Massachusetts Attorney General Martha Coakley said that the power company Unitil should pay $4.6 million in fines for its botched response to a December ice storm that knocked out electricity for thousands.
All of Unitil's 28,500 Massachusetts customers lost power in the storm. One in five had no power a week later, and more than 1,000 had no electricity for 12 days or more.
"Unitil's lack of preparation for the storm and ineptitude during the restoration efforts caused great hardship, suffering and financial loss," Coakley said in a press release.
In a statement, Unitil called the proposed fine "unreasonable and unprecedented" and "severely disproportionate" to its role in the outages.
The New Hampshire-based company is the state's smallest utility, serving four communities. The company said Coakley's decision not to fine any other utilities that had problems following the storm "has made it clear that this is an arbitrary proposal based more on public anger than the facts of the case."
Other utilities could later be fined. State utility regulators are investigating how three other companies responded to the storm. But those probes are in their early stages, and Coakley's office hasn't made any recommendations.
Coakley's office said it participated in public hearings and five days of evidentiary hearings before presenting the proposal to the Department of Public Utilities, which must approve a fine before it is imposed. The money would go into the state's general fund.
Coakley's office said it found numerous problems with Unitil's storm preparation, including an Emergency Response Plan that was insufficiently reviewed and tested and a failure to invest in any system to help restore power during an outage.
Most disturbingly, Coakley said, during the outage Unitil didn't try to contact 65 critical care customers whom it knew depended on electricity for survival.
Unitil has apologized for the lengthy outage. It released an internal report that was highly critical of its performance during the storm, saying managers lost track of work crews and felt overwhelmed. But the company also has said its employees worked as hard and efficiently as possible.
In its statement, Unitil said, "None of (the attorney general's) criticisms are new and most are shared among utilities across the region that responded to the worst natural disaster in decades."
The company said most of its Massachusetts customers had power restored at the same time as customers of other utilities even though its service area "was the epicenter of a natural disaster of unprecedented proportion for the region."
Unitil's serves the north central Massachusetts communities of Fitchburg, Townsend, Lunenburg and Ashby. It has 75,000 electric customers in New Hampshire.
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.
Taltson Hydro Electric Heating directs surplus hydro power in the South Slave to space heat via discounted rates, displacing diesel and cutting greenhouse gas emissions, with rebates, separate metering, and backup systems shaping adoption.
Key Points
An initiative using Taltson's surplus hydro to heat buildings, discount rates replace diesel and cut emissions.
✅ 6.3 cents/kWh heating rate needs separate metering, backup heat
✅ 4-6 MW surplus hydro; outages require diesel; rebates available
✅ Program may be curtailed if new mines or mills demand power
A Northwest Territories green energy advocate says there's an obvious way to expand demand for electricity in the territory's South Slave region without relying on new mining developments — direct it toward heating.
One of the reasons the N.W.T. has always had some of the highest electricity rates in Canada is that a small number of people have to shoulder the huge costs of hydro facilities and power plants.
But some observers point out that residents consume as much energy for heat as they do for conventional uses of electricity, such as lighting and powering appliances. Right now almost all of that heat is generated by expensive oil imported from the United States.
The Northwest Territories Power Corporation says the 18-megawatt Taltson hydro system that serves the South Slave typically has four to six megawatts of excess generating capacity, even as record demand in Yukon is reported. It says using some of that to generate heat is a government priority.
But renewable energy advocate and former N.W.T. MP Dennis Bevington, who lives in the South Slave and heats his home using electricity, says the government is not making it easy for people to tap into that surplus to heat their homes and businesses, a debate that some say would benefit from independent planning at the national level.
Discount rate for heating, but there are catches The power corporation offers hydro electricity from Taltson to use for heating at a much lower price than it charges for electricity generally. The discounted rate is not available to residential customers.
According to the corporation, consumers pay only 6.3 cents per kilowatt hour compared to the regular rate of just under 24 cents, while Manitoba Hydro financial pressures highlight the risks of expanding demand without new generation.
But to distinguish between the two, users are required to cover the cost of installing a separate power meter. Bevington, who developed the N.W.T.'s first energy strategy, says that is an unnecessary expense.
Taltson expansion key to reducing N.W.T.'s greenhouse gas emissions, says gov't "The billing is how you control that," he said. "You establish an average electrical use in the winter months. That could be the base rate. Then, if you use power in the winter months above that, you get the discount."
Users are also required to have a back-up heating system. Taltson hydro power offers heating on the understanding that when the hydro system is down — such as during power outages or annual summer maintenance of the hydro system — electricity is not available for heating. The president and CEO of the power corporation says there's a good reason for that. "The diesels are more expensive to run and they're actually greenhouse gas emitting," said Noel Voykin. "The whole idea of this [electric heat] program is to provide clean energy that is not otherwise being used."
According to the corporation, there have been huge savings for the few who have tapped into the hydro system to heat their buildings, and across Canada utilities are exploring novel generation such as NB Power's Belledune seawater project to diversify supply.
It's being used to heat Aurora College's Breynat Hall, and Joseph B. Tyrrell Elementary School and the transportation department garage in Fort Smith, N.W.T. Electricity is also used to heat the Jackfish power plant in the North Slave region.
The corporation says that during a four-year period, this saved more than 600,000 litres of diesel fuel and reduced greenhouse gas emissions by about 1,700 tonnes.
Bevington says the most obvious place to expand the use of electrical heat is to government housing.
"We have a hundred public housing units in Fort Smith," he said. "The government is putting diesel into those units [for heating] and they could be putting in their own electricity."
Heating a tiny part of energy market The corporation says it sells only about 2.5 megawatts of electricity for heating each year, which is less than four per cent of the power it sells in the region. It says with some upgrades, another two megawatts of electricity could be made available for electrical heat.
Bevington says the corporation could do more to market electricity for heating. Voykin said that's the government's job. There are three programs that offer rebates to residents and businesses converting to electric heating.
If you build it, will they come? N.W.T. gov't hopes hydro expansion will attract investment There are better options than billion dollar Taltson expansion, say energy leaders There may be a reason why the government and the corporation are not more aggressively promoting using surplus electricity in the Taltson system for heating, as large hydro ambitions have reopened old wounds in places like Quebec and Newfoundland and Labrador during recent debates.
It is anticipating that new industrial customers may require that excess capacity in the coming years, and experiences elsewhere show that accommodating new energy-intensive customers can be challenging for utilities. Voykin said those potential new customers include a proposed mine at Pine Point and a pellet mill in Enterprise, N.W.T., even as biomass use faces environmental pushback in some regions.
The corporation says any surplus power in the system will be sold at standard rates to any new industrial customers instead of at discount rates for heating. If that requires cutting back on the heating program, it will be cut back.
France Nuclear Power Outages threaten the grid as EDF reactors undergo stress corrosion inspections, maintenance delays, and staff shortages, driving electricity imports, peak-demand curtailment plans, and potential rolling blackouts during a cold snap across Europe.
Key Points
EDF maintenance and stress corrosion cut reactor output, forcing imports and blackouts as cold weather lifts demand.
✅ EDF inspects stress corrosion cracks in reactor piping
✅ Maintenance backlogs and skilled labor shortages slow repairs
✅ Government plans demand cuts, imports, and rolling blackouts
France is bracing for possible power outages in the coming days as falling temperatures push up demand while state-controlled nuclear group EDF struggles to bring more production on line.
WHY CAN'T FRANCE MEET DEMAND? France is one of the most nuclear-powered countries in the world, with a significant role of nuclear power in its energy mix, typically producing over 70% of its electricity with its fleet of 56 reactors and providing about 15% of Europe's total power through exports.
However, EDF (EDF.PA) has had to take a record number of its ageing reactors offline for maintenance this year just as Europe is struggling to cope with cuts in Russian natural gas supplies used for generating electricity, with electricity prices surging across the continent this year.
That has left France's nuclear output at a 30-year low, and mirrors how Europe is losing nuclear power more broadly, forcing France to import electricity and prepare plans for possible blackouts as a cold snap fuels demand for heating.
WHAT ARE EDF'S MAINTENANCE PROBLEMS? While EDF normally has a number of its reactors offline for maintenance, it has had far more than usual this year due to what is known as stress corrosion on pipes in some reactors, and during heatwaves river temperature limits have constrained output further.
At the request of France's nuclear safety watchdog, EDF is in the process of inspecting and making repairs across its fleet since detecting cracks in the welding connecting pipes in one reactor at the end of last year.
Years of under-investment in the nuclear sector mean that there is precious little spare capacity to meet demand while reactors are offline for maintenance, and environmental constraints such as limits on energy output during high river temperatures reduce flexibility.
France also lacks specialised welders and other workers in sufficient numbers to be able to make repairs fast enough to get reactors back online.
WHAT IS BEING DONE? In the very short term, after a summer when power markets hit records as plants buckled in heat, there is little that can be done to get more reactors online faster, leaving the government to plan for voluntary cuts at peak demand periods and limited forced blackouts.
In the very short term, there is little that can be done to get more reactors online faster, leaving the government to plan for voluntary cuts at peak demand periods and limited forced blackouts.
Meanwhile, EDF and others in the French nuclear industry are on a recruitment drive for the next generation of welders, pipe-fitters and boiler makers, going so far as to set up a new school to train them.
President Emmanuel Macron wants a new push in nuclear energy, even as a nuclear power dispute with Germany persists, and has committed to building six new reactors at a cost his government estimates at nearly 52 billion euros ($55 billion).
As a first step, the government is in the process of buying out EDF's minority shareholders and fully nationalising the debt-laden group, which it says is necessary to make the long-term investments in new reactors.
NRC Advanced Reactor Licensing streamlines a risk-informed, performance-based, technology-inclusive pathway for advanced non-light water reactors, aligning with NEIMA to enable predictable regulatory reviews, inherent safety, clean energy deployment, and industrial heat, hydrogen, and desalination applications.
Key Points
A risk-informed, performance-based NRC pathway streamlining licensing for advanced non-light water reactors.
✅ Aligned with NEIMA: risk-informed, performance-based, tech-inclusive
✅ Predictable licensing for advanced non-light water reactor designs
The US Nuclear Regulatory Commission (NRC) voted 4-0 to approve the implementation of a more streamlined and predictable licensing pathway for advanced non-light water reactors, aligning with nuclear innovation priorities identified by industry advocates, the Nuclear Energy Institute (NEI) announced, and amid regional reliability measures such as New England emergency fuel stock plans that have drawn cost scrutiny.
This approach is consistent with the Nuclear Energy Innovation and Modernisation Act (NEIMA), a nuclear innovation act passed in 2019 by the US Congress calling for the development of a risk-informed, performance-based and technology inclusive licensing process for advanced reactor developers.
NEI Chief Nuclear Officer Doug True said: “A modernised regulatory framework is a key enabler of next-generation nuclear technologies that, amid ACORE’s challenge to DOE subsidy proposals in energy market proceedings, can help us meet our energy needs while protecting the climate. The Commission’s unanimous approval of a risk-informed and performance-based licensing framework paves the way for regulatory reviews to be aligned with the inherent safety characteristics, smaller reactor cores and simplified designs of advanced reactors.”
Over the last several years the industry’s Licensing Modernisation Project, sponsored by US Department of Energy, led by Southern Nuclear, and supported by NEI’s Advanced Reactor Regulatory Task Force, and influenced by a presidential order to bolster uranium and nuclear energy, developed the guidance for this new framework. Amid shifts in the fuel supply chain, including the U.S. ban on Russian uranium, this approach will inform the development of a new rule for licensing advanced reactors, which NEIMA requires.
“A well-defined licensing path will benefit the next generation of nuclear plants, especially as regions consider New England market overhaul efforts, which could meet a wide range of applications beyond generating electricity such as producing heat for industry, desalinating water, and making hydrogen – all without carbon emissions,” True noted.
France Nuclear Heatwave Restrictions signal reduced nuclear power along the Rhone River as EDF imposes output limits due to high water temperatures, grid needs, with minimal price impact amid strong solar and exports.
Key Points
Temporary EDF output limits at Rhone River reactors due to hot water, protecting ecosystems and grid reliability.
✅ EDF expects halved output at Bugey and Saint Alban.
✅ Cuts align with water temperature and discharge rules.
✅ Weekend midday curtailments offset by solar supply.
The high temperature warning has come early this year but will affect fewer nuclear power plants. High temperatures could halve nuclear power production, with river temperature limits at plants along France's Rhone River this week.
Output restrictions are expected at two nuclear plants in eastern France due to high temperature forecasts, nuclear operator EDF said. It comes several days ahead of a similar warning that was made last year but will affect fewer plants, and follows a period when power demand has held firm during lockdowns across Europe.
The hot weather is likely to halve the available power supply from the 3.6 GW Bugey plant from 13 July and the 2.6 GW Saint Alban plant from 16 July, the operator said.
However, production will be at least 1.8 GW at Bugey and 1.3 GW at Saint Alban to meet grid requirements, and may change according to grid needs, the operator said.
Kpler analyst Emeric de Vigan said the restrictions were likely to have little effect on output in practice. Cuts are likely only at the weekend or midday when solar output was at its peak so the impact on power prices would be slim.
He said the situation would need monitoring in the coming weeks, however, noting it was unusually early in the summer for nuclear-powered France to see such restrictions imposed.
Water temperatures at the Bugey plant already eclipsed the initial threshold for restrictions on 9 July, as European power hits records during the heatwave. They are currently forecast to peak next week and then drop again, Refinitiv data showed.
"France is currently net exporting large amounts of power – and, despite a nuclear power dispute with Germany, single nuclear units' supply restrictions will not have the same effect as last year," Refinitiv analyst Nathalie Gerl said.
The Garonne River in southern France has the highest potential for critical levels of warming, but its Golfech plant is currently offline for maintenance until mid-August, as Europe faces nuclear losses, the data showed.
"(The restrictions were) to be expected and it will probably occur more often," Greenpeace campaigner Roger Spautz said.
"The authorities must stick to existing regulations for water discharges. Otherwise, the ecosystems will be even more affected," he added.
2022 US Renewable Power Milestone highlights EIA data: wind and solar outpaced coal and nuclear, hydropower contributed, with falling levelized costs, grid integration, battery storage, and transmission upgrades shaping affordable, reliable clean power growth.
Key Points
The year US renewables, led by wind and solar, generated more power than coal and nuclear, per EIA.
✅ Wind and solar rose; levelized costs fell 70%-90% over decade
✅ Renewables surpassed coal and nuclear in 2022 per EIA
✅ Grid needs storage and transmission to manage intermittency
Electricity generated from renewables surpassed coal in the United States for the first time in 2022, as wind and solar surpassed coal nationwide, the U.S. Energy Information Administration has announced.
Growth in wind and solar significantly drove the increase in renewable energy and contributed 14% of the electricity produced domestically in 2022, with solar producing about 4.7% of U.S. power overall. Hydropower contributed 6%, and biomass and geothermal sources generated less than 1%.
“I’m happy to see we’ve crossed that threshold, but that is only a step in what has to be a very rapid and much cheaper journey,” said Stephen Porder, a professor of ecology and assistant provost for sustainability at Brown University.
California produced 26% of the national utility-scale solar electricity followed by Texas with 16% and North Carolina with 8%.
“This booming growth is driven largely by economics,” said Gregory Wetstone, president and CEO of the American Council on Renewable Energy, as renewables became the second-most prevalent U.S. electricity source in 2020 nationwide. “Over the past decade, the levelized cost of wind energy declined by 70 percent, while the levelized cost of solar power has declined by an even more impressive 90 percent.”
“Renewable energy is now the most affordable source of new electricity in much of the country,” added Wetstone.
The Energy Information Administration projected that the wind share of the U.S. electricity generation mix will increase from 11% to 12% from 2022 to 2023 and that solar will grow from 4% to 5% during the period, and renewables hit a record 28% share in April according to recent data. The natural gas share is expected to remain at 39% from 2022 to 2023, and coal is projected to decline from 20% last year to 17% this year.
“Wind and solar are going to be the backbone of the growth in renewables, but whether or not they can provide 100% of the U.S. electricity without backup is something that engineers are debating,” said Brown University’s Porder.
This presents challenges for engineers and policy-makers, Porder said, because existing energy grids were built to deliver power from a consistent source. Renewables such as solar and wind generate power intermittently. So battery storage, long-distance transmission and other steps will be needed to help address these challenges, he said.
