Where can you find the largest number of cleantech startups under one roof? Try Somerville, which is home to Greentown Labs, a co-working space that’s three years old this week. That might come as a surprise; there’s a feeling that energy companies are down when it comes to investment. But Greentown’s 40-odd startups, including Altaeros Energies, Dynamo Micropower, and Grove Labs, are working around traditional venture capital and going straight to corporate partners and customers. This is a hot area to watch as we wait to see what’s next for green energy in Massachusetts.

In other innovation news:

• Boston cloud-software startup Stackdriver has been acquired by Google for an undisclosed sum. In recent years, the search giant has also acquired local firms ITA Software and Boston Dynamics.

• Our deal of the week is LogMeIn’s $12 million acquisition of software firm Ionia. The merger of the two Boston companies fits with the rise of the “Internet of Things”: more devices and appliances are becoming connected to the Web.

• And lastly, Cambridge-based InsideTracker has raised a venture round to advance its online platform for giving nutrition recommendations based on a blood sample. As giants like Apple dive into personal health, the startup is banking on the idea that what’s going on inside your body is more important than any wearable activity monitor. And also, you should probably cut back on all that salty restaurant food.