Wikimedia Commons conducts a monthly photo competition with 1/2 themes. The theme for the month of May 2018 is Renewable Energy. Those interested can submit your entries using the link below.
Commons:Photo challenge/2018 - May - Renewable energy - Wikimedia Commons
P.S - You will first need to upload your pictures by creating a account on their platform and link those pictures using the script editor. If you need any help, let me know.