Denmark plans to build two "energy islands" totalling 4GW of offshore wind capacity, under plans to reduce emissions by 70% from 1990s levels by 2030 and become a green energy exporter.

On Wednesday, the Danish government published a six-pillar proposal to meet the legally binding target – one of the most ambitious in the world – six months after it was adopted by Parliament as part of a new climate law. Denmark has also committed to become carbon neutral by 2050.

The government said the proposal, which is subject to parliamentary approval, opened a new era in the expansion of offshore wind and the creation of energy islands.

The two islands planned by Denmark would each have a capacity of at least 2GW, more than doubling the country’s current offshore wind capacity.

"Denmark must be a green pioneer country, which is why we hold on to the high climate ambitions even if we are in the midst of a historic crisis," said Denmark’s climate minister Dan Jørgensen in a statement, referring to the ongoing coronavirus pandemic.

"We present a package that delivers both CO2 reductions in the short term and paves the way for future climate neutral Denmark."

The islands are expected to generate more electricity than Danish households’ annual consumption and the government hopes to export its green power to neighbouring European countries.

One of the offshore energy hubs would be built on an artificial island in the North Sea and could be connected to the Netherlands. In the long-term, the island’s capacity could be expanded to 10GW.

The second hub has been earmarked for the Danish island of Bornholm in the Baltic Sea, with a potential connection to Poland. Denmark said it would open a dialogue to connect the islands to both countries.

In the longer term, excess electricity produced by the islands could be converted into green hydrogen and processed into fuels for aircrafts, trucks, ships and heating.

Brian Vad Mathiesen, professor of energy planning at Aalborg University, told Climate Home News he was "extremely optimistic" about the proposal, which formed "a good basis for political negotiations".

Now is the time to start establishing energy islands that can be scaled up, he said, adding his research pointed that both islands could be expanded to 4-5GW of offshore wind capacity in the next five to seven years.

However, expanding capacity further could become a technical challenge and would require large amounts of electricity to transport the energy, he said. Converting power into hydrogen on site could be explored as an option.

"It won’t be easy to transport that power to the main electricity demand hubs in Europe," he said. "That will require European collaboration."

The plan includes funding for research and development, including $58 million a year on carbon capture and storage technologies and further investments in biogas.

Incentives and subsidies have been proposed to further improve energy efficiency in homes and buildings and move to renewable-sourced heating. A roadmap for a carbon-neutral waste sector by 2030 is also part of the package.

The plan is the first stage of a broad strategy to wean Denmark off fossil fuels. Decarbonisation plans for the agriculture and transport sectors are expected later this year.