, in New Delhi on 31 May 2019. There was speculation that Singh would contest from the Bihar constituencies of either
Arrah or
Supaul in the
2014 Lok Sabha polls, though
Rashtriya Swayamsevak Sangh objected to him contesting from Supaul. On 13 December 2013, Singh joined the BJP. He contested the election as a BJP candidate in Arrah, beating his nearest rival, Sribhagwan Singh Kushwaha of
RJD by a margin of over 1,35,000 votes. In the
2019 General Elections conducted for the formation of the
17th Lok Sabha, he again contested from
Arrah and retained his seat becoming the first MP from Arrah since Chandradeo Prasad Verma to retain his seat in successive elections. He defeated his nearest rival Raju Yadav of
CPI (ML) Liberation by 1,47,285 votes. On 3 September 2017, Mr. Singh was appointed Minister of Power (Independent Charge) and Minister of New and Renewable Energy (Independent Charge) by
Narendra Modi. This post was previously held by
Piyush Goyal. In the
2024 Indian general election he lost his MP seat from Arrah, Bihar to
Communist Party of India (Marxist–Leninist) Liberation candidate
Sudama Prasad by the margin of 59808 votes. In September 2025, Singh claimed that his 2024 loss was due to a conspiracy by several BJP and
JD(U) leaders, stating that the BJP had ignored his concerns about independent candidate
Pawan Singh contesting against him and that several sitting
MLAs and
MLCs from the two parties had campaigned against him. Later that month, he again came into conflict with the party leadership after asking Bihar deputy chief minister
Samrat Choudhary (BJP) to either step down or respond to allegations made by
Jan Suraaj party leader
Prashant Kishor that Choudhary had lied about his age to avoid prosecution in a 1995 murder case and had also misrepresented his educational qualifications on election affidavits. In November 2025, days before the
2025 Bihar Legislative Assembly election, Singh accused the National Democratic Alliance-led Bihar government of purchasing electricity from
Adani Power Limited at inflated prices, estimating that the markup would cost the state
₹62,000 crore over the span of 25 years. On 15 November, Singh resigned from the BJP after being suspended for anti-party activities, stating that he could not defend himself because no specific offence had been cited and that he believed he was being targeted for suggesting the party avoid giving tickets to members with criminal backgrounds. == Personal life ==