Could renewable sources meet 100 percent of our energy demand? Yes, according to new research which scrutinises the arguments against. "There are no roadblocks on the way to a 100-percent renewable future," the research states, while pointing out that existing research already holds the answers to the common objections raised.

The article is a direct response to a review paper published in the journal Renewable and Sustainable Energy Reviews last year, written by Benjamin Heard and colleagues. This questioned a 100-percent renewable future, raising the risk of extreme weather events causing low sunlight and wind availability, as well as the ability of electricity grids to handle a high degree of variation in source power.

In response, scientists have scrutinized dozens of existing studies to address the concerns of last year's paper one by one. Their conclusion? There is nothing stopping a future when all our energy is provided by renewable sources. "Here we analyse the authors' methodology and find it problematic," the response says.

The new research counters that the technology already exists to address the supply concerns raised, pointing to synthetic gas, itself produced by renewable energy in times of surplus, as just one way to make up the temporary energy deficit in a worst case scenario.

They reject the claim that 100-percent renewable energy would require a "re-invention" of the power system – stating that "directed evolution" is sufficient instead, with the technologies needed for grid regulation already being used in many countries.

"While several of the issues raised by the Heard paper are important, you have to realize that there are technical solutions to all the points they raised, using today's technology," says lead author Tom Brown in a press release.

"Furthermore, these solutions are absolutely affordable, especially given the sinking costs of wind and solar power," adds co-author Christian Breyer.

Though the original research correctly states that Iceland is the only 100-percent renewable nation, the response points out that there are regions of other countries, including Germany, New Zealand, Scotland and Denmark, that have also achieved 100-percent renewable energy. Further, there are other countries getting very close, with Paraguay (99 percent), Norway (97 percent), Uruguay (95 percent) and Costa Rica (93 percent) top of the list.

The new paper highlights an example raised in the original research of an energy blackout in South Australia, blamed on wind as the power source. However, the new article counters by saying that subsequent improvements to the controls would have prevented the blackout, and that this wasn't down to a fundamental shortcoming in wind energy.

"There are some persistent myths that 100-percent renewable systems are not possible," adds co-author Brian Vad Mathiesen. "Our contribution deals with these myths one-by-one, using all the latest research. Now let's get back to the business of modelling low-cost scenarios to eliminate fossil fuels from our energy system, so we can tackle the climate and health challenges they pose."

The scientists come from five bodies: the Karlsruhe Institute of Technology, the South African Council for Scientific and Industrial Research, Lappeenranta University of Technology, Delft University of Technology and Aalborg University.

Their article appears in the same journal that the original was published in, Renewable and Sustainable Energy Reviews.