Powering Towards Net Zero: The UK Grid's Transformation Challenge

Raindrop Triboelectric Energy Harvesting converts falling water into electricity using Teflon (PTFE) on indium tin oxide and an aluminum electrode, forming a transient water bridge; a low frequency nanogenerator for renewable, static electricity harvesting.

Key Points

A method using PTFE, ITO, and an aluminum electrode to turn raindrop impacts into low frequency electrical power.

✅ PTFE on ITO boosts charge transfer efficiency.

✅ Water bridge links electrodes for rapid discharge.

✅ Low frequency output suits continuous energy harvesting.

Scientists at the City University of Hong Kong have used a Teflon-coated surface and a phenomenon called triboelectricity to generate a charge from raindrops. “Here we develop a device to harvest energy from impinging water droplets by using an architecture that comprises a polytetrafluoroethylene [Teflon] film on an indium tin oxide substrate plus an aluminium electrode,” they explain in their new paper in Nature as a step toward cheap, abundant electricity in the long term.

Triboelectricity itself is an old concept. The word means “friction electricity”—from the Greek tribo, to rub or wear down, which is why a diatribe tires you out—and dates back a long, long time. Static electricity is the most famous kind of triboelectric, and related work has shown electricity from the night sky can be harvested as well in niche setups. In most naturally occurring kinds, scientists have studied triboelectric in order to avoid its effects, like explosions inside of grain silos or hospital workers touching off pure oxygen. (Blowing sand causes an electric field, and NASA even worries about static when astronauts eventually land on Mars.)

One of the most studied forms of intentional and useful triboelectric is in systems such as ocean wave generators where the natural friction of waves meets nanogenerators of triboelectric energy. These even already use Teflon, which has natural conductivity that makes it ideal for this job. But triboelectricity is chaotic, and harnessing it generally involves a bunch of complicated, intersecting variables that can vary with the hourly weather. Promises of static electricity charging devices have often been, well, so much hot, sandy wind.

The scientists at City University of Hong Kong used triboelectric ideas to turn falling raindrops into energy. They say previous versions of the same idea were not very efficient, with materials that didn’t allow for high-fidelity transfer of electrical charge. (Many sources of renewable energy aren’t yet as efficient to turn into power, both because of developing technology and because their renewability means even less efficient use could be better than, for example, fossil fuels, and advances in renewable energy storage could help.)

“[A]chieving a high density of electrical power generation is challenging,” the team explains in its paper. “Traditional hydraulic power generation mainly uses electromagnetic generators that are heavy, bulky, and become inefficient with low water supply.” Diversifying how power is generated by water sources such as oceans and rivers is good for the existing infrastructure as well as new installations.

The research team found that as simulated raindrops fell on their device, the way the water accumulated and spread created a link between their two electrodes, one Teflon-coated and the other aluminum. This watery de facto wire link closes the loop and allows accumulated energy to move through the system. Because it’s a mechanical setup, it’s not limited to salty seawater, and because the medium is already water, its potential isn’t affected by ambient humidity either.

Raindrop energy is very low frequency, which means this tech joins many other existing pushes to harvest continuously available, low frequency natural energy, including underwater 'kites' that exploit steady currents. To make an interface that increases “instantaneous power density by several orders of magnitude over equivalent devices,” as the researchers say they’ve done here, could represent a major step toward feasibility in triboelectric generation.

Related News

• Electricity Forum News

• Renewable Energy News

U.S. Natural Gas Power Demand is surging for electricity generation amid summer heat, with ERCOT, Texas grid reserves tight, EIA reporting coal and nuclear retirements, renewables intermittency, and pipeline expansions supporting combined-cycle capacity and prices.

Key Points

It is rising use of natural gas for power, driven by summer heat, plant retirements, and new combined-cycle capacity.

✅ ERCOT reserve margin 9%, below 14% target in Texas

✅ Gas share of U.S. power near 40-43% this summer

✅ Coal and nuclear retirements shift capacity to combined cycle

As the hot months linger, it will be natural gas that is leaned on most to supply the electricity that we need to run our air conditioning loads on the grid and keep us cool.

And this is surely a great and important thing: "Heat causes most weather-related deaths, National Weather Service says."

Generally, U.S. gas demand for power in summer is 35-40% higher than what it was five years ago, with so much more coming (see Figure).

The good news is regions across the country are expected to have plenty of reserves to keep up with power demand.

The only exception is ERCOT, covering 90% of the electric load in Texas, where a 9% reserve margin is expected, below the desired 14%.

Last summer, however, ERCOT’s reserve margin also was below the desired level, yet the grid operator maintained system reliability with no load curtailments.

Simply put, other states are very lucky that Texas has been able to maintain gas at 50% of its generation, despite being more than justified to drastically increase that.

At about 1,600 Bcf per year, the flatness of gas for power demand in Texas since 2000 has been truly remarkable, especially since Lone Star State production is up 50% since then.

Increasingly, other U.S. states (and even countries) are wanting to import huge amounts of gas from Texas, a state that yields over 25% of all U.S. output.

Yet if Texas justifiably ever wants to utilize more of its own gas, others would be significantly impacted.

At ~480 TWh per year, if Texas was a country, it would be 9th globally for power use, even ahead of Brazil, a fast growing economy with 212 million people, and France, a developed economy with 68 million people.

In the near-term, this explains why a sweltering prolonged heat wave in July in Texas, with a hot Houston summer setting new electricity records, is the critical factor that could push up still very low gas prices.

But for California, our second highest gas using state, above-average snowpack should provide a stronger hydropower for this summer season relative to 2018.

Combined, Texas and California consume about 25% of U.S. gas, with Texas' use double that of California.

Across the U.S., gas could supply a record 40-43% of U.S. electricity this summer even as the EIA expects solar and wind to be larger sources of generation across the mix

Our gas used for power has increased 35-40% over the past five years, and January power generation also jumped on the year, highlighting broad momentum.

Our gas used for power has increased 35-40% over the past five years. DATA SOURCE: EIA; JTC

Indeed, U.S. natural gas for electricity has continued to soar, even as overall electricity consumption has trended lower in some years, at nearly 10,700 Bcf last year, a 16% rise from 2017 and easily the highest ever.

Gas is expected to supply 37% of U.S. power this year, even as coal-fired generation saw a brief uptick in 2021 in EIA data, versus 27% just five years ago (see Figure).

Capacity wise, gas is sure to continue to surge its share 45% share of the U.S. power system.

"More than 60% of electric generating capacity installed in 2018 was fueled by natural gas."

We know that natural gas will continue to be the go-to power source: coal and nuclear plants are retiring, and while growing, wind and solar are too intermittent, geography limited, and transmission short to compensate like natural gas can.

"U.S. coal power capacity has fallen by a third since 2010," and last year "16 gigawatts (16,000 MW) of U.S. coal-fired power plants retired."

This year, some 2,000 MW of coal was retired in February alone, with 7,420 MW expected to be closed in 2019.

Ditto for nuclear.

Nuclear retirements this year include Pilgrim, Massachusetts’s only nuclear plant, and Three Mile Island in Pennsylvania.

This will take a combined ~1,600 MW of nuclear capacity offline.

Another 2,500 MW and 4,300 MW of nuclear are expected to be leaving the U.S. power system in 2020 and 2021, respectively.

As more nuclear plants close, EIA projects that net electricity generation from U.S. nuclear power reactors will fall by 17% by 2025.

From 2019-2025 alone, EIA expects U.S. coal capacity to plummet nearly 25% to 176,000 MW, with nuclear falling 15% to 83,000 MW.

In contrast, new combined cycle gas plants will grow capacity almost 30% to around 310,000 MW.

Lower and lower projected commodity prices for gas encourage this immense gas build-out, not to mention non-stop increases in efficiency for gas-based units.

Remember that these are official U.S. Department of Energy estimates, not coming from the industry itself.

In other words, our Department of Energy concludes that gas is the future.

Our hotter and hotter summers are therefore more and more becoming: "summers for natural gas"

Ultimately, this shows why the anti-pipeline movement is so dangerous.

"Affordable Energy Coalition Highlights Ripple Effect of Natural Gas Moratorium."

In April, President Trump signed two executive orders to promote energy infrastructure by directing federal agencies to remove bottlenecks for gas transport into the Northeast in particular, where New England oil-fired generation has spiked, and to streamline federal reviews of border-crossing pipelines and other infrastructure.

Builders, however, are not relying on outside help: all they know is that more U.S. gas demand is a constant, so more infrastructure is mandatory.

They are moving forward diligently: for example, there are now some 27 pipelines worth $33 billion already in the works in Appalachia.

Related News

• Electricity Forum News

• Power Generation News

Black Hills Energy Corriedale Wind Farm Expansion earns regulatory approval in Wyoming, boosting capacity to over 52MW near Cheyenne with five turbines, supporting Renewable Ready customers and wind power goals under PUC and PSC oversight.

Key Points

An approved Wyoming wind project upgrade to over 52MW, adding five turbines to serve Renewable Ready customers.

✅ Adds 12.5MW via five new wind turbines near Cheyenne

✅ Cost increases to $79m; prior estimate $57m

✅ Approved by SD PUC after Wyoming PSC review

US company Black Hills Energy has received regulatory approval to increase the size of its Corriedale wind farm in Wyoming, where Wyoming wind exports to California are advancing, to over 52MW from 40MW previously.

The South Dakota Public Utilities Commission approved the additional 12.5MW capacity after the Wyoming Public Service Commission determined the boost was within commission rules, as federal initiatives like DOE wind energy awards continue to support the sector.

Black Hills Energy will install five additional turbines, raising the project cost to $79m from $57m, amid growing heartland wind investment across the region.
Corriedale will be built near Cheyenne and is expected to be placed in service in late 2020.

Similar market momentum is seen in Canada, where a Warren Buffett-linked Alberta wind farm is planned to expand capacity across the region.

Black Hills said that during the initial subscription period for its Renewable Ready program, applications of interest from eligible commercial, industrial and governmental agency customers were received in excess of the program's 40MW, underscoring the view that more energy sources can make stronger projects.

Black Hills Corporations chief executive and president Linden Evans said: “We are pleased with the opportunity to expand our Renewable Ready program, allowing us to meet our customers’ interest in renewable wind energy, which co-op members increasingly support.

“This innovative program expands our clean energy portfolio while meeting our customers’ evolving needs, particularly around cleaner and more sustainable energy, as projects like new energy generation coming online demonstrate.”

Related News

• Electricity Forum News

• Renewable Energy News

Alberta Solar Energy Contracts secure low-cost photovoltaic PPAs for government operations, delivering renewable electricity at 4.8 cents/kWh, beating natural gas LCOE, enhancing summer grid efficiency across Hays, Tilley, and Jenner with Canadian Solar.

Key Points

Low-cost PV power agreements meeting 55% of Alberta government electricity demand via new Canadian Solar facilities.

✅ Price: 4.8 cents/kWh CAD, under gas-fired generation LCOE.

✅ Sites: Hays, Tilley, Jenner; 50% equity with Conklin Métis Local #193.

✅ Supplies 55% of provincial government electricity demand.

Three new solar electricity facilities to be built in south eastern Alberta (Canada) amid Alberta's solar growth have been selected through a competitive process to supply the Government of Alberta with 55 per cent of their annual electricity needs. The facilities will be built near Hays, Tilley, and Jenner, by Canadian Solar with Conklin Métis Local #193 as 50-percent equity owners.

The Government of Alberta's operations have been powered 100 per cent with wind power since 2007. Upon the expiration of some of these contracts, they have been renewed to switch from wind to solar energy. The average contract pricing will be $0.048 per kilowatt hour (3.6 cents/kWh USD), which is less than the average historical wholesale power pool price paid to natural gas-fired electricity in the province in years 2008 - 2018.

"The conversation about solar energy has long been fixated on its price competitiveness with fossil fuels," said John Gorman, CanSIA President & CEO. "Today's announcement demonstrates that low cost solar energy has arrived as a mainstream option in Alberta, even as demand for solar lags in Canada according to federal assessments. The conversation should next focus on how to optimize an all-of-the-above strategy for developing the province's renewable and non-renewable resources."

"This price discovery is monumental for the solar industry in Canada" said Patrick Bateman, CanSIA Director of Policy & Market Development. "At less than five cents per kilowatt hour, this solar electricity has a cost that is less than that of natural gas. Achieving Alberta's legislated 30 per cent by 2030 renewable electricity target just became a whole lot cheaper!".

Quick Facts:

• The contract price of 4.8 cents/kWh CAD to be paid by Alberta Infrastructure for this solar electricity represents a lower Levelized Cost of Electricity (LCOE) than the average annual wholesale price paid by the power pool to combined-cycle and single-cycle natural gas-fired electricity generation which was 7.1 cents/kWh and 11.2 cents/kWh respectively from 2008 - 2018.

• Alberta receives more hours of sunshine than Miami, Florida in the summer months. Alberta's electricity supply is most strained in summer, highlighting challenges for solar expansion when high temperatures increase the resistance of the distribution and transmission systems, and reduce the efficiency of cooling thermal power plants. For this reason, solar facilities sited near to electricity demand improves overall grid efficiency. Supply shortages are atypical in Alberta in winter when solar energy is least available. When they do occur, imports are increased and large loads are decreased.

• In 2018, Alberta's solar electricity generation exceeded 50 MW. While representing much less than 1% of the province's electricity supply today, the Canadian Solar Industries Association (CanSIA) forecasts that solar energy could supply as much as 3 per cent of the province's electricity by 2030, supporting renewable energy job growth across Alberta. A recent supply chain study of the solar electricity sector in Alberta by Solas Energy Consulting Inc. found a potential of $4.1 billion in market value and a labour force rising to 10,000 in 2030.

To learn more about solar energy and the best way for consumers to go solar, please visit the Canadian Solar Industries Association at www.CanSIA.ca.

Related News

• Electricity Forum News

• Renewable Energy News

Brazil ICMS Tax Cap limits state VAT on fuels, natural gas, electricity, communications, and transit, promising short-term price relief amid inflation, with federal compensation to states and potential legal challenges affecting investments and ANP auctions.

Key Points

A policy capping state VAT at 17-18 percent on fuels, electricity, and services to temper prices and inflation.

✅ Caps VAT to 17-18% on fuels, power, telecom, transit

✅ Short-term relief; medium-long term impact uncertain

✅ Federal compensation; potential court challenges, investment risk

Brazil’s congress approved a bill that limits the ICMS tax rate that state governments can charge on fuels, natural gas, electricity, communications, and public transportation. 

Local lawyers told BNamericas that the measure may reduce fuel and power prices in the short term, similar to Brazil power sector relief loans seen during the pandemic, but it is unlikely to produce any major effects in the medium and long term. 

In most states the ceiling was set at 17% or 18% and the federal government will pay compensation to the states for lost tax revenue until December 31, via reduced payments on debts that states owe the federal government.

The bill will become law once signed by President Jair Bolsonaro, who pushed strongly for the proposal with an eye on his struggling reelection campaign for the October presidential election. Double-digit inflation has turned into a major election issue and fuel and electricity prices have been among the main inflation drivers, as seen in EU energy-driven inflation across the bloc this year. Congress’ approval of the bill is seen by analysts as political victory for the Brazilian leader.

How much difference will it make?

Marcus Francisco, tax specialist and partner at Villemor Amaral Advogados, said that in the formation of fuel and electricity prices there are other factors, including high natural gas prices, that drive increases.

“In the case of fuels, if the barrel of oil [price] increases, automatically the final price for the consumer will go up. For electricity, on the other hand, there are several subsidies and policy choices such as Florida rejecting federal solar incentives that are part of the price and that can increase the rate [paid],” he said. 

There is also a possibility that some states will take the issue to the supreme court since ICMS is a key source of revenue for them, Francisco added.

Tiago Severini, a partner at law firm Vieira Rezende, said the comparison between the revenue impact and the effective price reduction, based on the estimates made by the states and the federal government, seems disproportionate, and, as seen in Europe, rolling back European electricity prices is often tougher than it appears. 

“In other words, a large tax collection impact is generated, which is quite unequal among the different states, for a not so strong price reduction,” he said.

“Due to the lack of clarity regarding the precision of the calculations involved, it’s difficult even to assess the adequacy of the offsets the federal government has been considering, and international cases such as France's new electricity pricing scheme illustrate how complex it can be to align fiscal offsets with regulatory constraints, to cover the cost it would have with the compensation for the states” Severini added.

The compensation ideas that are known so far include hiking other taxes, such as the social contribution on net profits (CSLL) that is paid by oil and gas firms focused on exploration and production.

“This can generate severe adverse effects, such as legal disputes, reduced investments in the country, and reduced attractiveness of the new auctions by [sector regulator] ANP, and costly interventions like the Texas electricity market bailout after extreme weather events,” Severini said. 

Related News

• Electricity Forum News

• Energy Policy News

Illinois Zero Emission Credits support nuclear plants via tradable credits tied to wholesale electricity prices, carbon costs, created by the Future Energy Jobs Bill to avert Exelon closures and sustain low-carbon power.

Key Points

State credits that value nuclear power's zero-carbon output, priced by market and carbon metrics to keep plants running.

✅ Pegged to wholesale prices, carbon costs, and state averages.

✅ Created by Future Energy Jobs Bill to prevent plant retirements.

✅ Supports Exelon Quad Cities and Clinton nuclear facilities.

Nuclear plants have produced over half of Illinois electricity generation since 2010, but the states two largest plants would have been retired amid the debate over saving nuclear plants if the state had not created a zero emission credit (ZEC) mechanism to support the facilities.

The two plants, Quad Cities and Clinton, collectively delivered more than 12 percent of the states electricity generation over the past several years. In May 2016, however, Exelon, the owner of the plants, announced that they had together lost over $800 million dollars over the previous six years and revealed plans to retire them in 2017 and 2018, similar to the Three Mile Island closure later announced for 2019 by its owner.

In December 2016, Illinois passed the Future Energy Jobs Bill, which established a zero emission credit (ZEC) mechanism

to support the plants financially. Exelon then cancelled its plans to retire the two facilities.

The ZEC is a tradable credit that represents the environmental attributes of one megawatt-hour of energy produced from the states nuclear plants. Its price is based on a number of factors that include wholesale electricity market prices, nuclear generation costs, state average market prices, and estimated costs of the long-term effects of carbon dioxide emissions.

The bill is set to take effect in June, but faces multiple court challenges as some utilities have expressed concerns that the ZEC violates the commerce clause and affects federal authority to regulate wholesale energy prices, amid gas-fired competition in nearby markets that shapes the revenue outlook.

Illinois ranks first in the United States for both generating capacity and net electricity generation from nuclear power, a resource many see as essential for net-zero emissions goals, and accounts for approximately one-eighth of the nuclear power generation in the nation.

Related News

• Electricity Forum News

• Power Generation News