Wind farm in works for northwest Kansas

Wisconsin Solar and Wind Energy advances as rooftop solar, utility-scale farms, and NREL perovskite solar cells improve efficiency; wind turbines gain via wake modeling, yaw control, and grid-scale battery storage to cut carbon emissions.

Key Points

It is Wisconsin's growth in rooftop and utility-scale solar plus optimized wind turbines to cut carbon emissions.

✅ Perovskite solar cells promise higher efficiency, need longevity

✅ Wake modeling and yaw control optimize wind farm output

✅ Batteries and bids can offset reliance on natural gas

Solar energy in Wisconsin continued to grow in 2019, as more homeowners had rooftop panels installed and big utilities started building multi-panel solar farms.

Wind power is increasing more slowly in the state. However, renewable power developers are again coming forward with proposals for multiple turbines.

Nationally, researchers are working on ways to get even more energy from solar and wind, with the U.S. moving toward 30% electricity from wind and solar in coming years, as states like Wisconsin aim to reduce their carbon emissions over the next few decades.

One reason solar energy is growing in Wisconsin is due to the silicon panels becoming more efficient. But scientists haven't finished trying to improve panel efficiency. The National Renewable Energy Laboratory (NREL) in Golden, Col., is one of the research facilities experimenting with brushing a lab-made solution called perovskite onto a portion of a panel called a solar cell.

In a demonstration video supplied by NREL, senior scientist Maikel van Hest said that, in the lab anyway, the painted cell and its electrical connections called contacts, produce more energy:

"There you go! That's how you paint a perovskite solar cell. And you imagine that ultimately what you could do is you could see a company come in with a truck in front of your house and they would basically paint on the contacts first, dry those, and paint the perovskite over it. That you would have photovoltaic cells on the side of your house, put protective coating on it, and we're done."

Another NREL scientist, David Moore, says the new solar cells could be made faster and help meet what's expected to be a growing global demand for energy. However, Moore says the problem has been lack of stability.

"A solar cell with perovskites will last a couple years. We need to get that to 20-25 years, and that's the big forefront in perovskite research, is getting them to last longer," Moore told members of the Society of Environmental Journalists during a recent tour of NREL.

Another part of improving renewable energy is making wind turbines more productive. At NREL's Insight Center, a large screen showing energy model simulations dominates an otherwise darkened room. Visualization scientist Nicholas Brunhart-Lupo points to a display on the screen that shows how spinning turbines at one edge of a wind farm can cause an airflow called a wake, which curtails the power generation of other turbines.

"So what we find in these simulations is these four turbines back here, since they have this used air, this low-velocity wake being blown to their faces, they're only generating about 20% of the energy they should be generating," he explains.

Brunhart-Lupo says the simulations can help wind farm developers with placement of turbines as well as adjustments to the rotor and blades called the yaw system.

Continued progress with renewables may be vital to any state or national pledges to reduce use of fossil fuels and carbon emissions linked to climate change, including Biden's solar expansion plan as a potential pathway. Some scientists say to limit a rise in global temperature, there must be a big decline in emissions by 2050.

But even utilities that say they support use of more renewables, as why the grid isn't 100% renewable yet makes clear, aren't ready to let go of some energy sources. Jonathan Adelman of Xcel Energy, which serves part of Western Wisconsin, says Xcel is on track to close its last two coal-fired power plants in Minnesota. But he says the company will need more natural gas plants, even though they wouldn't run as often.

"It's not perfect. And it is in conflict with our ultimate goal of being carbon-free," says Adelman. "But if we want to facilitate the transition, we still need resources to help that happen."

Some in the solar industry would like utilities that say they need more natural gas plants to put out competitive bids to see what else might be possible. Solar advocates also note that in some states, energy regulators still favor the utilities.

Meanwhile, solar slowly marches ahead, including here in southeastern Wisconsin, as Germany's solar power boost underscores global momentum.

On the roof of a ranch-style home in River Hills, a work crew from the major solar firm Sunrun recently installed mounting brackets for solar panels.

Sunrun Public Policy Director Amy Heart says she supports research into more efficient renewables. But she says another innovation may have to come in the way regulators think.

"Instead of allowing and thinking about from the perspective of the utility builds the power plant, they replace one plant with another one, they invest in the infrastructure; is really thinking about how can these distributed solutions like rooftop solar, peer-to-peer energy sharing, and especially rooftop solar paired with batteries how can that actually reduce some of what the utility needs?

Large-scale energy storage batteries are already being used in some limited cases. But energy researchers continue to make improvements to them, too, with cheap solar batteries beginning to make widespread adoption more feasible as scientists race to reduce the expected additional harm of climate change.

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Solar Plus Storage is accelerating across utilities and microgrids, pairing rooftop solar with lithium-ion batteries to enhance grid resilience, reduce peak costs, prevent blackouts, and leverage tax credits amid falling prices and decarbonization goals.

Key Points

Solar Plus Storage combines solar generation with batteries to shift load, boost reliability, and cut energy costs.

✅ Cuts peak demand charges and enhances blackout resilience

✅ Falling battery and solar costs drive nationwide utility adoption

✅ Enables microgrids and grid services like frequency regulation

Todd Karin was prepared when California’s largest utility shut off power to millions of people to avoid the risk of wildfires last month. He’s got rooftop solar panels connected to a single Tesla Powerwall in his rural home near Fairfield, California. “We had backup power the whole time,” Karin says. “We ran the fridge and watched movies.”

Californians worried about an insecure energy future are increasingly looking to this kind of solution. Karin, a 31-year-old postdoctoral fellow at Lawrence Berkeley National Laboratory, spent just under $4,000 for his battery by taking advantage of tax credits. He's also saving money by discharging the battery on weekday evenings, when energy is more expensive during peak demand periods. He expects to save around $1,500 over the 10 years the battery is under warranty.

The economics don’t yet work for every household, but the green-power combo of solar panels plus batteries is popping up on a much bigger scale in some unexpected places. Owners of a rice processing plant in Arkansas are building a system to generate 26 megawatts of solar power and store another 40 MW. The plant will cut its power bill by a third, and owners say they will pass the savings to local rice growers. New York’s JFK Airport is installing solar plus storage to reduce its power load by 10 percent, while Pittsburgh International Airport is building a 20-MW solar and natural gas microgrid to keep it independent from the local utility. Officials at both airports are worried about recent power shutdowns due to weather and overload-related blackouts.

And residents of the tiny northern Missouri town of Green City (pop. 608) are getting 2.5 MW of solar plus four hours of battery storage from the state’s public utility next year. The solar power won’t go directly to townspeople, but instead will back up the town’s substation, reducing the risk of a potential shutdown. It’s part of a $68 million project to improve the reliability of remote substations far from electric generating stations.

“It’s a pretty big deal for us,” says Chad Raley, who manages technology and renewables at Ameren, a Missouri utility that is building three rural solar-plus-storage projects to better manage the flow of electricity across the local grid. “It gives us so much flexibility with renewable generation. We can’t control the sun or clouds or wind, but we can have battery storage.”

The first solar-plus-storage installations started about a decade ago on a small scale in sunny states like California, Hawaii, and Arizona. Now they’re spreading across the country, driven by falling prices of both solar panels and lithium-ion batteries the size of a shipping container imported from both China and South Korea, with wind, solar, and batteries making up most of the utility-scale pipeline nationwide. These countries have ramped up production efficiencies and lowered labor costs, leaving many US manufacturers in the dust. In fact, the price of building a comparable solar-plus-storage generating facility is now cheaper than operating a coal-fired power plant, industry officials say. In certain circumstances, the cost is equal to some natural gas plants.

“This is not just a California, New York, Massachusetts thing,” says Kelly Speakes-Backman, CEO of the Energy Storage Association, an industry group in Washington. She says more than 30 states have renewable storage on the grid. Utilities have proposed and states have approved 7 gigawatts to be installed by 2030, and most new storage will be paired with solar across the US.

Speakes-Backman estimates the unit cost of electricity produced from a solar-plus-storage system will drop 10 to 15 percent each year through 2024, supporting record growth in solar and storage investments. “If you have the option of putting out a polluting or non-polluting generating source at the same price, what are you going to pick?” says Speakes-Backman.

She notes that PJM, a large Mid-Atlantic wholesale grid operator, announced it will deploy battery storage to help smooth out fluctuating power from two wind farms it operates. “When the grid fluctuates, storage can react to it quickly and can level out the supply,” she says. In the Midwest, grid-level battery storage is also being used to absorb extra wind power. Batteries hold onto the wind and put it back onto the grid when people need it.

While the solar-plus-storage trend isn’t yet putting a huge dent in our fossil fuel use, according to Paul Denholm, an energy analyst at the National Renewable Energy Laboratory in Golden, Colorado, it is a good beginning and has the side effect of cutting air pollution. By 2021, solar and other renewable energy sources will overtake coal as a source of energy, and the US is moving toward 30% electricity from wind and solar, according to a new report by the Institute for Energy Economics and Financial Analysis, a nonprofit think tank based in Cleveland.

That’s a glimmer of hope in a somewhat dreary week of news on carbon emissions. A new United Nations report released this week finds that the planet is on track to warm by 3.9 degrees Celsius (7 Fahrenheit) by 2100 unless drastic cuts are made by phasing out gas-powered cars, eliminating new coal-fired power plants, and changing how we grow and manage land, and scientists are working to improve solar and wind power to limit climate change as well.

Energy-related greenhouse gas emissions in the US rose 2.7 percent in 2018 after several years of decline. The Trump administration has rolled back climate policies from the Obama years, including withdrawing from the Paris climate accords.

There may be hope from green power initiatives outside the Beltway, though, and from federal proposals like a tenfold increase in US solar that could remake the electricity system. Arizona plans to boost solar-plus-storage from today’s 6 MW to a whopping 850 MW by 2025, more than the entire capacity of large-scale batteries in the US today. And some folks might be cheering the closing of the West’s biggest coal-fired power plant, the 2.25-gigawatt Navajo Generating Station, in Arizona, which had spewed soot and carbon dioxide over the region for 45 years until last week. The closure might help the planet and clear the hazy smog over the Grand Canyon.

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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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US Electricity Demand 2018-2050 projects slower growth as energy consumption, power generation, air conditioning, and electric heating shift with efficiency standards, commercial floor space, industrial load, and household growth across the forecast horizon.

Key Points

A forecast of US power use across homes, commercial space, industrial load, and efficiency trends from 2018 to 2050.

✅ 2018 generation hit record; residential sales up 6%.

✅ Efficiency curbs demand; growth lags population and floor space.

✅ Commercial sales up 2%; industrial demand fell 3% in 2018.

Last year's Houston cold winter and hot summer drove power use to record levels, especially among households that rely on electricity for air conditioning during extreme weather conditions.

Electricity generation increased 4 per cent nationwide in 2018 and produced 4,178 million megawatt hours, driven in part by record natural gas generation across the U.S., surpassing the previous peak of 4,157 megawatt hours set in 2007, the Energy Department reported.

U.S. households bought 6 percent more electricity in 2018 than they did the previous year, despite longer-term declines in national consumption, reflecting the fact 87 percent of households cool their homes with air conditioning and 35 percent use electricity for heating.

Electricity sales to the commercial sector increased 2 percent in 2018 compared to the previous year while the industrial sector bought 3 percent less last year.

Going forward, the Energy Department forecasts that electricity consumption will grow at a slower pace than in recent decades, aligning with falling sales projections as technology improves and energy efficiency standards moderate consumption.

The economy and population growth are primary drivers of demand and the government predicts the number of households will grow at 0.7 percent per year from now until 2050 but electricity demand will grow only by 0.4 percent annually.

Likewise, commercial floor space is expected to increase 1 percent per year from now until 2050 but electricity sales will increase only by half that amount.

Globally, surging electricity demand is putting power systems under strain, providing context for these domestic trends.

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Community Solar for Low-Income Homes expands energy equity by delivering renewable energy access, predictable bill savings, and tax credit benefits to renters and energy-insecure households, accelerating distributed generation and storage adoption nationwide.

Key Points

A program model enabling renters and LMI households to subscribe to off-site solar and save on utility bills.

✅ Earn bill credits from shared solar generation.

✅ Expands access for renters and LMI subscribers.

✅ Often paired with storage and IRA tax credit adders.

On a square-foot basis, the issue of inequality is made worse by higher costs for energy usage in the nation. Efforts like community solar programs such as Maryland community solar are underway to boost low-income participation in the cost benefits of renewable energy.

The Energy Information Administration (EIA) shows that households that are considered energy insecure, or those that have the inability to adequately meet basic household energy costs, are paying more for electricity than their wealthier counterparts. 

On average in the United States in 2020, households were billed about $1.04 per square foot for all energy sources. For homes that did not report energy insecurity, that average was $0.98 per square foot, while homes with energy insecurity issues paid an average of $1.24 per square foot for energy. This means that U.S. residents that need the most support on their energy bills are stuck with costs 27% higher than their neighbors on square-foot-basis.

EIA said energy-insecure households have reduced or forgone basic necessities to pay energy bills, kept their houses at unsafe temperatures because of energy cost concerns, or been unable to repair heating or cooling equipment because of cost.

In 2020, households with income less than $10,000 a year were billed an average of $1.31 per square foot for energy, while households making $100,000 or more were billed an average of $0.96 per square foot, said EIA. Renters paid considerably more ($1.28 per square foot) than owners ($0.98 per square foot). There were also considerable differences between regions, with New England solar growth sparking grid upgrade debates, ethnic groups and races, and insulation levels, as seen below.

The energy transition toward renewables like solar has offered price stability, amid record solar and storage growth nationwide, but thus far energy-insecure communities have relatively been left behind. A recent Berkeley Lab report, Residential Solar-Adopter Income and Demographic Trends, indicates that even though the rate of solar adoption among low-income residents is increasing (from 5% in 2010 to 11% in 2021), that segment of energy consumers remains under-represented among solar adopters, relative to its share of the population.

Community solar efforts

As such, the United States is targeting communities most impacted by energy costs that have not benefitted from the transition, highlighting “Energy Communities” that are eligible for an additional 10% tax credit through funds made possible by the Inflation Reduction Act.

Additionally, a push for community solar development is taking place nationwide to extend access to affordable solar energy to renters and other residents that aren’t able to leverage finances to invest in predictable, low-cost residential solar systems. The Biden Administration set a goal this year to sign up 5 million community solar households, achieving $1 billion in bill savings by 2025. The community solar model only represents about 8% of the total distributed solar capacity in the nation. This target would entail a jump from 3 GW installed capacity to 20 GW by the target year. The Department of Energy estimates community solar subscribers save an average of 20% on their bills.

California this year passed AB 2316, the Community Renewable Energy Act takes aim at four acute problems in the state’s power market: reliability amid rising outage risks, rates, climate and equity. The law creates a community renewable energy program, including community solar-plus-storage, supported by cheaper batteries, to overcome access barriers for nearly half of Californians who rent or have low incomes. Community solar typically involves customers subscribing to an off-site solar facility, receiving a utility bill credit for the power it generates.

“Community renewable energy is a proven powerful tool to help close California’s clean energy gap, bringing much needed relief to millions struggling with high housing costs and utility debt,” said Alexis Sutterman, energy equity program manager at the California Environmental Justice Alliance.

The program has energy equity baked into its structure, working to make sure Californians of all income levels participate in the benefits of the energy transition. Not only does it open solar access to renters, the law ensures that at least 51% of subscribers are low-income customers, which is expected to make projects eligible for a 10% tax credit adder under the IRA.

“The money’s on the table now,” said Jeff Cramer, president and chief executive of the Coalition for Community Solar Access. “While there are groups pushing for solar access for all, and states with strong legislation, there are other pockets of interest in surprising places in the United States. For example, Louisiana has no policy for community solar or support for low-income residents going solar but the city of New Orleans has its own utility commission with a community solar program. In Nebraska, forward-looking co-operatives have created community solar projects.

Community solar markets are active in 22 states, with more expected to come online in the future as states pursue 100% clean energy targets across the country. However, the market is expected to require strong community outreach efforts to foster trust and gain subscribers.

“There is a distrust of community solar initially in LMI communities as many have been burned before by retail energy false promises,” said Eric LaMora, executive director, community solar, Nautilus Solar on a panel at the Solar Energy Industries Association Finance, Tax, and Buyers seminar. “People are suspicious but there really are no hooks with community solar.”

LMI residents are leery to provide tax records or much documents at all in order to sign up for community solar, LaMora said. “We were surprised to see less of a default rate with LMI residents. We attribute this to the fact that they see significant savings on their electric bill, making it easier to pay each month,” he said.

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Duke Energy Smart Meters enable remote meter reading, daily energy usage data, and two-way outage detection via AMI, with encrypted data, faster restoration, and remote connect/disconnect for Indiana customers in Howard County.

Key Points

Advanced meters that support remote readings, daily usage insights, two-way outage detection, and secure, encrypted data.

✅ Daily energy usage available online the next day

✅ Two-way communications speed outage detection and restoration

✅ Remote connect/disconnect; manual reads optional with opt-out fee

Say goodbye to your neighborhood meter reader. Say hello to your new smart meter.

Over the next three months, Duke Energy will install nearly 43,000 new high-tech electric meters for Howard County customers that will allow the utility company to remotely access meters via the digital grid instead of sending out employees to a homeowner's property for walk-by readings.

That means there's no need to estimate bills when meters can't be easily accessed, such as during severe weather or winter storms.

Other counties serviced by Duke Energy slated to receive the meters include Miami, Tipton, Cass and Carroll counties.

Angeline Protogere, Duke Energy's lead communication consultant, said besides saving the company money and manpower, the new smart meters come with a host of benefits for customers enabled by smart grid solutions today.

The meters are capable of capturing daily energy usage data, which is available online the next day. Having this information available on a daily basis can help customers make smarter energy decisions and support customer analytics that avoid billing surprises at the end of the month, she said.

"The real advantage is for the consumer, because they can track their energy usage and adjust their usage before the bills come," Protogere said.

When it comes to power outages, the meters are capable of two-way communications. That allows the company to know more about an outage through synchrophasor monitoring, which can help speed up restoration. However, customers will still need to notify Duke Energy if their power goes out.

If a customer is moving, they don't have to wait for a Duke Energy representative to come to the premises to connect or disconnect the energy service because requests can be performed remotely.

Protogere said when it comes to installing the meters, the changeover takes less than 5 minutes to complete. Customers should receive advance notices from the company, but the technician also will knock on the door to let the customer know they are there.

If no one is available and the meter is safely accessible, the technician will go ahead and change out the meter, Protogere said. There will be a momentary outage between the time the old meter is removed and the new meter is installed.

Kokomo and the surrounding areas are one of the last parts of the state to receive Duke Energy's new, high-tech meters, which are commonly used by other utility companies and in smart city initiatives across the U.S.

Protogere said statewide, the company started installing smart meters in August 2016 as utilities deploy digital transformer stations to modernize the grid. To date, they have installed 694,000 of the 854,000 they have planned for the state.

The company says the information stored and transmitted on the smart meters is safe, protected and confidential. Duke Energy said on its website that it does not share data with anyone without customers' authorization. The information coming from the meters is encrypted and protected from the moment it is collected until the moment it is purged, the company said.

Digital smart meter technology uses radio frequency bands that have been used for many years in devices such as baby monitors and medical monitors. The radio signals are far below the levels emitted by common household appliances and electronics, including cellphones and microwave ovens.

According to the World Health Organization, FCC, U.S. Food and Drug Administration and Electric Power Research Institute, no adverse health effects have been shown to occur from the radio frequency signals produced by smart meters or other such wireless networks.

However, customers can still opt-out of getting a smart meter and continue to have their meter manually read.

Those who choose not to get a smart meter must pay a $75 initial opt-out fee and an additional $17.50 monthly meter reading charge per account.

If smart meters have not yet been installed, Duke Energy will waive the $75 initial opt-out fee if customers notify the company they want to opt out within 21 days of receiving the installation postcard notice.

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