SAN FRANCISCO – Elon Musk has proposed  combining his electric-car and solar-energy companies, in a bold effort to consolidate his holdings and offer widespread clean-energy products from vehicles to power in homes.

Musk wants to combine Tesla Motors with SolarCity Corp. On Tuesday, he made a stock offer to acquire the portion of SolarCity he does not own for $2.8 billion. Musk is the chairman and largest shareholder of both companies, The Wall Street Journal reported.

Tesla in a letter to SolarCity’s chief executive said its offer represented a value of $26.50 to $28.50 a share, or a premium of roughly 21 percent to 30 percent over SolarCity’s Tuesday closing price of $21.19.

Musk, who has garnered attention for unusual financial maneuvers to support his companies, recused himself from voting on the deal at the Tesla board meeting at which it was approved and will do so for any vote on the SolarCity board as well, the letter said. Antonio Gracias, a director on the boards of both companies, also recused himself, the letter said.

Tesla said the deal is subject to approval of “a majority of disinterested stockholders” of both companies, suggesting Musk will also recuse himself from the shareholder voting.