CAS Energy is a pioneering Vietnamese startup in the field of energy and environment, founded on more than 20 years of experience in implementing climate adaptation systems. More than just a technology provider, CAS Energy positions itself as a comprehensive solution designer, offering low-cost, scalable green models tailored especially for small and medium-sized enterprises (SMEs) in Vietnam—a group often left behind in the green transition due to financial and infrastructural limitations.
The company’s flagship product is the REGreen green service model. This integrated solution enables SMEs to achieve three goals simultaneously: using renewable energy through solar power systems, processing organic waste onsite, and developing green spaces within industrial zones, factories, or urban areas. Notably, the model does not require upfront investment from businesses. Instead of bearing high installation costs for solar systems, companies simply pay a periodic electricity bill at a lower rate, thanks to an energy-as-a-service model developed and operated by CAS Energy. This service-based model effectively addresses one of the biggest barriers preventing SMEs from adopting green solutions: financial constraints.
Compared to other green energy solutions currently available in the market, REGreen stands out for its flexibility, high feasibility in resource-limited contexts, and most importantly, its tangible social impact. During the rollout of REGreen, CAS Energy has created green jobs for middle-aged women and farmers who have lost their livelihoods due to urbanization and industrialization. These vulnerable groups are trained to operate and maintain the systems locally, contributing to the creation of a sustainable community-level green value chain. This is a rare achievement in Vietnam’s renewable energy sector—successfully combining environmental effectiveness with meaningful social impact.
REGreen goes beyond simply applying solar energy—a relatively familiar concept—and focuses on integrating existing solutions into an efficient, accessible, and highly replicable operating model. Instead of developing new technologies from scratch, CAS Energy optimizes existing systems by combining clean energy generation, onsite organic waste processing, green space development, and flexible financing. The startup’s research and development journey has taken place not just in laboratories, but primarily in the field—within businesses, industrial zones, and local communities. Through this practical approach, CAS Energy has continuously refined the REGreen model to suit various implementation scales and conditions, helping to drive grassroots-level green transformation.
In 2024, CAS Energy signed an initial investment agreement with the impact investment fund Beacon Fund to promote renewable energy projects in combination with circular agriculture and climate-smart farming in Vietnam.
At the P4G Vietnam Summit 2025, CAS Energy had the opportunity to showcase its REGreen model to international partners through existing networking channels. This event significantly raised the startup’s visibility, connected it with impact-focused investors, and opened up new opportunities for regional expansion.
Looking at CAS Energy’s journey, there are valuable lessons for green technology startups. The first is the importance of a model-driven mindset rather than a product-centric one. Technology does not always have to be new; what matters is how it is integrated into solutions that deliver real value—especially to vulnerable groups with limited access. Second is the importance of understanding the domestic market and building solutions rooted in local needs, rather than importing foreign models without adaptation. Finally, it shows how a startup can expand its influence by aligning technology, finance, and social impact within an ecosystem eager for transformation—like Vietnam’s.
In an era where green transition is no longer a trend but a survival imperative, models like REGreen by CAS Energy are proving that even small and medium-sized enterprises can take part in this journey—provided that the solutions are smart, adaptable, and deeply empathetic to the real needs of the community.
