Pull into any truck stop in the early evening hours and you are likely to see rows of trucks all idling even though drivers are enjoying their evening meals or already bedded down for the night. That idling is the result of diesel-powered auxiliary power units (APUs) generating electricity for air conditioning, refrigeration, and general AC power needs.
The diesel-powered APU is nothing new to trucking. According to C.R. England, just about every truck on America’s roads is equipped with one. However, the industry may begin phasing APUs out in the near future if solar technology proves to be equally robust and more cost-efficient.
Fitting Trucks with Solar Panels
Engineers have been thinking about solar panels on trucks for decades now. This is by no means a new phenomenon. The problem though, at least until recently, is that solar panels have been too big and bulky to install on truck cabs and trailers. The amount of aerodynamic drag they create eliminates any savings that might be enjoyed by installing them. Thus, diesel-powered APUs have continued as the mainstay.
Modern technology is on the verge of changing that, thanks to flexible solar panels that can now be installed flat on roof fairings and trailers alike. Their thinner construction and lower profile reduce the aerodynamic drag to a negligible level. Along with these new panels are better deep-cycle batteries that can store more energy for a longer period of time.
The Benefits of Solar
Even with the new solar panels and batteries, no one is ready to completely replace the diesel-powered APUs. Yet the benefits of incorporating solar technology are undeniable. In short, solar systems reduce the amount of work diesel APUs have to do. Here are just a few examples:
- Additional Cooling Time – Solar systems provide supplemental electricity for running a truck’s cooling system, adding anywhere between four and six hours of total cooling time. That means more cooling time without spending more money on additional diesel fuel.
- Longer Battery Life – Solar systems tend to increase battery life. One trucking company told Trucking Info that they used to replace a truck’s batteries every year before adopting the solar system they are now currently using. Batteries now last years before needing replacement.
- Keeping Batteries Charged – Another trucking company told Trucking Info than their solar systems help to keep a truck’s batteries charged in cold weather. This is important for carriers that operate in environments with seriously harsh winters. The company estimates their 150 solar units will pay for themselves within 3.5 years.
- In-Cab Refrigeration – Finally is the issue of in-cab refrigeration. Truckers are normally instructed to clean out refrigerators and turn them off if they plan to be out of the truck for at least 24 hours. With a solar system that is no longer necessary. Refrigerators can be kept running without any additional fuel required.
Bringing solar to the trucking industry has the potential to save quite a bit of money on fuel. That is important because the single biggest expense of trucking after labor is fuel. Anything carriers can do to save fuel is a good thing. If they can also reduce the workload on their APUs, that also means less pollution created by trucks that idle for 10 to 12 hours at a time.
Next time you are driving down the highway, do not be surprised if you see a truck with solar panels mounted on the cab or trailer. Solar systems are likely to catch on pretty quickly now that major carriers have proven their effectiveness for generating auxiliary power.