Greenpeace UK: Weekly Geek

The (Not Very) Weekly Geek: Wave power

bex — Mon, 29 Sep 2008 11:48:44 +0100

A screengrab from our virtual, climate-friendly town, EfficienCity

With the UK government apparently bending over backwards to stop renewable energy development at the moment, it's refreshing to hear some good news from elsewhere in Europe; the world's first commercial wave power farm has gone live in Portugal.

I spent a fair bit of time researching the Pelamis sea snakes which Portugal is using while I was working on EfficienCity, so I thought I'd revive (temporarily at least) The Weekly Geek column – now reincarnated as The (Not Very) Weekly Geek, for obvious reasons.

First off, a bit of history.

Once upon a time, there was war in the Middle East, oil prices were soaring, people were panicking about energy supply, the dollar was depreciating and share prices were tumbling.

I'm talking about 1973 and the oil crisis, but I'll leave it up to you to draw your own parallels with today's situation (remind me, are we in the tragedy or the farce stage now?).

With the embargo of oil to the US, Japan and much of Europe and the fixing of oil prices after the Yom Kippur War, oil prices quadrupled to $12 a barrel in a few months (yes, $12...). A recession hit many oil importers. Brazil turned to ethanol to fuel its cars. Japan moved its economy away from oil-intensive industries towards areas like electronics. And the UK began to take a serious interest in renewable energy sources.

Wave power, especially, was seen as bit of a holy grail. Our mid-latitude islands benefit from prevailing westerly winds that carry the power of the Atlantic behind them, and these winds blow strongest in the winter, when our demand for electricity is at its highest. Perfect, if we could only harness the waves' energy on a commercial scale. And, but for a decimal point, we might now have been doing exactly that.

I'll explain. In 1974, the UK government started a major wave energy research and development programme. Prototypes were made and tested. Teething problems led to modifications, improvements and, some say, over-engineering, which pushed up the cost of the electricity.

But, during a government evaluation of the cost of wave power, somebody 'accidentally' moved a decimal point, making wave power 10 times more expensive than it actually was. By the time the mistake was discovered years later, the research had been first scaled down and then abandoned by the government.

(If you’re interested in the secret history of wave power, have a scroll through this testimony from wave power pioneer David Salter, from about halfway down. He explains that the UK’s wave power programme was shut down after a closed meeting of a government committee, whose members were recruited from the nuclear and fossil fuel industries. The head of the UK wave power programme wasn’t allowed to attend the meeting. Officials favouring Big Energy over renewables? Plus ça change. But I digress.)

In recent years, there's been an, um, resurgence in wave power, largely thanks to pioneering companies and researchers. The world's first commercial wave power generator was developed on Islay in Scotland, using the Limpet machine (animation). The Orkney Isles have a hugely important test centre for wave and tidal machines. And there are commercial wave farms planned, including a scheme on Lewis. The Aguçadoura Wave Park in Portugal, of course, went live this week. And what will become the world's largest wave power array, the Wavehub, will be sited off the coast of Cornwall.

So how does wave power work?

You could consider the world’s oceans to be an enormous system for gathering energy from the sun and efficiently distributing it across time and space.

Wind is created, ultimately, by the sun’s heat; as the Earth’s surface is unevenly heated, areas of different pressure form, creating wind. When wind blows across the sea, some of the wind’s energy is transferred into the sea, in the form of waves. The waves can still carry this energy long after the wind has died down, and their journeys across the planet tend to be more predictable than those of the wind.

How much energy is transferred to the wave depends on how strong the wind is, how long it blows for and the size of the fetch (the distance of open water before land is reached). All of these factors – along with the depth and topography of the sea floor – help to determine the size of the wave.

The wave power is determined by the height, speed and wavelength of the wave, and water density.

Wave energy converters work by harnessing some of the wave's kinetic energy and converting it into mechanical and then electrical energy.

There are several types of wave energy converters around, but I'm going to stick to talking about the Pelamis - partly because it's the technology being used in Portugal and partly because I like the fact it's named after a sea snake (and it's my column).

The Pelamis harnesses energy from a combination of both wave size and wave power: the oscillatory motion of the sea - that is, the height from the wave's trough to crest, the wavelength (distance between crests) and the time interval between waves:

The Pelamis resembles the sea snake it's named after, except it's about 3.5 metres wide and 150 metres long. It's made of four floating (well, semi-submerged) cylindrical tube sections, connected by hinged joints. It's held in place by an anchor on the sea bed - a system of weights and measures make sure the mooring line stays slack, allowing the Pelamis to swing head on to oncoming waves. This is important: it allows the Pelamis to span several wave crests at the same time.

As waves roll into shore, the sections of tubing roll up and down and from side to side. The relative movement of the sections causes the joints between them to move and be compressed. This compression causes the hydraulic pump or "hydraulic ram" inside each joint to pump oil through a hydraulic motor at pressure. The motor drives an electrical generator, which produces electricity, which is carried to shore (typically five to ten kilometres away) via a sub-sea cable. There's plenty more information on Pelamis Wave Power's website.

The opportunities for wave power in the UK are there for the taking; according to government and industry figures, wave and tidal power combined could meet 12.5 per cent of today's electricity demand in the UK - economically and practically - by 2025. 2025, by the way, is the earliest anticipated date that we could see up to eight of the new nuclear reactors the government wants providing up to three per cent of our electricity.

But British businesses won't take the lead in renewables while business secretary John Hutton is undermining them in favour of old, inefficient technologies like coal and nuclear power. As far as wave power goes, we don't have time to let history to repeat itself a third time.

Previously, in the Weekly Geek:

The Weekly Geek: combined heat and power (CHP)

bex — Fri, 07 Mar 2008 12:22:06 +0000

The ROCA 3 CHP plant in Rotterdam provides electricty and heat to 400,000 homes

Due to popular demand (well, demand anyway), The Weekly Geek now has its very own RSS feed.

Back in 1882, Thomas Edison built the United States' first electric power plant. Pearl Street Station, which supplied the good folks of Lower Manhattan with electricity for lighting and steam for manufacturing, was around 50 per cent efficient.

125 years on, the typical UK power plant is just 38 per cent efficient. But those modern power plants that have been built on the same principles as Edison's are reaching efficiency levels of up to 95 per cent.

So how did Edison do it? And where are we going so wrong?

In this week's slightly tardy Weekly Geek, we're looking at combined heat and power (CHP): the system Edison was using, and the heart of any truly clean and efficient decentralised energy system. (Those who read the first Weekly Geek on decentralised energy may notice a fair bit of crossover.)

A conventional energy system

I'm starting to feel like this is becoming my catchphrase but it's worth saying again: the UK's biggest source of greenhouse gas emissions comes from heat. Not electricity. Not transport. Not agriculture. Heat, for our homes, offices, hot water and industrial processes.

For most of the UK, the heating system is completely separate from electricity system. Space and water heating mostly comes from burning natural gas in boilers. Heat intensive industrial processes (like smelting, say) require vast quantities of fossil fuels to be burned in blast furnaces, smelters and the like.

Electricity is largely generated by burning more fossil fuels, this time in power plants. But, in this electricity generation process, heat is produced as a by-product - and just thrown away up the cooling dowers, or dumped in local water courses.

It's pretty obvious that this is a grossly inefficient way of using fuel; burning one load of fossil fuels to produce heat, and another to produce electricity and just throwing away heat. On average, our conventional power stations throw away two thirds of the energy they generate. Together, UK power plants throw away enough heat to provide hot water and heating for every building in the UK.

A CHP-based energy system

With his Pearl Street Station, Edison was essentially ‘recycling' energy. Aware that one of the by-products of electricity generation is waste heat, Edison captured that heat and delivered it to where it was needed - in this case as steam, to be used in industrial processes.

Edison was able to do this because, in the kind of DC system he pioneered, electricity proved to be poor at travelling long distances. So Pearl Street Station was built in an urban area, meaning that both the electricity and the steam could be delivered to nearby buildings. Today, we would call it a CHP plant as it combined the generation of both heat and power.

CHP plants carried on being common at the start of the twentieth century. It was just common sense: economical, efficient, local energy. But as coal became the fuel of choice, coal dust and particulate emissions became a public annoyance, and power plants were increasingly relegated to rural areas. This meant that the capture and transmission of heat became impractical and uneconomical.

Bar a few minor resurgences (after World War II, for example, newly built residential estates in London were supplied with waste heat from Battersea Power Station), electricity generation has been relegated to large remote power stations, and heat generation has been hived off into a separate system.

In the 1970s, the ‘energy crises' sparked a new interest in CHP but, by then, the large utility companies had become expert at protecting their interests. Today, although CHP is well established in countries like Denmark and the Netherlands, the UK's legislative and regulatory framework still favours large, centralised power plants over smaller, cleaner more efficient ones.

How it works

CHP is the most efficient way possible to burn both fossil fuels (usually natural gas) and renewable fuels (including biomass and biogas).

Pretty much any organic matter can be used to produce biogas; we could be reaping energy from farm waste, and from all of the organic waste - like uneaten food - that makes up about half of our landfill.

With gas-fired CHP, biogas or natural gas is burned in a combustion chamber. This produces a flow of hot air, which drives a turbine. A generator converts this rotational energy into electricity.

After the hot air is used to power the turbine, it's captured in a heat recovery boiler where it heats water which is pumped out through insulated pipes, to provide space and water heating for local buildings.

Low grade heat is also captured from the system and used to drive a steam turbine. This turbine boosts the efficiency of the system by producing yet more electricity.

Sometimes cooling is also produced (‘trigeneration'). Here, some of the heat drives an absorption chiller, producing cold air for air conditioning:

CHP in the UK

Whereas countries like the Netherlands and Denmark get up to half of their energy from ultra efficient CHP, in the UK today it's still a tiny fraction. But there are some pioneering examples (visit EfficienCity for more):

Southampton district energy scheme is one of the largest commercially developed community heating and cooling networks in the UK. The scheme now serves thousands of customers - including residential properties, office buildings, hotels, a hospital and a university.
Woking Borough Council is at the forefront of the decentralised energy revolution in the UK. By decentralising its energy, Woking Council has slashed its energy use by nearly half, and its CO2 emissions by a massive 77 per cent since 1990.
The Natural History Museum has reduced its CO2 emissions by 18000 tonnes a year following the installation of a tri-generation system (electricity, heating and cooling).
Scottish & Newcastle is installing a combined heat and power (CHP) plant in their Manchester brewery, which will be fuelled entirely by biomass - partly from spent grain produced in the brewing process.
Birmingham City Council is embracing large scale CHP, and believes that as well as saving 2,800 tonnes of carbon in its first year, the new system will cut bills for the organisations involved.
The industrial CHP plant at Immingham supplies two refineries in Humberside with heat, steam and power, and is about to be expanded to reach the same electricity generating capacity as the UK's flagship nuclear power station, Sizewell B.

The future

But there's still vast untapped potential for CHP in the UK. CHP plants can either be built in communities to supply building and space heating, or on industrial sites for industrial processes.

If we combine the potential for CHP on industrial sites and in communities, according to government figures, we could generate more than double the expected output of useful energy from the proposed nuclear programme. And the heat, which nuclear can't do.

CHP alone is not the complete solution - it still often uses fossil fuels. But, because it's the most efficient way possible to use these fuels, it cuts emissions and reduces fuel dependency immediately.

Moreover, some CHP plants - so-called flexi-fuel plants - can use diverse fuels in the same boilers. This means that, as more greener fuels like biomass (straw bales, for example, or waste wood pellets or certain specially grown crops) become available, they can be used in the CHP plants instead - with no need to refit the equipment, but with an immediate reduction in CO2 emissions and with the knowledge that these precious green fuels are also being used in the most efficient way possible.

If we combined the efficiencies of CHP with improved efficiencies in the home (proper insulation and minimum efficiency standards for appliances, say), we'd practically eliminate the profligate wastage of our current system.

For more on CHP and decentralised energy, visit EfficienCity or watch our 2006 film, What Are We Waiting For?:

The Weekly Geek: micro-hydro power

bex — Wed, 27 Feb 2008 20:23:35 +0000

It's Weekly Geek time, and this week we're looking at micro-hydro power: a truly reliable, highly efficient, and extremely clean (it has no direct carbon emissions) way of generating electricity.

It needs no fuel but offers a constant supply of electricity which often increases in winter, along with demand. It has a long life cycle (typically 25 years or more). It can have low implementation and maintenance costs. And, unlike some large scale hydroelectric power schemes, it has minimal environmental and visual impacts.

It's so brilliant, in fact, that the Ancient Greek Antipater of Thessalonica was prompted to write:

Hold back your hand from the mill, you rinding girls, even if the cock crow heralds the dawn, sleep on. For Demeter has imposed the labour of your hands on the nymphs, who leaping down upon the topmost part of the wheel, rotate the axle; with encircling cogs it turns the hollow weight of the Nisyrian millstones.

OK, he was talking about ancient water wheels, but the two technologies are based on pretty much identical principles (and I'll take any opportunity to shoe-horn a bit of poetry into this column…). Water wheels have been around for millennia; Ancient Indian texts seem to refer to a water wheel being used as far back as 350 BC, although the first time we know for sure one was used was in ancient Greece and Asia Minor, around 240 BC.

Essentially, waterwheels convert kinetic energy in flowing water into motive power, by re-directing flowing water from a stream and dropping it onto a water wheel to turn it. In the UK, water wheels were (and occasionally still are) used for all manner of agricultural and industrial processes - from milling grain and cutting timber to weaving cloth and shaping metal.

Around 150 years ago, some bright spark decided to borrow from the principles of the water wheel and started developing technologies to generate electricity from flowing water. Nowadays, micro-hydro is a hugely popular way to bring electricity to rural communities around the world (Vietnam has over 2,500 micro-hydro schemes supplying over 200,000 household), and it's deservedly enjoying a renaissance in many of our own rural communities.

(Micro-hydro, by the way, usually refers to plants generating up to 100KW, or 100 standard units of electricity in an hour. Large scale hydroelectric power plants generate a lot more, but have all sorts of damaging environmental and social impacts. Micro-hydro has none of these drawbacks.)

Micro-hydro plants are very site-specific and the kind of plant built depends on two factors: the amount of water flowing past and the "head", or distance of the drop onto the turbine.

How it works

First, water is diverted from a stream or river along a channel known as "leat", "flume" or "head race". Sluice gates control the passage of water into the channel (so it can be shut off during maintenance, and the plant can be somewhat protected during floods).

After passing through a screen to get rid of debris, water drops onto a turbine. The type of turbine chosen (there are all sorts out there) depends on the flow of the river and the head. (At a push, an original water wheel can also be used, usually the overshot style, although this is far from ideal.) For simplicity, we'll describe a cross-flow turbine.

The force of the water on the turbine's bladed surface rotates the turbine around its horizontal axle. Historically, this axle was used to drive a mill's machinery. With micro-hydro, it drives a generator which converts the mechanical power into electricity.

Water leaving the wheel is drained through another channel – also known as the "tail race" - back into the river.

As this animation from EfficienCity explains:

Where they're built

Micro-hydro plants can be built in old, redundant water mills scattered around our countryside; a number of old mills are being converted because re-using structures like the weir, the leat and the original stone millhouse (to house the machinery) mean using fewer resources, less time and less money to build the plant. And because they're pretty. Pedley Wood in Cheshire and Gants Mill in Somerset are both sited in converted mills.

Another option is to build micro-hydro plants in entirely new sites. The same considerations (flow rate and head) apply, but if a spring-fed stream has enough of a drop, new sites can be developed without the need for structures like weirs.

Either way, most micro-hydro schemes are "run-of-river", meaning they don't have a reservoir and only take water from the stream when there's water available.

As concerns about climate change and fuel security grow, hydro-power is getting a fair bit of attention as a small, clean electricity source that can fit perfectly into a decentralised energy system.

More information

We'll keep advocating a decentralised energy system to government and local councils, but if you can't wait that long and want to install your own micro-hydro plant, here are a few resources that may help:

You can calculate the hydropower available in a stream, work out the timescale and estimate the potential revenue at hydrogeneration.co.uk.

You can find out about grants available at the Low Carbon Buildings Programme.

You'll need permission – and an abstraction license - from The Environment Agency.

The Centre for Alternative Technology advises you to also discuss the details with the local planning officials, in case the work needs planning permission. Obviously, you also need permission from the landowner.

The British Hydropower Association has a list of projects in the UK.

If you're interested in finding out more about micro-hydro around the world, the excellent Practical Action has all the info, and The European Small Hydropower Association has Europe-specific info.

The Weekly Geek: anaerobic digestion

bex — Wed, 20 Feb 2008 11:59:24 +0000

Ken Livingstone wants it for London, Hilary Benn is giving money to it and Adam and Debbie are bringing it to Ambridge. After a couple of millennia in the sidelines, anaerobic digestion has finally hit the big time (well, The Archers, anyway) - which is why we've chosen it for this second edition of the Weekly Geek.

Every year, we bury thousands of tonnes of waste food in landfill sites around the UK. We produce almost one and a half million tonnes of sewage a year (don't do the maths - it's disturbing), which is mostly spread on land, incinerated or buried as landfill. And we produce enormous amounts of agricultural waste on our farms. All of this waste breaks down to release greenhouse gases as it decomposes.

In all, about half of our total landfill comes from biodegradable waste, where it becomes part of the problem that contributes to climate change. Instead of sending it to landfill, anaerobic digestion allows us to convert this waste into ‘biogas', making it part of the solution.

Anaerobic digestion can help us to replace fossil fuels, reduce methane emissions from landfill sites and increase the efficiency of our energy system. As well as helping us to fight climate change, it can solve many of our waste management problems, reduce freshwater pollution from organic wastes, increase fuel security and reduce our dependence on chemical fertilisers.

This is animation from EfficienCity outlines how it works:

The organic matter used can be pretty much any biodegradable material: food waste from households, markets, shops, restaurants, caterers, breweries, distilleries, industrial kitchens and companies that process food and drink; abattoir waste; agricultural waste like manure, slurry, straw, feathers and crop residues; industrial waste and residues from, say, pharmaceutical processes or paper manufacturing; and sewage sludge.

After being collected and stored in a sealed reception hall, shredded by a huge industrial shredding machine, this matter is pasteurised in a tank at about 70degC for an hour to eradicate any lurking nasties like salmonella or E. Coli before being pumped into the main digester.

In the sealed digestion tank, micro-organisms break the matter down (digestion) in the absence of oxygen (anaerobic). By releasing enzymes, bacteria convert the matter into fatty acids, hydrogen and acetic acid, eventually producing methane and carbon dioxide.

The composition of the matter determines how long it is digested for and at what temperature; liquid wastes are usually broken down for 15-30 days, heated to 30-35 oC whereas solid wastes usually take 12-14 days heated to 55 oC.

While the biogas produced is mostly methane (60-odd per cent) and carbon dioxide (about 40 per cent), it still contains some trace gases. So, before the gas is burned, these trace gases are removed. The end result, biogas, can either be burned as it is, or can be turned into ‘biomethane' by removing the carbon dioxide.

After being compressed, the biogas or biomethane is ready to be used. Obviously, the best place to do this and make the most out of the energy is to burn it in a combined heat and power plant - the most efficient way possible to burn a fuel - where it generates both electricity and heat:

On top of producing a renewable, very low carbon fuel, anaerobic digestion produces a useful by-product: a high nutrient solid ‘digestate' which can be used instead of normal compost and inorganic fertiliser. So, it can help stop climate change, solve our waste problems and produce biofertiliser. Not a bad result for a load of old muck. It's also far quicker to build than most other kinds of energy plants (in around two and a half years).

So why aren't we using it?

Well, we are - to a degree. But while a few places have built anaerobic digesters to supply district energy schemes or the national grid, as a country, we've been left way behind our European neighbours. For a change.

According to Defra, the UK has fewer than 20 agricultural anaerobic digesters producing electricity. Compare this to Germany, which already has over 3000 and where anaerobic digestion is the fastest growing renewable technology (digesters are being built at a rate of about 1000 every year). Germany has also taken the first steps towards providing a ‘biogas feed in law' which will allow anaerobic digesters to feed biogas into the natural gas network - exactly the kind of bold regulatory measures the UK needs to emulate if our renewables industry is to be allowed to thrive.

While Hilary Benn's £10m funding for showcasing commercial scale anaerobic digestion is all very nice, the technology has already been showcased around the world; now we need to actually start building it on a large scale.

Welcome to The Weekly Geek: decentralised energy

bex — Wed, 13 Feb 2008 14:16:27 +0000

This combined heat and power plant in Denmark is up to 95 per cent efficient

To celebrate our launch of EfficienCity, we're starting a new, weekly column for all the closet energy geeks out there. Every week, we'll take an in-depth look at one of the technologies we feature in EfficienCity - tidal power, wave power, wind energy, combined heat and power, micro-hydro power, anaerobic digestion, biomass and the rest. We'll also be looking at issues like baseload and the regulatory context for decentralised energy.

So remember to check back each Wednesday and, if you have any suggestions for energy solutions to climate change you'd like to see us cover, just post a comment at the bottom of this page and we'll try to slot it in.

This week, we're starting with an overview of decentralised energy: what it is, how it works and how it differs from our present system. So, with apologies to those of you who've already seen this on our EfficienCity pages, here's everything you ever wanted to know about decentralised energy but were too afraid to ask.

While our government promotes the fallacy that we need coal and nuclear power to keep the lights on, innovative councils, businesses and individuals are taking the leap into a cleaner, greener future with decentralised energy - and enjoying lower greenhouse gas emissions, a more secure energy supply, cheaper electricity and heating bills and a whole new attitude towards energy.

What is decentralised energy? Well, it's pretty much the opposite of our present, outrageously inefficient energy system, which was designed to meet the needs of a society that hadn't even heard of climate change. This centralised system is a shambles - in fact, it would be impossible to invent a less efficient way of generating energy.

The typical power plant in the UK is only 38 per cent efficient. By the time we use electricity in our homes and offices, we've lost nearly 80 per cent of the usable energy inside the fossil fuels we burn.

This is mostly because we have two separate energy systems: one for electricity, and another to heat water and buildings. It's news to some, but heat is a far bigger culprit than electricity when it comes to global warming.

For electricity, we burn fossil fuels in a few large power plants, miles away from the homes and offices they supply. Two thirds of the energy available in fossil fuels is lost in the power plant as waste heat (a by-product of electricity generation) and during transmission. Another 13 per cent is lost through inefficient use in our buildings.

For heat, we burn more fossil fuels (mostly natural gas) in boilers in our homes, offices and factories.

It's a little bit like putting radiators on the outside of your house instead of inside it; we're burning one lot of fossil fuels for electricity, and another lot for heat, but waste heat is a by-product of electricity generation. Can't we just burn one lot of fuel to generate electricity, and capture the 'waste' heat at the same time?

We can. Combined heat and power or CHP does exactly that.

Combined heat and power

CHP is the heart of an efficient, decentralised energy system like EfficienCity. It's the most efficient way possible to burn fuel because so little energy is lost as waste heat. That's how CHP plants in Denmark can reach up to 95 per cent efficiency.

Because the heat needs to be captured and piped around the local district, CHP plants are usually sited in the towns and cities where the electricity and heat will be used. This makes it more efficient for electricity generation as well as heat; very little energy is lost in transmission.

If we combined the efficiencies of CHP with improved efficiencies in the home (proper insulation say, and minimum efficiency standards for appliances), we'd practically eliminate the profligate wastage of our current system.

CHP is also brilliant in the transition from a fossil-fuelled energy system to one based on cleaner, greener fuels like biogas and biomass. CHP plants can run on a variety of fuels, which means that the fuel mix can include fossil fuels like natural gas but, as more cleaner fuels like biogas become more available, they can switch to those.

Pretty much any organic matter can be used to produce biogas; farm waste is the most famous example (thanks to The Archers) but we could be reaping energy from all of our food that ends up as landfill - food makes up about half of our total landfill, where it produces large amounts of methane, another greenhouse gas.

Local renewable energy sources

But decentralised energy isn't all about CHP. There's an abundance of energy out there in our natural world, ready to be harnessed. We could be harvesting energy from the wind, the sun's rays, the ocean, underground springs and even the earth itself. According to the government, just the wind, wave and tidal resources of our windswept island could meet 40 per cent of our energy needs by 2020. In the longer term, the sky's the limit.

A flexible, scalable energy system

Unlike our conventional power plants, decentralised energy is completely scalable and flexible. You can have a tiny CHP plant in a supermarket or an enormous industrial plant like Immingham, which will soon provide as much electricity as Sizewell B. You can have a single wind turbine like the one at Manchester City's stadium or a massive wind farm like the forthcoming London Array.

This also means that decentralised energy systems can be installed much faster than huge power plants, and can be tailored to fit local needs.

Energy security

Whereas decentralised systems like EfficienCity's rely on local, diverse energy sources, our current system will soon rely mostly on imported fossil fuels.

On top of that, using hundreds of small energy generators instead of a few major ones means there's a far lower risk of system failure; it's far less likely that several small plants will fail at the same time than that one big plant will.

If a local decentralised network did fail though, only one small area would be affected, and that area could import from neighbouring areas.

No more energy price hikes

Decentralised energy can also save consumers an enormous amount. Efficiency measures alone can save consumers a whopping £12 billion a year (the government's own figures) and they save more money than they cost to implement.

But there are other savings to be made. Although energy from decentralised systems may be more expensive per kilowatt hour than energy from coal, it can actually work out cheaper for the consumer. Why? Because only 37 per cent of the average British electricity bill is for the electricity. The rest goes to propping up the grossly inefficient infrastructure.

And of course, if the UK decoupled itself from the fossil fuel market, we'd be protecting ourselves from the massive price increases of gas, coal and oil, which will inevitably keep coming.