Hydro Generators Market Size & Share, By Type (On-Site Generation, Portable), Capacity (Up to 100 W, 101 to 250 W, 251 to 500 W, 501 to 750 W, 751 W and above) - Growth Trends, Regional Insights (U.S., Japan, South Korea, UK, Germany), Competitive Positioning, Global Forecast Report 2025-2034