Solar power gains ground in Vorarlberg as summer output rises

Photovoltaic power accounted for a significantly larger share of electricity generation in Vorarlberg this summer, as long periods of sunshine helped households produce more of their own electricity, ORF reported.

May, June and July are generally the sunniest months of the year, meaning photovoltaic systems produce the most electricity during that period, said Johannes Hofer, a spokesman for Vorarlberg’s energy grid operator.

The share of solar power in Vorarlberg’s energy mix is steadily increasing, according to the state energy supplier illwerke vkw. Its spokesman, Andreas Neuhauser, attributed the rise mainly to the continuing expansion of photovoltaic systems.

Photovoltaic Austria, an industry association, said solar systems produced 30 per cent of all electricity in July, compared with 13 per cent a year earlier. Over the same period, hydropower’s share fell from 70 per cent to 50 per cent because of dry conditions, said the association’s managing director, Vera Immitzer.

Households and small businesses with photovoltaic systems also drew less electricity from the grid. Customers used 2.6 per cent less grid electricity in May, June and July than in the same months a year earlier, despite consuming roughly the same amount overall. Vorarlberg’s energy grid operator said the reduction was probably due to increased solar generation for their own use.

High temperatures can reduce the efficiency of photovoltaic modules. Immitzer said solar power helped ensure sufficient electricity during the summer despite heat and low water levels, but added that less sunlight is converted into electricity when temperatures rise. The best conditions for generation are sunny and relatively cold, she said, although winter has fewer hours of sunshine.

Verena Engstler, an energy adviser at the Energy Institute, said production from standard photovoltaic modules could fall by up to 10 per cent in particularly hot weather. She also noted that a typical household produces more electricity than it consumes on a reasonably sunny summer day. The surplus is usually fed into the grid rather than increasing the household’s share of self-supplied power.

Payment rates for electricity fed into the grid are expected to become more flexible. illwerke vkw will still offer a fixed price next year, but pricing will then become variable. Electricity tends to be less valuable around midday in summer because of the large supply of solar power, while prices tend to be higher in the evening, at night and especially during winter, Engstler said.

Households can respond by shifting electricity use to sunny periods, for example by running water heating, air conditioning, cooling heat pumps or electric vehicle charging during the day. An energy management system or a timer for a hot-water tank can help. A battery can also store unused solar power during the day for use in the evening and overnight.