Governments, national funding bodies, and entrepreneurs are investing huge amounts of money in the seemingly global effort to generate energy from sustainable sources. These efforts are driven by the fears of the effects of anthropogenic global warming and the socio-political dangers of energy insecurity.
Industrial economies have accepted the need to source a larger proportion of society's energy from non-fossil derived sources, a point that was highlighted in a recent Climate Group report, which revealed that Germany heads the 2007 global league for absolute dollar investment in renewable energy totalling $14bn. Surprising to many in light of the media attention on its reliance on coal, China was ranked second at $12bn.
Funding for academics and entrepreneurs is another process that inspires innovation. The US Department of Energy has its fingers in many proverbial pies and only last month announced a $7m funding package to accelerate clean-energy technologies to the marketplace with a key focus on rapid prototype development, demonstration, market research and commercialisation, all in a bid to reduce US dependence on foreign oil.
Another quick example is Scotland's Saltire Prize, a $10m cheque is available to any scientist that can demonstrate, in Scottish waters, a commercially-viable wave power device that can take advantage of the nation's battered coast within two to five years and aid the government in achieving its target of generating half of all electricity needs from renewables by 2020. Scotland hopes its $10m carrot will inspire giant leaps and bounds in alternative energy research, much like the Ansari X prize achieved for private spacecraft development.
Now, many of the ideas being developed will fall by the wayside, like natural selection they won't have the innovative fitness to compete against their kin and survive. Some of course do survive, getting by purely by improving on their predecessors - a relatively small but important gain in solar efficiency for example, but other ideas carve out a new niche of their own and speciate into a new form of innovation. This is the category we're interested in. Let's take a look at three of the latest inspirational ideas in the fields of solar, wind, and wave, and examine the engineering and science behind them.
There have been a number of recent innovations in the solar collector sector, including a re-examination of the asphalt concept by Worcester Polytechnic Institute. Asphalt absorbs a lot of heat, so why not sink copper piping beneath our roadways and carparks and take advantage of the uncaptured heat? An interesting idea but not a new one - the UK Highways Agency funded a similar trial in 2005.
Another US-based research team has also tried rehashing old ideas but this one is far more innovative in its approach and succeeds in leaps and bounds where its ancestral idea barely got off the ground.
Electrical engineers at Massachusetts Institute of Technology (MIT) were aware of a 1970s luminescent solar concentrator concept that aimed to make solar concentrators from plastics impregnated with dyes. Unfortunately the project was discarded because of issues of light transmission efficiency and unstable dyes.
The MIT team realised that developments in optical techniques could overcome the old problems and breathe life into the concept.
The new solar collector consists of a mixture of dyes applied to the surface of a plastic sheet or a glass pane. Light from the sun strikes the dye mixture and is absorbed. It is then reemitted at a different wavelength and subsequently transported across the pane to the inorganic solar cells embedded in the frame (Fig.1).
The concept is simple and the technology offers some practical advantages to competing technologies. Firstly, it reduces the number of solar cells required to take advantage of the sun - this lowers capital cost as the cells are the expensive element of solar generation. Secondly, the researchers say the devices ability to focus light increases the electrical power obtained from each solar cell by a factor of 40, so it also promises a massive efficiency gain. Thirdly, you don't need the massive amount of space and mobile mirrors necessary in conventional concentrators that track the sun. More cost savings.
The research team is commercialising the technology through the spin-off company Covalent Solar and expects to bring the product to market within three years. They want to increase the dyes stability even further and aim to retrofit existing panels for consumers to increase efficiency and lower the cost per unit of electricity.
Environmental protests, poor wind profiles, and local opposition hamper many wind projects whether onshore or offshore. However, a new floating offshore wind concept piloted by StatoilHydro hopes to break these barriers down.
"Two of our engineers were sailing and saw a small floating lighthouse. They asked themselves if the same could be done for wind with floating elements from the offshore oil and gas industry. They sketched it, brought it to company, the company liked it, and it all started snowballing from there."
This from Oistein Johannessen, the StatoilHydro new energy spokesperson, who confirms the company was so pleased with the test results of its 'small 3m model', (Fig.2) that it's now evolved its Hywind concept into construction phase.
StatoilHydro says its $78m pilot project will sit 10km off the Norwegian coast where it aims to take advantage of the 'more stable strong winds'. The 2.3MW turbine is being built by Siemens and consists of a 65m tower and blades measuring 80m in diameter. Technip is building the floating base which will extend 100m below the sea surface and will be anchored to the seabed at three points. The technology, if proved, will function in waters between 120-700m deep.
This is a unique concept says Johannessen but it takes advantage of mature technology from the oil and gas, and the wind industry. The floating base, known as the Spar-buoy is derived from production platforms and offshore loading buoys.
StatoilHydro has two major goals with its Hywind pilot project. Firstly, qualifying the technology in the harsh offshore environment; the turbine will be moving, unlike the fixed offshore concept, so the company needs to optimise the technology to take advantage of the strong winds whilst its lolling up and down on the waves. Also, making the turbine float is a challenge because the structure will be very heavy. Making sure its stable is also essential, especially in light of the need for safe maintenance.
The second challenge is commercial. StatoilHydro has already said that the viability of the project could be dependent on incentive schemes if it's to reach the power market and remain competitive.
Johannessen says the perceived advantages of StatoilHydro's Hywind turbine is the option to adjust the farms location, that and the lack of conflict expected from environmental lobby groups and nimby-ists. The current timetable is to finish the construction phase by Autumn 2009, and then tow the unit offshore and begin testing.
Wave
Where solar has been dogged by efficiency and wind has been dogged by local opposition, wave power, though full of potential, has been limited by mass. Many devices have failed to reach commerciality because of their dependence on steel and concrete.
This problem could be overcome by the Anaconda wave device (Fig.3) being developed in the UK by Checkmate Seaenergy. The end product aims to be a 200m long device with a 5m diameter; imagine a water filled sausage, closed off at both ends, and made of natural rubber.
The device will sit just below the sea surface and face the oncoming waves. A wave reaching the head of the Anaconda forms a bulge wave inside the distensible tube and as it passes alongside, it squeezes the tube and creates an internal pulse that gathers energy as it goes. A turbine in the Anaconda's tail converts the wave energy into power which is fed onshore by cable. The idea was inspired by studies on bulge waves passing through arteries and canals.
The power take-off and the non-return valves are the only metal elements involved so the capital cost puts this device way ahead of its ancestors. Checkmate Seaenergy confirms that the detailed design is still being studied but the initial tests at Southampton University, UK, have matched the theory.
The team has yet to put a working device in the sea. It's currently working on a 1:25 scale model in a test tank, and will move to 1:10 scale models in 2009. The team is working to optimise the elastic properties of the rubber tube so that the bulge wave matches that of the oncoming waves to achieve peak performance. The aim is to have a commercially available product within three years, with one Anaconda generating 1MW of energy in water measuring 40-100m deep.
The biggest engineering challenge will be manufacturing the rubber tube. At 200m long, the Anaconda device will "probably represent the largest rubber device anyone has ever made." However, the team expects to scale the device without issue. So it's a challenge but not insurmountable one.
In conclusion, the future looks bright. From the US, to Norway and the UK, innovators are thinking and working hard and building on the triumphs of past experience. These products haven't generated a single watt of commercial energy to date, but such is their uniqueness and perceived viability that we may all soon live in a future where windows generate energy, turbines float, and snake-like wave devices face down ocean currents and draw the energy to shore.
