The researchers found that their source was able to produce just 25 percent of the energy of other experimental sources, but the neutrons produced were 10 times as energetic and 10 times more plentiful.
So, "energy production", is actually energy not going into the production of neutrons from the nuclear reactions, and is actually energy released as waste. In other words, the smaller the energy output, the more desirable the reactions if more energetic and more plentiful neutrons are desired.

This is a great development, because neutron spectroscopy is a very important and very useful analytical method. This will put the edge of science well ahead.

"The researchers found that their source was able to produce just 25 percent of the energy of other experimental source"

So does this mean this new method was 4x more efficient or 4x more wasteful? Was it producing more energetic neutrons while using up less energy?