Learn Dutch: Vanavond is de spanning zo hoog dat we niet slapen. - Tonight the tension will be so high that we won't sleep.

In Dutch, it is very common to use the present tense to talk about the future. Because the sentence starts with the time word Vanavond (tonight), the future context is already clear. You don't need to add a future auxiliary verb like zullen (will), so both clauses just use the simple present tense.

Why is the word order is de spanning instead of de spanning is?

This happens because the sentence starts with the time word Vanavond. In a standard Dutch main clause, the verb must be the second idea in the sentence. Since Vanavond takes up the first spot, the verb is takes the second spot, forcing the subject de spanning to move after it. This swapping of the subject and verb is called inversion.

Why does the verb slapen go at the very end of the sentence?

The word dat (that) links the two halves of the sentence and introduces a dependent clause. In Dutch dependent clauses, all conjugated verbs are pushed to the very end. This is also why niet appears right before the verb here, rather than after it as it normally would in a main clause.

Does spanning only mean negative "tension" or stress?