When Bio and Solar converge: 6 hot projects at the bio-solar-electric frontier

February 3, 2012 |

Six teams, six projects test the frontier — where the best of solar-electric and the best of bio-based create a new field of biosolar technologies — for fuels, materials, sensors and more.

When it comes down to it, a living organism such as a plant is an incredibly sophisticated next-gen solar panel, harvesting light as well as CO2, water and nutrients for the production of energy, proteins and more.

It’s a concept which the near-to-commercial Joule Unlimited has been exploring – where they use a modified microorganism that uses sunlight, water, CO2 and nutrients to directly produce renewable fuels and chemicals while bypassing the biomass stage – like an insect going straight from pupa to butterfly without the intermediate step of life as a caterpillar. In Joule’s case, the productivity gains are potentially enormous. Where an acre of, say, sugarcane can yield perhaps as much as 800 gallons of fuel, Joule Unlimited’s system, which looks like a field of solar panels, can generate up to 25,000 gallons of ethanol per acre, the company says.

New research is exploring the boundaries between bio and solar in a way that suggests that the two fields may ultimately converge.

You see, what is great about solar is the way that systems can achieve very high photosynthetic efficiencies. As high as 15-20 percent using today’s technology – whereas a plant might convert just 1-2 percent of the solar energy it receives into biomass.

Conversely, what is cool about bio is a lot more. Bio-based systems can utilize other inputs, such as CO2, or water. They make molecules, that can be used in zillions of useful ways, instead of just electrons that drive power systems. Most importantly, they can move, and think, and react. Imagine, if you will, a solar panel that could move a little to the left on a partly cloudy day, to hop out of a shadow. Or transfer some of its power to a set of wings that could allow it to follow the sun. Or, use some of its electricity to power data-gathering. For example, imagine if a sensor could act like an insect – moving around, collecting data, reporting back.

Sounds like weird conceptual technology from a futuristic novel. Actually, those systems are being built and explored today. Here are a few examples.

Power systems that use molecular structures from plants

In Tennessee, Barry D. Bruce and a team of researchers have developed a system that improves the efficiency of generating electric power using molecular structures extracted from plants. “As opposed to conventional photovoltaic solar power systems,” Bruce said, “we are using renewable biological materials rather than toxic chemicals to generate energy. Likewise, our system will require less time, land, water and input of fossil fuels to produce energy than most biofuels.” To produce the energy, the scientists harnessed the power of a key component of photosynthesis known as photosystem-I (PSI) from blue-green algae. This complex was then bioengineered to specifically interact with a semi-conductor so that, when illuminated, the process of photosynthesis produced electricity. More on that technology here.

Robot insects controlled and powered by bio-based systems

In Ohio, a team of researchers at Case Western Reserve University have engineered a bio-based fuel cell, implanted into cockroaches, which diverts some of sugars from their bloodstream and generates a small electric current, which could be stored in a tiny battery. As long as they continue to eat, the system continues to produce power, which could be used to manipulate the insect’s nervous system and control its movements, and provide power for attached sensors. (A team at Cornell has developed such a control system, in an early stage, check it out, here). The researchers point to uses such as putting these controlled insects into earthquake rubble to find victims. More on that technology here, from LiveScience.

Solar-based energy collection, bio-based energy conversion and storage

Perhaps most intriguingly, there are the electrofuel projects being funded and shepherded by ARPA-E. As a class, these directly look at the challenge of finding ways to decouple organic systems, such as plants, from their limiting skills at converting solar energy into usable energy. The key here – photosynthesis is great at storing energy, ways ahead of advanced battery technologies – but we have developed systems of our own that are far more effective at harnessing energy. So, how do you take the best of the one and combine it with the best of the other?

Enter the chemolithoautotrophic organisms. Now, try saying that three times real fast. What are those? These are organisms that can obtain energy from an inorganic material, instead of from sunlight. Why is that important – because if you can capture sunlight using inorganic material – with the 20 percent efficiencies of, say, silicon based PV materials, if you have an organisms that can take that energy, and use it to fix CO2 and make organic molecules like fuels – well, you have figured out a path to bypassing the limitations of biomass photosynthesis. You also have, for example, figured out a way past the limitations of battery systems, because molecules can store energy indefinitely and cheaply. Think how long all those oil molecules have been hanging out, way down below the ocean’s floor, for example.

More on three technologies being developed at ARPA-E using those strategies, from Chemical & Engineering News online, here.

Bio-based backing sheets for solar systems

BioSolar has developed a technology to produce bio-based materials from renewable plant sources that will reduce the cost of photovoltaic solar panels. In the past, conventional bio-based materials have not been successfully used in PV applications, due to their low melting temperature and fragile molecular structure. Most bio-based materials available today will not withstand existing solar cell manufacturing processes.  BioSolar is the first company to introduce a new dimension of cost reduction by replacing petroleum-based plastic panel components with durable bio-based components. More on that technology, here.

Where will this lead?

In the short term, more R&D, to turn useful proofs of concepts into scalable systems.

In the long term, toward a grand convergence of technologies, where bio and solar meet as bio-solar. And, keeping in mind that wind is a waste byproduct of solar power (generated from differential atmospheric pressures caused by solar heating), we may well find all of these technologies converging well down the line.

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