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Set targets. Measure and compare performance. Aim to improve!
Alternative energy sources
Modern human civilisation has an enormous demand for energy. Historically we have always relied on fossil fuels for our heat and light. Ever since man first lit a fire to heat his cave we have been consumers of fossil fuels. Unfortunately, since the Industrial Revolution our demand for this type of fuel has exceeded the rate at which the Earth can replace it; coal, oil and gas take millions of years to be created.
Our massive reliance on fossil fuels is doing damage to the environment we live in: Gases released as we burn fossil fuel are destroying the ozone layer and contributing to global warming. Fossil fuels are a non-renewable source of energy, which means that once they are used up there are no more. We need to change the way we live our lives and we need to make a dramatic change in our choice of energy source.
Fortunately, there are alternatives to fossil fuel burning methods of producing energy:
Renewable energy sources include wind, wave and solar power. These sources of energy are limitless and replenish themselves constantly. They create no harmful by-products and, after an initial expense in constructing the means of harnessing the energy, are essentially free!
This all sounds too good to be true, and in some peoples eyes it is. Opponents of renewable energy sources argue that wind, wave and solar power are too unreliable, as they all rely on the best meteorological conditions to be effective. Proponents concede that while this may be true: Solar power would not be the best way of generating electricity in the UK in winter perhaps, and inland cities such as Birmingham or Leeds do not have the means to generate power from waves, a combination of different methods all feeding power into the national grid may be the answer.
During the winter, storms mean that good, strong winds can blow for many days, which in turn generate powerful waves around our coasts. In the summer time we can rely more on solar power. In areas such as Wales or the north of England we can harness the power of fast-running water off the hills and mountains as a source of hydroelectric power. Taken together, these methods of energy production can supply the national grid all year round in any weather conditions.
This is the way forward for our civilisation if we are to satisfy our demand for power; clean, renewable methods of energy production must become our primary source of power in the 21st century and we must drastically cut down our reliance on fossil fuels if we are to prevent catastrophic damage being done to our global environment.
Wind power. In the past, we have harnessed the power of the wind to grind wheat into flour in windmills and to transport people and goods around the world in sailing ships and barges. Since the Industrial Revolution our reliance on this form of power has all but ceased. But for a few small pleasure-craft, this clean, abundant form of energy has remained completely untapped for almost a century. This is now beginning to change; all over the world enormous new wind turbines are being erected and wind power is now being used to provide electricity to heat and light our homes.
A modern wind farm.
Modern wind turbines are much more efficient than windmills used to be. A wind farm may have up to 50 of these structures, each with it’s own generator feeding electricity into a grid.
In the past, people complained that wind turbines were not cost-effective but now that their design has been refined over the last decade they are able to produce electricity as cheaply as coal-powered generating stations.
Another complaint of wind farm opponents was that they are too noisy for people living nearby. Modern wind turbines are much quieter than the earlier prototypes. The necessity for wind farms to be located where there is more wind means that many are sited on hill or cliff tops. These areas tend to away from areas of denser population and therefore less likely to disturb people.
Although wind turbines are very tall, they don’t actually take up much ground space and it is possible to graze sheep and cattle in the same area, as there are no emissions or by-products likely to contaminate or harm livestock.
Wave power. The power that could be generated by the movement of waves is incalculable. There is more than enough potential energy in the seas and oceans of the world to meet all mankind’s energy needs many times over. The problem we have is how do we harness that energy?
Since the 1970’s much research into methods of harnessing wave power has been done, but our wave technology is nowhere near as advanced as our solar and wind power technologies. One of the major problems in constructing a wave farm is that heavy waves are so destructive. We are still looking for a definitive solution to this problem; we need to be able to design a structure that can withstand the power that it is attempting to harvest.
Wave power is a very attractive alternative to traditional fossil fuel sources because, like wind power, it is clean and there is an unlimited supply of it. Wave power generators would be sited offshore so there are no complaints that they spoil the natural beauty of the landscape. They do not interfere with the fishing industry and any noise they create would not be heard over the sound of the waves themselves.
Unfortunately, more research needs to be done into a reliable and cost-effective design for a wave power station. Scotland is so far the world leader in this technology and is already beginning to construct its first experimental stations. By the end of this decade we should see many reliable and cost-effective wave power generating stations around our coasts.
Solar power. This type of renewable is probably the most established. Humans have been using heat energy from the sun in simple (passive) ways to heat their homes and water for thousands of years. We have all hung out washing to dry on a sunny day and found it to be very effective.
This source of energy is, again, free. It is clean, silent and produces no harmful by-product. There is an abundant supply of it for much of the time; enough sunlight shines on our planet every half hour to satisfy all our needs for a whole year!
What we need to do is make ourselves accustomed to thinking of solar energy as a possible primary power source. We already have the technology to convert sunlight directly into electricity using solar cells (also known as photovoltaic cells).
A bank of solar panels.
Although solar energy is not available 24 hours a day, it is possible to produce more solar electricity than we need while conditions are good and store it in large batteries for use on overcast days or during the night.
We are all familiar with the sight of solar powered water heaters on rooftops in countries such as Turkey or Greece when we go on our holidays. Why should this not become a familiar sight in our own country? After the initial small expense of installing solar panels, we would all welcome additional free power to our homes when the conditions are right. Homes would still be receiving power from the national grid, but this could be supplemented with solar power to lessen our reliance on fossil fuels.
Hydroelectric power. This type of renewable power source is already established in many parts of the country and has been for many years. It is reliant on fast flowing water to drive the turbines, which generate the electricity. The geography of Wales, Scotland and Northern England is ideally suited to hydroelectric power stations and electricity has been generated in this way since the 1950’s in these locations. Around one fifth of the world’s power comes from hydroelectric sources already, although the building of dams and the necessary flooding of river valleys has been the cause of many protests around the world. When the Aswan dam was built across the River Nile in Upper Egypt during the 1960’s for instance, hundreds of square miles of land became permanently flooded.
A hydroelectric power station.
ECOHOME
Ecohome is a competition winning demonstration of the latest methods of sustainable construction techniques. The building was commissioned by Bristol City Council and
designed and constructed by Bruges Tozer, a company who specialise in this type of modern sustainable development.
Bristol Docklands’ Ecohome.
The most striking feature of Ecohome is the buildings shape: Designed to make the best use of natural lighting and passive solar heating, the shape of the building is a cube sliced off at the roof. This maximises the area facing the southern sky and reduces the heat loss through surfaces that would not catch the sun.
Much thought has been given to the materials used in the construction:
- Internal walls are of building blocks manufactured using recycled furnace ash. This is a by-product of fossil fuel fired power stations. Use of this material means that even the waste produce from the energy generating process is being put to good use.
- The exterior walls are clad in reclaimed Victorian bricks, which were once used in local industrial construction. This local sourcing of materials means that energy expended in transporting the bricks to the construction site was minimal.
- All the blocks and bricks used in the construction are bonded together using a soft mortar, which means that when Ecohome itself is demolished, the bricks can be reclaimed more easily and re-used a second time.
- Much of the construction is in timber. This timber is all specified from sustainable forestry and is mostly of fast growing soft woods such as Western Red Cedar, which contains natural preservatives and can therefore be used outside in its raw state without the need to be treated with harmful toxic preservatives. Where treatment of the timber is unavoidable, preservatives used are of a ‘fixed’ variety, which will not allow leeching into the environment. Much of the structural work is in Masonite, a manufactured hardboard that is strong and light, thus reducing transportation costs. Masonite also requires 40-65% less raw materials than conventional timber. The joinery techniques used should prolong the life of the timber and reduce the need for future maintenance.
- The slates on the roof are locally sourced and reclaimed from redundant buildings. Again this reduces energy expended on both production and transportation of the material.
- All metals used in the fittings are of recycled aluminium. This material can be reclaimed again in the future for further recycling.
- The use of plastics in Ecohome is kept to a bare minimum, as this is a non-sustainable material. Plastics are only used in electrical fittings and for draught-sealing.
- All finishes in the building are kept to a minimum. Where surfaces are finished, this has either been with water-based paints or with naturally sourced oils or waxes.
Water conserving measures. Ecohome is fitted with a restricted flush w.c. as this can be one of the main uses of water in the home. There is also shallow bath, a low power shower and a low water consumption washing machine.
Rainwater is collected in a pond for gardening use.
Heating. Much use has been made of solar power to heat the Ecohome. The design of the building means that the roof and all south faces are largely of glass, allowing radiant solar heat inside the structure. Excellent insulation in the other walls and floor keep this heat in, thus reducing the need for additional heating measures. Radiators are hot water type and the majority of the energy required to heat all the water in Ecohome is from solar powered tanks on the roof. A 20 gallon capacity tank is heated by roof mounted evacuated tube solar panels; this provides water at an average temperature of around 60º, even on cloudy days.
In the winter, additional heating comes from a low demand Gas Condensing system:
Performance compared with a conventional boiler:
30% less fuel used
Reduced pollutant emissions:
30% less CO²………………………….(causes global warming)
Minimum SO² or nil SO³ releases……………………(acid rain)
Nitric oxides (NO²) less than 30ppm…………………(acid rain)
CFC’s trapped and neutralised.……………….(ozone depletion)
Natural gas is one of the cleanest burning natural fuels.
Natural air conditioning. Based on the simple principle that warm air rises, Ecohome makes use of an ingenious yet very simple method of controlling all air movement through the house: Fresh air is drawn in through vents at low level between the glass walls and the rainwater pool at the southern corner, humidifying and cooling the air in summer as the water evaporates. The air rises up through the building and, guided by the sloping roof, exits through a flap high up in the northern wall. This flap is manually controlled and regulates the temperature and airflow for the entire house, generating a cool breeze in summer and drawing warm air up through the house in winter.
The ventilation rate also changes with the seasons. The vent behind the pond, through which the fresh air is drawn into the building, widens as the water in the pond is evaporated by summer sunshine and closes again as the pond is filled by rain in the winter. As the air inside the building warms up with more sunshine in the summer, this causes the air to rise faster and exit through the flap in the top corner of the building. All this happens without the aid of any mechanical pumps or fans, which would require power to operate.
The Ecohome in cross section.
The construction techniques demonstrated in the designing and building of Ecohome must be adopted by the construction industry and implemented in every new home built in the 21st century if we are to reverse the progressive damage that has been done to our environment in past years.
By building in an environmentally sustainable way we are able to reduce the demand made on the planet’s resources by construction. Good use of locally sourced and salvaged materials mean less reliance on fossil fuels in both the production and transportation of materials to the site.
These techniques continue to be good for the environment after construction is completed, in that this type of building design requires less reliance on the burning of fossil fuels for heating and lighting during the buildings’ lifetime.
When the building eventually becomes redundant, much of the material used to construct it will be salvageable for use in future construction.
If 21st century planners and designers make sustainable construction techniques a priority then our dwindling stocks of fossil fuels such as oil and gas may well last us into the next century and beyond, making the world a cleaner, healthier place for everyone to live in.
