Renewables – the truth

The current generation of renewable energy systems make no commercial or environmental sense as they are all carbon positive.  Most renewable energy systems focus on electricity when it is a small part of the overall energy footprint of any individual.  The backing of governments for solutions that are based on consumer products is due to the political imperative to maintain the status quo and to create jobs.

wind turbine burn3_f3abb3917eToday’s children will have no future if governments continue to rely upon technology that was developed over 100 years ago such as wind turbines, photovoltaic panels, ground source heat pumps and bio fuels.  They made no sense 100 years ago.  They make no sense now.  They have only been resurrected to allow manufacturers, installers and financiers to benefit from a new range of consumer goods.  A full life cycle cost/energy/carbon analysis quickly demonstrates that they make no sense.  Almost always renewable energy systems have to be subsidised.

If an installation has to be subsidised then it cannot ever be low carbon, or zero energy.  For example wind turbines and photovoltaic panels contain components that are derived from oil.  They are manufactured in factories that are powered by fossil fuels, they are transported by machines that run on fossil fuels, and installed by people whose lives are based on fossil fuels.  The wind and the sun are intermittent sources of energy so they require a full backup system that almost always consumes fossil fuels.  The energy consumed by the infrastructure that is required to operate and maintain the systems, including personnel and their families, means that wind turbines and photovoltaic panels are carbon positive.  Using fossil fuels to save fossil fuels is pointless.

The world is still wholly reliant upon fossil fuels and this has to change.  Many people believe in a future that is based on wind turbines and photovoltaic cells.  As long as the wind blows or the sun shines they produce energy.  Nuclear power stations, and coal or gas fired power stations are not designed to be turned on and off so they have to be kept on standby.  Consumer demand can change every few minutes and the amount of wind and sun generated electricity can change in seconds.  This is a problem for the grid because consumption and production have to be perfectly balanced.

Nuclear power stations consume a large quantity of fossil fuel during the course of their construction and their subsequent operation. What is even more worrying is that the process of decommissioning a nuclear power station consumes a huge amount of fossil fuel.  The final insurmountable problem that is never discussed is the storage of nuclear waste for tens of thousands of years even after society has returned to its agrarian ancestry.

Most governments wish to generate an increasing amount of electricity from renewable sources and to move it via the grid.  Electricity that is produced in this way will always be expensive and its availability erratic.  The construction and maintenance requirements of renewable energy sources makes a nonsense of any environmental benefit that they might deliver.  In January 2012 the Scientific American reported as follows;

“To see the big obstacle confronting renewable energy, look at Denmark.  The small nation has some of the world’s largest wind farms.  Yet because consumer demand for electricity is often lowest when the winds blow hardest, Denmark has to sell its overflow of electrons to neighbouring countries for pennies only to buy energy back when demand rises, at much higher prices.  As a result, Danish consumers pay some of the highest electricity rates on the planet”.

There is an acute need to find new ways of cutting domestic energy use by an amount which goes far beyond anything that is currently possible.  The only way domestic energy consumption will be significantly reduced is if ever home can meet all or most of the energy demands of the people who live in them.

The reality of renewable energy systems is as follows;

Solar_panelsThe Photovoltaic effect was discovered by Edmund Becquerel in 1893.  In 1901 Nikola Tesla received a US patent for an apparatus for the utilization of radiant energy.  In theory, photovoltaic cells can reach an efficiency of 40% but this assumes a brand new installation that is set at a right angle to the source of light in perfect conditions.  In normal use the efficiency seldom exceeds 25% and it is frequently just 7% in Northern Europe.  Most installations only produce power for 6 hours a day and then only in summer.  Between the autumnal and spring equinoxes PV’s generate so little electricity in the temperate zones that they are worthless.  PV cells contain range of toxic materials like selenium, cadmium and nickel which means that they are destined to be a waste disposal problem for future generations.

The conclusion – photovoltaic cells have merit in a hot dry climate where intense sunlight is guaranteed throughout the year.  They are of limited value in the temperate zone.  They are good for powering minor control systems but are not a reliable or cost effective source of electricity for most homes.

Wind-Turbines2The first modern Wind Turbine was built in Cleveland in 1887 by Charles F. Brush.  They are ineffective unless they are installed off shore, or on land within 1 mile of the coast or on exposed ridge lines.  To function they require a wind speed of more than 6 m/s or 13 mph.  No turbine in Europe operates more than 25% of the time and most function less than 20% of the time.  The Danes produce more wind energy than anyone else in the world and have not decommission a single conventional power station.  This is because the wind does not blow at the right speed most of the time and conventional power stations take 6 to 8 hours to bring on line.

In conclusion – wind turbine generators are expensive and only worth considering when a strong steady wind can be guaranteed.  They do not work in conurbations where the airflow is turbulent and wind speeds low.  Large wind turbines are expensive to construct and are formed from non-renewable resources that have a high embodied energy content.  They make no commercial sense unless they are subsidised and unless a conventional electricity supply is permanently available.

ground sourceA Ground Source Heat Pump uses a refrigeration-style compressor to transfer heat from the soil near a building into the building.  The heat pump was first described by Lord Kelvin in 1853 and perfected by Peter Ritter Von Rittinger in 1855.  Robert C. Webber built the first direct exchange ground-source heat pump in the late 1940s.  A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe which is buried in the ground.  As the liquid travels through the pipe it draws heat from the ground.  GSHP’s deliver water at approximately 28°C so they are suitable for under-floor heating systems but not radiators.  Ground source heat pumps consume electricity and deliver low-grade heat for the same cost as burning gas.  It is necessary to have a conventional heating system on permanent standby.

The conclusion – Ground source heat pumps represent a considerable capital outlay and need a full back up system.  They use a considerable amount of electricity.  They are of little value when the soil starts to freeze.  If a supply of gas is commercially available then a conventional boiler is more effective than using a ground source heat pump.

Air Source and Water Source Heat Pumps use the same principle as Ground Source Heat Pumps.  Air Source Heat Pumps can be fitted outside or in a roof void.  They perform better when the air is warm.  Water Source Heat Pumps can heat homes that are located near rivers, streams and lakes.  It is easier to obtained heat from ground water so this is the preferred option.

The conclusion – Air and Water Source Heat Pumps multiply by a factor of three the energy that is present in the electricity that they consume.  They are not efficient and are invariably dependent upon a supply of electricity that is produced from burning fossil fuels.  They usually require a conventional heating system to be on standby.  As a result there are two sets of installation and maintenance costs.

Combined Heat and Power units use a petrol, diesel or gas engine to drive a generator.  The waste heat is recovered and used for heating or for the production of hot water.  They avoid the losses that occur in industrial power stations in the steam/condensing cycle.  CHP units frequently produce heat and electricity when they are not needed.  They represent a considerable outlay, need regular maintenance and burn expensive refined fuels.  They can reduce the combined electrical and heating loads of a building that has a continuous demand for both like a hospital.

The conclusion – Combined Heat and Power units are a major item of expenditure.  When their running and maintenance costs are taken into account they are of little benefit.

wood pelletBio-fuels can be used to warm water and heat buildings.  They are usually derived from trees.  The logic is that the carbon dioxide that is produced when they are burned is recycled.  Wood pellets cost as much as fossil fuel because of the labour and energy that goes into growing the trees, processing the wood, and transporting and delivering the finished product.  The boilers are expensive, complex and cost a great deal to maintain.  All commercial Bio-fuel systems are carbon positive.

The conclusion – Bio-fuels make no sense unless the system that is used to deliver them is technically crude, the raw material is produced locally and the raw material it is not processed.

Agri-fuels like bio-diesel have been in use for over 100 years.  In 1898, Rudolph Diesel exhibited his first diesel engine at the World’s Exhibition in Paris.  It ran on peanut oil.  Henry Ford’s first Model T cars ran on alcohol derived from hemp.  In World War II potatoes and grain were fermented and the resultant alcohol was added to petrol.  In West Africa lorries ran on palm oil.

In conclusion  –  Agri-fuels make no commercial sense.  It takes 1¼ to 1½ barrels of conventional diesel to make 1 barrel of bio-diesel.  As a result they are very carbon positive.

Solar Water Heating Systems use solar panels which are usually placed on roofs.  They collect heat from the sun and use it to warm water which is stored in a hot water cylinder.  A boiler or immersion heater is often provided to further heat the water.  This means that there are two installation and maintenance costs.  In the temperate zone they work some of the time but are not a reliable source of hot water.

In conclusion – solar water heating systems work well in warmer climes but are of very little value in the temperate zones.

heat exchangeDomestic Heat Exchangers allow the heat or coolth that is present in waste air that is leaving a building to be transferred to fresh incoming air.  Thin sheets of metal or plastic separate the used and new air.  Such systems are useful in winter as a way to conserve energy.

In conclusion – heat recovery is an important feature of any Near Zero Energy dwelling.  It is hard to capture heat.  Once it has been captured it is important to conserve it.

Most small Batteries are dry cell and non-rechargeable.  Hybrid vehicles and electric cars are driving the search to find ways to lower cost, reduce weight, and increase life expectancy.  For over a century lead acid batteries have been used to start engines.  They are efficient and robust but seldom last more than 5 years.  Batteries have a short life and the environmental damage that occurs when they are manufactured is considerable.  The cost of the batteries that would be needed to store the electricity for a conventional dwelling is so great that they are not a practical proposition.

The conclusion  –  It is impractical to store more than a small amount of electricity in batteries.  If all the batteries on the planet were fully charged they would contain enough energy for society to function for 10 minutes.