The British appetite for renewable energy

The UK is lagging behind the rest of Europe in adopting renewable energy sources for electricity production. However, a few key players in the most active areas of wind, solar and geothermal could by entering international markets sooner rather than later could avoid the risks associated with fickle government policies and subsidies.

Ted Sarmiento of Leeds Metropolitan University, UK, working alongside Alexander Brem of Friedrich-Alexander University of Erlangen-Nuremberg, Frank Muehlmann VEND Consulting GmbH suggest in a report published in the International Journal of Technology Marketing, that the UK is at a critical point in the development of renewable energy. Solar, wind, wave, hydroelectric, bio-energy, geothermal are a diverse group of technologies that seek to use natural phenomena to generate a sustainable electricity supply by avoiding the climate change issues of burning fossil fuels and the purported safety and public perception issues of nuclear power. Policy and market forces could ensure that the UK can guarantee energy security, meet its climate change targets on carbon emissions and prevent energy prices for consumers and industry from rising much higher.

“The current situation in the energy industry is characterised by a worldwide increase in the demand for energy,” the team explains. “At the beginning of the 20th century, worldwide energy consumption was less than 1 terawatt (1 TW equals 1 trillion Watts), while currently demand sits at around 11 TW and it is expected to rise to 28 TW by 2050.” The quadrupling of world population during that period is the main driving force, that and the industrialisation of emerging markets such as China, India and South America, as well as increasing mechanisation and the advent of consumer electronics.

As population rises and energy demands go up, the limited supply of fossil fuels is likely to be depleted within decades, the demand for renewable energy sources is reaching a critical point.

European Commission proposals published in 2008, demand that the UK achieve a 15% share of renewable energies within its overall energy use by 2020, although the UK government’s own targets are aiming for 20% by this time. However, although growth in the sector has been fairly rapid, many observers doubt that the UK will reach its renewable energy targets by 2020 without major policy changes. The planning system, for instance, repeatedly hinders the development of wind power. Nevertheless, the team’s survey of the market and companies within it suggest that wind power will be the main growth area in the UK.

The researchers’ data confirms that all sectors of renewable energies will grow, but the dynamic sectors of wind, solar and geothermal energy represent the most sensible options economically speaking because there are many issues to address with regards hydroelectric power and bioenergy.

“Marketing of new technologies: the case of renewable energies in the UK” in Int. J. Technology Marketing, 2011, 6, 162-177

Emulating nature for better engineering

UK researchers describe a novel approach to making porous materials, solid foams, more like their counterparts in the natural world, including bone and wood in the new issue of the International Journal of Design Engineering.

According to Carmen Torres-Sanchez of the Department of Mechanical Engineering, at Heriot-Watt University, Edinburgh and Jonathan Corney of the Department of Design, Manufacture and Engineering Management, at the University of Strathclyde, Glasgow in the natural world, the graduated distribution of porosity has evolved so that nature might transfer forces and minimise stresses to avoid whole structure failure. For instance, a crack in the branch of a tree will not lead to the felling of the tree in the same way that a broken ankle will not lead to collapse of the whole leg. “Porosity gradation is an important functionality of the original structure that evolution has developed in a trial and error fashion,” the team explains.

It is not just tree trunks and bones that have evolved graduated porosity, beehives, marine sponges, seashells, teeth, feathers and countless other examples display this characteristic. Researchers would like to be able to emulate the way in which nature has evolved solutions to the perennial issues facing engineers. In so doing, they will be able to develop structures that use the least amount of material to gain the lowest density structure and so the maximum strength-to-weight ratio.

“Many engineering applications, such as thermal, acoustics, mechanical, structural and tissue engineering, require porosity tailored structures,” the team says. If materials scientists could develop porous materials that closely mimic nature’s structural marvels, then countless engineering problems including bridge building and construction in earthquake zones, improved vehicle and aircraft efficiency and even longer-lasting more biocompatible medical prosthetics might be possible.

Unfortunately, current manufacturing methods for making porous materials cannot mass-produce graduated foams. The collaborators in Scotland, however, have turned to low power-low frequency ultrasonic irradiation that can “excite” molten polymers as they begin to foam and once solidify effectively trap within their porous structure different porosity distributions throughout the solid matrix. This approach allowed the team to generate polymeric foams with porosity gradients closely resembling natural cellular structures, such as bones and wood. The technology opens up new opportunities in the design and manufacture of bio-mimetic materials that can solve challenging technological problems, the team adds.

The researchers anticipate that using more sophisticated ultrasound energy sources as well as chemical coupling agents in the molten starting material will allow them to fine tune the formation of pores in the material. This is an area of current interest because it would facilitate the design of novel texture distributions or replicate more closely nature porous materials, the team concludes.

Sanchez, C., & Corney, J. (2011). A novel manufacturing strategy for bio-inspired cellular structures International Journal of Design Engineering, 4 (1) DOI: 10.1504/IJDE.2011.041406

Energy, all at sea

Floating wind turbines could capture the energy of higher wind speeds further out to sea and address some of the noise and unsightliness complained about by those with turbines closer to home.

Wind turbines represent one of the most reliable renewable energy solutions, along with solar power and tidal and hydroelectric power. As wind turbine designs increase their size they also get noisier and become more of an eyesore. The solution is either to site them remotely on dry land or to build them at sea with the tower embedded in the seabed of shallow waters, but this restricts them to near-shore waters with depths no greater than 50 metres, which means they cannot utilise the strong winds further out to sea.

Now, naval architect Dominique Roddier of Berkeley, California-based Marine Innovation & Technology has, together with his team, published a feasibility study of a novel platform design – WindFloat – that, as the name suggests uses floating wind turbines. The study is published in the Journal of Renewable and Sustainable Energy this month.

Floating wind turbines could use stronger offshore winds
Floating wind turbines could use stronger offshore winds (Credit: Roddier et al/JRSE/American Institute of Physics)

Roddier and colleagues, Christian Cermelli, Alexia Aubault, and Alla Weinstein, have tested a 1:65 scale model in a wave tank, which shows that a three-legged floating platform, based on existing gas and oil offshore platform designs. The team explains the main issue: “A floater supporting a large payload (wind turbine and nacelle) with large aerodynamic loads high above the water surface challenges basic naval architecture principles due to the raised centre of gravity and large overturning moment,” they say. In other words at first glance such a rig would capsize very easily. However, after several years work, their results show that the current design is stable enough to support a 5-megawatt wind turbine, the largest turbine that currently exists. These mammoth turbines are 70 metres tall and have rotors the size of a football field. Just one, Roddier says, produces enough energy “to support a small town.”

The next step is to continue construction of a prototype with electricity operator Energias de Portugal that will help the developers understand the life-cycle cost of such projects and to refine the economic model. The prototype will be tested in open water by the end of summer 2012, Roddier says. “The WindFloat [design] is envisioned to be located 15-20 km offshore so as to minimize risks/nuisance to the general public, and to mitigate the view impact from the coastline,” the team adds.

Links

J Renewable Sustainable Energy, 2010, 2, 3, 033104
Marine Innovation & Technology