Monthly archives: March 2010

The Chinese National Energy Administration has announced via the state run newspaper China Daily that they will be seeking to produce around 15 per cent of all the country’s energy by renewable means within the next 10 years.

China, despite being criticised for its heavily industrialised, polluting economy and images of Beijing obscured by dense smog during the 2008 Olympic Games, the government is taking proactive steps towards reducing carbon emissions with measures that would shame certain other attendees of the Copenhagen climate summit.

With the growing realisation of the fallibility on basing the huge Chinese economy on fossil fuel imports which could become untenable within the next 25 years, the Beijing government is planning to spend billions of dollars in investing in solar and wind farm sites in addition to research projects which could keep China at the cutting edge of green energy generation.

Renewable energy generation grew by 1 per cent in China in the last 12 months with the government hopeful that figures will grow from the present 9.9 per cent to 15 per cent by 2020. The Chinese government is keen to diversify its economy as well as its means of energy generation with the dual purpose of slowing the effects of climate change and making the economy more robust in the face of any potential fuel crises which could arise in the near future.

In spite of passing legislation designed to have an immediate impact on renewable energy uptake such as the feed-in tariff, a mechanism to incentivise investment in green technologies, government spokesman Zhang Guobao is realistic about the timescales involved in such projects. Speaking to China Daily, Zhang commented that,

“Power projects take a long time to be up and running, and we are basically allowing five years to complete them although it is a 10-year program, otherwise, the facilities cannot be put into use by 2020.”

Zhang added, “It appears that some local governments approved energy-guzzling projects during economic crisis so only by fully implementing our energy saving regulations can we realize economic growth with less energy consumption.”

The winter months have brought lots of snowfalls, or as they are known in the world of solar energy, ‘shading events.’ You might be forgiven for wondering what exactly happens to the performance of solar panels when they are covered in snow, or anything else for that matter.

Shading is a big issue for solar arrays. A small amount of shading on one solar panel can result in a big power loss for the entire system. This is because of how they are connected together; a solar panel is made of a number of solar cells connected in series. Each solar cell has a current of around 8 Amps and a small voltage of 0.6V or so when under full sunlight. For those who remember their physics classes from school, this means that when they are connected in series the voltages add up but the current stays equal. Solar panels are then connected together in series to make a string, so the current still stays the same (on large arrays multiple strings are connected in parallel).

What this means is that if one solar panel, or even one cell of one solar panel is affected, it will affect all the others. When a cell is shaded its output current decreases, which means the current for all the other cells and modules is also limited. So one small patch of shade can disproportionately reduce the power output of the whole system.
This effect can be limited by a number of means.

The best way is to make sure your solar panels are not going to be shaded in the first place. This should be checked as part of the site survey, conducted by your MCS accredited installer. You should ensure that nothing will shade the modules during the middle of the day, when your system should be producing the most energy. Shading can be checked using a special design tools that show the path of the sun behind various shading objects. This can be either a lens that shows the horizon and path of the sun in front of you, or a full design software package that uses photographs of the surroundings.

With snow it does help to clear it off. But there isn’t usually much sun when its snowing, and if the sun does come out, the snow melts pretty quickly.

If you cannot eliminate shading as is often the case in built up areas, there are several technologies that can limit the effect of it. Many solar panels now include bypass diodes that disconnect groups of solar cells if they are shaded. It is fairly crude but often works well. When you buy solar panels make sure to ask about bypass diodes.

A second technology that is not available yet in Europe but soon will be is distributed conversion. Here, rather than have power electronics (like the inverter) positioned all in one place, you have some electronics placed on each module. This allows each module to operate independently. One company in the US called Enphase claims this technology increases power output by upto 25 percent.

These are all things to bear in mind when buying a photovoltaic system.

Solar thermal heating systems could be something of a common sight on south-facing roofs in the UK with the introduction of a feed-in tariff. Previously, the high cost of solar thermal kits has put off householders wishing to invest in renewable energy generation but with the announcement of the introduction of feed-in tariffs for solar thermal in the UK in April 2011, solar thermal installation is set to become much more attractive.

The government’s feed-in tariff scheme to be called the Renewable Heat Incentive, will work by offering small-scale producers of renewable energy premium rates over a period of around 25 years for units of energy fed back into the national grid. Feed-in tariffs have been successful in countries such as Germany where they have proved to be an extremely effective way of off-setting the high costs of investing in solar power equipment.

Germany saw a massive uptake in all types of solar energy generation with tariff schemes rendering investments viable in the face of competition from traditional fossil fuel sources. For more information on how the tariff legislation is broken down year by year all of the information is available on

In the UK, the essential figures are that homeowners wishing to invest in a typical £5000 solar thermal kit for their properties can hope to expect healthy returns on investment of around £500 p/a over a period of around 25 years not including the average £100 saving on utility bills per year. Such returns and savings are the basis of the tariff scheme and is hopeful that these incentives will be sufficient to help the UK solar industry take off.

Through the installation of roof mounted solar panels, the sun’s energy is absorbed by the panel’s in-built technology which in turn is used to heat the water. The hot water is pumped through storage cylinders where it is heated further, providing households with south-facing roofs a good supply of hot water through the summer months and a contribution to water heating energy through the gloomier seasons.

Households aside, the government is also hopeful that the tariff legislation will bring about a grassroot change in attitude towards green energy as a whole and see technologies such as solar thermal become commonplace rather than an exceptional sight in the UK. is already hopeful that with the obvious environmental benefits of utilising renewable energy sources along with the financial incentives built in to green energy schemes, the UK is set to follow in the footsteps of what are generally regarded to be the ‘greener’ nations such as Germany and Sweden. Households and community projects will all be set to capitalise on the feed-in tariff in the coming years with cash savings, investment yields and carbon emission reduction providing ample rewards for investors and communities.