Tag Archives: engineering

Earth Day, Sustainable Energy

A ‘100% renewables’ target might not mean what you think it means. An energy expert explains

In the global effort to transition from fossil fuels to clean energy, achieving a “100% renewables” electricity system is considered ideal.

Some Australian states have committed to 100% renewable energy targets, or even 200% renewable energy targets. But this doesn’t mean their electricity is, or will be, emissions free.

Electricity is responsible for a third of Australia’s emissions, and making it cleaner is a key way to reduce emissions in other sectors that rely on it, such as transport.

So it’s important we have clarity about where our electricity comes from, and how emissions-intensive it is. Let’s look at what 100% renewables actually implies in detail.

Is 100% renewables realistic?

Achieving 100% renewables is one way of eliminating emissions from the electricity sector.

It’s commonly interpreted to mean all electricity must be generated from renewable sources. These sources usually include solar, wind, hydro, and geothermal, and exclude nuclear energy and fossil fuels with carbon capture and storage.

But this is a very difficult feat for individual states and territories to try to achieve.

The term “net 100% renewables” more accurately describes what some jurisdictions — such as South Australia and the ACT — are targeting, whether or not they’ve explicitly said so.

These targets don’t require that all electricity people use within the jurisdiction come from renewable sources. Some might come from coal or gas-fired generation, but the government offsets this amount by making or buying an equivalent amount of renewable electricity.

A net 100% renewables target allows a state to spruik its green credentials without needing to worry about the reliability implications of being totally self-reliant on renewable power.

So how does ‘net’ 100% renewables work?

All east coast states are connected to the National Electricity Market (NEM) — a system that allows electricity to be generated, used and shared across borders. This means individual states can achieve “net 100% renewables” without the renewable generation needing to occur when or where the electricity is required.

Take the ACT, for example, which has used net 100% renewable electricity since October 2019.

The ACT government buys renewable energy from generators outside the territory, which is then mostly used in other states, such as Victoria and South Australia. Meanwhile, people living in ACT rely on power from NSW that’s not emissions-free, because it largely comes from coal-fired power stations.

This way, the ACT government can claim net 100% renewables because it’s offsetting the non-renewable energy its residents use with the clean energy it’s paid for elsewhere.

SA’s target is to reach net 100% renewables by the 2030s. Unlike the ACT, it plans to generate renewable electricity locally, equal to 100% of its annual demand.

At times, such as especially sunny days, some of that electricity will be exported to other states. At other times, such as when the wind drops off, SA may need to rely on electricity imports from other states, which probably won’t come from all-renewable sources.

So what happens if all states commit to net 100% renewable energy targets? Then, the National Electricity Market will have a de-facto 100% renewable energy target — no “net”.

That’s because the market is one entire system, so its only options are “100% renewables” (implying zero emissions), or “less than 100% renewables”. The “net” factor doesn’t come into it, because there’s no other part of the grid for it to buy from or sell to.

How do you get to “200% renewables”, or more?

It’s mathematically impossible for more than 100% of the electricity used in the NEM to come from renewable sources: 100% is the limit.

Any target of more than 100% renewables is a different calculation. The target is no longer a measure of renewable generation versus all generation, but renewable generation versus today’s demand.

Australia could generate several times more renewable energy than there is demand today, but still use a small and declining amount of fossil fuels during rare weather events. Shutterstock

Tasmania, for example, has legislated a target of 200% renewable energy by 2040. This means it wants to produce twice as much renewable electricity as it consumes today.

But this doesn’t necessarily imply all electricity consumed in Tasmania will be renewable. For example, it may continue to import some non-renewable power from Victoria at times, such as during droughts when Tasmania’s hydro dams are constrained. It may even need to burn a small amount of gas as a backup.

This means the 200% renewable energy target is really a “net 200% renewables” target.

Meanwhile, the Greens are campaigning for 700% renewables. This, too, is based on today’s electricity demand.

In the future, demand could be much higher due to electrifying our transport, switching appliances from gas to electricity, and potentially exporting energy-intensive, renewable commodities such as green hydrogen or ammonia.

Targeting net-zero emissions

These “more than 100% renewables” targets set by individual jurisdictions don’t necessarily imply all electricity Australians use will be emissions free.

It’s possible — and potentially more economical — that we would meet almost all of this additional future demand with renewable energy, but keep some gas or diesel capacity as a low-cost backstop.

This would ensure continued electricity supply during rare, sustained periods of low wind, low sun, and high demand, such as during a cloudy, windless week in winter.

The energy transition is harder near the end — each percentage point between 90% and 100% renewables is more expensive to achieve than the previous.

That’s why, in a recent report from the Grattan Institute, we recommended governments pursue net-zero emissions in the electricity sector first, rather than setting 100% renewables targets today.

For example, buying carbon credits to offset the small amount of emissions produced in a 90% renewable NEM is likely to be cheaper in the medium term than building enough energy storage — such as batteries or pumped hydro dams — to backup wind and solar at all times.

The bottom line is governments and companies must say what they mean and mean what they say when announcing targets. It’s the responsibility of media and pundits to take care when interpreting them.

This article is by James Ha, Associate, Grattan Institute and republished from The Conversation under a Creative Commons license. Read the original article.

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Climate Solutions, News, Observation

Offshore wind farms could help capture carbon from air and store it long-term – using energy that would otherwise go to waste

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Off the Massachusetts and New York coasts, developers are preparing to build the United States’ first federally approved utility-scale offshore wind farms – 74 turbines in all that could power 470,000 homes. More than a dozen other offshore wind projects are awaiting approval along the Eastern Seaboard.

By 2030, the Biden administration’s goal is to have 30 gigawatts of offshore wind energy flowing, enough to power more than 10 million homes.

Replacing fossil fuel-based energy with clean energy like wind power is essential to holding off the worsening effects of climate change. But that transition isn’t happening fast enough to stop global warming. Human activities have pumped so much carbon dioxide into the atmosphere that we will also have to remove carbon dioxide from the air and lock it away permanently.

Offshore wind farms are uniquely positioned to do both – and save money.

Most renewable energy lease areas off the Atlantic Coast are near the Mid-Atlantic states and Massachusetts. About 480,000 acres of the New York Bight is scheduled to be auctioned for wind farms in February 2022. BOEM

As a marine geophysicist, I have been exploring the potential for pairing wind turbines with technology that captures carbon dioxide directly from the air and stores it in natural reservoirs under the ocean. Built together, these technologies could reduce the energy costs of carbon capture and minimize the need for onshore pipelines, reducing impacts on the environment.

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Capturing CO2 from the air

Several research groups and tech startups are testing direct air capture devices that can pull carbon dioxide directly from the atmosphere. The technology works, but the early projects so far are expensive and energy intensive.

The systems use filters or liquid solutions that capture CO2 from air blown across them. Once the filters are full, electricity and heat are needed to release the carbon dioxide and restart the capture cycle.

For the process to achieve net negative emissions, the energy source must be carbon-free.

The world’s largest active direct air capture plant operating today does this by using waste heat and renewable energy. The plant, in Iceland, then pumps its captured carbon dioxide into the underlying basalt rock, where the CO2 reacts with the basalt and calcifies, turning to solid mineral.

A similar process could be created with offshore wind turbines.

If direct air capture systems were built alongside offshore wind turbines, they would have an immediate source of clean energy from excess wind power and could pipe captured carbon dioxide directly to storage beneath the sea floor below, reducing the need for extensive pipeline systems.

Researchers are currently studying how these systems function under marine conditions. Direct air capture is only beginning to be deployed on land, and the technology likely would have to be modified for the harsh ocean environment. But planning should start now so wind power projects are positioned to take advantage of carbon storage sites and designed so the platforms, sub-sea infrastructure and cabled networks can be shared.

Using excess wind power when it isn’t needed

By nature, wind energy is intermittent. Demand for energy also varies. When the wind can produce more power than is needed, production is curtailed and electricity that could be used is lost.

That unused power could instead be used to remove carbon from the air and lock it away.

For example, New York State’s goal is to have 9 gigawatts of offshore wind power by 2035. Those 9 gigawatts would be expected to deliver 27.5 terawatt-hours of electricity per year.

Based on historical wind curtailment rates in the U.S., a surplus of 825 megawatt-hours of electrical energy per year may be expected as offshore wind farms expand to meet this goal. Assuming direct air capture’s efficiency continues to improve and reaches commercial targets, this surplus energy could be used to capture and store upwards of 0.5 million tons of CO2 per year.

That’s if the system only used surplus energy that would have gone to waste. If it used more wind power, its carbon capture and storage potential would increase.

Several Mid-Atlantic areas being leased for offshore wind farms also have potential for carbon storage beneath the seafloor. The capacity is measured in millions of metric tons of CO2 per square kilometer. The U.S. produces about 4.5 billion metric tons of CO2 from energy per year. U.S. Department of Energy and Battelle

The Intergovernmental Panel on Climate Change has projected that 100 to 1,000 gigatons of carbon dioxide will have to be removed from the atmosphere over the century to keep global warming under 1.5 degrees Celsius (2.7 Fahrenheit) compared to pre-industrial levels.

Researchers have estimated that sub-seafloor geological formations adjacent to the offshore wind developments planned on the U.S. East Coast have the capacity to store more than 500 gigatons of CO2. Basalt rocks are likely to exist in a string of buried basins across this area too, adding even more storage capacity and enabling CO2 to react with the basalt and solidify over time, though geotechnical surveys have not yet tested these deposits.

Planning both at once saves time and cost

New wind farms built with direct air capture could deliver renewable power to the grid and provide surplus power for carbon capture and storage, optimizing this massive investment for a direct climate benefit.

But it will require planning that starts well in advance of construction. Launching the marine geophysical surveys, environmental monitoring requirements and approval processes for both wind power and storage together can save time, avoid conflicts and improve environmental stewardship.

Originally published on The Conversation by David Goldberg, Lamont Research Professor, Columbia University and republished under a Creative Commons license. Read the original article.

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News, Observation, Politics, Science

Nuclear fusion hit a milestone thanks to better reactor walls – this engineering advance is building toward reactors of the future

Scientists at a laboratory in England have shattered the record for the amount of energy produced during a controlled, sustained fusion reaction. The production of 59 megajoules of energy over five seconds at the Joint European Torus – or JET – experiment in England has been called “a breakthrough” by some news outlets and caused quite a lot of excitement among physicists. But a common line regarding fusion electricity production is that it is “always 20 years away.”

photo collage / Lynxotic / adobe stock

We are a nuclear physicist and a nuclear engineer who study how to develop controlled nuclear fusion for the purpose of generating electricity.

The JET result demonstrates remarkable advancements in the understanding of the physics of fusion. But just as importantly, it shows that the new materials used to construct the inner walls of the fusion reactor worked as intended. The fact that the new wall construction performed as well as it did is what separates these results from previous milestones and elevates magnetic fusion from a dream toward a reality.

Fusing particles together

Nuclear fusion is the merging of two atomic nuclei into one compound nucleus. This nucleus then breaks apart and releases energy in the form of new atoms and particles that speed away from the reaction. A fusion power plant would capture the escaping particles and use their energy to generate electricity.

There are a few different ways to safely control fusion on Earth. Our research focuses on the approach taken by JET – using powerful magnetic fields to confine atoms until they are heated to a high enough temperature for them to fuse.

The fuel for current and future reactors are two different isotopes of hydrogen – meaning they have the one proton, but different numbers of neutrons – called deuterium and tritium. Normal hydrogen has one proton and no neutrons in its nucleus. Deuterium has one proton and one neutron while tritium has one proton and two neutrons.

For a fusion reaction to be successful, the fuel atoms must first become so hot that the electrons break free from the nuclei. This creates plasma – a collection of positive ions and electrons. You then need to keep heating that plasma until it reaches a temperature over 200 million degrees Fahrenheit (100 million Celsius). This plasma must then be kept in a confined space at high densities for a long enough period of time for the fuel atoms to collide into each other and fuse together.

To control fusion on Earth, researchers developed donut-shaped devices – called tokamaks – which use magnetic fields to contain the plasma. Magnetic field lines wrapping around the inside of the donut act like train tracks that the ions and electrons follow. By injecting energy into the plasma and heating it up, it is possible to accelerate the fuel particles to such high speeds that when they collide, instead of bouncing off each other, the fuel nuclei fuse together. When this happens, they release energy, primarily in the form of fast-moving neutrons.

During the fusion process, fuel particles gradually drift away from the hot, dense core and eventually collide with the inner wall of the fusion vessel. To prevent the walls from degrading due to these collisions – which in turn also contaminates the fusion fuel – reactors are built so that they channel the wayward particles toward a heavily armored chamber called the divertor. This pumps out the diverted particles and removes any excess heat to protect the tokamak.

The walls are important

A major limitation of past reactors has been the fact that divertors can’t survive the constant particle bombardment for more than a few seconds. To make fusion power work commercially, engineers need to build a tokamak vessel that will survive for years of use under the conditions necessary for fusion.

The divertor wall is the first consideration. Though the fuel particles are much cooler when they reach the divertor, they still have enough energy to knock atoms loose from the wall material of the divertor when they collide with it. Previously, JET’s divertor had a wall made of graphite, but graphite absorbs and traps too much of the fuel for practical use.

Around 2011, engineers at JET upgraded the divertor and inner vessel walls to tungsten. Tungsten was chosen in part because it has the highest melting point of any metal – an extremely important trait when the divertor is likely to experience heat loads nearly 10 times higher than the nose cone of a space shuttle reentering the Earth’s atmosphere. The inner vessel wall of the tokamak was upgraded from graphite to beryllium. Beryllium has excellent thermal and mechanical properties for a fusion reactor – it absorbs less fuel than graphite but can still withstand the high temperatures.

The energy JET produced was what made the headlines, but we’d argue it is in fact the use of the new wall materials which make the experiment truly impressive because future devices will need these more robust walls to operate at high power for even longer periods of time. JET is a successful proof of concept for how to build the next generation of fusion reactors.

The next fusion reactors

The JET tokamak is the largest and most advanced magnetic fusion reactor currently operating. But the next generation of reactors is already in the works, most notably the ITER experiment, set to begin operations in 2027. ITER – which is Latin for “the way” – is under construction in France and funded and directed by an international organization that includes the U.S.

ITER is going to put to use many of the material advances JET showed to be viable. But there are also some key differences. First, ITER is massive. The fusion chamber is 37 feet (11.4 meters) tall and 63 feet (19.4 meters) around – more than eight times larger than JET. In addition, ITER will utilize superconducting magnets capable of producing stronger magnetic fields for longer periods of time compared to JET’s magnets. With these upgrades, ITER is expected to smash JET’s fusion records – both for energy output and how long the reaction will run.

ITER is also expected to do something central to the idea of a fusion powerplant: produce more energy than it takes to heat the fuel. Models predict that ITER will produce around 500 megawatts of power continuously for 400 seconds while only consuming 50 MW of energy to heat the fuel. This mean the reactor produced 10 times more energy than it consumed – a huge improvement over JET, which required roughly three times more energy to heat the fuel than it produced for its recent 59 megajoule record.

JET’s recent record has shown that years of research in plasma physics and materials science have paid off and brought scientists to the doorstep of harnessing fusion for power generation. ITER will provide an enormous leap forward toward the goal of industrial scale fusion power plants.

[You’re smart and curious about the world. So are The Conversation’s authors and editors. You can read us daily by subscribing to our newsletter.]

David Donovan, Associate Professor of Nuclear Engineering, University of Tennessee and Livia Casali, Assistant Professor of Nuclear Engineering, University of Tennessee

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Accessories, Apple, Apple Watch, Tech

Apple is paving the way in Wearable Health Tech: Blood-Pressure Monitor and Thermometer in the Works

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New features in the pipeline along with the new iteration of the hit timepiece

The next version of the Apple Watch  (Series 7) is expected to be released in the coming weeks, and the WSJ reported that the company is currently working on additional health-related features and improvements for the smartwatch. While it is not certain that these to be included in Series 7, there is no doubt that they are coming, either as a software or hardware update.

Apple is already known for many of its current health conscious features, including the well known Exercise rings and Fitness App, as well as the ability to check your heart rate for irregularity with its electrocardiogram and check your Blood Oxygen levels with a Series 6.

One of the new capabilities that may be coming to your Apple Watch will include measuring blood-pressure which would prompt a user when their BP levels are too high (or increasing in rate). This can influence behavior, diet or give you a warning to seek medical attention is the reading is extreme, for example.

When Apple does roll out this feature, it could be a game changer (or rather a life-saver), as hundreds of millions of Americans suffer from high blood pressure and / or hypertension. The condition leads to almost half a million deaths a year according to the Centers for Disease Control and Prevention.  

Another feature said to be in the works is targeted towards females, a thermometer to help with fertility planning. Bloomberg also reported earlier of Apple’s additional health goals to add blood-sugar sensors to help those with diabetes monitor glucose levels. 

A useful, even sometimes addictive health aid, which is a good thing

Those who have an Apple Watch can likely attest to its effectiveness in promoting health and well being, particularly around exercise and weight control. The recent addition of of medical features, that in some cases have directly contributed to lives being saved, appear to be a high priority at the giant tech company.

Although it is tantalizing to speculate on the incredible features yet to be added to the device, it will take time for the technological innovations and solutions to be developed in order to make these possible.

Apple has some very ambitious improvements they want to add to its Watch, however there is no official timeline that has been announced and most likely will not be expected before 2022. 

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News, Science, Videos

NASA shares the Perseverance Rover’s epic arrival on Mars: video landing and even audio

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Above: Photo / NASA

Never before seen footage of rover descended through the Martian atmosphere 

Courtesy of NASA, now everyone can see firsthand how the Perseverance Mars Rover landed on the red planet. Launch in July of 2020 it reached it final destination on Thursday, February 18, 2021, at the landing site in Jezero Crater. 

https://video.twimg.com/amplify_video/1363899413450661899/vid/1280x720/n65fnFHX0GTEt5Mb.mp4?tag=13

The video of the landing has already provided what were, undoubtedly, some of the most iconic visuals we have seen in the history of space exploration.  Yet the Perseverance is only just getting started as its primary mission will be to search for signs of life (or rather to find out if remnants of past microbial life prove that it ever existed). 

Jezero Crater / NASA

In a press conference,  Michael Watkins the director of NASA’s Jet Propulsion Laboratory said: 

“This is the first time we’ve been able to actually capture an event like the landing of a spacecraft on Mars,” he continued,  “We will learn something by looking at the performance of the vehicle in these videos. But a lot of it is also to bring you along on our journey, our touchdown to Mars, and of course, our surface mission as well. These are really amazing videos.”

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In addition to the impressive photos that the cameras on the Mars rover has taken thus far, it also was equipped with two microphones that was able to capture the sounds of the wind blowing on the surface of Mars that you can listen to via soundcloud. 

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