I would think that whether or not 'election' should be plural would be dependent upon how many people are being elected.
If a single person were being elected, for example in a school's 'class president' election, I would use the singular as only one election is being held:
John is running against Mary in this year's Class President election.
However if we're talking on a broader scale where multiple people are being elected at once, such as if each population area is being allowed to vote for their representative and multiple elections are occurring at once, I would then use the plural:
The swing-vote states are expected to have high early-voting attendance in this year's elections.
As you mentioned the term general election in comments, I'd like to address that as well. From Wikipedia:
In a parliamentary system, a general election is an election in which all or most members of a given political body are chosen. The term is usually used to refer to elections held for a nation's primary legislative body, as distinguished from by-elections and local elections.
In presidential systems, the term refers to a regularly scheduled election where both the president, and either "a class" of or all members of the national legislature are elected at the same time. A general election day may also include elections for local officials.
This seems a rather clear explanation, which is backed up by The Free Dictionary in case we have cause to distrust wikipedia:
general election n.
An election involving all or most constituencies of a state or nation in the choice of candidates.
In this case I think the same rule would apply as for a standard election, just on a different scale. When referring to a single general election (which we know to be composed of multiple traditional elections), I would use the singular:
This year's general election is quite controversial.
But when referring to multiple general elections, I would use the plural:
The last three general elections have gone the way of a single party; I hope this year we will have some change.