  In the face of a substantial and uncertain growth of behind-the-meter
Distributed Energy Resources (DERs), utilities and regulators are currently in
the search for new network planning strategies for facilitating an efficient
Transmission & Distribution (T&D) coordination. In this context, here we
propose a novel distribution system planning methodology to facilitate
coordinated planning exercises with transmission system planners through the
management of long-term DER growth uncertainty and its impact on the substation
netload. The proposed approach is based on the design of a transmission-aware
distribution planning model embedding DER growth uncertainty, which is used to
determine a "menu" of secure distribution network upgrade options with
different associated costs and peak netload guarantees observed from the
transmission-side, referred here as Netload Range Cost Curves (NRCCs). NRCCs
can provide a practical approach for coordinating T&D planning exercises, as
these curves can be integrated into existing transmission planning workflows,
and specify a direct incentive for distribution planners to evaluate peak
netload reduction alternatives in their planning process. We perform
computational experiments based on a realistic distribution network that
demonstrate the benefits and applicability of our proposed planning approach.
