Respecting the question as to whether income earned by an individual taxpayer from the sale of electricity generated from a solar photovoltaic system to the Ontario Power Authority would be included in the computation of the income of the taxpayer from his business of operating a roofing business, CRA stated:
The CRA will generally consider income from activities undertaken outside the normal business operations of a taxpayer to be from the same business if the activities are incidental to the taxpayer's normal business operations and the income generated by these activities is not material in relation to the taxpayer's business revenue. The expression "incidental" is not defined in the Income Tax Act...but implies a subordinate relationship or "having a minor role in relation to". Factors that may be relevant in the determination of whether a particular activity is incidental to another would include the income generated and the capital or labour invested in each activity.