News

Posts tagged with: wind energy

A big issue for solar and wind energy is that the power they deliver is not constant. Unlike coal or nuclear power stations which produce a steady stream of power whatever the weather, wind and solar suffer from extreme fluctuations. For wind energy, a drop in wind speed can mean a 90% power loss over a large area in just a few seconds.

For solar energy, there are many different types of fluctuations. In the UK for instance, winter months produce only a quarter of the amount of energy as summer months. Obviously solar energy production takes place only between dawn and dusk, and even during the day, clouds can cause major fluctuations in solar energy output. These fluctuations make it hard for electricity grid operators to really use renewable energy since they need to guarantee power is delivered 100% of the time.

At the moment, because renewable energy makes up such a small component of our electricity generation in the UK these fluctuations are irrelevant. However as the proportion of renewables connected to the grid increases these effects will eventually become more significant. In southern Germany, where solar energy makes up over 4% of the electricity generated and at times represents 30% of the electricity on the grid, energy companies are starting to think carefully about how to use this resource most effectively.

Several can be done to decrease the impact from these fluctuations in renewable energy:

The first thing is to have a strong and efficient electricity grid. This is the case in Germany where energy can be efficiently and almost instantaneously moved from one part of the grid to another. This means that when there is a surplus of energy in one part of the country, energy can be transported at very short notice to where there is an energy deficit. Interestingly, as the amount of solar energy in a country increases, short term fluctuations caused by clouds are “ironed out” as shaded solar panels in one region are compensated for by unshaded solar panels in another.

In addition, as some of you may have heard, there is something called a ‘smart grid’ in development. This term is used to refer to lots of different things but on its most basic level it implies that energy demand can be controlled in some way. This could be very helpful for renewable energy since energy demand can be matched to when there is an abundance of solar energy in the middle of the day.

Another tool that can be used is prediction mechanisms. Using weather forecasting and remote monitoring, the amount of solar energy expected can be predicted. Providing this information to energy companies allows them to use various forms of reserve energy such as gas turbines or hydroelectricity which can be turned on and off in a matter of minutes.

The ultimate solution though, is to find a cheap means of storing energy. This would make all the fluctuations from renewable energy irrelevant. Researchers around the world are busy working on a wide range of different energy storage technologies. One of the most familiar ways of storing energy is to use a battery. Regular alkaline batteries are far too expensive and not durable enough to be used on a large scale, but there is huge number of new types of battery being worked on that could soon bring the cost down dramatically.

Besides batteries, there is a wide range of other technologies in development that could all be used to store renewable energy. Examples of these include; compressed-air energy storage, pumped hydro-electricity, molten-salt, fly-wheels and hydrogen, to name a few. Of course each technology has advantages and disadvantages, but it remains that we have a number of potential solutions for storing renewable energy. So the fact that the sun doesn’t always shine is certainly not a reason not to support solar energy.

REpower has successfully installed three of its six megawatt (MW) turbines near the German-Danish border, bringing the massive new turbines closer to their final destination: offshore wind farms.

More: continued here

East Kilbride based wind turbine manufacturer Proven Energy has said it wants the government to set a 20p per unit feed-in tariff rate for wind when they are introduced in the UK. Jamie Glover, UK channel manager for Proven, said: “Savings are entirely wind dependent but if they are on a good site, wind turbines pay themselves off in about five years on average, and will continue to make money after that. But feed-in tariffs will decrease the payback time proportionally, and will certainly drive demand.”

“Payback time will depend on what rate is decided when feed-in tariffs are introduced. In Europe there are many different rates but I would hope for a 20p rate for the UK – the payback time for people with small-wind turbines would be greatly reduced” added Glover.

The Energy Act legislation passed in November will see the full introduction of feed-in tariffs by early 2010 and allow small energy producers such as Proven to sell surplus back into the national grid at a fixed rate. Some in the energy industry have reservations about the public awareness of the feed-in tariffs at this point in time, however at is hoped that come the roll out, knowledge of the tariffs will have filtered through the media. Jamie Glover expressed this concern, “Widespread knowledge of the new feed-in tariffs is not available at the moment so we have not experienced a greater interest because of it. But I am sure that clarification of what the tariffs will be, as well as time, will ensure that the public are more aware of the savings and benefits of generating your own electricity.”

However, despite these concerns during the last year there was a 50% increase in public awareness of the new feed-in tariffs attributed to soaring household electricity bills and a general increase in technological knowledge. Proven, which has recently installed a turbine at a school in Leeds certainly believes that by 2010 a 20p tariff rate will make their business viable in the long term.