Two in three energy companies that offer long-term fixed price contracts for supplying gas and electricity are reluctant to take on customers who own solar panels, according to research by the Dutch consumers’ authority ACM. 

The ACM looked into 21 energy firms and found 10 do not offer long term fixed fee contracts to solar panel owners and a further four offer them less attractive terms. The other seven are willing to offer consumers with solar panels a contract that runs for longer than one year. 

The ACM says it believes energy firms are discouraging solar panel owners because of the costs associated with feeding excess energy back into the grid. On sunny days, for example, the price can drop enormously or even be negative, which costs the suppliers money. 

In August, green energy firm Vandebron said it would begin charging solar panel owners up to €46 a month to pay for the costs associated with their electricity production. 

When the weather is good and solar power generation high, the company has to sell the excess supply on the energy market for low prices. The fees will partly compensate for the losses, as well as the grid charges.

Fixed contracts of two or three years are currently cheaper than variable contracts, the ACM said. 

The price ceilings on gas and electricity, brought in to cushion consumers from soaring energy prices, end in January. 

The government is also considering reducing the current ruling which allows solar panel owners to subtract the amount of energy they supply to the grid from their own usage.

The credit system, the government says, is costing the treasury more than €400 million in lost energy taxes. Instead, it suggests, households should be paid a ‘reasonable sum’ for their surplus supply.