SCOTTISHPOWER has warned that the increasing burden of taxes and levies in the UK could mean further price rises for customers even though energy costs in the market remain stable.

The company, owned by Spanish utility giant Iberdrola, reported that a 137.7% rise in Government levies contributed to a 17.7% plunge in profit at its generation and supply business in the first six months of this year even as increasing success south of the Border took customer numbers to a record 5.6 million.

Keith Anderson, ScottishPower's chief corporate officer, said: "What the Department for Energy says, and we broadly agree with, is that you can see energy costs remaining stable and flat over the next period of time but there are increased cost pressures coming through."

These, he said, related to factors including green energy schemes and energy efficiency costs.

Iberdrola as a group 
said it expects a pre-tax impact of €170m (£146m) from energy sector reforms in Spain and the UK in 2013, excluding the impact of the measures on its renewable business.

Levies on ScottishPower's generation and supply business hit €155.8m in the six-month period, up €90m on last year.

It said that the new Energy Companies Obligation cost it €95m in the first six months of 2013, which accounts for around 60% of the expected cost of the scheme to the company this year.

The Carbon Tax which 
has been levied on coal 
and gas purchases since April, had a £10m impact, 
it reported.

In the first half of 2013, Glasgow-based ScottishPower's generation and supply business saw earnings before interest and taxation fall 17.7% to €74.9m.

At its regulated networks business, net profit fell 6.9% to €324.1m.

Despite the closure 
of the coal-fired Cockenzie plant in East Lothian 
in March, production rose 4.9% as the company 
benefited from the completion of the 500 megawatt Whitelees windfarm close to Glasgow.

ScottishPower sold greater volumes of fuel due to prolonged cold weather this year.

The company also added 400,000 customers to take its client base to a record 5.6m as customers took out its fixed term and fixed price deals to guard against rising prices.

Some 70% of its customers are now from outside Scotland.

Mr Anderson said: "It is a good positive story and there is a lot of improvement coming through the 
business following some significant investment we have made over the last 
few years."