The text book “Understanding Renewable Energy Systems, for a sustainable future” released in both printed and e book formats. Brings together the essential elements needed to gain an understand of the basic principles of, Energy, Energy Auditing, Solar Energy, Wind Energy and Micro Hydro , energy systems This resource includes; an understanding of basic electrical systems both AC and DC, safety , wind, micro hydro, stand-alone, hybrid, grid, connected systems. Alex Thorogood, Chris Thorogood