Many hybrid cars feature regenerative braking - they harness the energy generated when they brake, and store it in the battery for later use. This helps maximize the amount of time that the car can run on one charge. One can't help but wonder, then, how much energy could be harvested from heavy-duty construction, mining and agricultural machines, as they go about their business. A group of researchers from Finland's Aalto University decided to find out, and reportedly ended up cutting those machines' fuel consumption by 50 percent.

The Aalto team added electric power transmission systems (including motors) to a variety of existing internal-combustion non-road mobile machines, effectively turning them into hybrids. Unlike cars, these machines don't spend much time in stop-and-go traffic, so braking was not their primary energy-generation source. Instead, the majority of the energy came from work-related activities such as deceleration, and the lowering of loads.

The researchers are still in the process of determining which other actions provide the most energy.

By running partially on battery power derived from energy that they themselves generated, the test rigs use a claimed 50 percent less fuel. Such hybrid technology could also lead to lower emissions, better control, and more flexibility in the machines' design. Additionally, unused stored energy could be released into the grid.