Millions of children die annually from vaccine-preventable diseases. The problem is not the availability of vaccines, but the inability to provide effective vaccines due to vulnerability of the vaccine cold chain. EtC recognizes that the key to building an effective supply chain lies in building public-private partnerships that leverage the strengths and capacities of existing systems, technologies and infrastructures—a sustainable and scalable solution. By creating public-private partnerships with major telecom companies, ministries of health, global health organizations, NGOs and other private sector industry partners, EtC strengthens and extends country-wide systems for delivery, storage, and refrigeration of vaccines and essential medicines. Our fundamental insight is to use the power, distribution, and connectivity available at remote cell phone towers to provide the energy, data, and communications necessary to maintain and monitor a robust cold chain, thereby strengthening and extending the health system to address the needs of the most vulnerable populations.