Solar electricity has increased so quickly in Denmark that already this year it may reach the 200 megawatt target that was set for 2020.
With solar electricity increasing hundred-fold since 2010 – 36 additional megawatts are added every month – Dansk Energi, Energinet.dk and DONG Electricity estimate that solar energy will contribute 1,000 MW by 2020 and 3,400 MW by 2030 if the current rate continues.
The rapid increase in solar energy is mostly due to investments by private households and has helped increase the share of Danish electricity produced by renewable sources toward the 35 percent target set for 2020 and the 100 percent target for 2050.
Denmark currently produces 22 percent of its electricity from renewable electricity though the 200 MW produced through solar will still only amount to about 0.5 percent of all the electricity produced in Denmark.
But according to researchers from the University of Copenhagen, solar ought to contribute much more. The research by Martin Greiner and Gorm Andresen suggests that having 20 percent of electricity produced from solar, and 80 percent from wind, would be an ideal balance if Denmark is to rely entirely on renewables.
The benefit of raising the amount of solar electricity is that the sun tends to shine during the daylight hours when there is the most need for electricity. This means that fewer windmills are needed to provide electricity when there is a high demand.
“Developing wind and solar electricity at this ratio means that fewer windmills need to be built compared to how many we'd need if all our electricity was delivered by windmills,” Andresen told Berlingske newspaper, adding that the increased solar electricity will reduce the need to store excess electricity.
This is the main problem with producing electricity from renewable resources, as electricity has to be produced when it is needed. The sun does not shine, and the wind does not blow, when we need electricity the most.
So as the proportion of renewable energy increases, so too does the need to store excess electricity. For example, storing electricity produced on a windy night when there is little demand for a day when there is a high demand but no wind.
There is not yet a technological solution to storing high volumes of electricity, however. But Andresen believes increasing the amount of solar electricity in the mix will allow Denmark to postpone having to produce storage technology.
“The storage methods that we choose to use may also be significantly more effective than if we depended solely on wind,” Andresen.
Achieving a 20 percent target for solar electricity may prove difficult unless the generous subsidies that helped the current boom remain. The environment minister, Martin Lidegaard (Radikale), conceded that while solar complements wind well, subsidies for solar are currently very high.
“We have to see if we can adjust the subsidies without killing solar,” Lidegaard told Berlingske. “We need to assess the roles of different electricity sources in our system. It’s a very difficult job but we are currently working on finding the most optimal interplay."
While Lidegaard expressed some reservations, Pia Olsen Dyhr (Socialistisk Folkeparti), the minister for trade and investment, wrote that the government was investing in finding ways to increase the uptake of solar energy.
“To promote the transition to renewable electricity, we have dedicated 42 million kroner to analyse how we can make green solutions like solar electricity even more attractive in the future.”