Greenpeace: China power companies hurting climate

Sidi Mansour Wind Farm Tunisia will deliver 30 MW as an IPP, backed by UPC Renewables and CFM, under a STEG PPA, supporting 2030 renewable energy targets, grid connection, job creation, and CO2 emissions reduction.

Key Points

A 30 MW wind IPP by UPC and CFM in Sidi Mansour, supplying STEG and advancing Tunisia's 2030 renewable target.

✅ 30 MW capacity under STEG PPA, first wind IPP in Tunisia

✅ Co-developed by UPC Renewables and Climate Fund Managers

✅ Cuts CO2 by up to 56,645 t and creates about 100 jobs

UPC Renewables (UPC) and the Climate Fund Managers (CFM) have partnered to develop a 30 megawatt wind farm in Sidi Mansour, Tunisia, which, amid regional wind expansion efforts, will help the country meet its 30% renewable energy target by 2030.

Tunisia announced the launch of its solar energy plan in 2016, with projects like the 10 MW Tunisian solar park aiming to increase the role of renewables in its electricity generation mix ten-fold to 30%,

This Sidi Mansour Project will help Tunisia meet its goals, reducing its reliance on imported fossil fuels and, mirroring 90 MW Spanish wind build milestones, demonstrating to the world that it is serious about further development of renewable energy investment.

“Chams Enfidha”, the first solar energy station in Tunisia with a capacity of 1 megawatt and located in the Enfidha region. (Ministry of Energy, Mines and Energy Transition Facebook page)

This project will also be among the country’s first Independent Power Producers (IPP). CFM is acting as sponsor, financial adviser and co-developer on the project, in a landscape shaped by IRENA-ADFD funding in developing countries, while UPC will lead the development with its local team. The team will be in charge of permitting, grid connection, land securitisation, assessment of wind resources, contract procurement and engineering.

UPC was selected under the “Authorisation Scheme” tender for the project in 2016, similar to utility-scale developments like a 450 MW U.S. wind farm, and promptly signed a power purchase agreement with Société Tunisienne Electricité et du Gaz (STEG).

Brian Caffyn, chairman of UPC Group, said: “We can start the construction of the Sidi Mansour wind farm in 2020, helping stimulate the Tunisian economy, create local jobs and a social plan for local communities while respecting international environmental protection guidelines.”

Sebastian Surie, CFM’s regional head of Africa, added: “CFM is thrilled to partner with a leading wind developer in the Sidi Mansour Wind Project to assist Tunisia in meeting its renewable energy goals. As potentially the first Wind IPP in Tunisia, this Project will be a testament to how CI1’s full life-cycle financing solution can unlock investment in renewable energy in new markets, as seen in an Irish offshore wind project globally.”

The project will not only provide electricity, but also reduce CO2 emissions by up to 56,645 tonnes and create some 100 new jobs.

Wind turbine in El Haouaria, Tunisia, highlighting advances such as a huge offshore wind turbine that can power 18,000 homes. (Reuters)

Tunisia’s first power station, “Chams Enfidha,” inaugurated at the beginning of July, has a capacity of one megawatt, with an estimated cost of 3.3 million dinars ($1.18 million). The state invested 2.3 million dinars into the project ($820,000), with the remaining 1 million dinars ($360,000) provided by a private investor.

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California Managed Decline of Fossil Fuels aligns oil phaseout with carbon neutrality, leveraging ZEV adoption, solar and wind growth, severance taxes, drilling setbacks, fracking oversight, CARB rules, and CalGEM regulation to deliver a just transition.

Key Points

California's strategy to phase out oil and gas while meeting carbon-neutral goals through policy, regulation, and equity.

✅ Severance taxes fund clean energy and workforce transition.

✅ Setbacks restrict drilling near schools, homes, and hospitals.

✅ CARB and CalGEM tighten fracking oversight and ZEV targets.

California’s energy past is on a collision course with its future. Think of major oil-producing U.S. states, and Texas, Alaska or North Dakota probably come to mind. Although its position relative to other states has been falling for 20 years, California remains the seventh-largest oil-producing state, with 162 million barrels of crude coming up in 2018, translating to tax revenue and jobs.

At the same time, California leads the nation in solar rooftops and electric vehicles on the road by a wide margin and ranking fifth in installed wind capacity. Clean energy is the state’s future, and the state is increasingly exporting its energy policies across the West, influencing regional markets. By law, California must have 100 percent carbon-free electricity by 2045, and an executive order signed by former Governor Jerry Brown calls for economywide carbon-neutrality by the same year.

So how can the state reconcile its divergent energy path? How should clean-energy-minded lawmakers wind down California’s oil and gas sector in a way that aligns with the state’s long-term climate targets while providing a just transition for the industry’s workforce?

Any efforts to reduce fossil fuel supply must run parallel to aggressive demand-reduction measures such as California’s push to have 5 million zero-emission vehicles on the road by 2030, said Ethan Elkind, director of Berkeley Law's climate program, especially amid debates over keeping the lights on without fossil fuels in the near term. After all, if oil demand in California remains strong, crude from outside the state will simply fill the void.

“If we don’t stop using it, then that supply is going to get here, even if it’s not produced in-state,” Elkind said in an interview.

Lawmakers have a number of options for policies that would draw down and eventually phase out fossil fuel production in California, according to a new report from the Center for Law, Energy and the Environment at the UC Berkeley School of Law, co-authored by Elkind and Ted Lamm.

They could impose a higher price on California's oil production through a "severance" tax or carbon-based fee, with the revenue directed to measures that wean the state from fossil fuels. (California, alone among major oil-producing states, does not have an oil severance tax.)

Lawmakers could establish a minimum drilling setback from schools, playgrounds, homes and other sensitive sites. They could push the state's oil and gas regulator, the California Geologic Energy Management Division, to prioritize environmental and climate concerns.

A major factor holding lawmakers back is, of course, politics, including debates over blackouts and climate policy that shape public perception. Given the state’s clean-energy ambitions, it might surprise non-Californians that the oil and gas industry is one of the Golden State’s most powerful special interest groups.

Overcoming a "third-rail issue" in California politics
The Western States Petroleum Association, the sector’s trade group in California's capital of Sacramento, spent $8.8 million lobbying state policymakers in 2019, more than any other interest group. Over the last five years, the group, which cultivates both Democratic and Republican lawmakers, has spent $43.3 million on lobbying, nearly double the total of the second-largest lobbying spender.

Despite former Governor Brown’s reputation as a climate champion, critics say he was unwilling to forcefully take on the oil and gas industry. However, things may take a different turn under Brown's successor, Governor Gavin Newsom.

In May 2019, when Newsom released California's midyear budget revision (PDF), the governor's office noted the need for "careful study and planning to decrease demand and supply of fossil fuels, while managing the decline in a way that is economically responsible and sustainable.”

Related reliability concerns surfaced as blackouts revealed lapses in power supply across the state.

Writing for the advocacy organization Oil Change International, David Turnbull observed, “This may mark the first time that a sitting governor in California has recognized the need to embark upon a managed decline of fossil fuel supply in the state.”

“It is significant because typically this is one of those third-rail issues, kind of a hot potato that governors don’t even want to touch at all — including Jerry Brown, to a large extent, who really focused much more on the demand side of fuel consumption in the state,” said Berkeley Law’s Elkind.

California's revised budget included $1.5 million for a Transition to a Carbon-Neutral Economy report, which is being prepared by University of California researchers for the California Environmental Protection Agency. In an email, a CalEPA spokesperson said the report is due by the end of this year.

Winding down oil and gas production
Since the release of the revised budget last May, Newsom has taken initial steps to increase oversight of the oil and gas industry. In July 2019, he fired the state’s top oil and gas regulator for issuing too many permits to hydraulically fracture, or frack, wells.

Later in the year, he appointed new leadership to oversee oil and gas regulation in the state, and he signed a package of bills that placed constraints on fossil fuel production. The next month, Newsom halted the approval of new fracking operations until pending permits could be reviewed by a panel of scientists at Lawrence Livermore National Laboratory. The California Geologic Energy Management Division (CalGEM) did not resume issuing fracking permit approvals until April of this year.

Not all steps have been in the same direction. This month Newsom dropped a proposal to add dozens of analysts, engineers and geologists at CalGEM, citing COVID-related economic pressure. The move would have increased regulatory oversight on fossil fuel producers and was opposed by the state's oil industry.

Ultimately, more durable measures to wind down fossil fuel supply and demand will require new legislation, even as regulators weigh whether the state needs more power plants to maintain reliability.

A 2019 bill by Assemblymember Al Muratsuchi (D-Torrance), AB 345, would have codified the minimum 2,500-foot setback for new oil and gas wells. However, before the final vote in the Assembly, the bill’s buffer requirement was dropped and replaced with a requirement for CalGEM “to consider a setback distance of 2,500 feet.” The bill passed the Assembly in January over "no" votes from several moderate Democrats; it now awaits action in the Senate.

A bill previously introduced by Assemblymember Phil Ting (D-San Francisco), AB 1745, didn’t even make it that far. Ting’s bill would have required that all new passenger cars registered in the state after January 1, 2040, be zero-emission vehicles (ZEV). The bill died in committee without a vote in April 2018.

But the backing of the California Air Resources Board (CARB), one of the world's most powerful air-quality regulators, could change the political conversation. In March, CARB chair Mary Nichols said she now supports consideration of California establishing a 100 percent zero-emission vehicle sales target by 2030, as policymakers also consider a revamp of electricity rates to clean the grid.

“In the past, I’ve been skeptical about whether that would do more harm than good in terms of the backlash by dealers and others against something that sounded so un-California like,” Nichols said during an online event. “But as time has gone on, I’ve become more convinced that we need to send the longer-term signal about where we’re headed.”

Another complicating factor for California’s political leaders is the lack of a willing federal partner — at least in the short term — in winding down oil and gas production, amid warnings about a looming electricity shortage that could pressure the grid.

Under the Trump administration, the Bureau of Land Management, which oversees 15 million acres of federal land in California, has pushed to open more than 1 million acres of public and private land across eight counties in Central California to fracking. In January 2020, California filed a federal lawsuit to block the move.

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Canada Clean Electricity leads decarbonization, slashing power-sector emissions through coal phase-out, renewables like hydro, wind, and solar, and nuclear. Provinces cut carbon intensity, enabling electrification of transport and buildings toward net-zero goals.

Key Points

Canada Clean Electricity is the shift to low-emission power by phasing out coal and scaling renewables and nuclear.

✅ 38% cut in electricity emissions since 2005; 84% fossil-free power.

✅ Provinces lead coal phase-out; carbon intensity plummets.

✅ Enables EVs, heat pumps, and building electrification.

It's our country’s one big climate success so far.

"All across Canada, electricity generation has been getting much cleaner. It's our country’s one big climate success so far,"

To illustrate how quickly electric power is being cleaned up, what's still left to do, and the benefits it brings, I've dug into Canada's latest emissions inventory and created a series of charts below.

The sector that could

Climate pollution by Canadian economic sector, 2005 to 2017My first chart shows how Canada's economic sectors have changed their climate pollution since 2005.

While most sectors have increased their pollution or made little progress in the climate fight, our electricity sector has shined.

As the green line shows, Canadians have eliminated an impressive 38 per cent of the climate pollution from electricity generation in just over a decade.

To put these shifts into context, I've shown Canada's 2020 climate target on the chart as a gray star. This target was set by the Harper government as part of the global Copenhagen Accord. Specifically, Canada pledged to cut our climate pollution 17 per cent below 2005 levels under evolving Canadian climate policy frameworks of the time.

As you can see, the electricity sector is the only one to have done that so far. And it didn’t just hit the target — it cut more than twice as much.

Change in Canada's electricity generation, 2005 to 2017My next chart shows how the electricity mix changed. The big climate pollution cuts came primarily from reductions in coal burning, highlighting the broader implications of decarbonizing Canada's electricity grid for fuel choices.

The decline in coal-fired power was replaced (and then some) by increases in renewable electricity and other zero-emissions sources — hydro, wind, solar and nuclear.

As a result, Canada's overall electricity generation is now 84 per cent fossil free.

Every province making progress

A primary reason why electricity emissions fell so quickly is because every province worked to clean up Canada's electricity together.

Change in Canadian provincial electricity carbon intensity, 2005 to 2017

My next chart illustrates this rare example of Canada-wide climate progress. It shows how quickly the carbon-intensity of electricity generation has declined in different provinces.

(Note: carbon-intensity is the amount of climate pollution emitted per kilowatt-hour of electricity generated: gCO2e/kWh).

Ontario clearly led the way with an amazing 92 per cent reduction in climate pollution per kWh in just twelve years. Most of that came from ending the burning of coal in their power plants. But a big chunk also came from cutting in half the amount of natural gas they burn for electricity.

Manitoba, Quebec and B.C. also made huge improvements.

Even Alberta and Saskatchewan, which were otherwise busy increasing their overall climate pollution, made progress in cleaning up their electricity.

These real-world examples show that rapid and substantial climate progress can happen in Canada when a broad-spectrum of political parties and provinces decide to act.

Most Canadians now have superclean electricity

As a result of this rapid cleanup, most Canadians now have access to superclean energy.

Canadian provincial electricity carbon intensity in 2017

Who has it? And how clean is it?

The biggest climate story here is the superclean electricity generated by the four provinces shown on the left side — Quebec, Manitoba, B.C. and Ontario. Eighty per cent of Canadians live in these provinces and have access to this climate-safe energy source.

Those living in Alberta and Saskatchewan, however, still have fairly dirty electricity — as shown in orange on the right — and options like bridging the electricity gap between Alberta and B.C. could accelerate progress in the West.

A lot more cleanup must happen here before the families and businesses in these provinces have a climate-safe energy supply.

What's left to do?

Canada's electricity sector has two big climate tasks remaining: finishing the cleanup of existing power and generating even more clean energy to replace fossil fuels like the gasoline and natural gas used by vehicles, factories and other buildings.

Finishing the clean up

Climate pollution from Canadian provincial electricity 2005 and 2017

As we saw above, more than a third of the climate pollution from electricity has already been eliminated. That leaves nearly two-thirds still to clean up.

Back in 2005, Canada's total electricity emissions were 125 million tonnes (MtCO2).

Over the next twelve years, emissions fell by more than a third (-46 MtCO2). Ontario did most of the work by cutting 33 MtCO2. Alberta, New Brunswick and Nova Scotia made the next biggest cuts of around 4 MtCO2 each.

Now nearly eighty million tonnes of climate pollution remain.

As you can see, nearly all of that now comes from Alberta and Saskatchewan. As a result, continuing Canada's climate progress in the power sector now requires big cuts in the electricity emissions from these two provinces.

Generating more clean electricity

The second big climate task remaining for Canada's electricity is to generate more clean electricity to replace the fossil fuels burned in other sectors. My next chart lets you see how big a task this is.

Clean electricity generation by Canadian province, 2017

It shows how much climate-safe electricity is currently generated in major provinces. This includes zero-emissions renewables (blue bars) and nuclear power (pale blue).

Quebec tops the list with 191 terawatt-hours (TWh) per year. While impressive, it only accounts for around half of the energy Quebecers use. The other half still comes from climate-damaging fossil fuels and to replace those, Quebec will need to build out more clean energy.

The good news here is that electricity is more efficient for most tasks, so fossil fuels can be replaced with significantly less electric energy. In addition, other efficiency and reduction measures can further reduce the amount of new electricity needed.

Newfoundland and Labrador is in the best situation. They are the only province that already generates more climate-safe electricity than they would need to replace all the fossil fuels they burn. They currently export most of that clean electricity.

At the other extreme are Alberta and Saskatchewan. These provinces currently produce very little climate-safe energy. For example, Alberta's 7 TWh of climate-safe electricity is only enough to cover 1 per cent of the energy used in the province.

All told, Canadians currently burn fossil fuels for three-quarters of the energy we use. To preserve a safe-and-sane climate, most provinces will soon need lots more clean electricity in the race to net-zero to replace the fossil fuels we burn.

How soon will they need it?

According to the most recent report from the International Panel on Climate Change (IPCC), avoiding a full-blown climate crisis will require humanity to cut emissions by 45 per cent over the next decade.

Using electricity to clean up other sectors

Finally, let's look at how electricity can help clean up two of Canada’s other high-emission sectors — transportation and buildings.

Cleaning up transportation

Transportation is now the second biggest climate polluting sector in Canada (after the oil and gas industry). So, it’s a top priority to reduce the amount of gasoline we use.

Canadian provincial electricity carbon intensity in 2017, plus gasoline equivalent

Switching to electric vehicles (EVs) can reduce transportation emissions by a little, or a lot. It depends on how clean the electricity supply is.

To make it easy to compare gasoline to each province's electricity I've added a new grey-striped zone at the top of the carbon-intensity chart.

This new zone shows that burning gasoline in cars and trucks has a carbon-intensity equivalent to more than 1,000 gCO2e/kWh. (If you are interested in the details of this and other data points, see the geeky endnotes.)

The good news is that every province's electricity is now much cleaner than gasoline as a transportation fuel.

In fact, most Canadians have electricity that is at least 95 per cent less climate polluting than gasoline. Electrifying vehicles in these provinces virtually eliminates those transportation emissions.

Even in Alberta, which has the dirtiest electricity, it is 20 per cent cleaner than gasoline. That's a help, for sure. But it also means that Albertans must electrify many more vehicles to achieve the same emissions reductions as regions with cleaner electricity.

In addition to reducing climate pollution, switching transportation to electricity brings other big benefits:

It reduces air pollution in cities — a major health hazard.

It cuts the energy required for transportation by 75 per cent — because electric motors are so much more efficient.

It reduces fuel costs up to 80 per cent — saving tens of thousands of dollars.

And for gasoline-importing provinces, using local electricity keeps billions of fuel dollars inside their provincial economy.

As an extra bonus, it makes it hard for companies to manipulate the price or for outsiders to "turn off the taps.”

Cleaning up buildings

Canada's third biggest source of climate pollution is the buildings sector.

Burning natural gas for heating is the primary cause. So, reducing the amount of fossil gas burned in buildings is another top climate requirement.

Canadian provincial electricity carbon intensity in 2017, plus gasoline and nat gas heating equivalent

Heating with electricity is a common alternative. However, it's not always less climate polluting. It depends on how clean the electricity is.

To compare these two heating sources, look at the lower grey-striped zone I've added to the chart.

It shows that heating with natural gas has a carbon-intensity of 200 to 300 gCO2 per kWh of heat delivered. High-efficiency gas furnaces are at the lower end of this range.

As you can see, for most Canadians, electric heat is now the much cleaner choice — nearly eliminating emissions from buildings. But in Alberta and Saskatchewan, electricity is still too dirty to replace natural gas heat.

The climate benefits of electric heat can be improved further by using the newer high-efficiency air-source heat pump technologies like mini-splits. These can heat using one half to one third of the electricity of standard electric baseboard heaters. That means it is possible to use electricity that is a bit dirtier than natural gas and still deliver cleaner heating. As a bonus, heat pumps can free up a lot of existing electricity supply when used to replace existing electric baseboards.

Electrify everything

You’ve probably heard people say that to fight climate breakdown, we need to “electrify everything.” Of course, the electricity itself needs to be clean and what we’ve seen is that Canada is making important progress on that front. The electricity industry, and the politicians that prodded them, all deserve kudos for slashing emissions at more than twice the rate of any other sector.

We still need to finish the cleanup job, but we also need to turn our sights to the even bigger task ahead: requiring that everything fossil fuelled — every building, every factory, every vehicle — switches to clean Canadian power.

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Alberta Electricity Peak Demand surged to 10,638 MW, as AESO reported record summer load from air conditioning, Stampede visitors, and heatwave conditions, with ample generation capacity, stable grid reliability, and conservation urged during 5-7 p.m.

Key Points

It is the record summer power load in Alberta, reaching 10,638 MW, with evening conservation urged by AESO.

✅ Record 10,638 MW at 4 pm; likely to rise this week

✅ Drivers: A/C use, heat, Stampede visitors

✅ AESO reports ample capacity; conserve 5-7 pm

Consumer use hit 10,638 MW, blowing past a previous high of 10,520 MW set on July 9, 2015, said the Alberta Electric System Operator (AESO).

“We hit a new summer peak and it’s likely we’ll hit higher peaks as the week progresses,” said AESO spokeswoman Tara De Weerd.

“We continue to have ample supply, and as Alberta's electricity future trends toward more wind, our generators are very confident there aren’t any issues.”

That new peak was set at 4 p.m. but De Weerd said it was likely to be exceeded later in the day.

Heightened air conditioner use is normally a major driver of such peak electricity consumption, said De Weerd.

She also said Calgary’s big annual bash is also likely playing a role.

“It’s the beginning of Stampede, you have an influx of visitors so you’ll have more people using electricity,” she said.

Alberta’s generation capacity is 16,420 MW, said the AESO, with wind power increasingly outpacing coal in the province today.

There are no plans, she said, for any of the province’s electricity generators to shut down any of their plants for maintenance or other purposes in the near future as demand rises.

The summer peak is considerably smaller than that reached in the depths of Alberta’s winter.

Alberta’s winter peak usage was recorded last year and was 11,458 MW.

Though the province’s capacity isn’t being strained by the summer heat, De Weerd still encouraged consumers to go easy during the peak use time of the day, between 5 and 7 p.m.

“We don’t have to be running all of our appliances at once,” she said.

Alberta exports an insignificant amount of electricity to Montana, B.C. and Saskatchewan, where demand recently set a new record.

The weather forecast calls for temperatures to soar above 30C through the weekend.

In northern Canada, Yukon electricity demand recently hit a record high, underscoring how extreme temperatures can strain systems.

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BC Hydro EV Charging Stations expand provincewide with DC fast chargers, 80% in 30 minutes at 35 c/kWh, easing range anxiety across Vancouver, Vancouver Island, Coquihalla Highway, East Kootenay, between Kamloops and Prince George.

Key Points

Public DC fast-charging network across B.C. enabling 80% charge in 30 minutes to cut EV range anxiety.

✅ 28 new stations added; 30 launched in 2016

✅ 35 c/kWh; about $3.50 per tank equivalent

✅ Coverage: Vancouver, Island, Coquihalla, East Kootenay

B.C. Hydro is expanding its network of electric vehicle charging stations.

The Crown utility says 28 new stations complete the second phase of its fast-charging network and are in addition to the 30 stations opened in 2016.

Thirteen of the stations are in Metro Vancouver, seven are on Vancouver Island, including one at the Pacific Rim Visitor Centre near Tofino, another is in Campbell River, and two have opened on the Coquihalla segment of B.C.'s Electric Highway at the Britton Creek rest area.

A further six stations are located throughout the East Kootenay and B.C. Hydro says the next phase of its program will connect drivers travelling between Kamloops and Prince George, while stations in Prince Rupert are also being planned.

BC Hydro has also opened a fast charging site in Lillooet, illustrating expansion into smaller communities.

Hydro spokeswoman Mora Scott says the stations can charge an electric vehicle to 80 per cent in just 30 minutes, at a cost of 35 cents per kilowatt hour.

Mora Scott says that translates to roughly $3.50 for the equivalent of a full tank of gas in the average four-cylinder car.

“The number of electric vehicles on B.C. roads is increasing, there’s currently around 9,000 across the province, and we actually expect that number to rise to 300,000 by 2030,” Scott says in a news release.

In partnership with municipalities, regional districts and several businesses, B.C. Hydro has been installing charging stations throughout the province since 2012 with support from the provincial and federal governments and programs such as EV charger rebates available to residents.

Scott says the utility wants to ensure the stations are placed where drivers need them so charging options are available provincewide.

“One big thing that we know drivers of electric vehicles worry about is the concept called range anxiety, that the stations aren’t going to be where they need them,” she says.

Several models of electric vehicle are now capable of travelling up to 500 kilometres on a single charge, says Scott.

BC Hydro president Chris O’Riley says the new charging sites will encourage electric vehicle drivers to explore B.C. this summer.

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Carbon Nanotube Solvent Electricity enables wire-free electrochemistry as organic solvents like acetonitrile pull electrons, powering alcohol oxidation and packed bed reactors, energy harvesting, and micro- and nanoscale robots via redox-driven current.

Key Points

Solvent-driven electron extraction from carbon nanotube particles generates current for electrochemistry.

✅ 0.7 V per particle via solvent-induced electron flow

✅ Packed bed reactors drive alcohol oxidation without wires

✅ Scalable for micro- and nanoscale robots; energy harvesting

MIT engineers have discovered a new way of generating electricity, alongside advances in renewable power at night that broaden what's possible, using tiny carbon particles that can create a current simply by interacting with liquid surrounding them.

The liquid, an organic solvent, draws electrons out of the particles, generating a current, unlike devices based on a cheap thermoelectric material that rely on heat, that could be used to drive chemical reactions or to power micro- or nanoscale robots, the researchers say.

"This mechanism is new, and this way of generating energy is completely new," says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT. "This technology is intriguing because all you have to do is flow a solvent through a bed of these particles. This allows you to do electrochemistry, but with no wires."

In a new study describing this phenomenon, the researchers showed that they could use this electric current to drive a reaction known as alcohol oxidation—an organic chemical reaction that is important in the chemical industry.

Strano is the senior author of the paper, which appears today in Nature Communications. The lead authors of the study are MIT graduate student Albert Tianxiang Liu and former MIT researcher Yuichiro Kunai. Other authors include former graduate student Anton Cottrill, postdocs Amir Kaplan and Hyunah Kim, graduate student Ge Zhang, and recent MIT graduates Rafid Mollah and Yannick Eatmon.

Unique properties
The new discovery grew out of Strano's research on carbon nanotubes—hollow tubes made of a lattice of carbon atoms, which have unique electrical properties. In 2010, Strano demonstrated, for the first time, that carbon nanotubes can generate "thermopower waves." When a carbon nanotube is coated with layer of fuel, moving pulses of heat, or thermopower waves, travel along the tube, creating an electrical current that exemplifies turning thermal energy into electricity in nanoscale systems.

That work led Strano and his students to uncover a related feature of carbon nanotubes. They found that when part of a nanotube is coated with a Teflon-like polymer, it creates an asymmetry, distinct from conventional thermoelectric materials approaches, that makes it possible for electrons to flow from the coated to the uncoated part of the tube, generating an electrical current. Those electrons can be drawn out by submerging the particles in a solvent that is hungry for electrons.

To harness this special capability, the researchers created electricity-generating particles by grinding up carbon nanotubes and forming them into a sheet of paper-like material. One side of each sheet was coated with a Teflon-like polymer, and the researchers then cut out small particles, which can be any shape or size. For this study, they made particles that were 250 microns by 250 microns.

When these particles are submerged in an organic solvent such as acetonitrile, the solvent adheres to the uncoated surface of the particles and begins pulling electrons out of them.

"The solvent takes electrons away, and the system tries to equilibrate by moving electrons," Strano says. "There's no sophisticated battery chemistry inside. It's just a particle and you put it into solvent and it starts generating an electric field."

Particle power
The current version of the particles can generate about 0.7 volts of electricity per particle. In this study, the researchers also showed that they can form arrays of hundreds of particles in a small test tube. This "packed bed" reactor, unlike thin-film waste-heat harvesters for electronics, generates enough energy to power a chemical reaction called an alcohol oxidation, in which an alcohol is converted to an aldehyde or a ketone. Usually, this reaction is not performed using electrochemistry because it would require too much external current.

"Because the packed bed reactor is compact, it has more flexibility in terms of applications than a large electrochemical reactor," Zhang says. "The particles can be made very small, and they don't require any external wires in order to drive the electrochemical reaction."

In future work, Strano hopes to use this kind of energy generation to build polymers using only carbon dioxide as a starting material. In a related project, he has already created polymers that can regenerate themselves using carbon dioxide as a building material, in a process powered by solar energy and informed by devices that generate electricity at night as a complement. This work is inspired by carbon fixation, the set of chemical reactions that plants use to build sugars from carbon dioxide, using energy from the sun.

In the longer term, this approach could also be used to power micro- or nanoscale robots. Strano's lab has already begun building robots at that scale, which could one day be used as diagnostic or environmental sensors. The idea of being able to scavenge energy from the environment, including approaches that produce electricity 'out of thin air' in ambient conditions, to power these kinds of robots is appealing, he says.

"It means you don't have to put the energy storage on board," he says. "What we like about this mechanism is that you can take the energy, at least in part, from the environment."

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