The Pioneering Duo: Henrik Stiesdal and Andrew Garrad, the Godfathers of Wind Energy

The world of renewable energy has seen remarkable growth and transformation over the past few decades. Among the pioneers who have significantly contributed to this sector are Henrik Stiesdal and Andrew Garrad, two visionaries who have left an indelible mark on the wind energy industry. Their groundbreaking innovations and relentless dedication have enabled wind energy to become a crucial component of today’s electricity generation mix.

Henrik Stiesdal, a Danish engineer, is renowned for his early design principles for wind turbines and the installation of the world’s first offshore wind farm. Born out of concerns about escalating energy costs during the oil shocks of the 1970s, Stiesdal’s work laid the foundation for efficient and robust turbine design. His concept, which became known as the ‘Danish concept,’ set the fundamental parameters for wind turbines: three rotating blades mounted up-wind of a two-speed gearing and generator system, and a mechanism to control yaw, turning the whole set-up directly into the flow of air.

Stiesdal’s innovations have had a lasting impact on the wind energy sector. Despite the advancements in turbine technology, the fundamental design principles he established continue to influence modern wind turbines. All turbines in operation today rotate clockwise when viewed from the rear, a testament to the success of the early Danish designs. Stiesdal’s contributions extended beyond the design of wind turbines. He licensed his concept to Vestas, where he introduced numerous innovations and later moved to Bonus (later acquired by Siemens), managing the 1991 installation of the world’s first offshore wind farm at Vindeby. With 17m (56ft) blades, the turbine rotors could generate 450 kW, enough to power a few thousand Danish homes.

Andrew Garrad, a British engineer, played a pivotal role in wind energy by developing the computer models that optimize and certify turbine and farm designs. His software, which has been used in the design of approximately 70% of all turbines, has been instrumental in de-risking the industry and enabling it to access the necessary finance for expansion. As a consultant, Garrad has also been the go-between between engineering and finance, touching every turbine and ensuring that the industry’s growth remains sustainable.

Garrad’s innovations have had a profound impact on the wind energy sector. His software has been instrumental in proving that new turbine designs will work and how they will operate within an array. Furthermore, his role in de-risking the industry has been crucial in enabling it to access the finance needed for rapid expansion. The growth of renewable energy, particularly wind energy, has been remarkable. In 2000, wind and solar energy combined accounted for a very small percentage of the world’s renewable electricity capacity. Today, they make up about half of the world’s renewable electricity capacity, with wind energy accounting for over 8% of global electricity generation and close to a third in the UK.

The future of wind energy looks promising, with further innovation in floating turbines allowing for installation in much deeper waters. The industry’s focus should be on cutting the unit cost of production even further, as no blade-tip should rise higher than the Eiffel Tower, 330m. The journey of wind energy from an insignificant component of the energy mix to a major player has been remarkable. It took 40 years to achieve 1 TW of global installed capacity, but most commentators expect the next 1 TW to be installed before the end of the decade.

Lord Browne of Madingley, who chairs the Queen Elizabeth Prize for Engineering Foundation, acknowledged the significance of Stiesdal and Garrad’s contributions. “I remember even 15 years ago, people said, ‘Wind power, windmills – a ridiculous idea – they won’t work for the long term.’ And, actually, there were plenty of very distinguished engineers who were very negative about wind power. But it’s been a remarkable journey, all thanks to these two evangelists, who made change happen.”

Prof Dame Lynn Gladden, who chairs the QEPrize judges, emphasized the importance of Stiesdal and Garrad’s collaborative efforts. “I don’t think they could have got to where they got without each other’s contributions. These are the guys who laid the foundations for it all. The principles they developed, they shared and encouraged others to follow. If you removed one of them, you haven’t got the technology we have today – we wouldn’t be where we are now.”

In conclusion, Henrik Stiesdal and Andrew Garrad are the godfathers of wind energy. Their pioneering work in wind turbine design and optimization, as well as their role in de-risking the industry, have enabled wind energy to become a crucial component of today’s electricity generation mix. Their collaborative efforts have laid the foundation for the remarkable growth and transformation of the wind energy sector. As we look to a future where renewable energy continues to play an increasingly important role in our energy mix, the contributions of these two visionaries will continue to inspire and influence the industry.