Yes, under federal electoral law, it is compulsory for all eligible Australian citizens to enrol and vote in federal elections, by-elections and referendums.
Senators are elected by a preferential voting system known as proportional representation.
Candidates for the Senate stand for a state or territory. It is a Constitutional requirement that each state be equally represented regardless of its population.
There are a total of 76 Senators: 12 for each state and two for each territory. Senators for each state are elected for a six year term. Senators for each territory are elected for a term equivalent to the duration of the House of Representatives. When a House of Representatives and half Senate election are held at the same time, 40 Senate vacancies are contested.
When a Double Dissolution is declared, as there was in 1987 and 2016, all 76 Senate positions are made vacant.
A writ is a document commanding an electoral officer to hold an election, and contains dates for the close of rolls, the close of nominations, the polling day and the return of the writ. The Governor-General issues the writs for House of Representatives elections and the State Governors issue writs for States' Senate elections.
For a federal by-election, the Speaker of the House of Representatives issues the writ.
No. The AEC conducts federal elections in accordance with the Commonwealth Electoral Act 1918. The introduction of Electronic voting would require legislative change, which is a matter for Parliament.
The potential for different forms of electronic voting to be introduced for federal elections is often debated and below are two reference documents.