Power to the people

RENEWABLE energy systems are becoming more affordable and practical for home use. A rapidly expanding market offers more choice, but can also be confusing. LISA STURE, of Element Energies, is your guide to the options available

CLIMATE change is no longer a vague concept. Since the Industrial Revolution we have been pumping greenhouse gases into the atmosphere in ever-increasing amounts, and we are only now beginning to realise just how big is the price we will have to pay.

The rapidly changing polar ice caps and, closer to home, the floods and incredibly long summer have been very real evidence that something is happening to our climate. It might seem frightening and daunting, but there are things we can do - and everything we can do as individuals counts. It’s that eating an elephant parable again, or the pennies taking care of the pounds...from turning off a light, to bigger projects like installing a solar hot water system, we can all do something. And we can benefit from lower fuel bills too.

One of the major causes of greenhouse gases is the use of fossil fuels to power our homes and businesses. But at least having recognised that we are part of the problem, it means we can also be part of the solution - renewable energy, combined with energy efficiency, offers a viable and potent solution to countering the effects of global warming.

Renewable energy is developing quickly as people become increasingly aware of its relevance, impact and, yes, trendiness. And a fast-moving market can be confusing. There are many ways of capturing energy: some of them will always be in the domain of do-it-yourself and not commercially viable, and others are still developing technologies which are not yet commercially available, but there are others that are available to everyone.

This is a basic guide to the most readily available technologies and what you need to make use of them.

The first technology is solar energy, which splits into two, both of which directly use the sun’s energy: one heats water [sometimes called solar thermal] and the other creates electricity [called ‘photovoltaic’ or PV].

SUNNY DELIGHT: Solar panels can be used to heat hot water (directly or by heating another fluid that transfers its heat to water in a tank), or to create electricity using photovoltaic cells.

Solar hot water
Solar hot water is the technology that most people could install; it fits on a roof and has a payback period similar to double glazing.

The solar panels, also known as ‘collectors’, can be integrated into a building’s roof or positioned on top of the tiles on a frame. They use the sun to either heat the water directly, or another fluid, which passes through the panel and transfers its heat to the water in a hot water tank. The panels work throughout daylight hours, even if the sky is overcast and there is no direct sunshine. The system usually provides 50-75% of a household’s hot water needs over the year - which means it should meet all your hot water needs during the summer months and pre-heat your water, so that you use less fossil fuels, during the rest of the year. And if you have an east-west facing roof and, therefore, thought you couldn’t site solar panels effectively, think again - there are systems that work east-west. Just ask around.

There are two distinct types of solar hot water collectors: flat plate and heat pipe (also known as evacuated tubes).

As a guide, the heat pipe system will give you more in the winter, spring and autumn months when there is not enough sun to create all the hot water you might need, while flat-plate systems are robust and less expensive. Heat pipes were developed for use in space and are the hi-tech solution. Buy within the suggested price range and you will probably be paying about the same per kWh of energy produced as for a flat-plate, but will have a higher outlay at the beginning. A good independent website where you can look at the actual performance of heat pipes is www.solarious.co.uk.

Sometimes you come across flat-plate collectors that run from a small solar electricity panel instead of being wired to the mains. What this means is that, as well as not using the £5 of electricity it takes to run the pump each year, your system would also work during a powercut. There is also the angle that PV is relatively expensive and this is one way to have some on your roof!

Some people have asked me about using solar hot water to heat their house. It is possible, however, the time when you need the most heat is when there is least sun in the sky, so you need a pretty big system and, preferably, under-floor heating.

Solar hot water systems are also very good for heating swimming pools (the Clear-skies grant is available for this application too). If you have an outdoor pool that only needs heating in summer, there are some cheaper unglazed systems especially made for this use.

Solar electricity
There are also solar panels that create electricity - these are called ‘photovoltaics’ or PV. A PV system can be ‘stand-alone’ and charge batteries, or it can be linked to the national grid, which means that when you produce more power than you need, it goes into the grid, and when you use more than you produce, you take from the grid. So the grid acts like a giant battery!
Some panels are fitted on top of your tiles and others are like tiles and form your roof covering.

Wind turbines
A wind turbine converts wind to electricity. Although there has been controversy over large commercial wind turbines, there is usually little argument over domestic size ones. There are wind turbines on both Dartmoor and Exmoor National Parks.
Modern turbine designs are virtually silent in operation - the wind in the leaves on trees can be louder! However, there are some small wind chargers for use on boats and caravans, which can be noisy.
So, is your property suitable for generating wind power? Some of the things you look for when siting a turbine would be: do you have a spot that is high up, exposed (especially to the south west), and not near trees or buildings (these mess up the wind and take the useable energy out of it).

Small-scale hydro turbines
Electricity can also be made from flowing water. Hydro is a good source of power because the water is flowing and creating energy for you 24 hours a day, which soon adds up to a lot of power!
If you have a reasonable size river on your property, some of it can be directed into a pipe taking it down to a turbine, which the water turns to make electricity. The potential to produce power is determined by two factors: how far the water falls (the head) and the flow rate.

Modern automatic wood heating systems
Wood-burning systems, unlike other renewables, do emit carbon dioxide. However, as the wood fuel is cultivated, it absorbs the exact same amount of carbon dioxide as is released when burnt. As such, it is a balanced cycle and does not add to the carbon dioxide in the atmosphere.

But what about pollution from the smoke? Well, modern wood-burning heaters and boilers are different from the ‘old fashioned’ ones because they are high efficiency and automatic, which means they give you more energy from the fuel, and they burn it at a higher temperature, so that you get an absolutely minimal amount of emissions (and ash). On these systems you set the temperature and they continuously burn at that temperature. The smaller household sized systems usually run on wood pellets, larger systems on wood chips or logs.
You can get stand alone room heaters, ones with back boilers to heat water and ones that do the heating as well. Wood chips are comparable in price to gas, whereas wood pellets work out at about 4p per kWh of energy, which is very attractive if you do not have gas and are currently heating with electricity or oil.

Ground source heat pumps
These draw heat from the ground and concentrate it so that it can be used in (mainly) underfloor heating systems. GSHPs use electricity for their operation and produce 3-4 times the energy they use. They consist of a small fridge-sized housing and a pipe which is placed in the ground. The pipe can be installed in two ways: under a piece of land (perhaps a lawn) via six feet deep trenches, or in a borehole.
Although GSHPs use electricity, if you also subscribe to Unit(e), which supplies completely green electricity, you have a co2-free system that is cheap to run!

Green tariffs
There are two types of electricity supply tariffs that you can sign up for:
Green power supply - here the electricity company ensures that for every unit of electricity you use, the same amount of green electricity is generated.
Green fund - here the electricity company takes the extra that you pay on your bill and invests the money into new renewable energy projects.
Unit[e] is the only company that supplies only green energy and at a unit cost of 7.94p, and an annual standing charge of £38.51, it is not very much more expensive than a standard electricity supplier for most users. To find out more go to: www.greenelectricity.org

We want to know more!
Already got renewables installed in your house? We would really like to celebrate the people who have already installed renewable energy in their homes in Devon. So if you have, go to www.elementenergies.co.uk/revolution and enter your installation. If you do not have access to the internet, you can still take part by calling 01271 866960 to get yours entered.