Bosses want clarity on the Government's approach to renewable energy when the Energy Minister John Hayes speaks at a Lincolnshire conference.
Business leaders say the current message is "confusing" and could be discourage overseas investors from ploughing millions of pounds into the country.
Mr Hayes, MP for South Holland and the Deepings, will appear at Green Energy Lincs on Tuesday, November 20.
He will join industry experts at the Lincolnshire Showground event as they explain the latest opportunities in the renewables industry.
Dirk Terjung, of Stow-based Freewatt, last week told a panel of MPs in Lincoln: "I'm getting confused and so is the industry."
He later told the Echo: "It's not support, it's clarity on the long-term aims of what the Government wants to achieve that we need.
"I'm hoping Mr Hayes will offer a consistent message that is in line with the Prime Minister and Deputy Prime Minister's message about green energy."
Mr Terjung joined business figures at a Question Time-style event held by the Institute of Directors (IoD) on Friday, November 2.
Panelist Herman Kok, finance director at Lindum Group, said his company had taken the message that the Government "isn't interested in green energy".
"The message from the Government is confusing and it's a big issue for us," he said.
"In December we were ready to install solar panels on 400 schools across the country, which would have generated £35 million.
"In January that went down to 20 schools, because of changes to the Feed-in Tariff, and eventually it was four."
Karl McCartney, MP for Lincoln, defended Mr Hayes, who reportedly said wind farms were "peppered" across Britain and "enough is enough".
"What John Hayes said was that if we had all the projects that are in the pipeline we would by far exceed our targets," he said.
This week, Green Energy Lincs delegate Russell Wallis, a director at Globe Consultants, agreed a clearer message was needed.
"The more surety the Government can offer the better the situation will be," he said. "It will be useful if Mr Hayes could help provide that."
Green Energy Lincs, which is being organised by Lincolnshire Media and Footprint Renewables, will take place between 8.30am and 2pm.
To attend or book a stand, e-mail Sarah Carter on firstname.lastname@example.org or call 01522 820000.