The single currency was first planned to be introduced in 2003 but the launch has been postponed several times; in 2005, 2010 and 2014.
It is possible, although ambitious, that some countries will meet the current criteria for the 2020 deadline - the primary four being:
- A budget deficit of not more than 3%
- An average annual inflation rate of less than 10%
- Central Bank financing of budget deficits should be no more than 10% of the previous year's tax revenue
- Gross external reserves worth at least three months of imports must be available
These criteria, along with two other secondary ones, are due to be assessed by Ecowas by the end of 2019.
One of the problems is inconsistency: countries could, for example, meet the criteria next year, and then fall behind the following year.
In 2016, only one country, Liberia, met all the six conditions, and no single criterion was met by all the countries.
Economist Martial Belinga, author of Liberate Africa From Monetary Slavery, says 2020 is a symbolic goal.
If the goal is to boost trade, some analysts are sceptical that a single currency is key.
"We struggle in Nigeria alone to get produce from the north to Lagos, and to other southern parts where it can be consumed," said Sanyade Okoli, head of Alpha African Advisory.
"If goods can't move freely, how can we even talk about a single currency? she asked. "We need to address poor infrastructure, bureaucracy - the lower-hanging fruits first".
For Mr Belinga, the real impediment to trade in the region is not the lack of a single currency but that countries don't have much to trade.
"West African countries must transform their economies, with diversification and added value industries," he says.
"That's the real solution to face external shocks and volatility."
Currently, most countries rely on commodities whose prices are regulated on international markets.
