Luke Skelton, 20, took pictures of targets and wrote about starting a race war that would kill thousands of people, Teesside Crown Court heard.
He was found guilty of one count of preparing a terrorist act.
Prosecutors said he was dangerous, but his lawyers argued his autism made him vulnerable to radicalization and he did not actually intend an attack.
Skelton, from Washington, was arrested in October 2021, a month after taking pictures of Forth Banks police station in Newcastle.
He was found to have researched bomb-making and used the username Adolf Hitler in online communications in which he espoused extremist views and discussed starting a race war.
Prosecutor Nick de la Poer KC said the chance of Skelton succeeding in a bomb attack was "not very likely," but some notes he wrote implied he wanted to enact a "significant terrorist atrocity"”
One message talked about triggering a "racial war" for which he blamed the government, adding that the "number of dead" would be in the thousands.
The prosecutor also said these were not "impulsive" thoughts but a "preoccupation for a lengthy period of time"”
Skeleton targeted Forth Banks police station
In mitigation, Crispin Aylett KC said Skelton had autism which made him more prone to radicalization.
He said the planned attacks discussed in emails and social media chats were "nonsense" and "lunatic" suggestions which Skelton "lost interest" in and then "changed his mind" about actually going through with.
Mr. Aylett said Skelton did nothing more than take pictures, and even if he had built a device, it would have been so small that any risk of death to anyone "would be not very likely."
Skelton took pictures of the police station a month before he was arrested, and in that time, he did nothing more to prepare an attack, the court heard.
His Honour Judge Paul Watson KC, the recorder of Middlesbrough, said Skelton was a "committed and active right-wing extremist dedicated to white supremacy and provoking racial hatred" who had also openly expressed attacking multiple minority groups.
He said Skelton "made heroes of those who carried out atrocities in the names of fascism," and his fantasy was to "turn back the pages of the history books" when such xenophobic and hate-fuelled views were "tolerated and admired," adding he wanted a "full-on war.”
The judge said Skelton was "entitled" to his right-wing views thanks to the very society he wanted to attack, but he went "far beyond testing the boundaries of freedom of thought and expression," and they were "not empty fantasies," and he was "committed to using violence to propagate [his] beliefs.”
He said there were several attempts to deradicalize Skelton, but they failed, such was the-then teenager's "all-consuming obsession.”
The judge said Skelton wanted to risk multiple lives, but he lacked the "intellectual, financial or technical wherewithal" to build a bomb capable of causing "even modest injury.”
He said: "Despite your extremist ambitions, you would have never been capable of creating anything remotely viable."
The judge said Skelton was diagnosed with autism at the age of six and had a "borderline level of functioning" but high verbal skills, which made people think he had a higher intellect than he did.
He said Skelton was "isolated" as a child, and the right-wing extremism he became obsessed with as a teenager in 2019 may have given him a "sense of excitement and purpose which [he] readily latched on to.”
The judge also said the offenses were committed against the background of "loneliness" of the coronavirus pandemic.
Skelton was jailed for four years with a further year to be served on an extended license and made subject to a serious crime prevention order.
He was found guilty of the offenses in May after a jury the previous year failed to reach a verdict.