Italy's Council of Ministries approved a legislative decree setting the instruments, mechanisms and incentives, as well as the institutional, financial and legal framework required for the achievement of the 17 quota of renewable energy required in the country by 2020, as established by European Union directive 2009/28/CE.
In general, the decree establishes modifications on the permitting procedures and foresees a new incentives system for renewable sources of energy that begin operations after January 1, 2013. While the legislation makes differences for smaller and larger facilities, the main issue within the decree is the regulation of photovoltaic facilities, which is aimed to limit the construction of these facilities for speculative reasons and to help ensure long-term development in the sector.
The most relevant measures include:
• a new incentives scheme for photovoltaic PV facilities connected to the grid after May 31, 2011. This incentives system will be defined by April 30.
• Photovoltaic facilities with an installed capacity of more than 1 megawatt MW on agricultural lands will be excluded from federal incentives.
• Photovoltaic facilities on agricultural lands with installed capacity less than or equal to 1 MW will be included in the incentives scheme, as long as the area for construction does not exceed 10 of the area owned by the developer. This restriction vanishes if the lands are idle for more than five years.
The decree is an attempt to bring order to this sector, which exploded last year, moving from 1,142 MW at the end of 2009 to 7,000 MW by the end of 2010. This boom was experienced throughout Europe, with a 115 increase in photovoltaic facilities on the continent, reaching 25 gigawatts of generating capacity. This can be explained by overly generous incentive schemes, forcing the major players in the European photovoltaic market Germany, Spain and France to review and reduce their incentives systems.
In Italy, regional governments also tried to control and regulate renewable energy development in their territories. For example, Sardinia changed the regulation of renewable energy production in March 2010 by banning offshore windfarms, monopolizing the development of onshore windfarms through an ad-hoc state company, and changing the permitting procedures and limiting the installation of solar photovoltaic facilities on farmland. The Northern region of Veneto, which is establishing a new regional energy plan, has blocked all regional authorizations for photovoltaic facilities larger than 0.2 MW on agricultural lands and biomass or biofuel-fired facilities larger than 0.5 MW and 1 MW, respectively, until the approval of the plan.
Illinois NextGrid redefines utility, customer, and provider roles with grid modernization, DER valuation, upfront rebates, net metering reform, and non-wires alternatives, leveraging rooftop solar, batteries, and performance signals to enhance reliability and efficiency.
Key Points
Illinois NextGrid is an ICC roadmap to value DER and modernize the grid with rebates and non-wires solutions.
✅ Upfront Value-of-DER rebates reward location, time, and performance.
✅ Locational DER reduce peak demand and defer wires and substations.
✅ Encourages non-wires alternatives and data-driven utility planning.
How does the electric utility fit in to a rapidly-evolving energy system? That’s what the Illinois Commerce Commission is trying to determine with its new effort, "NextGrid". Together, we’re rethinking the roles of the utility, the customer, and energy solution providers in a 21st-century digital grid landscape.
In some ways, NextGrid will follow in the footsteps of New York’s innovative Reforming the Energy Vision process, a multi-year effort to re-examine how electric utilities and customers interact. A new approach is essential to accelerating the adoption of clean energy technologies and building a smarter electricity infrastructure in the state.
Like REV, NextGrid is gaining national attention for stakeholder-driven processes to reveal new ways to value distributed energy resources (DER), like rooftop solar and batteries. New York and Illinois’ efforts also seek alternatives, such as virtual power plants, to simply building more and more wires, poles, and power plants to meet the energy needs of tomorrow.
Yet, Illinois is may go a few steps beyond New York, creating a comprehensive framework for utilities to measure how DER are making the grid smarter and more efficient. Here is what we know will happen so far.
On Wednesday, April 5, at the second annual Grid Modernization Forum in Chicago, I’ll be discussing why these provisions could change the future of our energy system, including insights on grid modernization affordability for stakeholders.
Value of distributed energy
The Illinois Commerce Commission’s NextGrid plans grew out of the recently-passed future energy jobs act, a landmark piece of climate and energy policy that was widely heralded as a bipartisan oddity in the age of Trump. The Future Energy Jobs Act will provide significant new investments in renewables and energy efficiency over the next 13 years, redefine the role and value of rooftop solar and batteries on the grid, and lead to significant greenhouse gas emission reductions.
NextGrid will likely start laying the groundwork for valuing distributed energy resources (DER) as envisioned by the Future Energy Jobs Act, which introduces the concept of a new rebate. Illinois currently has a net metering policy, which lets people with solar panels sell their unused solar energy back to the grid to offset their electric bill. Yet the net metering policy had an arbitrary “cap,” or a certain level after which homes and businesses adding solar panels would no longer be able to benefit from net metering.
Although Illinois is still a few years away from meeting that previous “cap,” when it does hit that level, the new policy will ensure additional DER will still be rewarded. Under the new plan, the Value-of-DER rebate will replace net metering on the distribution portion of a customer’s bill (the charge for delivering electricity from the local substation to your house) with an upfront payment, which credits the customer for the value their solar provides to the local grid over the system’s life. Net metering for the energy supply portion of the bill would remain – i.e. homes and businesses would still be able to offset a significant portion of their electric bills by selling excess energy.
What is unique about Illinois’ approach is that the rebate is an upfront payment, rather than on ongoing tariff or reduced net metering compensation, for example. By allowing customers to get paid for the value solar provides to the system at the time it is installed, in the same way new wires, poles, and transformers would, this upfront payment positions DER investments as equally or more beneficial to customers and the electric grid. This is a huge step not only for regulators, but for utilities as well, as they begin to see distributed energy as an asset to the system.
This is a huge step for utilities, as they begin to see distributed energy as an asset to the system.
The rebate would also factor-in the variables of location, time, and performance of DER in the rebate formula, allowing for a more precise calculation of the value to the grid. Peak electricity demand can stress the local grid, causing wear and tear and failure of the equipment that serve our homes and businesses. Power from DER during peak times and in certain areas can alleviate those stresses, therefore providing a greater value than during times of average demand.
In addition, factoring-in the value of performance will take into account the other functions of distributed energy that help keep the lights on. For example, batteries and advanced inverters can provide support for helping avoid voltage fluctuations that can cause outages and other costs to customers.
EU Renewable Energy Shift is cutting gas dependence as wind and solar expand, reshaping Europe's power mix, curbing emissions, and pressuring coal use amid a supply crisis and rising natural gas prices.
Key Points
An EU trend where wind and solar growth reduce gas reliance, curb coal, and lower power-sector emissions.
✅ Wind and solar displace gas in EU power mix
✅ Coal use rises as gas prices surge
✅ Emissions fall, but not fast enough for 1.5 C target
The European Union’s renewable energy sources are helping reduce its dependence on natural gas, under the current European electricity pricing framework, that’s still costing the region dearly.
Renewables growth has helped reduce the EU’s dependence on gas, as wind and solar outpaced gas across the bloc last year, which has soared in price since the middle of last year as the region grapples with a supply crisis that’s dealt blows to industries as well as ordinary consumers’ pockets. More than half of new renewable generation since 2019 has replaced gas power, according to a study by London-based climate think tank Ember, with the rest replacing mainly nuclear and coal sources.
“These are moments and paradigm shifts when governments and businesses start taking this much more seriously,” said Charles Moore, the lead author on the study, amid Covid-19 responses accelerating the transition across Europe. “The alternatives are available, they are cheaper, and they are likely to get even cheaper and more competitive. Renewables are now an opportunity, not a cost.”
The high price of gas relative to coal has meant utilities are leaning more on coal as a back-up for renewable generation, as stunted hydro and nuclear output has constrained low-carbon alternatives in parts of Europe, which risks the trajectory of Europe’s phase-out of the dirtiest fossil fuel. Last year, the EU’s coal use jumped disproportionately high relative to the rise in power generation as high gas prices boosted the relative profitability of burning coal instead.
Europe Coal Use Jumps as Costly Gas Turns Firms to Dirty Fuel EU power generation from renewables reached a record high in 2021 of 547 terawatt-hours last year, accounting for an 11% increase compared to two years before, according to Ember’s Europe Electricity Review. It’s more than doubled in a decade, representing a 157% increase since 2011.
Gas use declined last year for the second year in a row, as Europe explores storing electricity in gas pipelines to leverage existing infrastructure, reaching a level 8.1% lower than 2019. By contrast, coal use fell just 3.3% in the same period. Put simply, wind and solar did a great job of replacing coal during 2011-2019 but since then renewables have mostly been nudging out gas-fired power stations.
Ember’s Moore warned that the slowing phase-out of coal might require legislation to accelerate. The International Energy Agency recommends OECD countries cease using coal by the end of the decade to ensure alignment with the Paris Agreement target of keeping the world’s temperature increase below 1.5 Celsius, with renewables poised to eclipse coal globally by the mid-2020s lending momentum.
“Europe can accelerate the phasing out of coal by building more renewable energy and faster,” said Felicia Aminoff, an energy-transition analyst at BloombergNEF. “Wind and solar have no fuel costs, so as soon as you have made the initial investments to build wind and solar capacity it will start replacing generation that uses any kind of fuel, whether it is coal or gas.”
Overall, EU power sector emissions fell at less than half the rate required to hit that target, Ember’s report said. Spain produced the largest emissions reduction in the last two years, with renewables adding about 25 TWh and gas falling 15 TWh, and in Germany renewables topped coal and nuclear for the first time to support the shift. In contrast, heavy use of coal dragged down the bloc’s climate progress in Poland, where coal use rose about 8 TWh and renewables gained only 4 TWh.
New England oil-fired generation surges as ISO New England manages a cold snap, dual-fuel switching, and a natural gas price spike, highlighting winter reliability challenges, LNG and pipeline limits, and rising CO2 emissions.
Key Points
Reliance on oil-burning power plants during winter demand spikes when natural gas is costly or constrained.
✅ Driven by dual-fuel switching amid high natural gas prices
✅ Raises CO2 emissions despite coal retirements and renewables growth
New England is relying on oil-fired generators for the most electricity since 2018 as a frigid blast boosts demand for power and natural gas prices soar across markets.
Oil generators were producing more than 4,200 megawatts early Thursday, accounting for about a quarter of the grid’s power supply, according to ISO New England. That was the most since Jan. 6, 2018, when oil plants produced as much as 6.4 gigawatts, or 32% of the grid’s output, said Wood Mackenzie analyst Margaret Cashman.
Oil is typically used only when demand spikes, because of higher costs and emissions concerns. Consumption has been consistently high over the past three weeks as some generators switch from gas, which has surged in price in recent months. New England generators are producing power from oil at an average rate of almost 1.8 gigawatts so far this month, the highest for January in at least five years.
Oil’s share declined to 16% Friday morning ahead of an expected snowstorm, which was “a surprise,” Cashman said.
“It makes me wonder if some of those generators are aiming to reserve their fuel for this weekend,” she said.
During the recent cold snap, more than a tenth of the electricity generated in New England has been produced by power plants that haven’t happened for at least 15 years.
Burning oil for electricity was standard practice throughout the region for decades. It was once our most common fuel for power and as recently as 2000, fully 19% of the six-state region’s electricity came from burning oil, according to ISO-New England, more than any other source except nuclear power at the time.
Since then, however, natural gas has gotten so cheap that most oil-fired plants have been shut or converted to burn gas, to the point that just 1% of New England’s electricity came from oil in 2018, whereas about half our power came from natural gas generation regionally during that period. This is good because natural gas produces less pollution, both particulates and greenhouse gasses, although exactly how much less is a matter of debate.
But as you probably know, there’s a problem: Natural gas is also used for heating, which gets first dibs. Prolonged cold snaps require so much gas to keep us warm, a challenge echoed in Ontario’s electricity system as supply tightens, that there might not be enough for power plants – at least, not at prices they’re willing to pay.
After we came close to rolling brownouts during the polar vortex in the 2017-18 winter because gas-fired power plants cut back so much, ISO-NE, which has oversight of the power grid, established “winter reliability” rules. The most important change was to pay power plants to become dual-fuel, meaning they can switch quickly between natural gas and oil, and to stockpile oil for winter cold snaps.
We’re seeing that practice in action right now, as many dual-fuel plants have switched away from gas to oil, just as was intended.
That switch is part of the reason EPA says the region’s carbon emissions have gone up in the pandemic, from 22 million tons of CO2 in 2019 to 24 million tons in 2021. That reverses a long trend caused partly by closing of coal plants and partly by growing solar and offshore wind capacity: New England power generation produced 36 million tons of CO2 a decade ago.
So if we admit that a return to oil burning is bad, and it is, what can we do in future winters? There are many possibilities, including tapping more clean imports such as Canadian hydropower to diversify supply.
The most obvious solution is to import more natural gas, especially from fracked fields in New York state and Pennsylvania. But efforts to build pipelines to do that have been shot down a couple of times and seem unlikely to go forward and importing more gas via ocean tanker in the form of liquefied natural gas (LNG) is also an option, but hits limits in terms of port facilities.
Aside from NIMBY concerns, the problem with building pipelines or ports to import more gas is that pipelines and ports are very expensive. Once they’re built they create a financial incentive to keep using natural gas for decades to justify the expense, similar to moves such as Ontario’s new gas plants that lock in generation. That makes it much harder for New England to decarbonize and potentially leaves ratepayers on the hook for a boatload of stranded costs.
Nuclear Power for Net-Zero Grids anchors reliable baseload, integrating renewables with grid stability as solar, wind, and battery storage scale. Advanced reactors complement hydropower, curb natural gas reliance, and accelerate deep decarbonization of electricity systems.
Key Points
Uses nuclear baseload and advanced reactors to stabilize power grids and integrate higher shares of variable renewables.
✅ Provides firm, zero-carbon baseload for renewable-heavy grids
✅ Reduces natural gas dependence and peaker emissions
✅ Advanced reactors enhance safety, flexibility, and cost
Declining solar, wind, and battery technology costs are helping to grow the share of renewables in the world’s power mix to the point that governments are pledging net-zero emission electricity generation in two to three decades to fight global warming.
Yet, electricity grids will continue to require stable baseload to incorporate growing shares of renewable energy sources and ensure lights are on even when the sun doesn’t shine, or the wind doesn’t blow. Until battery technology evolves enough—and costs fall far enough—to allow massive storage and deployment of net-zero electricity to the grid, the systems will continue to need power from sources other than solar and wind.
And these will be natural gas and nuclear power, regardless of concerns about emissions from the fossil fuel natural gas and potential disasters at nuclear power facilities such as the ones in Chernobyl or Fukushima.
As natural gas is increasingly considered as just another fossil fuel, nuclear power generation provides carbon-free electricity to the countries that have it, even as debates over nuclear power’s outlook continue worldwide, and could be the key to ensuring a stable power grid capable of taking in growing shares of solar and wind power generation.
The United States, where nuclear energy currently provides more than half of the carbon-free electricity, is supporting the development of advanced nuclear reactors as part of the clean energy strategy.
But Europe, which has set a goal to reach carbon neutrality by 2050, could find itself with growing emissions from the power sector in a decade, as many nuclear reactors are slated for decommissioning and questions remain over whether its aging reactors can bridge the gap. The gap left by lost nuclear power is most easily filled by natural gas-powered electricity generation—and this, if it happens, could undermine the net-zero goals of the European Union (EU) and the bloc’s ambition to be a world leader in the fight against climate change.
U.S. Power Grid Will Need Nuclear For Net-Zero Emissions
A 2020 report from the University of California, Berkeley, said that rapidly declining solar, wind, and storage prices make it entirely feasible for the U.S. to meet 90 percent of its power needs from zero-emission energy sources by 2035 with zero increases in customer costs from today’s levels.
Still, natural gas-fired generation will be needed for 10 percent of America’s power needs. According to the report, in 2035 it would be possible that “during normal periods of generation and demand, wind, solar, and batteries provide 70% of annual generation, while hydropower and nuclear provide 20%.” Even with an exponential rise in renewable power generation, the U.S. grid will need nuclear power and hydropower to be stable with such a large share of solar and wind.
The U.S. Backs Advanced Nuclear Reactor Technology
The U.S. Department of Energy is funding programs of private companies under DOE’s new Advanced Reactor Demonstration Program (ARDP) to showcase next-gen nuclear designs for U.S. deployment.
“Taking leadership in advanced technology is so important to the country’s future because nuclear energy plays such a key role in our clean energy strategy,” U.S. Secretary of Energy Dan Brouillette said at the end of December when DOE announced it was financially backing five teams to develop and demonstrate advanced nuclear reactors in the United States.
“All of these projects will put the U.S. on an accelerated timeline to domestically and globally deploy advanced nuclear reactors that will enhance safety and be affordable to construct and operate,” Secretary Brouillette said.
According to Washington DC-based Nuclear Energy Institute (NEI), a policy organization of the nuclear technologies industry, nuclear energy provides nearly 55 percent of America’s carbon-free electricity. That is more than 2.5 times the amount generated by hydropower, nearly 3 times the amount generated by wind, and more than 12 times the amount generated by solar. Nuclear energy can help the United States to get to the deep carbonization needed to hit climate goals.
Europe Could See Rising Emissions Without Nuclear Power
While the United States is doubling down on efforts to develop advanced and cheaper nuclear reactors, including microreactors and such with new types of technology, Europe could be headed to growing emissions from the electricity sector as nuclear power facilities are scheduled to be decommissioned over the next decade and Europe is losing nuclear power just when it really needs energy, according to a Reuters analysis from last month.
In many cases, it will be natural gas that will come to the rescue to power grids to ensure grid stability and enough capacity during peak demand because solar and wind generation is variable and dependent on the weather.
For example, Germany, the biggest economy in Europe, is boosting its renewables targets, but it is also phasing out nuclear by next year, amid a nuclear option debate over climate strategy, while its deadline to phase out coal-fired generation is 2038—more than a decade later compared to phase-out plans in the UK and Italy, for example, where the deadline is the mid-2020s.
The UK, which left the EU last year, included support for nuclear power generation as one of the ten pillars in ‘The Ten Point Plan for a Green Industrial Revolution’ unveiled in November.
The UK’s National Grid has issued several warnings about tight supply since the fall of 2020, due to low renewable output amid high demand.
“National Grid’s announcement underscores the urgency of investing in new nuclear capacity, to secure reliable, always-on, emissions-free power, alongside other zero-carbon sources. Otherwise, we will continue to burn gas and coal as a fallback and fall short of our net zero ambitions,” Tom Greatrex, Chief Executive of the Nuclear Industry Association, said in response to one of those warnings.
But it’s in the UK that one major nuclear power plant project has notoriously seen a delay of nearly a decade—Hinkley Point C, originally planned in 2007 to help UK households to “cook their 2017 Christmas turkeys”, is now set for start-up in the middle of the 2020s.
Nuclear power development and plant construction is expensive, but it could save the plans for low-carbon emission power generation in many developed economies, including in the United States.
Philippines coal dependency underscores energy transition challenges, climate change risks, and air pollution, as rising electricity demand, fossil fuels, and emissions shape policy shifts toward renewable energy, grid reliability, and sustainable development.
Key Points
It is rising reliance on coal for power, driven by demand and cost, with climate, air pollution, and policy risks.
✅ Driven by rising demand, affordability, and grid reliability.
✅ Worsens emissions, air pollution, and public health burdens.
✅ Policy shifts aim at renewable energy, efficiency, and standards.
In a striking development, the Philippines has surpassed China and Indonesia to become the nation most dependent on coal-generated power in recent years. This shift highlights significant implications for the country's energy strategy, environmental policies, and its commitment to sustainable development, and comes as global power demand continues to surge worldwide.
Rising Dependency on Coal
The Philippines' increasing reliance on coal-generated power is driven by several factors, including rapid economic growth, rising electricity demand, and regional uncertainties in China's electricity sector that influence fuel markets, and the perceived affordability and reliability of coal as an energy source. Coal has historically been a key component of the Philippines' energy mix, providing a stable supply of electricity to support industrialization and urbanization efforts.
Environmental and Health Impacts
Despite its economic benefits, coal-generated power comes with significant environmental and health costs, especially as soaring electricity and coal use amplifies exposure to pollution. Coal combustion releases greenhouse gases such as carbon dioxide, contributing to global warming and climate change. Additionally, coal-fired power plants emit pollutants such as sulfur dioxide, nitrogen oxides, and particulate matter, which pose health risks to nearby communities and degrade air quality.
Policy and Regulatory Landscape
The Philippines' energy policies have evolved to address the challenges posed by coal dependency while promoting sustainable alternatives. The government has introduced initiatives to encourage renewable energy development, improve energy efficiency, and, alongside stricter emissions standards on coal-fired power plants, is evaluating nuclear power for inclusion in the energy mix to meet future demand. However, balancing economic growth with environmental protection remains a complex and ongoing challenge.
International and Domestic Pressures
Internationally, there is growing pressure on countries to reduce reliance on fossil fuels and transition towards cleaner energy sources as part of global climate commitments under the Paris Agreement, illustrated by the United Kingdom's plan to end coal power within its grid. The Philippines' status as the most coal-dependent nation underscores the urgency for policymakers to accelerate the shift towards renewable energy and reduce carbon emissions to mitigate climate impacts.
Challenges and Opportunities
Transitioning away from coal-generated power presents both challenges and opportunities for the Philippines. Challenges include overcoming entrenched interests in the coal industry, addressing energy security concerns, and navigating the economic implications of energy transition, particularly as clean energy investment in developing nations has recently declined, adding financial headwinds. However, embracing renewable energy offers opportunities to diversify the energy mix, reduce dependence on imported fuels, create green jobs, and improve energy access in remote areas.
Community and Stakeholder Engagement
Engaging communities and stakeholders is crucial in shaping the Philippines' energy transition strategy. Local residents, environmental advocates, industry leaders, and policymakers play essential roles in fostering dialogue, raising awareness about the benefits of renewable energy, and advocating for policies that promote sustainable development and protect public health.
Future Outlook
The Philippines' path towards reducing coal dependency and advancing renewable energy is critical to achieving long-term sustainability and resilience against climate change impacts. By investing in renewable energy infrastructure, enhancing energy efficiency measures, and fostering innovation in clean technologies, as renewables poised to eclipse coal indicate broader momentum, the country can mitigate environmental risks, improve energy security, and contribute to global efforts to combat climate change.
Conclusion
As the Philippines surpasses China and Indonesia in coal-generated power dependency, the nation faces pivotal decisions regarding its energy future. Balancing economic growth with environmental stewardship requires strategic investments in renewable energy, robust policy frameworks, and proactive engagement with stakeholders to achieve a sustainable and resilient energy system. By prioritizing clean energy solutions, the Philippines can pave the way towards a greener and more sustainable future for generations to come.
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.
