Ontario needs nuclear boost, Manley says

Nighttime thermoradiative power converts outgoing infrared radiation into electricity using semiconductor photodiodes, leveraging negative illumination and sky cooling to harvest renewable energy from Earth-to-space heat flow when solar panels rest, regardless of weather.

Key Points

Nighttime thermoradiative power converts Earth's outgoing infrared heat into electricity using semiconductor diodes.

✅ Uses negative illumination to tap Earth-to-space heat flow

✅ Infrared semiconductor photodiodes generate small nighttime current

✅ Theoretical output ~4 W/m^2; lab demo reached 64 nW/m^2

There's a stark contrast between the freezing temperatures of space and the relatively balmy atmosphere of Earth, and that contrast could help generate electricity, scientists say – and alongside concepts such as space-based solar power, utilizing the same optoelectronic physics used in solar panels. The obvious difference this would have compared with solar energy is that it would work during the night time, a potential source of renewable power that could keep on going round the clock and regardless of weather conditions.

Solar panels are basically large-scale photodiodes - devices made out of a semiconducting material that converts the photons (light particles) coming from the Sun into electricity by exciting electrons in a material such as silicon, while concepts like space solar beaming could complement them during adverse weather.

In this experiment, the photodiodes work 'backwards': as photons in the form of infrared radiation - also known as heat radiation - leave the system, a small amount of energy is produced, similar to how raindrop electricity harvesting taps ambient fluxes in other experiments.

This way, the experimental system takes advantage of what researchers call the "negative illumination effect" – that is, the flow of outgoing radiation as heat escapes from Earth back into space. The setup explained in the new study uses an infrared semiconductor facing into the sky to convert this flow into electrical current.

"The vastness of the Universe is a thermodynamic resource," says one of the researchers, Shanhui Fan from Stanford University in California.

"In terms of optoelectronic physics, there is really this very beautiful symmetry between harvesting incoming radiation and harvesting outgoing radiation."

It's an interesting follow-up to a research project Fan participated in last year: a solar panel that can capture sunlight while also allowing excess heat in the form of infrared radiation to escape into space.

In the new study, this "energy harvesting from the sky" process can produce a measurable amount of electricity, the researchers have shown – though for the time being it's a long way from being efficient enough to contribute to our power grids, but advances in peer-to-peer energy sharing could still make niche deployments valuable.

In the team's experiments they were able to produce 64 nanowatts per square metre (10.8 square feet) of power – only a trickle, but an amazing proof of concept nevertheless. In theory, the right materials and conditions could produce a million times more than that, and analyses of cheap abundant electricity show how rapidly such advances compound, reaching about 4 watts per square metre.

"The amount of power that we can generate with this experiment, at the moment, is far below what the theoretical limit is," says one of the team, Masashi Ono from Stanford.

When you consider today's solar panels are able to generate up to 100-200 watts per square metre, and in China solar is cheaper than grid power across every city, this is obviously a long way behind. Even in its earliest form, though, it could be helpful for keeping low-power devices and machines running at night: not every renewable energy device needs to power up a city.

Now that the researchers have proved this can work, the challenge is to improve the performance of the experimental device. If it continues to show promise, the same idea could be applied to capture energy from waste heat given off by machinery, and results in humidity-powered generation suggest ambient sources are plentiful.

"Such a demonstration of direct power generation of a diode facing the sky has not been previously reported," explain the researchers in their published paper.

"Our results point to a pathway for energy harvesting during the night time directly using the coldness of outer space."

The research has been published in Applied Physics Letters.

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Offshore wind power accelerates low-carbon electrification, leveraging floating turbines, high capacity factors, HVDC transmission, and hydrogen production to decarbonize grids, cut CO2, and deliver competitive, reliable renewable energy near demand centers.

Key Points

Offshore wind power uses offshore turbines to deliver low-carbon electricity with high capacity factors and falling costs.

✅ Sea-based wind farms with 40-50% capacity factors

✅ Floating turbines unlock deep-water, far-shore resources

✅ Enables hydrogen production and strengthens grid reliability

The need for affordable low-carbon technologies is greater than ever

Global energy-related CO2 emissions reached a historic high in 2018, driven by an increase in coal use in the power sector. Despite impressive gains for renewables, fossil fuels still account for nearly two-thirds of electricity generation, the same share as 20 years ago. There are signs of a shift, with increasing pledges to decarbonise economies and tackle air pollution, and with World Bank support helping developing countries scale wind, but action needs to accelerate to meet sustainable energy goals. As electrification of the global energy system continues, the need for clean and affordable low-carbon technologies to produce this electricity is more pressing than ever. This World Energy Outlook special report offers a deep dive on a technology that today has a total capacity of 23 GW (80% of it in Europe) and accounts for only 0.3% of global electricity generation, but has the potential to become a mainstay of the world's power supply. The report provides the most comprehensive analysis to date of the global outlook for offshore wind, its contributions to electricity systems and its role in clean energy transitions.

The offshore wind market has been gaining momentum

The global offshore wind market grew nearly 30% per year between 2010 and 2018, benefitting from rapid technology improvements. Over the next five years, about 150 new offshore wind projects are scheduled to be completed around the world, pointing to an increasing role for offshore wind in power supplies. Europe has fostered the technology's development, led by the UK offshore wind sector alongside Germany and Denmark. The United Kingdom and Germany currently have the largest offshore wind capacity in operation, while Denmark produced 15% of its electricity from offshore wind in 2018. China added more capacity than any other country in 2018.

The untapped potential of offshore wind is vast

The best offshore wind sites could supply more than the total amount of electricity consumed worldwide today. And that would involve tapping only the sites close to shores. The IEA initiated a new geospatial analysis for this report to assess offshore wind technical potential country by country. The analysis was based on the latest global weather data on wind speed and quality while factoring in the newest turbine designs. Offshore wind's technical potential is 36 000 TWh per year for installations in water less than 60 metres deep and within 60 km from shore. Global electricity demand is currently 23 000 TWh. Moving further from shore and into deeper waters, floating turbines could unlock enough potential to meet the world's total electricity demand 11 times over in 2040. Our new geospatial analysis indicates that offshore wind alone could meet several times electricity demand in a number of countries, including in Europe, the United States and Japan. The industry is adapting various floating foundation technologies that have already been proven in the oil and gas sector. The first projects are under development and look to prove the feasibility and cost-effectiveness of floating offshore wind technologies.

Offshore wind's attributes are very promising for power systems

New offshore wind projects have capacity factors of 40-50%, as larger turbines and other technology improvements are helping to make the most of available wind resources. At these levels, offshore wind matches the capacity factors of gas- and coal-fired power plants in some regions – though offshore wind is not available at all times. Its capacity factors exceed those of onshore wind and are about double those of solar PV. Offshore wind output varies according to the strength of the wind, but its hourly variability is lower than that of solar PV. Offshore wind typically fluctuates within a narrower band, up to 20% from hour to hour, than solar PV, which varies up to 40%.

Offshore wind's high capacity factors and lower variability make its system value comparable to baseload technologies, placing it in a category of its own – a variable baseload technology. Offshore wind can generate electricity during all hours of the day and tends to produce more electricity in winter months in Europe, the United States and China, as well as during the monsoon season in India. These characteristics mean that offshore wind's system value is generally higher than that of its onshore counterpart and more stable over time than that of solar PV. Offshore wind also contributes to electricity security, with its high availability and seasonality patterns it is able to make a stronger contribution to system needs than other variable renewables. In doing so, offshore wind contributes to reducing CO2 and air pollutant emissions while also lowering the need for investment in dispatchable power plants. Offshore wind also has the advantage of avoiding many land use and social acceptance issues that other variable renewables are facing.

Offshore wind is on track to be a competitive source of electricity

Offshore wind is set to be competitive with fossil fuels within the next decade, as well as with other renewables including solar PV. The cost of offshore wind is declining and is set to fall further. Financing costs account for 35% to 50% of overall generation cost, and supportive policy frameworks are now enabling projects to secure low cost financing in Europe, with zero-subsidy tenders being awarded. Technology costs are also falling. The levelised cost of electricity produced by offshore wind is projected to decline by nearly 60% by 2040. Combined with its relatively high value to the system, this will make offshore wind one of the most competitive sources of electricity. In Europe, recent auctions indicate that offshore wind will soon beat new natural gas-fired capacity on cost and be on a par with solar PV and onshore wind. In China, offshore wind is set to become competitive with new coal-fired capacity around 2030 and be on par with solar PV and onshore wind. In the United States, recent project proposals indicate that offshore wind will soon be an affordable option, even as the 1 GW timeline continues to evolve, with potential to serve demand centres along the country's east coast.

Innovation is delivering deep cost reductions in offshore wind, and transmission costs will become increasingly important. The average upfront cost to build a 1 gigawatt offshore wind project, including transmission, was over $4 billion in 2018, but the cost is set to drop by more than 40% over the next decade. This overall decline is driven by a 60% reduction in the costs of turbines, foundations and their installation. Transmission accounts for around one-quarter of total offshore wind costs today, but its share in total costs is set to increase to about one-half as new projects move further from shore. Innovation in transmission, for example through work to expand the limits of direct current technologies, will be essential to support new projects without raising their overall costs.

Offshore wind is set to become a $1 trillion business

Offshore wind power capacity is set to increase by at least 15-fold worldwide by 2040, becoming a $1 trillion business. Under current investment plans and policies, the global offshore wind market is set to expand by 13% per year, reflecting its growth despite Covid-19 in recent years, passing 20 GW of additions per year by 2030. This will require capital spending of $840 billion over the next two decades, almost matching that for natural gas-fired or coal-fired capacity. Achieving global climate and sustainability goals would require faster growth: capacity additions would need to approach 40 GW per year in the 2030s, pushing cumulative investment to over $1.2 trillion. 

The promising outlook for offshore wind is underpinned by policy support in an increasing number of regions. Several European North Seas countries – including the United Kingdom, Germany, the Netherlands and Denmark – have policy targets supporting offshore wind. Although a relative newcomer to the technology, China is quickly building up its offshore wind industry, aiming to develop a project pipeline of 10 GW by 2020. In the United States, state-level targets and federal incentives are set to kick-start the U.S. offshore wind surge in the coming years. Additionally, policy targets are in place and projects under development in Korea, Japan, Chinese Taipei and Viet Nam.

 The synergies between offshore wind and offshore oil and gas activities provide new market opportunities. Since offshore energy operations share technologies and elements of their supply chains, oil and gas companies started investing in offshore wind projects many years ago. We estimate that about 40% of the full lifetime costs of an offshore wind project, including construction and maintenance, have significant synergies with the offshore oil and gas sector. That translates into a market opportunity of $400 billion or more in Europe and China over the next two decades. The construction of foundations and subsea structures offers potential crossover business, as do practices related to the maintenance and inspection of platforms. In addition to these opportunities, offshore oil and gas platforms require electricity that is often supplied by gas turbines or diesel engines, but that could be provided by nearby wind farms, thereby reducing CO2 emissions, air pollutants and costs.

Offshore wind can accelerate clean energy transitions

Offshore wind can help drive energy transitions by decarbonising electricity and by producing low-carbon fuels. Over the next two decades, its expansion could avoid between 5 billion and 7 billion tonnes of CO2 emissions from the power sector globally, while also reducing air pollution and enhancing energy security by reducing reliance on imported fuels. The European Union is poised to continue leading the wind energy at sea in Europe industry in support of its climate goals: its offshore wind capacity is set to increase by at least fourfold by 2030. This growth puts offshore wind on track to become the European Union's largest source of electricity in the 2040s. Beyond electricity, offshore wind's high capacity factors and falling costs makes it a good match to produce low-carbon hydrogen, a versatile product that could help decarbonise the buildings sector and some of the hardest to abate activities in industry and transport. For example, a 1 gigawatt offshore wind project could produce enough low-carbon hydrogen to heat about 250 000 homes. Rising demand for low-carbon hydrogen could also dramatically increase the market potential for offshore wind. Europe is looking to develop offshore "hubs" for producing electricity and clean hydrogen from offshore wind.

It's not all smooth sailing

Offshore wind faces several challenges that could slow its growth in established and emerging markets, but policy makers and regulators can clear the path ahead. Developing efficient supply chains is crucial for the offshore wind industry to deliver low-cost projects. Doing so is likely to call for multibillion-dollar investments in ever-larger support vessels and construction equipment. Such investment is especially difficult in the face of uncertainty. Governments can facilitate investment of this kind by establishing a long-term vision for offshore wind and by drawing on U.K. policy lessons to define the measures to be taken to help make that vision a reality. Long-term clarity would also enable effective system integration of offshore wind, including system planning to ensure reliability during periods of low wind availability.

The success of offshore wind depends on developing onshore grid infrastructure. Whether the responsibility for developing offshore transmission lies with project developers or transmission system operators, regulations should encourage efficient planning and design practices that support the long-term vision for offshore wind. Those regulations should recognise that the development of onshore grid infrastructure is essential to the efficient integration of power production from offshore wind. Without appropriate grid reinforcements and expansion, there is a risk of large amounts of offshore wind power going unused, and opportunities for further expansion could be stifled. Development could also be slowed by marine planning practices, regulations for awarding development rights and public acceptance issues.

The future of offshore wind looks bright but hinges on the right policies

The outlook for offshore wind is very positive as efforts to decarbonise and reduce local pollution accelerate. While offshore wind provides just 0.3% of global electricity supply today, it has vast potential around the world and an important role to play in the broader energy system. Offshore wind can drive down CO2 emissions and air pollutants from electricity generation. It can also do so in other sectors through the production of clean hydrogen and related fuels. The high system value of offshore wind offers advantages that make a strong case for its role alongside other renewables and low-carbon technologies. Government policies will continue to play a critical role in the future of offshore wind and  the overall pace of clean energy transitions around the world.

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U.S. Electricity Trade by State, 2013-2017 highlights EIA grid patterns, interstate imports and exports, cross-border flows with Canada and Mexico, net exporters and importers, and market regions like ISOs and RTOs shaping consumption and generation.

Key Points

Brief EIA overview of interstate and cross-border power flows, ranking top net importers and exporters.

✅ Pennsylvania was the largest net exporter, averaging 59 million MWh.

✅ California was the largest net importer, averaging 77 million MWh.

✅ Top cross-border: NY, CA, VT, MN, MI imports; WA, TX, CA, NY, MT exports.

According to the U.S. Energy Information Administration (EIA) State Electricity Profiles, from 2013 to 2017, Pennsylvania was the largest net exporter of electricity, while California was the largest net importer.

Pennsylvania exported an annual average of 59 million megawatt-hours (MWh), while California imported an average of 77 million MWh annually.

Based on the share of total consumption in each state, the District of Columbia, Maryland, Massachusetts, Idaho and Delaware were the five largest power-importing states between 2013 and 2017, highlighting how some clean states import 'dirty' electricity as consumption outpaces local generation. Wyoming, West Virginia, North Dakota, Montana and New Hampshire were the five largest power-exporting states. Wyoming and West Virginia were net power exporting states between 2013 and 2017.

New York, California, Vermont, Minnesota and Michigan imported the most electricity from Canada or Mexico on average from 2013 to 2017, reflecting the U.S. look to Canada for green power during that period. Similarly, Washington, Texas, California, New York, and Montana exported the most electricity to Canada or Mexico, on average, during the same period.

Electricity routinely flows among the Lower 48 states and, to a lesser extent, between the United States and Canada and Mexico. From 2013 to 2017, Pennsylvania was the largest net exporter of electricity, sending an annual average of 59 million megawatthours (MWh) outside the state. California was the largest net importer, receiving an average of 77 million MWh annually.

Based on the share of total consumption within each state, the District of Columbia, Maryland, Massachusetts, Idaho, and Delaware were the five largest power-importing states between 2013 and 2017. Wyoming, West Virginia, North Dakota, Montana, and New Hampshire were the five largest power-exporting states. States with major population centers and relatively less generating capacity within their state boundaries tend to have higher ratios of net electricity imports to total electricity consumption, as utilities devote more to electricity delivery than to power production in many markets.

Wyoming and West Virginia were net power exporting states (they exported more power to other states than they consumed) between 2013 and 2017. Customers residing in these two states are not necessarily at an economic disadvantage or advantage compared with customers in neighboring states when considering their electricity bills and fees and market dynamics. However, large amounts of power trading may affect a state’s revenue derived from power generation.

Some states also import and export electricity outside the United States to Canada or Mexico, even as Canada's electricity exports face trade tensions today. New York, California, Vermont, Minnesota, and Michigan are the five states that imported the most electricity from Canada or Mexico on average from 2013 through 2017. Similarly, Washington, Texas (where electricity production and consumption lead the nation), California, New York, and Montana are the five states that exported the most electricity to Canada or Mexico, on average, for the same period.

Many states within the continental United States fall within integrated market regions, referred to as independent system operators or regional transmission organizations. These integrated market regions allow electricity to flow freely between states or parts of states within their boundaries.

EIA’s State Electricity Profiles provide details about the supply and disposition of electricity for each state, including net trade with other states and international imports and exports, and help you understand where your electricity comes from more clearly.

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5G Energy Costs highlight base station power consumption, carrier electricity bills, and carbon emissions in China, while advances in energy efficiency, sleep modes, and cooling systems aim to optimize low-latency networks and reduce operational expenses.

Key Points

5G energy costs rise with power-hungry base stations, yet per-bit efficiency and sleep modes help cut bills.

✅ 5G base stations use ~4x 4G electricity

✅ Per-bit 5G energy efficiency is ~4x better than 4G

✅ Sleep modes and advanced cooling reduce OPEX and emissions

As 5G developers look desperately for a "killer app" to prove the usefulness of the superfast wireless technology, mobile carriers in China are complaining about the high energy cost of 5G signal towers.

And the situation is, according to experts, more complicated than many have thought.

The costly 5G

5G technology can be 10 or more times faster than 4G and significantly more responsive to users' input, but the speed comes at a cost.

A 5G base station consumes "four times more electricity" than its 4G counterpart, said Ding Haiyu, head of wireless and terminals at the China Mobile Research Institute, during a symposium on 5G and carbon neutrality in Beijing, a key focus for countries pursuing a net-zero grid by 2050 worldwide.

But concerning each bit of data transmitted, 5G is four times more energy-efficient than 4G, according to Ding.

This means that mobile carriers should fully occupy their 5G network for as long time as possible, but that can be hard at this moment, as many people are still holding 4G smartphones.

"When the 5G stations are running without people using them, they are really electricity guzzlers," said Zhu Qingfeng, head of power supply design at China Information Technology Designing and Consulting Institute Co., Ltd., who represents China Unicom at the symposium. "Each of the three telecom carrier giants are emitting about ten million tonnes of carbon in the air."

"We have to shut down some 5G base stations at night to reduce emission," he added.

Some utilities are testing fuel cell solutions to keep backup batteries charged much longer, supporting network resilience at lower emissions.

A representative from China Telecom said electricity bills of the nationwide carrier reached a new high of 100 billion yuan (about $15 billion) a year, mirroring the power challenges for utilities as data center demand booms elsewhere.

Getting better

While admitting the excessive cost of 5G, experts at the symposium also agreed that the situation is improving, even as climate pressures on the grid continue to mount.

Ding listed a series of recent technologies that is helping reduce the energy use of 5G, including chips of better process, automatic sleeping and wake-up of base stations and liquid nitrogen-based cooling system, and superconducting cables as part of ongoing upgrades.

"We are aiming at halving the 5G electricity cost to only two times of 4G in two years," Ding said.

Experts also discussed the possibility of making use of 5G's low latency features to help monitoring the electricity grid, thus making the digital grid smarter and more cost effective.

G's energy cost is seen as a hot topic for the incoming World 5G Convention in Beijing in early August, alongside smart grid transformation themes. Stay tuned to CGTN Digital as we bring you the latest news about the convention and 5G technology.
 

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Space solar power promises wireless energy from orbital solar satellites via microwave or laser power beaming, using photovoltaics and rectennas. NRL and AFRL advances hint at 24-7 renewable power delivery to Earth and airborne drones.

Key Points

Space solar power beams orbital solar energy to Earth via microwaves or lasers, enabling continuous wireless electricity.

✅ Harvests sunlight in orbit and transmits via microwaves or lasers

✅ Provides 24-7 renewable power, independent of weather or night

✅ Enables wireless power for remote sites, grids, and drones

Earlier this year, a small group of spectators gathered in David Taylor Model Basin, the Navy’s cavernous indoor wave pool in Maryland, to watch something they couldn’t see. At each end of the facility there was a 13-foot pole with a small cube perched on top. A powerful infrared laser beam shot out of one of the cubes, striking an array of photovoltaic cells inside the opposite cube. To the naked eye, however, it looked like a whole lot of nothing. The only evidence that anything was happening came from a small coffee maker nearby, which was churning out “laser lattes” using only the power generated by the system as ambitions for cheap abundant electricity gain momentum worldwide.

The laser setup managed to transmit 400 watts of power—enough for several small household appliances—through hundreds of meters of air without moving any mass. The Naval Research Lab, which ran the project, hopes to use the system to send power to drones during flight. But NRL electronics engineer Paul Jaffe has his sights set on an even more ambitious problem: beaming solar power to Earth from space. For decades the idea had been reserved for The Future, but a series of technological breakthroughs and a massive new government research program suggest that faraway day may have finally arrived as interest in space-based solar broadens across industry and government.

Since the idea for space solar power first cropped up in Isaac Asimov’s science fiction in the early 1940s, scientists and engineers have floated dozens of proposals to bring the concept to life, including inflatable solar arrays and robotic self-assembly. But the basic idea is always the same: A giant satellite in orbit harvests energy from the sun and converts it to microwaves or lasers for transmission to Earth, where it is converted into electricity. The sun never sets in space, so a space solar power system could supply renewable power to anywhere on the planet, day or night, as recent tests show we can generate electricity from the night sky as well, rain or shine.

Like fusion energy, space-based solar power seemed doomed to become a technology that was always 30 years away. Technical problems kept cropping up, cost estimates remained stratospheric, and as solar cells became cheaper and more efficient, and storage improved with cheap batteries, the case for space-based solar seemed to be shrinking.

That didn’t stop government research agencies from trying. In 1975, after partnering with the Department of Energy on a series of space solar power feasibility studies, NASA beamed 30 kilowatts of power over a mile using a giant microwave dish. Beamed energy is a crucial aspect of space solar power, but this test remains the most powerful demonstration of the technology to date. “The fact that it’s been almost 45 years since NASA’s demonstration, and it remains the high-water mark, speaks for itself,” Jaffe says. “Space solar wasn’t a national imperative, and so a lot of this technology didn’t meaningfully progress.”

John Mankins, a former physicist at NASA and director of Solar Space Technologies, witnessed how government bureaucracy killed space solar power development firsthand. In the late 1990s, Mankins authored a report for NASA that concluded it was again time to take space solar power seriously and led a project to do design studies on a satellite system. Despite some promising results, the agency ended up abandoning it.

In 2005, Mankins left NASA to work as a consultant, but he couldn’t shake the idea of space solar power. He did some modest space solar power experiments himself and even got a grant from NASA’s Innovative Advanced Concepts program in 2011. The result was SPS-ALPHA, which Mankins called “the first practical solar power satellite.” The idea, says Mankins, was “to build a large solar-powered satellite out of thousands of small pieces.” His modular design brought the cost of hardware down significantly, at least in principle.

Jaffe, who was just starting to work on hardware for space solar power at the Naval Research Lab, got excited about Mankins’ concept. At the time he was developing a “sandwich module” consisting of a small solar panel on one side and a microwave transmitter on the other. His electronic sandwich demonstrated all the elements of an actual space solar power system and, perhaps most important, it was modular. It could work beautifully with something like Mankins' concept, he figured. All they were missing was the financial support to bring the idea from the laboratory into space.

Jaffe invited Mankins to join a small team of researchers entering a Defense Department competition, in which they were planning to pitch a space solar power concept based on SPS-ALPHA. In 2016, the team presented the idea to top Defense officials and ended up winning four out of the seven award categories. Both Jaffe and Mankins described it as a crucial moment for reviving the US government’s interest in space solar power.

They might be right. In October, the Air Force Research Lab announced a $100 million program to develop hardware for a solar power satellite. It’s an important first step toward the first demonstration of space solar power in orbit, and Mankins says it could help solve what he sees as space solar power’s biggest problem: public perception. The technology has always seemed like a pie-in-the-sky idea, and the cost of setting up a solar array on Earth is plummeting, as proposals like a tenfold U.S. solar expansion signal rapid growth; but space solar power has unique benefits, chief among them the availability of solar energy around the clock regardless of the weather or time of day.

It can also provide renewable energy to remote locations, such as forward operating bases for the military, which has deployed its first floating solar array to bolster resilience. And at a time when wildfires have forced the utility PG&E to kill power for thousands of California residents on multiple occasions, having a way to provide renewable energy through the clouds and smoke doesn’t seem like such a bad idea. (Ironically enough, PG&E entered a first-of-its-kind agreement to buy space solar power from a company called Solaren back in 2009; the system was supposed to start operating in 2016 but never came to fruition.)

“If space solar power does work, it is hard to overstate what the geopolitical implications would be,” Jaffe says. “With GPS, we sort of take it for granted that no matter where we are on this planet, we can get precise navigation information. If the same thing could be done for energy, especially as peer-to-peer energy sharing matures, it would be revolutionary.”

Indeed, there seems to be an emerging race to become the first to harness this technology. Earlier this year China announced its intention to become the first country to build a solar power station in space, and for more than a decade Japan has considered the development of a space solar power station to be a national priority. Now that the US military has joined in with a $100 million hardware development program, it may only be a matter of time before there’s a solar farm in the solar system.

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Proton Conducting Fuel Cells enable reversible hydrogen energy storage, coupling electrolyzers and fuel cells with ceramic catalysts and proton-conducting membranes to convert wind and solar electricity into fuel and back to reliable grid power.

Key Points

Proton conducting fuel cells store renewable power as hydrogen and generate electricity using reversible catalysts.

✅ Reversible electrolysis and fuel-cell operation in one device

✅ Ceramic air electrodes hit up to 98% splitting efficiency

✅ Scalable path to low-cost grid energy storage with hydrogen

If we want a shot at transitioning to renewable energy, we’ll need one crucial thing: technologies that can convert electricity from wind, sun, and even electricity from raindrops into a chemical fuel for storage and vice versa. Commercial devices that do this exist, but most are costly and perform only half of the equation. Now, researchers have created lab-scale gadgets that do both jobs. If larger versions work as well, they would help make it possible—or at least more affordable—to run the world on renewables.

The market for such technologies has grown along with renewables: In 2007, solar and wind provided just 0.8% of all power in the United States; in 2017, that number was 8%, according to the U.S. Energy Information Administration. But the demand for electricity often doesn’t match the supply from solar and wind, a key reason why the U.S. grid isn't 100% renewable today. In sunny California, for example, solar panels regularly produce more power than needed in the middle of the day, but none at night, after most workers and students return home.

Some utilities are beginning to install massive banks of cheaper solar batteries in hopes of storing excess energy and evening out the balance sheet. But batteries are costly and store only enough energy to back up the grid for a few hours at most. Another option is to store the energy by converting it into hydrogen fuel. Devices called electrolyzers do this by using electricity—ideally from solar and wind power—to split water into oxygen and hydrogen gas, a carbon-free fuel. A second set of devices called fuel cells can then convert that hydrogen back to electricity to power cars, trucks, and buses, or to feed it to the grid.

But commercial electrolyzers and fuel cells use different catalysts to speed up the two reactions, meaning a single device can’t do both jobs. To get around this, researchers have been experimenting with a newer type of fuel cell, called a proton conducting fuel cell (PCFC), which can make fuel or convert it back into electricity using just one set of catalysts.

PCFCs consist of two electrodes separated by a membrane that allows protons across. At the first electrode, known as the air electrode, steam and electricity are fed into a ceramic catalyst, which splits the steam’s water molecules into positively charged hydrogen ions (protons), electrons, and oxygen molecules. The electrons travel through an external wire to the second electrode—the fuel electrode—where they meet up with the protons that crossed through the membrane. There, a nickel-based catalyst stitches them together to make hydrogen gas (H2). In previous PCFCs, the nickel catalysts performed well, but the ceramic catalysts were inefficient, using less than 70% of the electricity to split the water molecules. Much of the energy was lost as heat.

Now, two research teams have made key strides in improving this efficiency, and a new fuel cell concept brings biological design ideas into the mix. They both focused on making improvements to the air electrode, because the nickel-based fuel electrode did a good enough job. In January, researchers led by chemist Sossina Haile at Northwestern University in Evanston, Illinois, reported in Energy & Environmental Science that they came up with a fuel electrode made from a ceramic alloy containing six elements that harnessed 76% of its electricity to split water molecules. And in today’s issue of Nature Energy, Ryan O’Hayre, a chemist at the Colorado School of Mines in Golden, reports that his team has done one better. Their ceramic alloy electrode, made up of five elements, harnesses as much as 98% of the energy it’s fed to split water.

When both teams run their setups in reverse, the fuel electrode splits H2 molecules into protons and electrons. The electrons travel through an external wire to the air electrode—providing electricity to power devices. When they reach the electrode, they combine with oxygen from the air and protons that crossed back over the membrane to produce water.

The O’Hayre group’s latest work is “impressive,” Haile says. “The electricity you are putting in is making H2 and not heating up your system. They did a really good job with that.” Still, she cautions, both her new device and the one from the O’Hayre lab are small laboratory demonstrations. For the technology to have a societal impact, researchers will need to scale up the button-size devices, a process that typically reduces performance. If engineers can make that happen, the cost of storing renewable energy could drop precipitously, thereby moving us closer to cheap abundant electricity at scale, helping utilities do away with their dependence on fossil fuels.

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