Three New Innovative Ways To Capture And Use Solar Power

Looking beyond the simple rooftop photovoltaic panels, there are a number of exciting new options for efficient and innovative ways to capture solar power.

High-efficiency indoor solar cells working with artificial light

We are used to installing solar cells outdoors on roofs to harvest sunlight, but what about the light energy inside our buildings that is going to waste? Sunlight typically shines around 110,000 lux while interior lighting is usually between 100 and 500 lux. These indoor values may seem quite low, but researchers at Tor Vergata University of Rome, Colombia’s Universidad Surcolombiana, and the Fraunhofer Institute in Germany have designed a model that makes it an efficient energy source. The team says the new system of flexible perovskite solar cells possess the highest efficiency of any indoor flexible solar cells.

• These solar cells are made of an ultra-thin (100 micrometer) flexible glass, with transmittance of more than 80%, and that is coated in indium tin-oxide (ITO). The latter is a transparent conductor that enables the passage of light as well as the flow of current. 
• The cells are both bendable and strong, and can harvest light in environments with low illumination.
• The team conducted several tests under LED illumination and found that the cells reach efficiencies of 20.6% under 200 lux, and 22.6% under 400 lux. 
  
• These efficiency levels are the highest ever recorded of any flexible and curvable photovoltaic cells designed for indoor use, according to the researchers. As the power density is relatively low, they could be used as indoor light harvesters for low-power electronics, small wireless sensors or Internet of Things devices.
• The roll-to-roll fabrication process that they used for the indium tin-oxide coat could also be applied to other layers of the solar cell, to lower the manufacturing cost — meaning that these cells could be relatively cheap to produce on a large scale.

Solar canopies over waterways

Solar panels are usually set up on rooftops or in open lands, but the latter can be problematic if it disrupts natural habitats or takes croplands out of agricultural production. This is why many companies are working to find new areas for solar deployment such as canals, train lines, parking lots or highways. P4P Energy, a company based in Colorado in the United States, has created an innovative design to reduce the amount of racking required to support the solar panels. This has enabled the company to install several solar canopies over canals in India. The waterways stretch for thousands of kilometers to supply the country’s agricultural region and now thanks to the over-canal solar panels, they can also provide electric power to villages.

• The design of these canopies rely on long string cables to support the panels instead of fixed racking. This cabling system helps reduce the cost of the equipment and also provides a more aesthetic design with the natural curve.
• P4P Energy estimates that the over-canal structures can help reduce evaporative water loss by as much as 15 million cubic meters annually for each gigawatt of installed capacity, which could be a real benefit for areas regularly subjected to drought.
• The structures can be adapted to canals from 15 to 100 meters wide, address different canal orientation, be placed at various heights above the water and according to the company, are 40 to 50% lighter than rigid structures.
  

Trucks as mobile solar parks

Heavy-duty vehicles such as trucks and semi-trailers are extreme polluters, emitting around 130 grams of CO2 per kilometer. They also consume a large amount of electricity produced by the alternator — another source of pollution, which is aggravated when the truck is idling. That is why Dutch start-up IM Efficiency is working on the project SolarOnTop, to empower trucks with onboard clean energy by installing solar panels on their roofs, with the hope of reducing costs and emissions.

• The panels are a few millimeters thick and therefore do not add extra weight on the truck. The company has conducted long-distance tests that have proved that up to 5.5% fuel costs can be saved — thanks to a lower load on the engine when driving and as idling to generate electricity becomes unnecessary. 
  
• Depending on the type of journey and vehicle, this could mean a typical annual saving of €2,500, and 6,000 kilograms of CO2 per truck.
• Adding solar panels can also help lower maintenance costs and extend the life of the truck’s battery. The panels can also be used to power other devices such as liftgates and pallet jacks.
• IM Efficiency is planning a final four-month practical test starting in June 2020, in cooperation with several companies, to collect data for the manufacture of the panels.