Ms Greig was giving evidence with other specialists and experts as part of the committee's inquiry into the Scottish government's renewable energy targets at 10am on 28 March 2012.
The government has published its plans for renewable energy to provide 100% of Scotland's electricity needs by 2020.
The director of commercialisation and business development at Carnegie College was answering a question put to the panel of witnesses from SNP MSP John Wilson, who asked did Scotland have the skills base to reach its renewables targets by 2020.
Ms Greig said: "No, because we're not even taking into account people who are leaving or the fact we have a work force skewed over 35 years old." In answer to the same question Jim Brown from Scotland's Colleges Energy Skills Partnership said "I think we can".
Gordon McGuiness from Skills Development Scotland said: "Our intention is to put infrastructure in place to meet the target".
Rob Moore from National Skills Academy of Power said: "Potentially, but it's going to take a lot of work, if we don't do anything differently then, no".
And Professor Sean Smith from Edinburgh Napier University said: "I doubt it, and my main concern is the other sectors pulling away some of the resources and the likes of Green Deal is going to pull a huge amount of resource, and it is a slow car crash waiting to happen."
Earlier Ms Greig said the level of employees ready to work in the renewable sector was "worrying".
She said "To go through an apprenticeship we're really talking about four years, five years in some cases.
"And when you start to look at the targets and what has to be achieved by then that's worrying because this idea that there is a group of people out there just waiting to be employed is not the case".
Ms Greig said her college was starting a new transition course in December to try and get adults into the renewables sector.
The committee then took evidence from Andrew Scott from Pelamis Wave; John Robertson from BiFab; Martin McAdam from Aquamarine Power; Robin McLaren from the Institute of Engineering and Technology and Simon Forrest from Nova Innovation Ltd which will be available to view below:
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