Inspections of Renewable Heating Incentive (RHI) boiler sites are to begin imminently.
However, the number being visited, at least in the initial stage, is nowhere near the 100% promised.
At least 20 sites will be visited in the first phase of a planned inspection programme. A second phase will then be put out to tender in late autumn.
There are 1,270 businesses with 2,100 boilers in the scheme.
Half of the inspections will be announced, the other half unannounced.
Inspectors will be looking for evidence that the boilers are producing useful heat and the owners are complying with the regulations.
If they are not, officials may be able to place conditions on how the boilers are being operated.
The Renewable Heat Association, a group representing hundreds of RHI boiler owners, said it welcomed the beginning of the inspections process.
But it added that the announcement had been "broadcast on Twitter" by the Department for the Economy.
It said it is concerned that "all communications" between the department and RHI scheme beneficiaries "had broken down".
The RHI scheme was an attempt by the Northern Ireland Executive to help to increase consumption of heat from renewable sources.
But flaws in setting the scheme's subsidy rate left it open to abuse as claimants could earn more cash the more fuel they burned, with the overspend estimated to be about £490m.
There was an outcry last year after claims that boiler owners were generating overgenerous subsidies from a scheme with no cost controls.
There were also allegations of abuse, with heat being generated just to claim the subsidy.
A plan for 100% inspections had to be shelved earlier this year after problems identifying a suitable contactor to do the work.
It was meant to have started in May and be finished by November of this year.
But officials now believe that specification was too ambitious given the workload and the timeframe.
A complete inspections process was a key plank of a Northern Ireland Executive plan to restore public confidence in the handling of the controversial scheme.
It is thought that lessons learned in the first 20 or so inspections will be applied when the second stage is put out to tender.
That tender will cover the balance of the sites, and while it is thought a considerable number could be seen, not all may be inspected under this process.
If officials see evidence from quarterly meter readings of a change in how boilers are being used they may suspend accelerated inspections, unless a minister demands otherwise.
Inspection rates would then revert to the scheme standard that would see installations inspected at some point in their 20-year contract.
The energy consultants, Ricardo, have been given the contract for the first phase of inspections.
It has knowledge of the Northern Ireland scheme as it does inspections for the regulator Ofgem.