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Big sewer pipes take all sewage to a place where it is treated. This place is called a sewage treatment plant. Flickr/Dean Hochman, CC BY-SA

This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

Where does my poo go when I flush the toilet? Does it go into the ocean? – Clancy, age 4, Austinmer, NSW.

When you press the flush button, your wee, poo, toilet paper and water go down a pipe called a sewer. The toilet flushes the wastes down the sewer pipe. The sewer pipe from your house also collects and removes other wastes. This might be soapy water from baths and showers, or water left over from washing dishes and clothes. Together, all of these wastes are called “sewage”. The pipes they travel through are called “sewerage pipes”. People sometimes get “sewage” and “sewerage” mixed up.

The wastes from your house flow downhill. They join those from other homes and flow into bigger sewer pipes. Some of these pipes are bigger than a bus! If you live in a big city the wastes from thousands of people looks like a river of sewage.

The big sewer pipes take all the sewage to a place where it is treated. This place is called a sewage treatment plant. All towns and cities have these. They are like a big factory where any harmful materials are removed. This is a very important part of our city life.

This video shows how a sewage treatment plant in England works. Flushing is fun, but there are some things you should never flush down the toilet – like baby wipes. Flickr/GoonSquadSarah, CC BY

Sewage contains lots of germs and if people come into contact with it, it can make them very sick. The treatment also removes things that people have flushed down the toilet. This includes things like toys, jewellery or even money. There are some things you should never flush down the toilet, like baby wipes – even if it says “flushable” on the packet – because they clump up and cause big problems for the sewerage system.

The sewage is cleaned in the treatment plant. This can take many days. It makes sure that harmful parts of the sewage are removed. Chemicals are added to kill as many germs as possible. Then the treated water is released into a local river or even the ocean. If you live near the coast your treated sewage probably goes into the ocean.

This is a bottle of recycled water from Singapore. It was made from treated sewage and is safe to drink. Flickr/Tristan Schmurr, CC BY

The treated sewage is cleaned to make sure that it does not cause environmental problems. This means that it should not harm the plants and fish that live in the river or ocean where it is released. If the sewage is not fully treated it can cause water pollution. It also should not make people sick if they swim in the river or ocean. Scientists test the water and the sewage wastes to make sure that it is OK.

Some treated sewage can be used to make energy or recycled to make water that can be used in factories or farms. Some countries, including parts of Australia, can even make water from treated sewage that is safe enough to drink. Singapore makes “recycled” drinking water out of treated sewage that is even purer than the level that the World Health Organisation (which is a group that makes a lot of suggestions about what’s healthy and what’s not) says is safe to drink.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:

* Email your question to curiouskids@theconversation.edu.au
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Please tell us your name, age and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.

Ian Wright does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

The total solar eclipse that captivated the United States this week was more than just a celestial spectacle (and a reminder to take care of your eyes). It was also a valuable lesson in how to manage electricity grids when a crucial generation source – solar power, in this case – goes temporarily offline.

The last total solar eclipse to pass over the US was in 1979, a year when President Jimmy Carter was in the midst of the energy crisis and struggling with ballooning oil prices. In response, he made a concerted shift to greater energy independence through alternative energy sources such as solar.

In 2017, almost the whole world is grappling with the transformation of the electricity industry and the move to renewable energy.

Read more: Scientist at work: why this meteorologist is eager for an eclipse.

Eclipses have – and always will have – a lot to teach us. While this eclipse did not cause major disruption to the US electricity network, it gave system operators a better understanding of how future intermittencies can be managed.

The path of the eclipse, shown relative to the positions of major US solar power installations. US Energy Information Administration

Despite the rapid decline and rebound in solar power output during the event, operators were able to manage without a hitch. Their thankless task reminds us of the importance of having resilient and robust electricity systems with sufficient backup capacity.

Solar plants lost around half of their ability to generate electricity during the two and a half hours of the eclipse, dipping and rising almost three times faster than the average rate at which power stations can ramp their output up and down. The shortfall was covered largely by gas-fired power plants, and extra hydro capacity.

California faced a particularly tough challenge because of its relatively high level of renewable energy; last year 10% of the state’s electricity came from solar photovoltaic (PV) power.

California’s solar output during the eclipse. California ISO

Given the recent scrutiny on Australia’s beleaguered electricity grid, it makes sense to ask how our power system would fare if faced with the same challenge. Take a walk through almost any suburb and you’ll see dozens of solar panels glinting from roofs. How much have they destabilised our grid? Would we pass the eclipse test?

System managers and market operators such as the Australian Energy Market Operator already intricately balance demand and supply levels throughout the day, and must deal with unexpected outages at power stations, extreme weather events (think of South Australia), and increasingly predict how the share of intermittent generation from renewable resources will be matched and secured.

According to the Clean Energy Council, Australian renewables provided 17% of the country’s electricity generation in 2016. In world terms that looks rather unimpressive. But this figure does not reflect the growing impact of behind-the-meter solar PV that is slowly but surely reducing reliance on grid electricity during the day.

As outlined in a previous FactCheck, Australia has the highest proportion of households with PV systems on their roof of any country in the world, at over 15%. (However our total energy produced from solar is somewhat less than Germany, Italy, Belgium and Japan, which have a propensity for larger systems).

Of course, all this distributed solar adds to the complexity for utilities and grid operators, and underpins why we have technical rules and connection standards to ensure that households connecting individual systems to the grid do not cause unintended consequences for local network areas. As the forecasts for rooftop solar installations continue to be revised upwards, AEMO nevertheless remains sanguine about the potential for grid disruption:

…it is technically feasible to integrate this amount of rooftop PV into the network over the forecast horizon, through a mix of market, network, and non-network (such as storage) solutions to address issues such as increasing variability in system demand, low daytime demand, and increased ramping at morning and afternoon electricity system peaks.

Utilities themselves are acutely aware of the “non-negotiable social contract of keeping the lights on”, as mused by Frank Tudor, chief executive of Western Australia’s regional utility Horizon Power, in an opinion piece written before the eclipse. The emboldened South Australian government may take further comfort in the fact that its newly minted 150-megawatt Aurora Solar Energy Project would come into its own during such weather interruptions (more often due to clouds than eclipses), with its capacity to store solar power in molten salt storage tanks, to be dispatched as required during peak periods.

Lean and green machines

The eclipse also underlines how crucial the innovations in technology and data analytics will be in ensuring that electricity grids can still operate seamlessly as the share of renewable energy grows.

We are seeing this already in many small, isolated power networks across the country, where microgrids, particularly in coastal tourist towns with a proclivity for clean technology, are already pushing the limits of hosting capacity and driving utilities to explore big data solutions to assist with the integration of increased levels of solar PV.

One such example is the sky camera trial being conducted in Carnarvon, Western Australia, that will track weather patterns and anticipate cloud cover to help with grid stability. The trial is using machine learning to help predict the impact of weather on the grid, and to balance the fluctuations with other energy sources, thus helping the network to withstand such events without losing reliability.

Read more: Five things the east coast can learn from WA about energy.

With our energy systems becoming ever more distributed and decentralised, the US eclipse provides another of nature’s lessons on the need to be smart about creating resilient networks.

The next total solar eclipse for Australia will be in 2028, and will pass straight over Sydney. In the meantime, a hybrid eclipse will cross Australia’s northwest in April 2023.

Time will tell how much of an impact these events will have on our power grids. But given the importance of electricity for our health, wealth, transport and so much more, let’s hope our system operators and policy makers aren’t blindsided.

Dev Tayal also works as a strategist for Horizon Power.

If so, Ford should prove there’s merit to its new scrapping scheme, writes Dr Kevin Bannon

As the motor car industry is at the forefront of environmental degradation both globally and locally, it is only right that manufacturers take a lead in tackling the problem (Ford launches £2,000 scrappage scheme, 22 August). Instead, they offer only a scheme to sell more cars based on an unproven theory. This appears to posit that the pollution created by running an “old” car is so much greater than that of running a “new” one, that an environmental disaster might be delayed if we buy new cars more quickly. If Ford will reveal their figures for this old/new pollution differential and compare them with an evaluation of the pollution created in manufacturing a brand-new vehicle, then we might establish whether or not they know what they are talking about.
Dr Kevin Bannon
London

• Join the debate – email guardian.letters@theguardian.com

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Former Marshall Islands minister Tony De Brum, who played a key role in securing the Paris pact passes away aged 72.

Two baby apes were discovered in tiny cages in Ketapang, Borneo. A man has been arrested for trafficking wildlife via social media

A UK charity has helped rescue two baby orangutans who were found by police in West Borneo caged and ready to be sold through social media to illegal buyers.

The two apes, a one-year-old male and an eight-month-old female, who were discovered in tiny cages are now in the care of International Animal Rescue (IAR) at its centre in Ketapang, Borneo.

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Australia Zoo has asked the public to name a white koala joey.

Scientists create bacteria covered in tiny solar panels that generate a potential new fuel from the Sun.

Research finds endangered Antarctic blue, fin and southern right whales struggling to recover despite hunting bans

Populations of the endangered blue and fin whales, which were hunted nearly to extinction in the 20th century, will not have recovered to even half of their pre-whaling numbers by 2100, according to a new Australian study.

The research, published in the Fish and Fisheries journal next month, analysed 122 years of whaling data from the International Whaling Commission (IWC) and current population survey data to project future population growth, based on predicted food availability in the southern oceans.

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Find out when you can next witness a solar eclipse in your country with our eclipse calculator.

Nadya Peek/Flickr, CC BY-SA

The next stage of humanity’s fight to reduce greenhouse emissions may revolve around seaweed, according to tonight’s episode of ABC’s Catalyst, presented by Professor Tim Flannery, which asks the question “can seaweed save the world?”

With the help of me and colleagues around the world, the documentary explores seaweed’s enormous potential to reduce greenhouse gases and draw CO₂ out of the atmosphere. In the case of seaweed, that could include giant kelp farms that de-acidify oceans, or feeding algae to cattle and sheep to dramatically reduce their methane emissions.

Read more: How farming giant seaweed can feed fish and fix the climate

But while these possibilities are exciting, early adopters are dealing with unproven technology and complex international treaties. Globally, emissions are likely to keep rising, which means seaweed-related carbon capture should only be one part of a bigger emissions reduction picture.

Net negative emissions

To stay within the Paris climate agreement’s 2℃ warming threshold, most experts agree that we must remove carbon from the atmosphere as well as reduce emissions. Many scientists now argue that 2℃ will still cause dangerous climate change, and an upper limit of 1.5℃ warming by 2100 is much safer.

To achieve that goal, humanity must begin reducing global emissions from 2020 (in less time than it takes an undergrad enrolling now to finish their degree) and rapidly decarbonise to zero net emissions by 2050.

Read more: We need to get rid of carbon in the atmosphere, not just reduce emissions

Zero net carbon emissions can come from radical emissions reductions, and massive geoengineering projects. But it could be vastly helped by what Flannery calls “the third way”: mimicking or strengthening Earth’s own methods of carbon capture.

Studies support the need to remove carbon from the atmosphere, but there are serious technical, economic and political issues with many large-scale plans.

On the other hand, seaweed solutions could be put to work in the biologically desert-like “doldrums” of the ocean, and have positive side effects such as helping to clear up the giant ocean rubbish patches. However, there are many technical problems still to be solved to make this a reality.

We probably haven’t reached peak emissions

Removing carbon from the atmosphere is an attractive proposition, but we can’t ignore the emissions we’re currently pumping out. For any negative emissions technology to work, our global emissions from fossil fuels must start to drop significantly, and very soon.

But wait a second, haven’t we already hit peak emissions? It’s true that for the third year in a row, global carbon dioxide emissions from fossil fuels and industry have barely grown, while the global economy has continued to grow strongly.

This is great news, but the slowdown in emissions growth has been driven primarily by China, alongside the United States, and a general decline of emissions in developed countries.

China’s reductions are impressive. The country peaked in coal consumption in 2014, and tends to under-promise and over-deliver on emissions reductions. However, under the Paris agreement, China has committed to a 60-65% reduction in emissions intensity, which means there’s still room for them to rise in the future.

India’s emissions, on the other hand, are major wild card. With a population of 1.3 billion and rising, about 300 million of whom are still not connected to an electrical grid, and potential increases in coal use to provide energy, India will be vital to stabilising greenhouse gases.

Read more: To slow climate change, India joins the renewable energy revolution

India’s emissions today match those of China in 1990. A study that combined India’s Paris agreement targets with OECD estimates about its long-term economic growth, suggested India’s CO₂ emissions could still grow significantly by 2030 (although per capita emissions would still be well below China and the US).

The emissions reduction relay race

So how do we deal with many competing and interconnected issues? Ideally, we need an array of solutions, with complementary waves of technology handling different problems.

Clearly the first wave, the clean energy transition, is well under way. Solar installations are breaking records, with an extra 75 gigawatts added to our global capacity in 2016, up from 51 gigawatts installed in 2015. But this still represents just 1.8% of total global electricity demand.

In addition to renewable energy generation, limiting warming to below 1.5°C also means we must increase the efficiency of our existing grid. Fortunately, early-stage financiers and entrepreneurs are focusing on a second wave of smart energy, which includes efficiency and optimisation technologies. Others in Australia have also noted the opportunities offered by the increasing use of using small, smart devices connected to the internet that respond to user demand.

Although early user results have been mixed, research shows better system control reduces the emissions intensity of energy generation. These energy efficient devices and optimisation software are on the cusp of becoming widely commercially available.

Critically, these efficiency technologies will be needed to complement structural change in the fossil fuel energy mix. This is especially in places where emissions are set to grow significantly, like India. Building renewable energy capacity, optimising with new software and technologies, and better understanding the opportunity for net negative emissions all play an important part in the emissions reductions relay race over the next 50 years to get us to 1.5°C.

With further research, development, and commercialisation, the possibilities offered by seaweed – outlined in more detail in the Catalyst documentary – are potentially game-changing.

But, as we saw with the development of renewable energy generation technology, it takes a long time to move from a good idea to wide implementation. We must support the scientists and entrepreneurs exploring zero-carbon innovations – and see if seaweed really can save the world.

Can Seaweed Save the World? airs on the ABC on Tuesday 22 August at 8.30pm.

Adam Bumpus receives funding from the University of Melbourne Faculty of Science, the Australian Research Council (DECRA fellowship), and received financial compensation from the ABC for time working on the documentary.

Report reveals improvement but also details danger posed by tourist-generated pollution, oil extraction and climate change

Just below the surface of the turquoise sea, coral flutters majestically amid schools of puffed up porcupinefish and fluorescent blue and yellow angelfish.

The gangly staghorn and fanning elkhorn corals are thriving in swimming distance of Laughing Bird Caye, a tiny Caribbean sandy islet in southern Belize, thanks to a restoration project that is yielding striking results.

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BOC will support CSIRO during its $3.4 million ammonia to hydrogen cracking and membrane purification project that is set to revolutionise the global supply chain for hydrogen.

Are Australia's wind farms living up to expectations? Why the market preferred Origin's results to AGL's; and a dive into the Windlab prospectus and its "busload" wind and solar plant.

Changes to the draft Australian Standard for installing home battery units are essential, but it is also important to ensure appropriate technical standards are in place to ensure consumers are protected, the Clean Energy Council said today.

Major renewable energy tender announcements expected from Victoria, along with more details of state renewable energy target architecture.

The Sill, Once Brewed, Northumberland Planting at the National Landscape Discovery Centre aims to recreate the area’s rare whin grasslands

Standing on the roof of the Sill with the wind in my hair, I have a new view of familiar countryside. For years I’ve driven along Hadrian’s Wall, enjoying the way the land forms a series of waves like a frozen sea.

Now, from the highest point of this building, I watch a buzzard circling above the Roman quarry at Barcombe Hill, see walkers labouring up the craggy steps at Steel Rigg, glimpse far-off bales in a recently cut hay field and cows tail flicking in the summer heat.

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California's solar-centric grid manages eclipse without a hitch. In Australia, preparations already being made for 2028 eclipse.

Solar pioneer Martin Green says solar PV will fall to $US10/MWh within a few years, but this will be good news for Australia's mining industry because the fall in Australia's thermal coal exports will be offset by a factor of more than 5 by demand for other resources.

Energy market rule maker backs down on proposal to charge solar households to export excess PV generation back to the grid.

Taronga Western Plains zoo in Dubbo, New South Wales, has welcomed two brand new additions to the giraffe herd, born within one week of each other. This video was shot within minutes of the first calf’s birth and shows it taking its first steps and bonding with adult members of the giraffe herd. The first calf is named Zuberi, which means strong in Swahili, and the second calf is Kibo, which means the highest. The zoo says that in just 30 years the global giraffe population has fallen by up to 40% due to poaching for bush meat and habitat encroachment. The zoo aims to spread awareness of their plight and raise money for conservation in Kenya

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