Plan to secure Savannah manhole caps after blasts

Duration Portfolio Energy Storage aligns layered peak demand with right-sized batteries, enabling peak shaving, gas peaker replacement, and solar-plus-storage synergy while improving grid flexibility, reliability, and T&D deferral through two- to four-hour battery durations.

Key Points

An approach that layers battery durations to match peaks, cut costs, replace peakers, and boost grid reliability.

✅ Layers 2- to 4-hour batteries by peak duration

✅ Enables solar-plus-storage and peak shaving

✅ Cuts T&D upgrades, emissions, and fuel costs

The debate over energy storage replacing gas-fired peakers has raged for years, but a new approach that shifts the terms of the argument could lead to an acceleration of storage deployments.

Rather than looking at peak demand as a single mountainous peak, some analysts now advocate a layered approach that allows energy storage to better match peak needs and complement ongoing efforts to improve solar and wind power across the grid.

"You don’t have to have batteries that run to infinity."

Some developers of solar-plus-storage projects, bolstered by cheap batteries, say they can already compete head-to-head with gas-fired peakers. "I can beat a gas peaker anywhere in the country today with a solar-plus-storage power plant," Tom Buttgenbach, president and CEO of developer 8minutenergy Renewables, recently told S&P Global.

Customers are very busy these days and rebate programs need to fit the speed of their life. Participation should be quick, easy, and accessible anywhere.

Others disagree. Storage is not disruptive for generation, but will be disruptive for transmission and distribution, Kris Zadlo, executive vice president and chief development officer at Invenergy, told the audience at a Bloomberg New Energy Finance conference last spring. Invenergy, like many renewable power developers, develops generation, energy storage and transmission projects.

But there is another path that avoids the pitfalls of positions on either end of the all-or-none approach. "Do the analysis of the need itself," Ray Hohenstein, market applications director at Fluence, told Utility Dive. If the need is only two hours in duration, it may be best served by a two-hour battery. "You don’t have to have batteries that run to infinity."

Storage vs. fossil fuel peakers

Energy storage has several benefits over traditional fossil fuel peaking plants, Hohenstein said. It is instantaneous, it has no emissions and requires no fuel, and has limited infrastructure needs. It can also help the grid absorb higher levels of renewable generation by soaking up excess output, such as solar power at noon, and many planned storage additions will be paired with solar in the next few years. But the one thing energy storage cannot do, he said, is provide limitless energy.

So, instead of looking at replacing an individual peaker, Hohenstein advocated a "duration portfolio" approach that uses energy storage to shave peak load.

If the need is for 150 MW of resources that will never need to run for more than two hours at a time, then a battery is "quite cheap," significantly less than a four or eight-hour battery, said Hohenstein. "If you fill up your peak by duration layer, it could be more cost effective."

NREL research driver

Fluence’s approach is informed by research by Paul Denholm and Robert Margolis at the National Renewable Energy Laboratory (NREL), released last spring.

The NREL researchers looked at the California market where they said 11 GW of fossil fuel capacity is expected to be retired by 2029 because of new once-through-cooling requirements that are taking effect. A lot of that capacity is peaking capacity and, according to NREL’s analysis, a large fraction could be replaced with four-hour energy storage, assuming continued storage cost reductions and growth in solar installations.

The key in NREL’s research was the level of solar power penetration. There is a "synergistic" relationship between solar penetration and storage deployment, the researchers wrote, and other studies suggest wind and solar could meet 80% of U.S. demand as these trends continue.

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E.ON Digital Transformer Stations modernize distribution grids with smart grid monitoring, voltage control, and remote switching, enabling bidirectional power flow, renewables integration, and rapid fault isolation from centralized grid control centres.

Key Points

Remotely monitored grid nodes enhancing smart grid stability and speedier fault response.

✅ Real-time voltage and current data along feeders and laterals

✅ Remote switching cuts outage duration and truck rolls

✅ Supports renewables and bidirectional power flows

E.ON plans to commission 2500 digital transformer stations in the service areas of its four German distribution grid operators - Avacon, Bayernwerk, E.DIS and Hansewerk - by the end of 2019. Starting this year, E.ON will solely install digital transformer stations in Germany, aligning with 2019 grid edge trends seen across the sector. This way, the digital grid is quite naturally being integrated into E.ON's distribution grids.

With these transformer stations as the centrepiece of the smart grid, it is possible to monitor and control using synchrophasors in the power grid from the grid control centre. This helps to maintain a more balanced utilisation of the grid and, with increasing complexity, ensures continued security of supply.

Until now, the current and voltage parameters required for safe grid operation could usually only be determined at the beginning of a power line, where there is usually a grid substation in place. Controlling current flow and voltage in the downstream system was physically impossible.

In the future, grids will have to function in both directions: they will bring electricity to the customer while at the same time collecting and transmitting more and more green electricity via HVDC technology where appropriate. This requires physical data to be made available along the entire route. To ensure security of supply, voltage fluctuations must be kept within narrowly defined limits and the current flow must not exceed the specified value, while reducing line losses with superconducting cables remains an important consideration. To manage this challenge, it is necessary to install digital technology.

The possibility of remotely controlling grids also reduces downtimes in the event of faults and supports a smarter electricity infrastructure approach. With the new technology, our grid operators can quickly and easily access the stations of the affected line. The grid control centres can thus limit and eliminate faults on individual line sections within a very short space of time.

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U.S. Wind Power 2025 drives record capacity additions, with FERC data showing robust renewable energy growth, IRA incentives, onshore and offshore projects, utility-scale generation, grid integration, and manufacturing investment boosting clean electricity across key states.

Key Points

Overview of record wind additions, IRA incentives, and grid expansion defining the U.S. clean electricity mix in 2025.

✅ FERC: 30.1% of new U.S. capacity in Jan 2025 from wind

✅ Major projects: Cedar Springs IV, Boswell, Prosperity, Golden Hills

✅ IRA incentives drive onshore, offshore builds and manufacturing

In early 2025, wind power has significantly strengthened its position in the United States' electricity generation portfolio. According to data from the Federal Energy Regulatory Commission (FERC), wind energy accounted for 30.1% of the new electricity capacity added in January 2025, and as the most-used renewable source in the U.S., it also surpassed the previous record set in 2024. This growth is attributed to substantial projects such as the 390.4 MW Cedar Springs Wind IV and the 330.0 MW Boswell Wind Farm in Wyoming, along with the 300.0 MW Prosperity Wind Farm in Illinois and the 201.0 MW Golden Hills Wind Farm Expansion in Oregon. 

The expansion of wind energy capacity is part of a broader trend where solar and wind together accounted for over 98% of the new electricity generation capacity added in the U.S. in January 2025. This surge is further supported by the federal government's Inflation Reduction Act (IRA) and broader policy support for renewables, which has bolstered incentives for renewable energy projects, leading to increased investments and the establishment of new manufacturing facilities. 

By April 2025, clean electricity sources, including wind and solar, were projected to surpass 51% of total utility-scale electricity generation in the U.S., building on a 25.5% renewable share seen in recent data, marking a significant milestone in the nation's energy transition. This achievement is attributed to a combination of factors: a seasonal drop in electricity demand during the spring shoulder season, increased wind speeds in key areas like Texas, and higher solar production due to longer daylight hours and expanded capacity in states such as California, Arizona, and Nevada, supported by record installations across the solar and storage industry. 

Despite a 7% decline in wind power production in early April compared to the same period in 2024—primarily due to weaker wind speeds in regions like Texas—the overall contribution of wind energy remained robust, supported by an 82% clean-energy pipeline that includes wind, solar, and batteries. This resilience underscores the growing reliability of wind power as a cornerstone of the U.S. electricity mix. 

Looking ahead, the U.S. Department of Energy projects that wind energy capacity will continue to grow, with expectations of adding between 7.3 GW and 9.9 GW in 2024, and potentially increasing to 14.5 GW to 24.8 GW by 2028. This growth is anticipated to be driven by both onshore and offshore wind projects, with onshore wind representing the majority of new additions, continuing a trajectory since surpassing hydro capacity in 2016 in the U.S.

Early 2025 has witnessed a notable increase in wind power's share of the U.S. electricity generation mix. This trend reflects the nation's ongoing commitment to expanding renewable energy sources, especially after renewables surpassed coal in 2022, supported by favorable policies and technological advancements. As the U.S. continues to invest in and develop wind energy infrastructure, the role of wind power in achieving a cleaner and more sustainable energy future becomes increasingly pivotal.

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Rising Greenhouse Gas Concentrations drive climate change, with CO2, methane, and nitrous oxide surging; WMO data show higher radiative forcing, elevated pre-industrial baselines, and persistent atmospheric concentrations despite Paris Agreement emissions pledges.

Key Points

Increasing atmospheric CO2, methane, and nitrous oxide levels that raise radiative forcing and drive warming.

✅ WMO data show CO2 at 407.8 ppm in 2018, above decade average

✅ Methane and nitrous oxide surged, elevating total radiative forcing

✅ Concentrations differ from emissions; sinks absorb about half

The World Meteorological Organization (WMO) says the increase in CO2 was just above the average rise recorded over the last decade.

Levels of other warming gases, such as methane and nitrous oxide, have also surged by above average amounts.

Since 1990 there's been an increase of 43% in the warming effect on the climate of long lived greenhouse gases.

The WMO report looks at concentrations of warming gases in the atmosphere rather than just emissions.

The difference between the two is that emissions refer to the amount of gases that go up into the atmosphere from the use of fossil fuels, such as burning coal for coal-fired electricity generation and from deforestation.

Concentrations are what's left in the air after a complex series of interactions between the atmosphere, the oceans, the forests and the land. About a quarter of all carbon emissions are absorbed by the seas, and a similar amount by land and trees, while technologies like carbon capture are being explored to remove CO2.

Using data from monitoring stations in the Arctic and all over the world, researchers say that in 2018 concentrations of CO2 reached 407.8 parts per million (ppm), up from 405.5ppm a year previously.

This increase was above the average for the last 10 years and is 147% of the "pre-industrial" level in 1750.

The WMO also records concentrations of other warming gases, including methane and nitrous oxide, and some countries have reported declines in certain potent gases, as noted in US greenhouse gas controls reports, though global levels remain elevated. About 40% of the methane emitted into the air comes from natural sources, such as wetlands, with 60% from human activities, including cattle farming, rice cultivation and landfill dumps.

Methane is now at 259% of the pre-industrial level and the increase seen over the past year was higher than both the previous annual rate and the average over the past 10 years.

Nitrous oxide is emitted from natural and human sources, including from the oceans and from fertiliser-use in farming. According to the WMO, it is now at 123% of the levels that existed in 1750.

Last year's increase in concentrations of the gas, which can also harm the ozone layer, was bigger than the previous 12 months and higher than the average of the past decade.

What concerns scientists is the overall warming impact of all these increasing concentrations. Known as total radiative forcing, this effect has increased by 43% since 1990, and is not showing any indication of stopping.

There is no sign of a slowdown, let alone a decline, in greenhouse gases concentration in the atmosphere despite all the commitments under the Paris agreement on climate change and the ongoing global energy transition efforts," said WMO Secretary-General Petteri Taalas.

"We need to translate the commitments into action and increase the level of ambition for the sake of the future welfare of mankind," he added.

"It is worth recalling that the last time the Earth experienced a comparable concentration of CO2 was three to five million years ago. Back then, the temperature was 2-3C warmer, sea level was 10-20m higher than now," said Mr Taalas.

The UN Environment Programme will report shortly on the gap between what actions countries are taking to cut carbon, for example where Australia's emissions rose 2% recently, and what needs to be done to keep under the temperature targets agreed in the Paris climate pact.

Preliminary findings from this study, published during the UN Secretary General's special climate summit last September, indicated that emissions continued to rise during 2018, although global emissions flatlined in 2019 according to the IEA.

Both reports will help inform delegates from almost 200 countries who will meet in Madrid next week for COP25, following COP24 in Katowice the previous year, the annual round of international climate talks.

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California Electricity Reliability covers grid resilience amid heat waves, rolling blackouts, renewable energy integration, resource adequacy, battery storage, natural gas peakers, ISO oversight, and peak demand management to keep homes, businesses, and industry powered.

Key Points

Dependable California power delivery despite heat waves, peak demand, and challenges integrating renewables into grid.

✅ Rolling blackouts revealed gaps in resource adequacy.

✅ Early evening solar drop requires fast ramping and storage.

✅ Agencies pledge planning reforms and flexible backup supply.

One hallmark of an advanced society is a reliable supply of electrical energy for residential, commercial and industrial consumers. Uncertainty that California electricity will be there when we need it it undermines social cohesion and economic progress, as demonstrated by the travails of poor nations with erratic energy supplies.

California got a small dose of that syndrome in mid-August when a record heat wave struck the state and utilities were ordered to impose rolling blackouts to protect the grid from melting down under heavy air conditioning demands.

Gov. Gavin Newsom quickly demanded that the three overseers of electrical service to most of the state - the Public Utilities Commission, the Energy Commission and the California Independent Service Operator – explain what went wrong.

"These blackouts, which occurred without prior warning or enough time for preparation, are unacceptable and unbefitting of the nation's largest and most innovative state," Newsom wrote. "This cannot stand. California residents and businesses deserve better from their government."

Initially, there was some fingerpointing among the three entities. The blackouts had been ordered by the California Independent System Operator, which manages the grid and its president, Steve Berberich, said he had warned the Public Utilities Commission about the potential supply shortfall facing the state.

"We have indicated in filing after filing after filing that the resource adequacy program was broken and needed to be fixed," he said. "The situation we are in could have been avoided."

However, as political heat increased, the three agencies hung together and produced a joint report that admitted to lapses of supply planning and grid management and promised steps to avoid a repeat next summer.

"The existing resource planning processes are not designed to fully address an extreme heat storm like the one experienced in mid August," their report said. "In transitioning to a reliable, clean and affordable resource mix, resource planning targets have not kept pace to lead to sufficient resources that can be relied upon to meet demand in the early evening hours. This makes balancing demand and supply more challenging."

Although California's grid had experienced greater heat-related demands in previous years, most notably 2006, managers then could draw standby power from natural gas-fired plants and import juice from other Western states when necessary.

Since then, the state has shut down a number of gas-fired plants and become more reliant on renewable but less reliable sources such as windmills and solar panels.

August's air conditioning demand peaked just as output from solar panels was declining with the setting of the sun and grid managers couldn't tap enough electrons from other sources to close the gap.

While the shift to renewables didn't, unto itself, cause the blackouts, they proved the need for a bigger cushion of backup generation or power storage in batteries or some other technology. The Public Utilities Commission, as Beberich suggested, has been somewhat lax in ordering development of backup supply.

In the aftermath of the blackouts, the state Water Resources Control Board, no doubt with direction from Newsom's office, postponed planned shutdowns of more coastal plants, which would have reduced supply flexibility even more.

Shifting to 100% renewable electricity, the state's eventual goal, while maintaining reliability will not get any easier. The state's last nuclear plant, Diablo Canyon, is ticketed for closure and demand will increase as California eliminates gasoline- and diesel-powered vehicles in favor of "zero emission vehicles" as part of its climate policies push and phases out natural gas in homes and businesses.

Politicians such as Newsom and legislators in last week's blackout hearing may endorse a carbon-free future in theory, but they know that they'll pay the price as electricity prices climb if nothing happens when Californians flip the switch.

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Income Graduated Fixed Charge aligns CPUC billing with utility fixed costs, lowers usage rates, supports electrification, and shifts California investor-owned utilities' electric bills by income, with CARE and Climate Credit offsets for low-income households.

Key Points

A CPUC proposal: an income-based monthly fixed fee with lower usage rates to align costs and aid low-income customers.

✅ Income-tiered fixed fees: $0-$42; CARE: $14-$22, by utility territory

✅ Usage rates drop 16%-22% to support electrification and cost-reflective billing

✅ Lowest-income save ~$10-$20; some higher earners pay ~$10+ more monthly

The Public Advocates Office (PAO) for the California Public Utilities Commission (CPUC) has proposed adding a monthly income-based fixed charge on electric utility bills based on income level.  

The rate change is designed to lower bills for the lowest-income residents while aligning billing more directly with utility costs. 

PAO’s recommendation for the Income Graduated Fixed Charge places fees between $22 and $42 per month in the three major investor-owned utilities’ territories, including an SDG&E minimum charge debate under way, for customers not enrolled in the California Alternative Rates for Energy (CARE) program. As seen below, CARE customers would be charged between $14 per month and $22 a month, depending on income level and territory.

For households earning $50,000 or less per year, the fixed charge would be $0, but only if the California Climate Credit is applied to offset the fixed cost.

Meanwhile, usage-based electricity rates are lowered in the PAO proposal, part of major changes to electric bills statewide. Average rates would be reduced between 16% to 22% for the three major investor-owned utilities.

The lowest-income bracket of Californians is expected to save roughly $10 to $20 a month under the proposal, while middle-income customers may see costs rise by about $20 a month, even as lawmakers seek to overturn income-based charges in Sacramento.

“We anticipate the vast majority of low-income customers ($50,000 or less per year) will have their monthly bills decrease by $10 or more, and a small proportion of the highest income earners ($100,000+ per year) will see their monthly bills rise by $10 or more,” said the PAO.

The charges are an effort to help suppress ever-increasing electricity generation and transmission rates, which are among the highest in the country, with soaring electricity prices reported across California. Rates are expected to rise sharply as wildfire mitigation efforts are implemented by the utilities found at fault for their origin.

“We are very concerned. However, we do not see the increases stopping at this point,” Linda Serizawa, deputy director for energy, PAO, told pv magazine. “We think the pace and scale of the [rate] increases is growing faster than we would have anticipated for several years now.”

Consumer advocates and regulators face calls for action on surging electricity bills across the state.

The proposed changes are also meant to more directly couple billing with the fixed charges that utilities incur, as California considers revamping electricity rates to clean the grid. For example, activities like power line maintenance, energy efficiency programs, and wildfire prevention are not expected to vary with usage, so these activities would be funded through a fixed charge.

Michael Campbell of the PAO’s customer programs team, and leader of the proposed program, likened paying for grid enhancements and other social programs with utility rate increases to “paying for food stamps by taxing food.” Instead, a fixed charge would cover these costs.

PAO said the move to lower rates for usage should help encourage electrification as California moves to replace heating and cooling, appliances, and gas combustion cars with electrified counterparts. In addition, lower rates mean the cost burden of running these devices is improved.

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