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(Credit: Getty Images)

How China's giant solar farms are transforming world energy

China is not only home to some of the biggest solar farms; its technology looks set to influence energy policy across the globe. But how feasible are these grand plans?

Fly over “Datong County”, a region in northern China, and you’ll see two giant pandas. One is waving at you. They are made of thousands of solar panels.

Together, and with the other adjacent panels included, they form a 100-megawatt farm covering 248 acres. It’s actually a relatively small solar park by China’s standards – but it is certainly patriotic.

“It is designed and built as the image of the Chinese national treasure – the giant panda,” explains a document from Panda Green Energy, the company that constructed the farm.

China has more solar energy capacity than any other country in the world, at a gargantuan 130 gigawatts

China has more solar energy capacity than any other country in the world, at a gargantuan 130 gigawatts. If it were all generating electricity at once, it could power the whole of the UK several times over. China is home to many sizeable solar farms – including the huge 850-megawatt Longyangxia Dam facility on the Tibetan Plateau, with its four million panels. And the largest solar plant in the world at the moment is in China’s Tengger Desert – its capacity exceeds 1,500 megawatts.

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These projects have cost many millions of dollars to build – but have they been worth it? And will enough of these sprawling farms ever be constructed to meet its green energy targets?

China is the world’s largest manufacturer of solar panel technology, points out Yvonne Liu at Bloomberg New Energy Finance, a market research firm. “The market is really big,” she says. “It is like industrial policy for the government.” According to the International Energy Agency (IEA) more than 60% of the world’s solar panels are made in China. The government has a clear economic interest, then, in ensuring that there is high demand for solar panels.


(Credit: Getty Images)
More than 60% of the world's solar panels are made in China (Credit: Getty Images)

Plus, by increasing the renewable energy resource, authorities can allow themselves a pat on the back. Cleaning up the Chinese energy mix is a key policy objective. Roughly two thirds of the country’s electricity still comes from burning coal.

It’s no wonder that the vast, sun-drenched plains of north and north-western China have become home to huge solar farms. There’s lots of space there to build them and the solar resource is reasonably reliable. Their construction has also been moving at a blistering pace. The IEA notes that China met its own 2020 target for solar energy capacity additions three years early.

One extraordinary venture uses solar panels to melt permafrost, so that trees will grow on the reclaimed land

There may be another incentive behind China’s drive to build solar farms in some politically sensitive regions. In recent decades, many have observed that China has been keen to encourage infrastructure investment in and around Tibet – an autonomous region that is home to many who reject China’s claim on the territory. Some argue that such investment is politically motivated in part – an effort to cement Chinese authority and support ethnic Chinese who have moved to these areas.

One extraordinary venture uses solar panels to heat an underground grid designed to melt permafrost, so that trees will grow on the reclaimed land. It is reportedly an attempt to make the area more appealing to Chinese settlers.

But building gigantic solar farms in the middle of nowhere has its downsides. To understand why, we need to look at China from above once more. In 1935 geographer Hu Huanyong famously drew what is known as the “Hu Line” from north-east to south-central China. It divides the country into two roughly equal portions. Less equal is the population distribution. The vast majority of China’s people, 94%, live in the eastern portion. The remaining 6% live to the west.

“The distribution of China’s wind and solar energy resources [is] entirely the opposite,” says Yuan Xu at the Chinese University of Hong Kong.

Many of the country’s solar panels are therefore located as far as can be from the large towns and cities that need them. The result of this is a staggeringly low capacity factor – the percentage of electricity actually taken from any given resource.


(Credit: Getty Images)
The solar farms in Qinghai make the most of the clear skies and beating sun above the Tibetan Plateau (Credit: Getty Images)

Citing data from the China Electricity Council, in the first six months of 2018, the capacity factor of Chinese solar equipment was just 14.7%, says Xu. So while a Chinese solar farm may be billed as having a capacity of, say, 200 megawatts, less than a sixth of that on average actually gets used.

The reasons for a low capacity factor can include things over which we have no control, such as the weather. But China’s capacity factors are unusually low. Part of the problem, says Xu, is that power is lost along the huge transmission lines, many kilometres long, that connect distant solar farms to places that need electricity. It’s a situation that Xu terms a “serious mismatch”.

China has tried to address this issue by developing better transmission line technology, says Jeffrey Ball at Stanford University's Steyer-Taylor Centre for Energy Policy and Finance.

Innovations include high-capacity direct current (DC) lines – but these are not being built as quickly as some expected.

And there’s another complication currently looming large for the Chinese solar industry. In May, the government dropped crucial subsidies for large scale solar projects, meaning they are now much more expensive to build.

The cut in public finance has come about because the state-run renewable energy fund is in debt to the tune of more than $15bn. “They can’t pay the subsidy anymore,” says Liu. The knock-on effect is drastic. Last year, 53 gigawatts of solar capacity were installed in China. This year, Liu expects installations to total no more than 35 gigawatts – a drop of more than 30%.


(Credit: Nasa Earth Observatory)
A hydroelectric dam is connected to a solar farm at Longyangxia - it is one of the largest photovoltaic power stations in the world (Credit: Nasa Earth Observatory)

In such a climate, energy investors are turning away from gigantic, remote solar farms, and toward other opportunities, says Liu. Covering rooftops in the big cities with solar panels and selling electricity directly to consumers is a more attractive prospect right now for some, she explains. Clients can be booked in as these projects grow, and the cash flow is in theory better, especially now that the subsidies are gone for big solar park installations.

But Liu, Ball and Xu all agree – we have not seen the last of supersized solar farms, in China or elsewhere.

China’s influence is not simply in the projects within its own borders, but also in the mega solar projects built outside of China – Jeffrey Ball

“I think it’s important to realise that China’s influence here is not simply in the mega solar projects that it builds within its own borders, but also in the mega solar projects that are built outside of China,” says Ball.

Several large solar farms are currently under construction around the world, many in India. As they near completion, they will vie for the title of the new “world’s largest solar park”. Many will have clear links to China. Take the Benban complex in Egypt.

Covering 37 sq km and boasting a planned capacity of between 1,600 and 2,000 megawatts, it is an impressive venture. One firm currently building part of it is – yes – Chinese.


(Credit: Getty Images)
Given the inefficiency of transmitting electricity over large distances, rooftop solar panels tend to be more efficient than remote solar farms (Credit: Getty Images)

Elsewhere, Panda Green Energy, which built the panda-shaped arrays in Datong, has plans to install many more solar farms in China that look like the black-and-white bears from above. That’s the goal of the firm’s “Panda 100 Program”. The designers have even chosen two different kinds of photovoltaic cells, dark and light ones, to approximate panda markings.

The company also aims to build its eye-catching solar parks in other countries – including what it describes as a “panda + rugby design” in Fiji and a “panda + maple leaf design” in Canada.

Liu points out that solar panels continue to get cheaper and cheaper. As such, it may only be a few years before China’s slashed subsidies become irrelevant – solar energy will just be too deliciously inexpensive for investors to ignore. It will be between three and five years before solar is cheap enough to build confidently without subsidy, she says.

But should giant solar parks continue to be built, one oft-ignored complication will have to be dealt with in future decades: solar panel waste. The panels last just 30 years or so, after which they must be broken up. It is hard to recycle them because they contain harmful chemicals like sulphuric acid. China is expected to experience a sudden boom in solar panel waste from around 2040 onwards and there is currently no clear plan for what to do with all that material.

Not quite as problematic as nuclear waste, perhaps, but it is one more hurdle to overcome when ensuring that large-scale solar energy really is a ‘green’ technology.

We’re going to have to deal with that problem at some stage. As Ball explains, the huge interest in cheap solar power, subsidies or not, will likely lead to enormous farms in coming years. “However big these projects are that seem so huge now, there are going to have to be many more of them and they’re going to have to be even bigger,” he says.

In other words, we ain’t seen nothing yet.

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(Credit: Chris Baraniuk)

The giant coal plant converting to green energy

The UK plans to end coal-fired electricity by 2025. But what happens to the massive plants left behind? One facility is pioneering an unusual idea: converting to green energy.

On the train to visit one of the last places in Britain that burns coal for electricity, I pass three solar farms soaking up sunshine. I also pass a coal plant called Eggborough that has all but ceased operations. No steam rises from its giant cooling towers. It will shut in September.

But the coal plant I’m visiting is different. It’s named Drax, after a local village, and is the largest power plant in Western Europe. By 2023, its owners plan to stop burning coal entirely. They hope that instead their plant will consume only natural gas and biomass – wood pellets crushed into powder.

The European Union has some key targets for reducing pollution in the coming decades and coal power plants have been earmarked for closure by many countries seeking to meet these objectives. In the UK, government plans mean coal-fired electricity generation will end by 2025.

A similar story is unfolding elsewhere in the world. Many nations, including the US, are moving away from coal as other energies become cheaper and as environmental regulations cool the market for this fossil fuel.

But this leaves a big question: what do we do with all of those old power stations?

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For the past century, these facilities have been huge players in the world’s energy market. The plants have expensive connections to national grids – meaning that simply knocking them down might not be so smart. Many, including Drax’s management, are insisting that there is another way.


(Credit: Getty Images)
Biomass will only reduce carbon emissions if the fallen trees are replaced with new saplings that can absorb CO2 from the air (Credit: Getty Images)

The scale of Drax is immediately apparent. On either side of the huge buildings that house its boilers and turbines stand six beige cooling towers. White steam drifts skyward. In the middle of the complex stands a 259m-tall chimney. And at the back of the facility there is a huge pile of coal – but staff members tell me it is much smaller now than it once was.

Coal is left here until it is brought into the power station on conveyor belts, ground up and burnt at ferocious temperatures. The furnace heats up water, turning it into steam that rushes through a complex system of pipes and spins turbines at a steady 3,000 revolutions per minute. It’s an easy way of producing electricity. It’s also a dirty one.

Energy shift

This is a large part of why coal’s days here really are numbered. In April, Britain went for more than three full days without any coal power at all – a decline that has happened far more quickly than many expected. This trend has meant that since the start of 2018, the country has managed a total of 1,000 hours without coal energy, already topping last year’s tally.

“In 2012, coal-fired generation was 45% of the power mix,” says Matthew Gray at Carbon Tracker, a think tank. “Today it’s at a very low amount.”

From the perspective of a plant operator, though, replacing coal isn’t easy. That’s because biomass is a far less forgiving material than coal, says chief executive Andy Koss.

“It clogs things up,” says Koss, remembering how early experiments in moving the biomass on coal conveyors led to the pellets disintegrating and creating dust. The biomass also has to be kept dry at all times, unlike coal, lest it swell into a useless porridge-like mix. It’s even liable to burst into flames as it slowly oxidises so piles of it have to be constantly checked for temperature rises. Drax spent £700m on converting Drax and ensuring that the new biomass could be handled gently and along rain-safe pathways through the plant.

And the power station also has invested in four bulbous domes, each one 50 metres high, to store biomass in on site. Every day, 16 covered trains arrive and deposit more of the wood pellets to keep the plant’s supplies topped up. The wagons pass through a shed and open automatically, triggered by magnets, as they roll over a grate in the ground. The wood pellets spill down through the grate, deep into a cavern below before being taken to the domes for temporary storage.


(Credit: Chris Baraniuk)
The conversion of the Drax powerplant - from coal to biomass - cost £700m (Credit: Chris Baraniuk)

In terms of biomass operations, “I would say it’s the largest in the world,” says Koss. At the time of my visit, Drax had two gigawatts of coal capacity and the same for biomass. It has now completed its fourth generating unit for biomass. The remaining two will eventually burn gas.

Drax has tried to rebrand itself as a poster boy for what can be done with an old coal plant – where there’s enough will and, indeed, money to pay for conversions. Many small coal facilities in the US have recently converted to burning gas – a cheaper kind of transition than biomass.

And Drax wants to build large batteries on site to store electricity for when the grid needs it most. There are other, similar projects around the world. A Canadian firm, Hydrostor, has designed schemes for turning old coal plants into compressed air batteries. The air can be released to force the plant’s turbines back into action whenever electricity is needed.

There are plenty of other ideas for reinventing former coal-burning facilities, too. In 2016, China announced it had plans to convert some of its coal plants to nuclear power stations – though there has not been much news about the proposals since. And Drax is far from the only coal-to-biomass project in the world, even if it is the largest. In Denmark, a coal plant in Copenhagen is set to be turned into a 100% biomass facility. A new incinerator nearby will feature an artificial ski slope on the roof.

Why is coal so polluting?
Coal produces a range of pollutants – notably carbon dioxide (CO2), a greenhouse gas. A lump of coal can contain between 60-80% carbon. The CO2 is produced when coal is burnt. Greenhouse gases build up in the earth’s atmosphere where they form a layer that traps heat, preventing it from escaping at night.
Burning coal also releases substances harmful to human health, like mercury, nitrogen oxides and sulphur dioxides. Finally, there’s the particulate, or soot, that also disperses into the atmosphere. It is estimated that thousands of deaths every year can be attributed to these pollutants.

Not all coal plant conversions are energy-producing ventures. Google is turning one old facility in Alabama into a data centre.

King coal

It’s also true that, in some places, coal is still hanging on. Although it has abandoned more than 100 coal plants, China still relies heavily on this dusty black fossil fuel for its energy needs. And Germany, which has decided to close all of its nuclear power stations, currently gets more than a fifth of its energy from coal, including lignite – an even more polluting form of the fuel.

An interactive map of the world’s coal-fired power stations from climate news site CarbonBrief reveals a swathe of plants closing in the US and Western Europe, but plenty of new ones under construction in Asia.

Meanwhile, some markets have questioned coal and then returned to it. Back in 2015, the New South Wales government in Australia sold a major coal plant for A$1 million (£570,000), a tiny sum. At the time, politicians believed the facility would close within 10 years but then electricity prices in the region hit the roof. The plant is now valued at A$730 million (£415m) and its new owners have no plans to shut it any time soon.

Faith in coal may not always be rewarded, though. In Poland, energy giant PGE has been investing heavily in old coal infrastructure, hoping to keep coal units burning for years to come. But this costs hundreds of millions of dollars at a time when the price of renewable energy, particularly wind and solar, is falling rapidly.


(Credit: Getty Images)
It can take years for newly planted trees to absorb the equivalent amount of carbon released through the burning of wood (Credit: Getty Images)

It’s also fair to question exactly how green some of the coal plant conversion options really are.

Take biomass. Although the wood pellets release carbon when they burn, it is touted as ‘green’ because the trees cut down for them can be replaced over time, thus sequestering carbon again later. But not everyone agrees that this truly makes biomass carbon-neutral. Even page 33 of Drax’s annual report reveals that biomass belches out more CO2 per unit of electricity generated than coal does – a serious problem with the fuel.

Echoing the main pro-biomass arguments, one boss at Drax tells me this is offset by replenishing the forests that supplied the biomass in the first place. Drax also says that, after accounting for replenished forests and supply chain emissions, using biomass means 80% less CO2 is ultimately emitted than it would be if coal had been used.

But it takes new trees decades to grow. Plus, on a global scale, forests are shrinking in size overall. The capacity of the world’s forests for re-absorbing atmospheric CO2, then, is getting worse rather than better.

“I agree that’s a bad thing,” says Koss. But regarding deforestation, he insists, “it’s happening in areas outside of the areas that we source from… we are not connected to that at all.”


(Credit: Getty Images)
To generate electricity from biomass, food chips are crushed into powder, which is then fed into the incinerator (Credit: Getty Images)

True, but not enough to convince some environmentalists. And some experts point out that we need   rapid emissions cuts now, not in the decade or several it will take for new trees to grow.

Drax is hoping to mitigate its emissions in another way: with a pilot of bioenergy carbon capture storage (BECCS) technology. Gases from burning biomass at the plant will, if it all goes ahead, be passed through a solvent that reacts with emitted CO2, capturing it before it enters the atmosphere. This CO2 can then be retrieved so that the solvent can be used for capture again and again. It’s clever stuff and has been shown to work commercially before at one or two sites - but Drax is testing a new version.

There clearly can be life after coal. But if we are to make the most of these lumbering old plants, we need to be savvy, green-minded and prepared to pay in advance for meaningful results.

Coal powered the world for many decades. It was a symbol of Victorian achievement. Instead of simply sweeping it away, we might well benefit from making novel use of the structures that the once great industry is leaving behind.

Correction: We incorrectly stated that BECCS technology had not yet been used commercially. We have also clarified the number of generating units at Drax that are currently devoted to biomass. We regret the errors.

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