For multinational enterprises (MNEs) to contribute to the far reaching commitment nations made at the 2015 Paris Accord on Climate Change, they must take up the task of introducing cleaner energy solutions. However, the efforts made by MNEs to innovate are fraught with uncertainty. Increasingly, MNEs are addressing this uncertainty by acquiring successful start-up firms working in cleaner energy technology spaces. Such firms are typically supported by venture capital (VC) funding – either from dedicated private VC firms or through VC activates of the MNEs themselves. Understanding how MNEs are able to promote the diffusion of clean energy technologies therefore requires attending to the strategies VCs and start-up firms use to navigate the inherent risks of innovation they confront. Attempting to convert society’s need for cleaner energy into a business opportunity exposes such firms to formidable technological, political, and economic challenges that cannot be anticipated beforehand. In this chapter, we identify the steps that investors (Khosla Ventures, KPCB, Intel Capital, and Google Ventures), and young firms (First Solar, Suntech, Tesla, and Better Place) took to make mitigate the risks. The chapter highlights the late and calculated entry of the VCs, their diversification, and the side-benefits for established firms like Intel and Google of having their corporate VC arms invest in cleaner technologies. For the start-up firms the risk mitigation techniques that the chapter brings to light are their reliance on patient capital, the flexible business models that they used, and their ability to gain and establish stakeholder confidence by adopting staged, but achievable, goals. Important lessons for MNEs aiming to commercialize cleaner energy technologies emerge from this chapter’s analysis. The uncertainty of investing in these technologies, especially in their most advanced forms, where they are really likely to make a dent in alleviating climate change, remains substantial. For MNEs to succeed in advancing the wide-scale adoption and diffusion of these technologies, they must hedge their bets. They must scan the activities of specialized ecologically devoted entities to determine where profitable opportunities may lie, broadly diversify their bets on these opportunities to assure that they have some likelihood of success, and try to secure for themselves some side-benefits in the face of inevitable failure. To build socially responsible cleaner energy businesses that enable the world to deal with challenge of climate change, they must be patient in their support, flexible in the strategies they adopt, and careful about the scope of their goals to assure that they are achievable.