DN Opinion. Without nuclear power threatened in Sweden by the power shortage

But el stops in Sweden. Parts of the public transport stop to work and phone networks are knocked out. Hundreds of thousands of individuals and businesses suffer.

the Last outage one day will have serious consequences, especially if it were to happen in winter with the cold weather. And after 48 hours many of the critical institutions of the problems to run the business.

How can we guarantee a stable electricity production? We face big challenges then this should be done without great klimatpåverkning and achieve the targets set internationally.

there is, as in a letter to the editor on the DN View, renewable electricity systems such as wind, sun and water. The trend for these is very positive. In the international energy council, the IEA's latest report shows that the technological development has gone strongly for wind and solar and that the cost of production dropped significantly.

The renewable energy shall have a main function. For the Swedish part to the production of electricity to be based on these to 2040. It means that there are no nuclear power plants then in operation. The question is whether this will work and respond to security of supply and effektstabilitet in the grid.

the Challenge for renewable electricity production is to reach effektstabilitet with the functioning of the system services. It is about the ability to meet the power requirement at each time, frequency stability, voltage stability and rotorvinkelstabilitet.

if kraftsystemets ability to keep a stable level during normal operation. An example is the rotational energy, provided by the large rotating generators such as water and nuclear power, which counteracts the frekvensförändringar at the sudden events.

the Swedish national Grid, in its report ”Långsiktsscenarier for system development up to 2040” studied this in more detail. The report shows an increased risk of power shortages, with 100 per cent renewable energy sources.

the Swedish power Grid lacks the tools to based on marknadssimuleringsdata analyze the future system's voltage stability and rotorvinkelstabilitet. The analysis shows a strong reduction of the rotational energy, particularly between 2030 and 2040 in line with the decommissioning of Swedish nuclear power.

will the system's sensitivity to disturbances increase. This can lead to the manual disconnect can be a common occurrence in the future.

We get a more svårbalanserat system with increased volatility in the power system. It had been more predictable becomes more stochastic, and the variations more and more.

This places new demands on the operation. A certain amount of technical potential to ”shift” the production and use of electricity, for example, with the help of batteries, may possibly be, but for longer periods of time are the solutions hard to see.

will play an important role in the balancing of the system. The risk with this solution is that the lifespan of the hydropower is decreasing because this is not designed for this.

With the decommissioning of the reactors has a power system 2040 fewer synkrongeneratorer which is directly connected to the backbone. This reduces the rotational energy and reduces the ability to spänningsreglera and to attenuate effektpendlingar.

the simulation results also show that hours with low rotational energy to a greater extent occurs during hours with high electricity use, which increases the challenge to keep a stable frekvensnivå.

the use of nuclear power reduces the amounts of dynamically spänningsreglerande components, mainly in the south of Sweden. The new production, which will be added to the lower voltage levels in distribution networks will be difficult to replace spänningsreglerande on stamnätsnivå.

Flexibility in the use and production is a large source of uncertainty, which may also be a major impact. Without förbrukningsflexibilitet and storage is a significant risk that electricity prices will rise substantially during parts of the year and that services will not function fully.

We go into an uncertain future. Actually, there is no one who can say with certainty that a fully renewable power system is going to work.

with a variety of stakeholders to analyze the progress. The authority claims to have the solutions and the measures in place on the day as nuclear power is phased out.

A 100 percent renewable electricity system could lead to power shortages and bortkopplingar with shorter or longer power outages. It affects the common people, but also of industry and new electricity-intensive companies, which will probably apply to other countries. The question is whether we will effectively manage the changes required for the climate as regards the transport sector and the industry with more electricity to replace fossil power.

there Are some other options that could meet the requirements of effektstabilitet and stable system to ensure functioning electrical systems, including large rotating generators? An expansion of hydroelectric power can be excluded. That leaves nuclear power with a focus on new reactors can be in operation when the existing will be phased out.

also has the advantages that it will be much cheaper compared with 100 per cent renewable production. It depends on the cost of new network capacity, new hydro power, inertia, batteries, and efterfrågeflexibilitet that can be directly attributed to the proposed expansion of wind and solar power.

The big extra, however, is that for a 100 per cent renewable system is the life of production facilities and the inertia of 20-25 years compared with new nuclear power in 60 years. The additional cost of investment in 100% renewable energy will be over 1,000 billion 2017-2090.