How Solar Energy Works

Solar Panels On Homes

Our planet revolves around the sun at just about the perfect distance to provide the optimum conditions that sustain life. The light from the sun contains vast amounts of energy, which, when it hits an object, causes heat to be transferred.

But with some materials found on Earth, sunlight has another, equally profound effect – it turns on the lights.

How a solar cell works
How a solar cell works

Take silicon for example. As the sun strikes it, electrons are dislodged and, when these little things start moving, you get an electric current. The amount of electricity produced depends to a large extent on the purity of the crystal used. With top of the range silicon photovoltaic cells, the efficiency is around 20-22%, which means they convert that percentage of light to electricity. For the production of our solar panels that can affect the cost as well as the efficiency.

Solar power is a renewable source of power, meaning it has an unlimited source and we can use it to provide sustainable, and clean, electricity rather than depend on fossil fuels such as coal and oil. The challenge is to find a way of harnessing this power intelligently and making it more efficient and cheaper to access. At the moment, we use large solar panels that incorporate silicon photovoltaic cells, but in the future we may be able to produce cheaper and more carbon friendly materials that do the job better.

How Solar Energy Powers Our Homes

Unless you have been living in a cave for the last twenty years, you’ll know that we need to find greener ways to live. You’ll also have noticed those glass panels on top of roofs where people have solar panels installed. These are usually south facing to collect the most sunlight and their purpose is to generate electricity. The photovoltaic cells inside a panel create a DC current which is then fed into an inverter that changes it to AC. That can then either be used to power a house, stored in batteries, or passed onto the National Grid to provide energy for other uses.

Several things influence how much electricity an array of solar panels produces. First, it needs to be at the optimum angle and facing the right way. Secondly, the quality of the photovoltaic cells make a difference and often influence the size of the installation. Most homes use a lower grade silicon that has about a 13% efficiency, mainly because it is cheaper but still provides the level of power needed. Finally, the more panels you have and the bigger the array, then the more electricity you will have the potential of producing.

You can expect a domestic solar panel installation to last between 20 and 25 years and they have started to become more popular in recent years because of government initiatives such as the Feed in Tariff which means you can earn money back by selling the power you generate to the energy companies. A typical solar panel installation would cost around £7,000 and earn you around £6-700 a year with savings on electricity bills and profits from the tariff.

Solar Energy on a Grand Scale

It’s not just on roofs that you see solar panels doing their stuff. Over the last few years solar farms have started to proliferate. Acres of land have been taken up by huge arrays of panels that provide valuable electricity for the grid. Despite recent cuts in government subsidies, green technologies in the renewable industry are still thriving and for many landowners having a sizeable solar farm installed offers a chance to help the environment and make a profit at the same time.

Solar Farm
Solar Farm

One of the largest solar projects in the UK is at Wymsewold Airfield in Leicestershire that has 130,000 panels producing 35 MWp, but by far the biggest, so far, is located in the Mojave Dessert in the US and boasts 350,000 panels that provide electricity for around 140,000 homes.

Solar farms are also being funded in a variety of ways. In some places, communities are coming together to find the money themselves, whilst with other developments companies are willing to take on the investment and installation in exchange for the Feed in Tariff, paying the landowner a rent for use of the land. As with most large scale, renewable technologies, solar farms have their detractors, mainly from people who think they are an eyesore or are believe they are not as efficient as many make out.

How Much Energy Does Solar Provide?

An average solar array on top of your roof should provide around 3,400 kWh per year, depending on the size and the type of photovoltaic cells used. According to statistics though, the total solar energy production in the UK last year only amounted to around 0.64%, compared to 8.7% for wind power. The reason may well be that more has been invested in wind farm development, both onshore and off.

A more startling statistic is that solar energy seems to have increased rapidly over the last two years, providing just 77 MW in 2010 but exploding to 3,375 MW in 2013, perhaps due to government initiatives to reduce our carbon footprint.

As a localised source of energy, solar panels have a few more advantages than some of its renewable counterparts such as wind. First of all, and maybe most importantly, it can be fitted onto the roof of a house. The right system can provide all the electricity needs for a home and may even produce an excess that can be fed into the National Grid. Because homeowners and businesses can earn a profit and get a decent return on investment with their installation, it is often seen as a good option for those wanting to simply reduce their fuel bills and / or make a little money on the side.

Solar Energy Myths

It takes more energy to create a solar cell than it actually produces in your solar panel array.

The misconception is that solar cells are, secretly, not a green technology. Yes, we need to use energy to create them in the first place and there are some processes that need to be improved, but your average solar cell will probably return that initial investment in the first 2 to 3 years of its life.

Solar panels need a hot, sunny day to work properly.

Actually, that’s not strictly true. Solar panels work at their optimum at lower temperatures than you get in the dessert and the UK is just fine for producing electricity from them and they even produce on cloudy days.

Solar power means an unstable electricity supply.

Far from it. If you have the right size array for your property you will probably make excess for your needs. Even so, you will still be connected to the grid and any shortfall can be made up from there. Other myths are that solar power can’t run a big building. Again, the right array can power a whole factory.

Solar energy is too expensive.

Yes the initial cost of installing solar panels may seem daunting to some but the return is pretty good with the Feed in Tariff and savings on energy bills – you could be making extra money and have paid off your loan within 6 or 7 years. And there are different ways you can fund your solar panels installation including the Green Deal and even having them put in for free.

The weight of the panels damages your roof.

Your installer will assess your roofs capacity to hold the weight of the panels, a frame is built that anchors onto a number of rafters so the weight is spread out and won’t damage the roofs supporting structure underneath. Also solar panels are reducing in weight as time goes on and manufacturing processes improve.

Solar panels need a lot of maintenance.

Again this is not strictly true. If you’ve had your array installed by a reputable company then your panels should last for the next 20-25 years. Yes, they will need a regular maintenance plan but so does your boiler – solar panels are pretty robust and don’t have that many moving parts that can go wrong.

Installing solar panels is complicated.

In fact it isn’t. A reputable installer will normally undertake a free consultation and take you through any issues and paperwork. The actual installation can be done in less than a week (normally 1 or 2 days). Tying into the Feed in Tariff and earning an income is also simple and, once you are registered, you can start benefiting from that extra income.

Solar panels will reduce the value of my house.

There is no evidence of this. Actually, with people’s awareness growing and an increasing desire to incorporate renewables into our everyday lives, having solar panels may well increase the value of your property and recent studies show this to be the case.

It is hard to remortgage a home or get a mortgage with solar panels.

This is not true, many people have sold and bought properties with solar panels on the roof and they have little or no impact on a mortgage company’s decision to provide the finance. The only issues that may arise are if the array has not been MCS certified or has a complicated ‘Rent-a roof’ (free solar panels) scheme attached to it.

Picking the Right Installer for your Solar Panels

As you might expect, solar panel installation is a growing industry, fuelled by the increase in people who want access to clean, renewable energy that reduces their reliance on energy companies and fossil fuels. As with any industry, there are good and there are bad companies, so if you are looking for the right one there are some top tips that you should keep in mind.

First of all, a reputable installer will have the right certification and in the renewable energies world this is pretty specific. They should be part of the Microgeneration Certification Scheme and they should also be members of the Renewable Energy Consumer Code. Other bodies include the Renewable Energy Association and the Solar Trade Association.

Micro Certification Scheme Logo
Microgeneration Certification Scheme Logo

These certification bodies also stretch to the manufacturers of solar panels – if you want to avoid substandard or poor performing arrays then make sure they carry the certificate marks.

As with any big project, you should be looking to get a number of quotes from different installers and they should do a full survey of your site to make sure it is suitable for a solar panels array. Things you will need to consider:

  • The load bearing capacity of the roof – as mentioned previously, most modern roofs should be able to take a solar panel installation but you should make sure and get independent advice if you are not totally confident. The general rule is that if installing a panel array increases the load by more than 15% you will need formal building approval, usually from the local council.
  • Do you need a south facing roof? Technically, yes you do. Though this may be about to change. South facing provides the most access to direct sun. But in Germany, builds are starting to include east and west facing panels which provide more coverage throughout the day for the grid. It might be that in the near future, there will be government subsidies and incentives to build on east and west facing roofs.

The Future of Solar Energy

Developments are afoot in the world of solar panels. The race is on to find cheaper and more efficient alternatives to the heavy duty silicon photovoltaic cells. That includes window glass that can double as a solar panel and new materials such as plastic that can be used to replace the existing technology.

Another area where advances are being made is in the manufacture of panels which, in the past, has come under attack for being less than carbon friendly. One of the main components has been the toxic substance cadmium chloride but this could well soon be replaced by the salt magnesium chloride which is a lot safer and cleaner to use.

Whilst scientists are searching for cleaner and cheaper ways to produce photovoltaic cells, others are thinking big. Californian based company Solaren are looking at the possibility of giant panels beaming down our power from space in the future.

Meanwhile, the battle to harness the sun’s energy goes on. While more households start to seriously consider the benefits of having solar panels on their roof, and businesses seek ways to reduce their own carbon footprints, there’s no doubt that the industry itself is beginning to thrive.

Find out all you need to know about solar energy here.

Should You Give Away You’re Feed in Tariff?

Free Solar Panels

Free Solar Panels?

On the surface it seems like a good idea. You want to get solar panels installed, get cheaper electricity bills and a company is offering to do it for free. The catch? They want control of your Feed in Tariff.

The Feed in Tariff, for those who don’t know, is a scheme whereby you can sell the electricity you produce back to the grid and make a profit. So, if you have solar panels you can produce the energy to power your home and earn a profit on the excess you produce. It’s one of the more attractive features of something like solar, apart from the lower bills and carbon friendly technology.

It costs around £5-10,000 to install solar panels on a roof. Most people will either use the money they have saved or take out a loan to pay for it. The benefit of the Feed in Tariff is that you will at some point pay off the initial investment and start making a profit. A number of people want solar power but can’t afford it or are unable to take out a loan to cover the initial cost. For them, companies have, for some time, been offering the free installation deal.

But is it right for you?

First of all, the number of companies offering the free solar deal has dropped recently with a reduction in the Feed in Tariff, meaning that profits are not so great as they were. Secondly, you need enough roof space and the prospect of generating a significant amount of electricity for many companies to consider you.

If you are simply looking to go green and get a little off your electricity bill then opting for free panels, or any of the other renewables that are locked into the Feed in Tariff, may well be good for you. There are some other things that you need to consider though:

  • You are going to be tied to a long term contract which has a number of caveats attached to it.
  • If you are looking to sell your house you need to be sure that the buyer is aware of the contract and willing to take it on.
  • If you need to do work on your roof during the lifetime of the contract you may have to pay the company compensation for the time that the solar panels are offline.

When entering into something long term such as a free solar panels installation then it pays to take a very close look at the contract being agreed and to take the appropriate legal advice.

Free Solar Panels Vs Buying Them

There are undoubtedly more benefits if you can get the money together to purchase the installation of your solar panels. For instance, if you have a 4 kW system put in, then you could be missing out on a potential profit of £23,000 over its life time according to a recent Which? article. That includes savings from having a low carbon renewable energy source and the returns from the Feed in Tariff.

Alternatives to Free Solar

There’s no doubt that getting a renewable energy installed is more lucrative if you can take advantage of the Feed in Tariff. One possible source of funding to consider is the Government’s Green Deal that can provide low cost loans for households trying to improve their green credentials.

Are Your Solar Panels Facing the Wrong Way?

Solar Panels direction

According to researchers at Loughborough University, people might have spent thousands of pounds investing in solar panels only to find that they are not facing the right way. The excepted wisdom for a while now has been that panels should face south to collect the most amount of energy.

Professor Ralph Gottshalg has undertaken some studies suggesting that adding east and west facing panels may well be more efficient. There are nearly half a million homes with solar panels on their roofs, producing an average return of £500 a year, contributing to the grid and energy bill savings on a daily basis.

Before you start worrying that you are, in fact, facing the wrong way, it is more a matter of providing an even power supply. In a recent report in The Telegraph Professor Gottshalg stated that “in Germany they are advising people to go east-west so they are smoothing out the supply of power from all these solar panels. We get similar spikes of power too, although it wouldn’t make sense for people to change their solar panels if they have already been installed.”

The issue has arisen following on from a change in policy in Germany where they are moving to west and east facing panels because they are producing too much power at certain times a day with those directed towards the south. It’s backed up by research from America that suggests west facing panels may well produce more energy and at more convenient times – later in the day when it is most needed by the grid.

At the moment the UK produces around 2.8 Giga Watts of power from solar energy as opposed to 20 in Germany but the principle remains the same – how to get the most out of this renewable energy source. The problem for domestic properties that are hoping to benefit from the Feed in Tariff that pays them money for their electricity supply is that south facing panels generally produce the best return on investment. If consumers are forced into providing east and west facing installations, with a reduced return, they may well think twice about investing in solar in the future.

On the brighter side, it means that if your roof faces east west and you have been put off getting panels because it is not directed to the south then there may be government incentives coming your way in the future. Gottshalg has also suggested that there should be subsidies introduced for larger scale solar farms that could be produced to face east-west, perhaps producing less electricity but filling a need to provide an even coverage of production throughout the daylight hours.

According to Forbes recently: “They should be pointed west because, in many cases, the power they produce is more valuable.  Utilities and governments should structure their incentives accordingly.”

Are We Reaching the Renewables Tipping Point?

Renewables Tipping Point

With problems in the Ukraine recently and the call for further sanctions on Russia, it suddenly became clear how dependent certain European countries are on fossil fuels such as gas. While the UK only gets a small amount of its gas from Russia, Germany is dependent for around 30% of its supply. Sanctioning Russia by not using their power source may seem morally right but it is financially disastrous.

This raises the old problem of being dependent on other countries and states for fuel supplies, one of the issues that creating more renewable energies is supposed to address. According to one of the world’s largest private investment banks, we may be reaching the tipping point with renewables becoming the main provider rather than supplementing the production of large scale power stations that depend heavily on fossil fuels.

The Guardian recently reported that UBS bank in Zurich had produced a report stating that centralised power stations were becoming too inflexible to provide the energy that we need for the future. Indeed, it is going to be cheaper, according to the bank, for households and business to produce their own energy rather than get it off the grid in the future.

The key, say the authors of the UBS report, is that batteries enabling storage are coming down in price which means that by 2020, they will be a viable and cost effective option for homes and business who want to store electricity. Not only will this help develop the electric car market and make it more competitive with petrol powered vehicles, but will enable businesses and homes to generate greater savings by storing their own power more efficiently.

The other key factor will be the reduced cost of installing solar power and more advanced technology for turning sunlight into electricity. Earlier in the year the CEO of Bloomberg New Energy Finance suggested that  “wind and solar have joined a long list of clean energy technologies – geothermal power, waste-to-energy, solar hot water, hydro-power, sugar-cane based ethanol, combined heat and power, and all sorts of energy efficiency – which can be fully competitive with fossil fuels in the right circumstances.”

There is a suggestion in the renewables industry that we are reaching the tipping point. At last, governments seem to be accepting that a reliance on fossil fuels is unviable and, with the costs coming down for renewables, we may at last be looking at future where super efficiency in the way we use energy is combined with a wide range of renewable technologies. Gas and nuclear power may well pay a significant role in this, especially with new initiatives to exploit shale gas reserves.

Should we Follow Denmark’s Example with District Heating?

District Heating

Why Denmark Leads the way in District Heating?

Beneath the streets of Denmark is an enormous network of pipes just like in any other developed country in Europe. The difference? These pipes provide heating direct to houses. Whereas most of us in the UK have our own individual boiler, in Denmark they are using district heating. In this country it has fallen somewhat under the radar, but for others it is fast becoming a major source of green and cheap energy.

The idea of district heating rose out of the oil crisis in the 1970s where Denmark suffered badly with blackouts and shutdowns. At the time the country was importing almost all of its oil and the effects of a long, cold winter left the politicians with a stark choice – continue to be dependent on external sources of energy or find an alternative. More than many countries, Denmark has invested heavily in the renewables market and particularly in district heating – huge boilers and systems that service a whole area and bring hot water directly into houses and businesses.

What is District and Community Heating?

A district heating operation works to deliver heat via a network of insulated pipes and utilises hot water or steam produced by one or two major sources. It is energy efficient in that it keeps down energy wastage and can balance out the supply of heat, for example providing more to domestic suburbs in the evening when most people are at home.

With district heating like that found in Demark, everything that is possibly wasteful is funnelled into the system. From the heat produced by factories to public transport networks, everything is captured and used. According to The Guardian, “district heating networks provide heat to a whopping 63% of Danish households.”

The country is no longer dependent on oil imports and, with the help of its renewable energy investment, it is becoming less and less dependent on the outside world.

Would District Heating Work in the UK?

It is a major step to move towards district heating for our towns and cities – you would need to have the infrastructure in place and the central ‘boiler’ to produce the hot water or steam. If you take London as an example though, a report by Buro Happold suggests that the city is wasting heat and that waste is enough to provide 70% of its heating needs, if the infrastructure was present to capture it and feed it into businesses and households.

The difference is that the UK has spent the last 40 or so years developing its continuing dependence on gas and other fossil fuels, despite the recent growing importance of renewables. We remain far behind countries like Denmark who have invested heavily in systems that reduce their reliability on outside sources for their energy needs.

The Department of Energy and Climate change is now playing catch up, putting in plans for towns and cities to become connected to district networks. Unfortunately, it is only at the planning stage, with many councils still undertaking feasibility studies. The plan is for 40% of properties to be connected to a heat network by 2050.

In Denmark, that figure is already at 63% with the added advantage of lower heating bills and a significantly reduced carbon footprint.

The Winds of Change?

The Future of Wind Turbines

They seem to polarize opinion in a way that no other renewable technology does. They are a blot on the landscape or the future of energy production in the UK. Whatever you think of them, wind turbines are here to stay and they have become a part of our landscape in a way we would not have contemplated just a few years ago.

Despite government aims to curb subsidies to wind farm development, the future remains bright for this renewable technology. We have been using wind power for centuries and it is one of the simplest forms of energy production we have yet developed – blades turn in the wind, drive a central shaft and that turns a generator which makes valuable electricity.

Tubular Wind Turbines

In the future we may have to get used to the different shapes and sizes of wind turbines as research and development looks to improve on the initial propeller design. Earlier this year, the Daily Mail reported on the Invelox wind system developed in Minnesota in the US.

Capable of generating electricity from wind speeds as low as 2mph it uses funnels and tubes rather than huge blades to drive the turbine. It’s all about creating kinetic energy and it is estimated that something like the Invelox system will be able to produce 600% more electrical energy compared to their bladed counterparts.

Flying Wind Turbines

It’s not just ground based projects that are starting to catch the eye. According to Greenpeace, there are no less than 50 high altitude projects on the go that are attempting to harness the wind energy in our atmosphere. While it might sound like the stuff of science fiction, airborne wind energy could potentially provide a lot more power than the normal wind farms we know and love/hate today.

It may be that in the future we’ll be seeing arrays like the Altaeros BAT in our skies. And it has more potential uses than just simply providing large quantities of electricity:

Artistic  Wind Turbines

Wind turbine design might also be changing in the near future with art meeting energy as we try to make our landscape more appealing. One of the major sticking points in recent years for the wind turbine has been that communities have balked at the prospect of large farms despoiling their beautiful landscapes.

The future may well see a change in design with the stuff of science fiction filling our landscapes like this wind sail from Lake Ladoga in Russia.

Not Everyone Hates Wind Turbines

According to The Guardian recently our notion that wind farms are a blot on the landscape may amount to a media storm and be more than a little apocryphal. Nearly 50% of respondents to a survey said that they wouldn’t mind a wind farm being built within 5 miles of their home. It comes as another survey suggested that people are far more in favour of renewable energy sources than perhaps our own government are, and would like to see us moving more quickly towards a sustainable, independent, and cleaner future.

Whatever our feelings about the wind turbine, it is set to continue as one of the major sources of energy production in the world, and future developments may well see greater efficiency that take us beyond a need to rely on fossil fuels.