Aeronautical engineer and balloonist Per Lindstrand

Balloon expert and world record holder Per Lindstrand explains how inflatable structures could become power stations and why big airships aren’t coming back.

It sounds like a pretty mad idea by most people’s standards. But Per Lindstrand is confident that building a kilometre-tall electricity-generating inflatable chimney in the middle of the desert is a good solution, if not to all our energy needs, then at least those of remote locations with plenty of sun and a danger of earthquakes. And Lindstrand — the aeronautical-engineer-turned-adventurer who was the first to cross the Atlantic and Pacific oceans in a hot-air balloon — is used to defying disbelief.

The idea originated with the ALMA observatory located 5,000m above sea level in the Atacama desert in Chile, an area hundreds of kilometres away from a power station and at risk of earthquakes. The solution is known as a solar updraft chimney, a tower that uses rising air heated by the desert sun to drive turbines that generate electricity.

Put like this, it sounds like a neat solution, especially compared with fuel-hungry and polluting diesel generators. But people have been trying to make solar updraft work for more than 100 years and, so far, few have managed it — and none commercially. It doesn’t help that to produce sufficient amounts of energy for ALMA, the chimney would need to be 1km tall with a canopy at its base to heat and collect the air with a radius of 7km. And such a tall structure made from concrete or metal is unlikely to fare well in an earthquake.

/r/x/n/Inflatable_solar_chimney_1.jpg
Tower power: the solar updraft chimney uses rising air heated by the desert sun to drive turbines that generate electricity

This is why the observatory turned to Lindstrand, one of the world’s foremost experts on inflatable structures but probably most famous for setting the world distance record in lighter-than-air travel when he and Richard Branson crossed the Pacific in a balloon emblazoned with the Virgin logo. After visiting ALMA, Lindstrand decided an inflatable chimney was not just possible but actually the smartest way to harness the sun in an area where traditional solar photovoltaic generators are impractical due to the fine sand that would clog up solar panels. By comparison, an inflatable solar updraft tower would need very little maintenance — and wouldn’t be susceptible to earthquake damage. ‘Typically an inflatable such as that would have a life of about 15 years and then the fabric eventually breaks down from UV. But 15 years is enough to make your money back on it.’

Lindstrand’s company, supported by funds from the 1851 Commission, has now begun a project to build a 3.5m prototype chimney. It’s a small start and scaling up the technology could take years. A big part of the challenge will be in choosing the right materials to enable it to withstand the sun and prevent static electricity build-up that could ignite the hydrogen inside. But Lindstrand is confident they can create a 1km-tall tower that is a commercially attractive proposition.

‘No one ever built anything of that size, of course, but in theory I think we should be able to do it,’ he says. ‘There is a company in the US trying to do it in the desert with concrete, and it is talking about a $750m building. We can probably build something of that size for about $20m. So we can get it to work. All the numbers stack up. And there’s a lot of applications where they have desert and they have safety problems that we can apply this to.’

/l/p/l/Inflatable_solar_chimney.jpg
Flexible friend: an inflatable solar updraft tower would not be susceptible to earthquake damage

Lindstrand also has experience on his side. He’s been at the forefront of inflatable structures since the late 1970s, developing not only temporary buildings for exhibitions, parties and even the US Marine Corps, but also plugs to halt the spread of tunnel fires and barriers to contain nuclear power stations in the event of a meltdown. And it all started with a skiing accident that put an end to Lindstrand’s early career as a flight test engineer in the Swedish air force.

‘The doctor said if you eject out of an aircraft you could split your spine and you’d be paralysed, so you’re grounded,’ Lindstrand says. ‘I thought “bugger this”, left the air force and went into industry.’ As something of a natural adventurer, however, the established industry didn’t hold his interest for long. And when a neighbour bought a hot-air balloon that was supposedly top of the market but displayed obvious flaws, Lindstrand saw an opportunity to strike out on his own and change the way balloons were designed.

‘The advantage I had was I came in brand new to the industry but I used my experience as an aircraft engineer in materials, in technology,’ he says. ‘We built more powerful light burners. The basket before was just a basket: we built proper frames, made them more impact absorbent, and so on. And we quickly got a technical lead.’

Moving to Britain to take advantage of the lower costs and weaker currency, Lindstrand eventually came into contact with Branson in 1986 after providing him with his famous Virgin-branded advertising balloon. Branson was intrigued by Lindstrand’s plans to cross the Atlantic in a hot-air balloon — the business mogul had just done the same in a speedboat — and a year later the pair became the first in the world to do just that. In 1991, they repeated the feat across the Pacific, setting records for the largest hot-air balloon ever flown, the longest flight duration and the furthest distance, although their later world circumnavigation attempt was less successful (they had to be rescued off the coast of Hawaii).

/f/g/i/Richard_Branson___Per_Lindstrand_1.jpg
Lindstrand: “It’s not just the flying; it’s the designing that attracts me.”

Lindstrand is rather nonchalant when relating these amazing adventures, perhaps because, as he describes them, they are an added bonus to his real motivation. ‘Every car designer probably dreams about designing a Formula One car: it is the ultimate example of your engineering,’ he says. ‘But before me there wasn’t much in the way of long-distance flying. There was just a basket with fuel in it. We changed the whole picture of long-distance ballooning. It’s not just the flying; it’s the designing that attracts me.’

Having reached the top of the world in ballooning (even if he didn’t make it all the way around), Lindstrand turned his attention to another challenge: developing much more complicated inflatable structures — something that has become increasingly possible thanks to advances in materials. However, conservatism and scepticism of the abilities of inflatables is also holding the industry back, he claims. The take-up of his protective structures for nuclear power plants and tunnels, for example, has been low. ‘It’s always difficult with this technology because people imagine it’s going to go “poof” like a balloon,’ he says. ‘But look at air bags in cars. Twenty years ago people didn’t believe they worked. Now everybody believes in it. And that did a lot for fabric engineering to make it established.’

One area in which Lindstrand himself is sceptical — if not dismissive — of the use of inflatables is airship transport. He sees potential in niche areas such as research and has built airships for studying the rainforest canopy, but says freight airships will never come back and seems pessimistic about their wide use as unmanned spy drones. Several projects have been announced in recent years but have typically ended up going nowhere after being taken over by big aerospace companies that later change their minds and shut the projects down.

The latest company to show an interest in inflatables is Google, which wants to use balloons to set up wireless internet networks in remote areas. Lindstrand thinks airships might actually have a part to play here. ‘If you let off a balloon anywhere in the world, sooner or later it will end up at the North or South Pole,’ he says. ‘So why have a balloon that can’t be steered? The high-altitude airships that sit well above the jet streams can stay up there for five years.’ He claims a five-airship network could provide access to the whole of the UK for a capital cost of £200m. But once again he has been stymied by scepticism, conservatism and a lack of willingness to take a risk on funding development.

Like so many engineers, Lindstrand relates his frustration in the form of the story of Frank Whittle, who spent years trying to convince people of the merits of his turbojet engine before it eventually became one of the most significant inventions in transport history. ‘Just because it’s a good idea doesn’t mean that it will automatically get accepted,’ he says.

Whether Lindstrand’s designs will ever achieve the recognition of Whittle’s is unclear, but given the pleasure he takes from the process of creating them — and the success he has already found as an aeronaut — perhaps it ultimately doesn’t matter.

/j/f/r/Per_Lindstrand.jpg

Per Lindstrand

Founder, Lindstrand Technologies

Education

1973: MSc in aeronautical engineering, Sweden

2002: PhD in aeronautical engineering, UK

Education

1973: MSc in aeronautical engineering, Sweden

2002: PhD in aeronautical engineering, UK

 

Career

1973 – 1976: Worked for SAAB Aircraft and Lockheed Martin

1976: Founded Colt Balloons (later Thunder & Colt) in Ireland, before eventually moving to the UK

1987: Completed first trans-Atlantic lighter-than-air balloon flight with Richard Branson

1991: Completed world’s longest lighter-than-air balloon flight over Pacific Ocean

1991: Founded Lindstrand Balloons (later Lindstrand Technologies)

1998: Attempted (and ultimately failed) the first global circumnavigation by balloon

2006: Awarded an honorary fellowship by the Royal Institute of British Architects