When muscle cells have more glucose than they need for energy, they may store some of the excess as?

I think the answer is glycogen. Glycogen functions as one of the two forms of long-term energy reserves, with the other form being triglyceride stores in adipose tissue. In human body, glycogen is made and stored primarily in the cells of the liver and skeletal muscle. In the muscles it is the primary fuel the muscles use for energy production.