https://energysavingtrust.org.uk/renewable-energy/heat/solar-water-heating
https://energysavingtrust.org.uk/renewable-energy/electricity/solar-panels
https://www.energy.gov/eere/solar/articles/solar-photovoltaic-technology-basics
https://www.energy.gov/eere/wind/how-do-wind-turbines-work
https://www.gov.scot/binaries/content/documents/govscot/publications/advice-and-guidance/2013/03/microgeneration-planning-advice/documents/microgeneration-pdf/microgeneration-pdf/govscot%3Adocument/Microgeneration.pdf
