Renewables changing the nature of power
Halfway through April this year, scientists at Harvard and MIT announced something extraordinary: they had found a way to create solar cells that can store accumulated energy from sunlight, and then — with no more than a burst of a few photons — release that energy in a steady and continuous form. These new types of solar cells — called photoswitches — are made from a form of carbon nanotube called azobenzene, which can exist in two different configurations. One collects energy from the photons that hit it and stores it, another releases it. Because they can be switched from one form to another, the cell is essentially a battery, and this solves many of the problems of storage that arise with a weather-dependent system such as solar.
The great advantage of such a technology is that it would make possible solar cells that were an utterly stable continuous power supply. When you combine it with work being done elsewhere on solar cells that can perform in cloudy conditions, you have the plan for an entirely stable solar delivery system — indeed, one that is more stable than the large-scale privatised power systems that we currently rely on, subject to mass technical failure, Enron-style credit events, and routine under-maintenance.
Such technology is small miracle, yet it’s only one examples of dozens of advances occurring as renewable energy technology comes into contact with new materials and starts to be transformed by them. Thus, in the weeks and months before this recent announcement, news in renewables included: a new nanomaterial that can increase solar fuel cell efficiency by up to 80%, a solar-powered hybrid car that can charge up without needing to dock at a recharge station; and a plane the size of a 747 that will be able to fly around the world without refuelling. On every front, the renewables revolution is gaining pace — not merely gaining pace, but accelerating exponentially — and the overwhelming reason for this is new materials.
Graphene and related forms of carbon have busted open the limits that solar technology hit in the 1990s — limits that made it easy for smug members of the fossil and nuclear lobby to argue that renewables would never be able to supply the energy needs of a modern civilisation. That supposition was based on a crude version of what we might call “molecularism” — a willingness to accept given limits of technology based on the aspects of it that used to be close to us: the limit of the molecule. In that conception, it is easy to see why people could believe that there were limits to the capacities of solar and other renewables. There is no excuse now. The new materials revolution means that anything is possible with regard to renewable energy. The 3D/additive revolution means that we can make machines whereby anyone can print these things out from machines that are themselves powered by this energy. The material revolution makes it first conceivable — and then unavoidable — that these new technologies will converge on an energy revolution, one that will leave existing old-school technologies hopelessly behind.
“These new materials also promise a revolution in the capacity for energy storage.”
In the decade since this new field was opened up, the possibility of cheap, simple and easily reproducible and distributable power and power technologies has opened up afresh. The simplicity and manipulability of new materials such as azobenzene makes possible a re-engineering of solar cells at the molecular level, reaching into the mechanism of the cell at a level not previously accessible. The 80% increase in cell efficiency comes about by coating the cell with a material composed of tungsten and a new ceramic called hafnium that allows the cell to collect much of the heat energy that it would otherwise lose. Graphene itself can also be used directly with solar cells, the conductivity of the material allowing it to act as a super-efficient charge carrier within the cell — retaining its properties even if combined with other materials such as silicon.
Alternatively, the current expense of mass producing such graphene-based cells can be reduced if the silicon is replaced entirely with graphene, combined with titanium oxide and perovskite. Because the cell can be produced at low temperatures, around 150 degrees Celsius, they can be mass-produced at a cost comparable to existing solar cells, and eventually much cheaper — or, indeed, printed out. In wind power, graphene combined with various metals would make possible wind turbines that are significantly lighter with a larger surface area for generation. This would work in conjunction with a plethora of new wind turbine designs that go well beyond the propeller-style turbine that have become a fixture of the landscape.
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