Can I claim HST on my MicroFIT system?

Yes! Canada Revenue Agency allows HST claims on eligible MicroFIT projects. The purchase and installation of MicroFIT solar systems will be interpreted as a ‘Capital Personal Property’, which is eligible for an HST ITC. See here for a relevant information sheet:

https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/gst-hst-businesses/complete-file-input-tax-credit.html

Or you can skip the HST number and just capitalize the HST along with your system cost and connection cost, then depreciate the whole amount year after year. As always, consult a tax adviser for details.