As energy prices rise and both environmental awareness and concerns increase, interest in renewable energy (RE) systems is growing rapidly. Media coverage is at an all-time high, but RE literacy isn’t necessarily keeping pace with the interest and reporting. Not everyone reading or reporting on the technologies understands the basic concepts and terminology, which makes confusion more likely.
Key Energy Concept
If you only have time to understand one energy concept, make it kilowatt-hours.
Kilowatt-hours is a fundamental measure of energy, commonly applied to electricity, but also useful as a more general measure. Utilities sell us kilowatt-hours, and RE system owners “sell” renewable kilowatt-hours back to the utilities or put them into their battery banks. A kilowatt is a completely different animal—it’s the rate of energy generation, use, or transfer (also called “power”). A kilowatt is like miles per hour (a rate), while a kilowatt-hour is like miles (a quantity).
When it comes to solar energy, understanding daily peak sun-hours is critical to good system design and performance projections. This is not something you observe, but a measured value of how much solar energy your site gets over the course of the year, accounting for weather, but not for shading. In Canada average daily peak sun-hours vary from about 1.2 to 6.6, with most sites falling in the 3 to 5 peak sun-hours range. You can check your areas sun hours here.
Using wind as your renewable resource? The most important concept for you to understand is average wind speed. While utility wind farmers use more sophisticated measurements, simple average wind speed is enough to make realistic design choices for small scale sites. Home-scale wind sites fall in the 10 to 18 kph average wind speed range, with most below 18 kph average. This is not an instantaneous speed, nor is it a rough guesstimate or observation. Without it, you can only guess about how much energy you might get from a wind generator. You can check your areas average wind speeds at https://www.windfinder.com/#10/47.5770/-52.9802
Hydroelectric system production is based on two factors. One is head, the vertical distance between where you take the water out of the stream and the turbine. The other is flow, commonly measured in gallons per minute. These are equal factors in the hydropower equation, so doubling or halving either will double or halve production. You need either significant head or flow (or both!) to make a significant amount of hydro-electricity.
These basic terms will get you started on understanding renewable energy concepts. Understanding and using the terms of the trade clearly and carefully will help you have reasonable expectations, and then reach them!