Apple, Google, Tesla and SolarCity dominated our traffic this year. We also saw readers drawn to the cheapest and biggest solar plants in development.

Here's what our readers were most interested in.

1. The mystery around where Tesla would site its Giga factory for batteries

2. Why Google engineers stopped R&D efforts in renewable energy

3. Is Apple ready to get into the connected home market in a big way?

4. The Ivanpah CSP Plant finally went on-line. Will more CSP follow?

5. Would Solar Roadways Actually Work?

6. Topaz, the World's Biggest PV Project, Finally Became Operational

7. Will Batteries Paired With PV Create an Unstoppable Force on the Grid?

8. Austin, Texas Purchases Some of the Cheapest Solar Ever

9. Why Tesla's CTO Says We Should Be Thinking Bigger About Batteries

Photo: Niall Kennedy via Flickr

10. Are Tesla and SolarCity a Utility's Worst Nightmare or Its Best Business Opportunity?