by the mid-2030s. The goal is to link clean energy production in the north of the state with the population centers of the south, similar to sending Canadian hydropower to New York to meet demand.
Right now, there are major congestion issues between southern and central Queensland, and subsea links like Scotland-England renewable corridors highlight how to move power at scale. Strategically locating superconducting cables here would be the best location, serving to future-proof infrastructure, reduce emissions and avoid power loss.
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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