Virtually all wind turbines, which produce more than 5 percent of the world’s electricity, are controlled as if they were individual, free-standing units. In fact, the vast majority are part of larger wind farm installations involving dozens or even hundreds of turbines, whose wakes can affect each other.

Now, engineers at MIT and elsewhere have found that, with no need for any new investment in equipment, the energy output of such wind farm installations can be increased by modeling the wind flow of the entire collection of turbines and optimizing the control of individual units accordingly.

The increase in energy output from a given installation may seem modest—it’s about 1.2 percent overall, and 3 percent for optimal wind speeds. But the algorithm can be deployed at any wind farm, and the number of wind farms is rapidly growing to meet accelerated climate goals. If that 1.2 percent energy increase were applied to all the world’s existing wind farms, it would be the equivalent of adding more than 3,600 new wind turbines, or enough to power about 3 million homes, and a total gain to power producers of almost a billion dollars per year, the researchers say. And all of this for essentially no cost.

[…]

“Essentially all existing utility-scale turbines are controlled ‘greedily’ and independently,” says Howland. The term “greedily,” he explains, refers to the fact that they are controlled to maximize only their own power production, as if they were isolated units with no detrimental impact on neighboring turbines.

But in the real world, turbines are deliberately spaced close together in wind farms to achieve economic benefits related to land use (on- or offshore) and to infrastructure such as access roads and transmission lines. This proximity means that turbines are often strongly affected by the turbulent wakes produced by others that are upwind from them—a factor that individual turbine-control systems do not currently take into account.

[…]

a new flow model which predicts the power production of each turbine in the farm depending on the incident winds in the atmosphere and the control strategy of each turbine. While based on flow-physics, the model learns from operational wind farm data to reduce predictive error and uncertainty. Without changing anything about the physical turbine locations and hardware systems of existing wind farms, they have used the physics-based, data-assisted modeling of the flow within the wind farm and the resulting power production of each turbine, given different wind conditions, to find the optimal orientation for each turbine at a given moment. This allows them to maximize the output from the whole farm, not just the individual turbines.

[…]

In a months-long experiment in a real utility-scale wind farm in India, the predictive model was first validated by testing a wide range of yaw orientation strategies, most of which were intentionally suboptimal. By testing many control strategies, including suboptimal ones, in both the real farm and the model, the researchers could identify the true optimal strategy. Importantly, the model was able to predict the farm power production and the optimal control strategy for most wind conditions tested, giving confidence that the predictions of the model would track the true optimal operational strategy for the farm. This enables the use of the model to design the optimal control strategies for new wind conditions and new wind farms without needing to perform fresh calculations from scratch.

Then, a second months-long experiment at the same farm, which implemented only the optimal control predictions from the model, proved that the algorithm’s real-world effects could match the overall energy improvements seen in simulations. Averaged over the entire test period, the system achieved a 1.2 percent increase in energy output at all wind speeds, and a 3 percent increase at speeds between 6 and 8 meters per second (about 13 to 18 miles per hour).

[…]

Source: A new method boosts wind farms’ energy output, without new equipment

“Switch to solar panels to help save the planet,” they say.

And they’re (mostly) right. Solar panels are a great source of clean energy because, unlike fossil fuels, solar energy doesn’t produce harmful carbon emissions while creating electricity. But how “clean” is the process of creating solar panels?

Ironically enough, solar panel production is reliant on fossil fuels. It also involves mining for precious metals, which contributes to greenhouse gasses and pollution.

Before we explore the extent of it, we want to be clear that we’re not here to tear down the use of solar panels. EcoWatch is a huge fan of solar energy and has helped hundreds of homeowners reduce their carbon emissions by going solar. But we want to be transparent about the impact that solar panels have on the environment — both good and bad.

The Carbon Footprint of a Solar Panel

While solar panels are an environmentally friendly energy solution, the materials and manufacturing process used to create them do have a decent-sized carbon footprint, as they involve mining, melting and cooling to be used.

Environmental Impact of Mining for Solar Panel Materials

Most solar cells are made up of silicon semiconductors and glass, as well as metals like silver, copper, indium and tellurium. And if we’re including solar batteries, add lithium to the list.

When it comes to environmental impact, gathering silicon and glass are both non-issues, as they’re abundant and non-toxic. However, the process of mining for those metals creates greenhouse gas emissions and can lead to soil, water and air pollution.¹

Environmental Impact of Solar Panel Facilities

First thing to consider: Solar facilities are massive. It’s safe to assume that, in most cases, some wildlife and recreation land has been cleared to create solar panel production facilities.

Solar panel facilities also require a lot of energy to keep up and running, and unfortunately, a lot of the energy used for melting down silicon comes from coal burning, especially in China where pollution emissions are already high.²

There’s also a great need for water for the cooling process, which can be an environmental strain in more arid areas where water isn’t as available. And like any big production facility, solar panel production facilities cause air pollution.

Environmental Impact of Solar Panel Manufacturing

There are three different types of solar panels — monocrystalline, polycrystalline and thin-film — and each are manufactured differently, meaning they each leave a different sized carbon footprint.

Manufacturing Monocrystalline Panels

Monocrystalline panels are the most common and have the highest energy conversion efficiency, typically ranging between 19 and 22%. Monocrystalline solar panels are made of pure, single-cell silicon crystals wedged between thin glass.

To make a monocrystalline solar panel, a huge piece of silicon is molded into a block, then cut into small wafers to be affixed onto a solar panel. It’s a complex process and, therefore, produces the highest emissions compared to any other solar panel manufacturing method.³

Manufacturing Polycrystalline Panels

Polycrystalline solar panels are also made of silicon, but instead of coming from a block, the silicon crystals are melted together and then placed onto the panel. Because of the melting process, polycrystalline solar panels do require a bit of electricity to create, although not as much as monocrystalline.⁴

Manufacturing Thin-Film Panels

Lastly, you have thin-film solar panels, which can be made from several different types of materials, like amorphous silicon, cadmium telluride (a type of silicon) or copper indium gallium selenide. T

ypically, thin-film solar panels are going to leave a smaller carbon footprint compared to their more popular counterparts.⁵ But on the downside, they’re created from extremely toxic materials that can lead to both human and environmental harm if not handled properly.⁶

Environmental Impact of Transporting Solar Panels

Emissions from solar panel transportation present another challenge. Solar panels are produced all over the world, but primarily in China, followed by the U.S. and Europe. And solar panels that are produced in one country may require shipments of parts from another.

To be honest, it’s hard to say exactly how big the carbon footprint is for each stage of making a solar panel — no matter which type. There hasn’t been much research or data released on the environmental impact of solar panel production. However, the Coalition on Materials Research Transparency is reportedly working to measure and report the carbon impacts associated with mining, producing and transporting solar panels.

It’s important to note that the amount of carbon emissions produced to create solar panels is still nowhere near that of traditional energy facilities, and it is quite small when compared to oil drilling, fracking or coal mining.⁷

But production aside, another common challenge surrounding solar panels is what happens after their average 25-year lifespan.

A Larger Issue: Solar Panel Recycling

The Solar Energy Industries Association (SEIA) set a target for solar energy to account for 30% of energy generation in the U.S. by 2030.⁸ If that target is hit, more than 1 billion solar panels will be actively collecting solar energy throughout the U.S. alone over the next decade.

While this is great news for reducing carbon emissions, it brings up a larger issue the solar industry hasn’t quite nailed down yet: solar panel recycling.

Scientists have been working on a better solution, but as of now, there isn’t a flushed-out system to recycle old solar panels. And there certainly aren’t enough places to do it.

As mentioned earlier, solar panels are made up of a lot of precious metals, and the carbon footprint of producing solar panels could be reduced if these materials could be recycled and repurposed instead of having to mine for more. Instead, lack of solar panel recycling availability is only creating more e-waste, which could eventually lead to solar panel material scarcity.

How Much Better is Solar for the Environment?

We’ve discussed all the ways in which solar panels can be harmful to the environment, but let’s not forget that they’re still a far better option than non-renewable energy alternatives.

Taking the carbon footprint of solar panels into account, one study still found that coal generates a footprint 18 times the size, while natural gas creates an emissions footprint 13 times the size of solar.⁹ It’s also worth repeating that solar energy produces zero emissions after production. For that reason alone, studies have revealed solar to be an essential solution to slowing climate change.¹⁰

But if solar continues to grow as the SEIA predicts it will, technology will also need to improve to minimize the effects that solar panel production will have on the environment, and proper solar panel recycling methods must be created.

Source: The Environmental Impact of Solar Panels – EcoWatch

The aviation industry’s attempts to go green are getting a boost from an unlikely place: carbon-neutral jet fuel pulled from thin air.

That may seem far-fetched, but it’s a concept that engineers at the Swiss Federal Institute of Technology (ETH) have not only proved experimentally, but apparently proven again at scale. Even better, the fuel created by the process is allegedly a drop-in alternative to fossil-derived aviation fuel that can be used without changes to storage or distribution infrastructure.

Here’s how the system works:

Synthesizing kerosene pure enough to be used as jet fuel from thin air isn’t even a new concept. We know it can be formed from something called synthesis gas, or syngas, which is a mixture of hydrogen and carbon monoxide.

Crucially, the goal of this particular project is to produce a clean, carbon-neutral form of syngas that doesn’t create additional emissions. According to the researchers, the best way to do that is with solar energy.

For their test-scale unit, the researchers built an array of 169 sun-tracking reflectors that focus approximately 15kW of solar energy at a 16-inch aperture on a tower-mounted solar reactor. According to the researchers, the solar energy directed at the reactor “corresponds to an average solar concentration ratio of approximately 2,500 suns, with a peak above 4,000 suns.”

Inside the reactor, temperatures reach approximately 1,500°C (2,732°F), which is hot enough to split captured carbon dioxide and atmospheric water vapor to form syngas. As it cools, the syngas flows out of the reactor to a gas-to-liquid unit that processes it into kerosene.

According to the researchers, the syngas produced by the reactor has selectivity, purity, and quality high enough to make it suitable for Fischer–Tropsch synthesis, which turns liquid syngas made from hydrogen and carbon monoxide into hydrocarbons we can use to fly planes.

The system isn’t the most efficient – only managing a 4.1 percent solar-to-syngas efficiency. Still, project lead and ETH engineering professor Aldo Steinfeld told IEEE, 4.1 percent is a record for thermochemical fuel production.

The test-scale project didn’t use any heat capture technology, meaning that 4.1 percent record should be easily beaten. If heat capture technology were added to a future iteration of the facility, efficiency rates could reach as high as 20 percent, the researchers claimed.

Jet fuel that begins life as air and captured carbon, the researchers explained, is completely carbon-neutral because the fuel only produces as much carbon dioxide as went into its manufacturing.

[…]

Source: Pull jet fuel from thin air? We can do that, say scientists • The Register