renewable

1. ADJ Renewable resources are natural ones such as wind, water, and sunlight which are always available. (资源) 可再生的

...renewable energy sources. …可再生能源。

2. ADJ If a contract or agreement is renewable, it can be extended when it reaches the end of a fixed period of time. (合同、协议) 可延长有效期的

A formal contract is signed which is renewable annually. 签署的一份正式合同每年可续签一次。