One question that gets asked periodically is how green are technologies like solar panels given that there much be some emissions created in their manufacture and ultimate disposal.
It’s probably no surprise that the rooftop solar PV is considerably less carbon-intensive than any fossil fuel (1/20th of coal for example) but that it beats biomass or even utility scale solar (I.e. solar farms) may be a surprise. My understanding is that the recent switch of emphasis in the UK from rooftop solar (with elimination of FiTs) to solar farms is driven more by investment costs than ultimate carbon-intensity.
Source: Intergovernmental Panel on Climate Change (IPCC) as quoted by Spirit Energy