When Holger Giebel, chief executive of Hanover-based TimberTower, told his wind energy contacts he wanted to build turbine towers out of wood, they were sceptical. In an industry dominated by steel and concrete, the idea seemed bizarre.

“They were very suspicious and thought we were crazy,” he says. “It seemed as inappropriate to them as using wood to build a car engine.”

But when Mr Giebel explained further, they became interested. Steel turbine towers are very heavy and have to be transported in large pieces on special vehicles. To fit under motorway bridges, their diameter is limited to 4.2m. This restricts their maximum height to 110m.

By contrast, wooden panels are relatively light and modular, so can be transported much more cheaply on standard trucks, and once on site used to build wider, taller towers. Higher towers are more efficient.

“Every extra metre corresponds to an extra per cent in revenue,” says Mr Giebel. The first timber tower will be built over the next few months in Hanover with a turbine belonging to Vensys Energy, which is based in southern Germany and owned by China’s GoldWind. It will generate 1.5MW of energy.

TimberTower uses spruce and pine, although most woods are suitable, so the company hopes the idea will prove attractive in forested areas such as North America and Scandinavia.

In addition to being greener to manufacture and transport, each timber tower locks up 367 tonnes of carbon dioxide that would have been released if the timber had been burnt or the tree had been left to rot or die.

The fact that Mr Giebel and his partners understood wind power and worked in the sector for 10 years helped establish credibility for TimberTower, he says.

“Lots of people in green energy have ideas about making the world a better place, but they have not thought of their potential customers, and this is particularly true of techies.”

Having the courage of his convictions also worked for Alex Berger, chief executive of Johannesburg-based AAP Carbon, which has designed the world’s first system to produce clean electricity from waste gases at ferrochrome smelting plants.

Production of ferrochrome, which is used to make stainless steel, traditionally involves flaring off waste gases into the atmosphere. “Industry experts initially thought our plan to capture and clean this gas to generate electricity was too ambitious,” says Mr Berger.

The doubters were worried about waste gas impurities, storage, safety, expense and fluctuations in supply. But AAP Carbon gained financial backing for its system, which is customised to the ferro-alloy industry and eliminates the need for storage.

Its first implementation will be switched on shortly at International Ferro Metals in Buffelsfontein, South Africa.

To generate electricity, the system uses internal combustion engines developed by GE Jenbacher of Austria. With a capacity of 17MW, it does the equivalent of capturing 160,000 tonnes of CO2 a year or taking 45,000 cars off the road.

The new system will generate 140,000MW hours of electricity a year – about 12 per cent of IFM’s overall energy consumption – helping ensure continuous operation in a region where electricity supplies are unreliable.

AAP Carbon is designing a similar system for Tata Steel’s Richards Bay smelting plant, and hoping to sign up further customers in South Africa, which accounts for more than 60 per cent of global ferrochrome production.

In the UK, Martin Wright, managing director of Bristol-based Marine Current Turbines (MCT), has fought hard to win credibility for his tidal power technology and has raised some £38m ($58m) funding, of which about £7m came from government.

Tidal power has the advantage of being more predictable than wind and is more energy-efficient, says Mr Wright. The company’s 1.2MW SeaGen prototype tidal turbine is feeding electricity into the grid in Northern Ireland and can supply the needs of 1,500 homes.

It is “on the cusp of commercialisation,” but will need up to £30m more to become fully commercialised, Mr Wright says. “Otherwise, it will wither on the vine.”

To achieve this, he says, governments should create incentives for energy companies to become customers. “Subsidies are not necessary, but governments should use their legislative powers to create a market.”

This would let investors understand the level of risk and decide how much capital to deploy.

“It’s no good expecting something just out of the egg to be massively capital-efficient on day one,” says Mr Wright. “But the single most important thing is that there has to be a market.”

Even the relatively developed solar market is not yet fully commercialised. While solar panels are cheap to maintain, installation is labour-intensive and expensive.

Dow Chemical has received $20m of US government funding to develop a roof tile, or shingle, that is “intuitive and straightforward” enough to be installed by existing roofers.

The shingle, which is in pilot production in Michigan, is designed for the US. Russel Mills, Dow’s global director of energy and climate change policy, acknowledges that it may not suit countries with different climates and construction methods.

Once US sales of the shingle have taken off, Dow will look at adapting it for other markets.

But as with all renewable energy, the challenge is bringing the cost down, says Mr Mills. “Whether green or brown, it looks exactly the same to the consumer, so it has to be priced competitively.”

Despite progress, coal will continue to be by far the world’s biggest source of fuel for at least 20 years, he says.

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