The integration of distributed energy resources (DERs), such as renewable energy (RE) and energy storage systems, can have many environmental and economic benefits. The sharing of medium-scale DERs can enhance these benefits by ensuring efficient resource utilisation and can promote sharing economy and economies of scale opportunities. In this paper, we design a combinatorial double auction (CDA) for DER sharing between multiple DER providers and a community of consumers. The proposed DER market addresses the complementarity of DER services and supports the environmentally sustainable behaviour of consumers. The purpose of the proposed auction is to allocate the limited DER resources efficiently without compromising the privacy or the comfort of consumers. First, the combinatorial bidding rules are designed and the social welfare optimisation problem is formulated. Then, utility maximising strategies for consumers with both economic and environmental objectives are proposed. Additionally, three types of DER providers are introduced, and their revenue maximising strategies are investigated. A case study with real world RE