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.

As a solution to the global economic crisis, Gordon Brown has called for an international ‘Green New Deal’ in order to spark investment in new technologies and create jobs in the emerging renewable sector. In reference to F.D. Roosevelt’s economic plan to revitalise the US economy during the Great Depression the Prime Minister explained that he believes striving to evolve the UK in to a low carbon economy will create jobs while at the same time help the government to meet its climate change targets.

The British government has already set the target of an 80 per cent reduction in greenhouse gases by 2050 and have taken some measures to instigate this reduction. Overseeing this gradual change towards a low carbon economy will be the Secretary of State for the Department for Energy and Climate Change, Ed Milliband. The minister has already advocated government investment in renewable energy technology and research and was a key figure behind last November’s Energy Act which set out the main provisions for government funding for green energy and paved the way for the implementation of a feed-in tariff in 2010.

Despite these changes, some environmental lobbies and members of the renewable industry have criticized the government for not providing enough funding for green projects and not setting out a concrete breakdown of the feed-in tariff which will be necessary to attract investment as it has done for example in Germany. Spokesman for Friends for the Earth, Andy Atkins summed up the frustration in certain circles by commenting,

“We need urgent and decisive action, not more token gestures and hot air.”

Gordon Brown is confident that the green sector will provide some relief to the recession in the jobs that it creates, not just in the UK but globally and he was keen to make this point last week at a summit in London. The prime minister produced the results of an independent report which states that the renewable energy sector will generate around 400,000 new jobs within the next 8 years meaning that by 2017 1.3 million people will be involved in the renewable sector in the UK.

During his historic visit to Washington last week for his meeting with US President Barack Obama, Brown stated that it was imperative both for the economy and the environment that changes are made to the way governments approach renewable funding stating,

“We know that the more we are able to co-ordinate these measures internationally, the more confidence and certainty we will build and the more investment we will be able to bring forward.  That’s why I want to create a global ‘green new deal’ that will pave the way for a low-carbon recovery and to help us build tomorrow’s green economy today.”

Key to this shift towards a low carbon economy is the feed-in tariff which has already proved extremely successful where it has been implemented elsewhere. Members of the industry have already expressed the need for a tariff which is more than a token gesture and is able to attract investors through coherent, long term, viable contracts. Some have suggested that a rate of 50p per unit of kWh energy fed-in to the grid by renewable systems under 5 Megawatts would be sufficient to help Britain catch up with nations such as Germany where feed-in tariffs are now well established. The feed-in tariff rate is crucial as it will offset the cost of producing energy by renewable means by offering investors long term contracts with fixed rates for their megawatts production.

Andy Atkins of Friends of the Earth, regarding the summit and the need for government action on tariffs and project funding added,

“Today’s summit is an encouraging development, but ministers must grasp the scale of the challenge we face. We need urgent and decisive action, not more token gestures and hot air”.