Advancements in Solar Technology and it's Impact on Packaging

November 10, 2011

Advancements in Solar Technology
and it's Impact on Packaging


by Kristine Lickstein, Product Ventures Technologies and Commercialization Engineer 
 

In today’s market it is unlikely to find an industry that hasn’t been affected by the pressure to become more sustainable. Consumers are more knowledgeable about the products they purchase and are making a conscience effort to select items that have less impact on the environment. Actions like buying Coke’s new PlantBottleTM or bringing reusable bags to the grocery store have transformed previously foreign words like “reusable” and “renewable”. Renewable materials and ingredients however, are not the only factors consumers consider prior to purchase. The switch from incandescent light bulbs to compact florescent lights (CFL’s) and the dramatic increase in sales among hybrid cars are just two cases where “green” energy is the main buying incentive.

With these trends continuing to grow it’s only a matter of time before consumers also begin thinking about the energy that goes into making their everyday packaged goods. Renewable sources of energy offer numerous benefits over traditional pollution emitting fossil and nuclear energy sources. Solar energy in particular is largely an untapped resource which has the potential to revolutionize the way products and packaging are produced and delivered to consumers globally.
 

Advantages of Solar Power

The energy that reaches the earth’s surface in the form of light and heat radiation makes it one of the most abundant sources of renewable energy available. In fact according to the US Department of Energy, the amount of sunlight that reaches the earth every minute is enough to satisfy the world’s energy needs for a whole year. Unlike fossil fuel, sunlight is readily available worldwide. Developing countries with poor infrastructure and limited electricity have the ability to use solar energy to keep their cities, towns and villages running throughout the night.

Equally as important as the abundance of sunlight, is the fact that solar is a clean source of energy. Solar energy is non-polluting and will not emit harmful emissions into the earth’s atmosphere. This lack of toxins means a safe living and working environment for citizens in direct or close proximity to solar power plants. With the fight against global warming on an upsurge and an increasing number of companies and organizations committing to reduce greenhouse gases, the interest in solar energy is growing fast.
 

Problems with the current system

When looking at the overall advantages of solar energy, it’s difficult to understand why there hasn’t been more focus on using sunlight and heat to power our homes and infrastructures. One argument is that sunlight is not as accessible in all climates and parts of the world. Although it is true that the sun shines brighter in Nevada than it does the UK, this does not necessarily mean countries with cloudy weather can’t take advantage of solar energy. Germany for example, often known for its overcast weather, is the world leader in the number of installed solar photovoltaic panels, demonstrating that the system can be established in a variety of climates.

Also, like most forms of power systems, space is required for installation. A popular solution has been to position solar panels upon rooftops, and although this may not be an issue for expansive buildings with considerable roof space, smaller establishments may not be as equipped to handle such systems. Large solar panels and array fields spreading out over rooftops and fields also do not blend into natural surroundings as easily as many would like, which has hindered the acceptance of installing such systems.

Trumping both climate and space is the cost that is required to install solar panel systems. Significant investments are required to initially set up solar panels and power plants, and these costs have been the primary setback for implementation on a larger scale. Simply put, compared to current energy options, the cost of solar power is just not worth it for most people to convert.

Putting all of the disadvantages aside, it is obvious that the world is in need of alternative energy sources. Recent crises like BP’s Gulf oil spill and Japan’s nuclear power plant meltdown are constant reminders of the obstacles we face when relying on traditional fossil and nuclear power. Unless we are content with the notion that any number of similar disasters could arise anytime, a solution must be found. The US Department of Energy recognizes this, which is why they have set a goal to develop self sufficient solar energy systems that unlike countries such as Germany and Japan, do not require the need for government subsidies. Collaborative endeavors like the DOE’s SunShot Initiative are urging companies and researchers to invent new solutions that will in turn make solar power a viable option. Following are significant innovations making headway in overcoming the current limitations of establishing solar power as a primary source of energy.

Thin Film Technology

One of the reasons costs for traditional solar modules are so high is due to the actual cost of the panel materials, which are mainly comprised of glass. Establishing new ways to apply solar cells on less expensive materials could mean a breakthrough on lowering prices of these panels. Researchers at MIT are using this premise to apply solar cells to one of the cheapest materials available, paper. The technique includes printing solar cells on the paper substrate within a vacuum chamber, allowing the cells to be evenly deposited in five layers. The same process was used to print solar cells onto a sheet of flexible PET plastic, which was folded over 1,000 times without damage to demonstrate its resiliency.

Flexible Solar Cells Printed on Paper, Developed at MIT 

Flexible Solar Cells Printed on Paper, Developed at MIT 

Most promising is the idea that these thin flexible solar panels could be easily delivered to remote locations where classic glass panels would normally be impossible to transport. Applications for thin solar cells also include the ability to move beyond the current unattractive panels that are widely disliked. The flexibility of the material allows for the cells to be made into decorative and functional wallpaper or window shades. And if wallpaper can be created out of solar cells, why not also create flexible paperboard and plastic packaging? Imagine the potential. One day, your new iPhone may be packaged in a paperboard carton that not only protects your phone but also acts as a solar charger. Charging electronics through the cartons they are packaged in significantly increases the portability of such devices, making the rampant “on-the-go consumer” even more mobile.
 

Declining Costs

SunPrint, cofounded by Chris Rivet from MIT, has developed a way to dramatically cut costs of solar cells. The new process is called acoustic printing, which was originally developed by Xerox for ink-jet printers. The concept includes focusing sound waves onto a pool of ink, causing ink droplets to spatter onto a nearby surface. By adding cadmium telluride, a cost-effective solar cell material, to the ink, SunPrint was able to deposit the cells on glass, plastic and metal. The preciseness of acoustic printing allows for 50% less solar cell material use, eliminating extra tooling normally required.
 

Improving Efficiencies

Advances in solar cell efficiency are also making progress. Just recently, First Solar, Inc. announced a record for solar cell efficiency, achieved in their 2.5 hour vapor deposition manufacturing process of cadmium-telluride (CdTe) photovoltaic solar cells. These cells now reach 17.3% efficiency compared to previous efficiencies set in 2001 at 15.7%. Taking it one step further is SunPower, a world leader in solar panel efficiency at 22.4%. SunPower’s patented MaxeonTM silicon solar cells are what also allow the company to claim up to 50% more energy over conventional panels, which in turn require less space and fewer panels than conventional systems.

The highest efficiency rating however, goes to Spire Semiconductor who collaborated with the National Renewable Energy Laboratory (NREL), to produce concentrated

photovoltaic (CPV) solar cells with 42.3% efficiency. The competitive race between these companies to improve solar efficiencies will benefit all of those investing in these power systems including packaging manufacturers, and fortunately it seems like new efficiency records are popping up every day.
 

Solar Power Without Sunlight

One of the most recent and breakthrough solar technologies currently being developed at MIT, includes the process of converting photovoltaic energy solely through heat in the absence of sunlight. The conversion process includes a material with billions of nanoscale pits etched on its surface. As the surface absorbs heat, it is able to radiate energy at specific wavelengths (equal to photovoltaic wavelengths) that can be converted to electricity. The benefit is that any heat source can be used, whether it’s from the sun, hydrocarbon fuel, or from radioactive decay. Researchers were able to use this technology to create button sized power generators fueled with butane that run three times longer than the same sized lithium batteries. This technology is a way to efficiently scale down the conversion of energy to smaller devices, something that existing large mechanical systems are unable to do.
 

Transparent Solar Cells

Another groundbreaking solar innovation from MIT includes the development of transparent solar cells that are able to harness infrared light for energy. The advantage of these transparent solar cells is that they could potentially be applied to the interior of existing window panes, therefore eliminating the land and installation costs necessary for current solar power systems. Researchers created the new cells by combining a chemical formula based on organic molecules with a coating of partially infrared-reflective indium tin oxide, which successfully resulted in an efficient transparent part that performed better than past attempts at similar cells. Most importantly is the pure aesthetic advantage of this new system, which could conceivably change the overall acceptance of solar panels as a means of primary energy.
 

Solar Power Storage

As encouraging as the advancements in increasing solar cell efficiency are, what does it really matter if the energy captured in these cells cannot be stored and converted into power equally as well? BrightSource Energy has been concentrating on just that. The company has recently been recognized for their work in thermal storage, which allows for the generation of power even when the sun isn’t shining. Their solar thermal system uses power towers that house mirrors that focus the sun’s light on to a centralized tower. The light that’s generated produces temperatures higher than standard thermal solar systems, high enough to generate steam, which is then used to drive turbines. The storage system also includes heating and storing molten salt in a tank, which is then pumped through heat exchangers to generate the steam. This system allows BrightSource to produce 4,300 hours of electricity annually compared to that of standard thermal plants producing about 2,700 hours.
 

Solar’s Impact on Packaging

What does all of this mean for the packaging industry? To start, it’s best to understand the lifecycle that any particular package goes through and determine the stages at which energy is used. What’s realized is that almost every stage requires a certain amount of energy, including raw material extraction, production, disposal and transportation. Upon a closer look, energy is also used to grow the raw materials and build the factories, trucks, trains and boats that are required for any package to exist.

Companies like PepsiCo have already been making headway in using solar energy to power their manufacturing facilities. In 2010 they made a commitment to spend $30 million dollars over three years to develop green power in the U.S. A five-acre solar concentrator system was set up by PepsiCo in Modesto, California to support powering a Frito- Lay plant. The new system has helped the facility reduce electric energy by nearly 25%. A thermal solar system has also been implemented to create steam that is used to cook Frito-Lay chips. These initiatives along with others have helped in awarding the manufacturing site LEED® Gold existing building certification from the U.S. Green Building Council (USGBC).

Along with the installation of these new systems comes marketing, and producers have also begun advertising their efforts in using green energy solutions on the products they make. WindMade is a new initiative that plans to label products which are produced with wind power, similar to symbols which consumers are already familiar with like recycling and fair trade icons. The hope is that the new labeling will give consumers the option to choose products based on their environmental impact. With the start of promoting wind power directly on packaging it’s likely that other alternative energy sources, such as solar power, will soon follow suit.

The reality of packaging donning “Made with Solar Power” may actually be nearer than we think. As researchers continue developing new innovations to improve solar cell efficiencies and manufacturing processes, costs will eventually decline, making solar energy attainable for all. Additionally, with the multiple stages where energy is required to produce packaging, the opportunity is high for solar to work as a clean fuel source and reduce the dependency of fossil fuels. PepsiCo may be one of the first to jump on the solar bandwagon, but they definitely won’t be the last, so let’s see whose next in implementing solar power to improve the world of packaging.

 

Kristine Lickstein is the Packaging Technologies and Commercialization Engineer for Product Ventures.  Contact Kristine at 203.319.1119 or kwerner@productventures.com

 

View Article