The positive reaction in ALCE's stock price can be attributed to the market's optimistic view on the joint venture's potential to generate significant value through the development of renewable energy projects. The partnership with Acadia Energy, a company with a strong track record in the region, and the focus on sustainability and local economic growth are likely seen as strategic moves that will enhance Alternus's position in the renewable energy market. The announcement of the joint venture and the expected start of operations within two years provide a clear timeline for anticipated progress, further boosting investor confidence.