He planned a major speech Thursday at the Columbus convention center outlining the look and direction of his administration if elected.
McCain's focus on green technology followed his speech Monday -- an attempt to distance himself from President Bush and Republicans in general -- declaring global warming real.
Going green resonates in a state with seven ethanol plants under construction and Democratic Gov. Ted Strickland pushing Ohio utilities to have 12.5 percent of their total power portfolio come from renewable resources, such as wind, solar and water, by 2025.
As a result, Democrats aren't ready to concede the issue to someone they see as a recent environmental convert.
"John McCain's campaign rhetoric doesn't match up with his long record of opposing common sense renewable energy proposals in the Senate," Ohio Democratic Party Chairman Executive Director Doug Kelly said Wednesday.
Distortions and false accusations, responded McCain spokesman Brian Rogers.
"The reality is John McCain has been an incredibly foresighted leader on the issue of climate change," Rogers said. "He has actually earned the praise of both Barack Obama and Hillary Clinton for his leadership on the issue."
McCain first sponsored a global-warming bill with Independent Sen. Joseph Lieberman, then a Democrat, in 2003.
Ohio is a must-win state for any candidate running for president. No Republican has gone to the White House without winning here and only two Democrats in more than a century. The state re-elected President Bush in 2004.
A Gallup Poll last month found the two Democratic presidential contenders with slight leads over McCain in states that were closely contested four years ago, including Ohio.
On April 22, McCain ventured into Youngstown where he defended the North American Free Trade Agreement in a city hard hit by manufacturing losses that many blame on free trade. One union official quipped that day that NAFTA was a four-letter word.
May 1, McCain explained his plan to provide a $5,000 refundable tax credit for families to seek their own health care at a campaign stop at the Cleveland Clinic research hospital. The stop was part of a cross-country swing spent discussing his health care plan.
Gov. Ted Strickland, a supporter of Hillary Rodham Clinton, says McCain is vulnerable on health care issues because he hasn't backed states who want to use a federal health insurance program to cover more poor children.
Rogers says McCain's approach is part of his upfront campaign style.
"He's not afraid to sometimes disagree, but at the end of the day voters know that John McCain is giving them straight talk, and being honest about the challenges that the country faces and how he thinks we need to move forward," Rogers said.
Political scientist Joe White says McCain is doing nothing more than the "delicate dance of reaching out and shoring up your base."
"The way you usually do this is say different things in different places," said White, chairman of the political science department at Case Western Reserve University. "You go around the country appealing to different groups in different ways, talking to different constituencies. If you can do it in swing states, all the better."