Renewable Energy

• Solar
• Wind
• Ground-Source Heat Pumps
• Geothermal
• Biomass
• Combined Heat & Power
• Fuel Cells
• Sequestration

Green Living

• Carbon
• Education
• Energy at Home
• Funerals
• The Future
• Gardens
• Health
• Homes
• Kidz Zone
• Ladies Only
• Lifestyle
• Recycling
• Resources
• Shopping
• Travel
• Vehicles
• Weddings

Green Work

• Business
• Farming
• Jobs
• Manufacturing
• Purchasing
• Teaching
• Work
• Thailand

Solar

Solar panels have been used in mainland Europe for decades, but the rising trend in the use of solar power is only a recent development in the UK. Advances in technology mean they will utilize many different kinds of sunlight, so that even on a cloudy day they will produce energy. Solar panels are normally used to heat water and can supply up to 80% of the energy needed to heat water in your home, giving you a significant reduction on your heating bill.

Solar panels collect energy from the sun, which is then transferred to a generator. This generator converts the solar power into usable energy, which is then used to heat the hot water cylinder. In many applications solar energy is used to pre-heat water, thus reducing the amount of energy used by the boiler to bring the pre-heated water up to the desired temperature.

We can also change the sunlight directly to electricity using solar cells.

Solar cells are also called photovoltaic cells - or PV cells for short - and can be found on many small appliances, like calculators, and even on spacecraft. They were first developed in the 1950s for use on U.S. space satellites. They are made of silicon, a special type of melted sand.

When sunlight strikes the solar cell, electrons (red circles) are knocked loose. They move toward the treated front surface (dark blue color). An electron imbalance is created between the front and back. When the two surfaces are joined by a connector, like a wire, a current of electricity occurs between the negative and positive sides.

These individual solar cells are arranged together in a PV module and the modules are grouped together in an array. Some of the arrays are set on special tracking devices to follow sunlight all day long.

The electrical energy from solar cells can then be used directly. It can be used in a home for lights and appliances. It can be used in a business. Solar energy can be stored in batteries to light a roadside billboard at night. Or the energy can be stored in a battery for an emergency roadside cellular telephone when no telephone wires are around.

Some experimental cars also use PV cells. They convert sunlight directly into energy to power electric motors on the car.

The price for installing solar panels is coming down, and the range of manufacturers and products available is expanding. Although the payback time can be long compared with other energy efficient products, they can be fitted to an existing or new-build properly, and can be used in domestic, commercial or industrial applications. As you are collecting and using the energy direct, the usual wastage that occurs between the place of energy production and transference to your home does not apply. Some manufacturers claim their solar panels will save up to 700kgs of carbon-dioxide a year, which helps to combat global warming.

Great potential is seen for Sharp's electricity-generating "solar-windows" which let the light shine through. Their main application would be for large areas provided by curtain-walling in high-rise towers. Read on.

Solar Factories

As solar houses begin to be much more common, it is the emergence of solar powered factories that will be the real sign of a solar economy.

Here are few companies leading the field:

1. Ford at their Bridgend, Wales factory have installed $2.3m worth of solar panels. The panels are 'solar skylights' that not only contribute to the plant's power and lighting requirements, but also allow natural daylight to reach the workspace. Covering 25,000 square metres of the plant's roof, 26 solar units (incorporating 1540 photovoltaic cells) have been installed. This 97 kW system provides all the lighting requirements for the building beneath.
2. Interface Carpets sell a 'solar-made' carpet using Icelandic wool. The wool is washed in water straight from the hot geothermal springs nearby, the electricity to run the machines comes from natural hydroelectric schemes (lakes not dams) in the unpopulated centre of Iceland. Interface then weaves the wool into the high quality wilton 'Reykjavik' carpet using electricity from renwables at Firth Carpets in Yorkshire, England. Another Interface company, Bentley Mills (California), has one of the largest industrial solar installations in the U.S. Their huge, 100kW array of photovoltaic modules provides 6% of the power needs of the plant. This is enough energy to power one of the plant’s 29 carpet tufting machines around the clock.
3. Sony Chemical Corporation introduced a solar power generation system on the rooftop of its No. 3 Site in Kanuma. The system's lifetime of over 30 years will help the site to secure a long-term supply of clean energy. During February 2000, its first month of full-scale operation, it generated 7,120 kWh of electric power, or 8% of the electric power used in the plant.
4. Urtekram make a range of food, household and personal care products at their hay- and wind powered factory in Denmark. 100% of their electricity comes from their windmill, and 100% of their heat comes from burning hay.
5. Patagonia, the California outdoor clothing manufacturer, were the first California company to buy all their electricity from newly constructed renewable energy plants, using almost a million kilowatt-hours annually. They offset the additional cost of renewables by investing in energy conservation such as new lighting, insulation, new more efficient motors to drive the conveyor belts, and Patagonia has achieved a roughly 20% reduction on its electricity consumption. So although it will pay a small premium for using 100% renewable energy, its net costs will be less. The Patagonia Service Center in Reno has 88 solar-tracking mirrors on the roof to reflect its light to the work floor below. It also has a PV installation. "Every time I've done the right thing for the environment, I've made a profit." Yvon Chouinard (Founder & Owner, Patagonia)
6. Wilkhahn manufacture office furniture at their factory near Hannover in Germany. They have paid great attention to the ecological impact of design of their factory buildings, and one feature is a solar PV array on the south face.
7. Trannon also make furniture, using fast growing English ash from forests near to their Wiltshire factory. They need some heat to bend the wood into the desired shape, and this comes from a furnace that burns offcuts and sawdust.
8. The Village Bakery in Cumbria uses organic ingredients and bakes bread using a state-of-the-art clean-burn wood furnace and a computer-controlled 4-rack walk-in oven. A sophisticated system of heat exchangers, flues and filters ensures that the maximum heat is extracted from the wood fire while minimising emissions to the atmosphere. The wood used is offcuts and sawdust from local wood processors - an estimated 150 acres of woodland provides a sufficient supply in perpetuity.
9. Ecover is the most famous ecological factory, but it has no solar electricity or heating to speak of. Belgium has not deregulated electricity supply, so there are no green electrons for Ecover to buy. Ecover consider the costs of installing a solar power station to be too high. Still, the factory does have a couple of photosynthetically-solar powered elements: The grass roof uses the transpiration of water as cooling for the building, and there are reed beds at the back to help with effluent processing.
10. Sharp are taking many initiatives in prioritising environmentally-conscious practices and products. See what they do at their Kameyama super green factory.
11. Solarex made their PV factory solar powered, so creating a 'solar breeder'.

Word of warning: PV cells are manufactured in processes using a greenhouse gas called NF3 which is 17,000 more toxic than CO₂! So check it out before using PV solar cells and visit our article on "NF3: the greenhouse gas that nobody knew".

Firth Carpets and Patagonia, buy 'green electrons' from local energy suppliers, so they can have their factories 100% solar powered with very little additional cost.

Harnessing the Wind

Wind can be used to do work. The kinetic energy of the wind can be changed into other forms of energy, either mechanical energy or electrical energy. When a boat lifts a sail, it is using wind energy to push it through the water. This is one form of work. Farmers have been using wind energy for many years to pump water from wells using windmills like the one on the right. In Holland, windmills have been used for centuries to pump water from low-lying areas. Wind is also used to turn large grinding stones to grind wheat or corn, just like a water wheel is turned by water power.

Today, the wind is also used to make electricity.

Blowing wind spins the blades on a wind turbine -- just like a large toy pinwheel. This device is called a wind turbine and not a windmill. A windmill grinds or mills grain, or is used to pump water. The blades of the turbine are attached to a hub that is mounted on a turning shaft. The shaft goes through a gear transmission box where the turning speed is increased. The transmission is attached to a high speed shaft which turns a generator that makes electricity. If the wind gets too high, the turbine has a brake that will keep the blades from turning too fast and being damaged. You can use a single smaller wind turbine to power a home or a school.

We have many windy areas in the UK, but only some sites are viable for efficient wind power.

In order for a wind turbine to work efficiently, wind speeds usually must be above 12 to 14 miles per hour. Wind has to be this speed to turn the turbines fast enough to generate electricity. The turbines usually produce about 50 to 300 kilowatts of electricity each. A kilowatt is 1,000 watts (kilo means 1,000). You can light ten 100 watt light bulbs with 1,000 watts. So, a 300 kilowatt (300,000 watts) wind turbine could light up 3,000 light bulbs that use 100 watts! As of 1999, there were 11,368 wind turbines in California, USA. These turbines are grouped together in what are called wind farms. Together three wind farms in California make enough electricity to supply an entire city the size of San Francisco! About 11 percent of the entire world's wind-generated electricity is found in California. Other countries that use a lot of wind energy are Denmark and Germany.

Once electricity is made by the turbine, the electricity from the entire wind farm is collected together and sent through a transformer. There the voltage is increase to send it long distances over high power lines.

Ground Source Heat Pumps (GSHP)

Almost everywhere across the entire planet, the upper 10 feet below ground level stays the same temperature, between 50 and 60°F (10 and 16°C). If you've ever been in a basement of a building or in a cavern below ground, the temperature of the area is almost always cool.

A geothermal or ground source heat pump (GSHP) system can use that constant temperature to heat or cool a building. Pipes are buried in the ground near the building. Inside these pipes a fluid, like the antifreeze in a car radiator, is circulated. In winter, heat from the warmer ground goes through the heat exchanger of a heat pump, which sends warm air into the home or business. During hot weather, the process is reversed. Hot air from inside the building goes through the heat exchanger and the heat is passed into the relatively cooler ground. Heat removed during the summer can also be used to heat water. For another FLASH "movie" about how GSHP's work, go to the GeoExchange website here.

Heat pumps are very versatile and can use earth, air and water to conduct heat, however, in the UK the most effective heat pumps use the earth. They are environmentally friendly, extremely efficient and can be used to both heat and cool your house. In essence Ground Source Heat Pumps use the refrigeration cycle to upgrade a source of heat, at a low temperature, to a higher one.

A pipe circuit is laid beneath the earth’s surface and through this an anti-freeze mixture is pumped. This then passes back through an evaporator exchanger in the heat pump to the refrigerant circuit. In turn this is compressed and then condensed and passed through another exchanger into the heating system pipework at a working temperature of around 50°C or even higher if additional circuitry is included in the heat pump.

The important difference with conventional boiler heating is that the geothermal energy (GSHP) system will be designed for an output temperature of 50°C rather than the 60°C to 80°C typical for systems fueled by oil or gas.

Simplified this means that during colder weather, the fluid collects low grade heat from the earth and carries it through the system to be converted to high grade heat for use within the building. During hotter weather the system can be reversed to cool the building by taking high grade heat from the building, using the energy to heat water etc and placing the left over low grade heat back into ground. This process creates free hot water in the summer and delivers substantial hot water savings in the winter.

Heat pumps have a service life of up to 20 years and can be installed in a structure of any size providing there is room to install the underground piping – i.e. the property will need an area of land such as a garden in which to place the underground pipework. It is a system better suited to new-build housing – if you have a well established or landscaped garden you may not wish to have it dug up to lay underground pipework! The payback time can be as little as five years as they produce up to 75% energy for free.

Underfloor Heating

Conventional radiators heat the walls more than the air where you need it. Whereas underfloor heating can be laid in exactly where you need it, making your living areas more pleasing to the eye and being the ethical choice to boot!

Visit some of the links at the bottom of this page for more.

Geothermal Energy

For every 100 meters you go below ground, the temperature of the rock increases about 3°C. So, if you went about 10,000 feet below ground, the temperature of the rock would be hot enough to boil water.

A geothermal power plant is like in a regular power plant except that no fuel is burned to heat water into steam. The steam or hot water in a geothermal power plant is heated by the earth. Some areas have so much steam and hot water that it can be used to generate electricity. Holes are drilled into the ground and pipes lowered into the hot water. The hot steam or water comes up through these pipes and into a special turbine. The turbine blades spin and the shaft from the turbine is connected to a generator to make electricity. The steam then gets cooled off in a cooling tower.

Biomass: Food for Fuel?

Are corn husks better than corn for producing energy? Ethanol is the alternative fuel that could finally wean the U.S. from its expensive oil habit and in turn prevent the millions of tons of carbon emissions that go with it.

The Department of Energy has doubled its 2005 commitment to funding research into biofuels—any non-petroleum fuel source, including corn, soybean, switchgrass, municipal waste and (ick) used cooking oil.

Already, half of the nearly 11 billion bushels of corn produced each year is turned into ethanol, and most new cars are capable of running on E10 (10% ethanol and 90% gas). Yet the eco-friendly fuel is beginning to look less chummy of late. Some of the 114 ethanol plants in the U.S. use natural gas and, yes, even coal to run the processors. And ethanol has to be trucked. Existing gas pipelines can't carry it because it corrodes iron. Then there are the economics. Producers depend on federal subsidies, and increasing demand for corn as fuel means the kernels keep getting pricier. That's why researchers are prospecting for more alternatives, preferably ones that don't rely on food crops or a 51 cents-per-gallon tax break. Municipal waste, wood pulp and leftover grain and corn husks are all quite attractive; they can produce something called cellulosic ethanol, which contains more energy than corn. But they don't give up their bounty easily, so for now they're more expensive than corn-based ethanol to produce.
Undeterred, researchers at several cellulosic-ethanol plants are developing innovative enzyme concoctions and heating methods to make the process more economic. Nothing like haste to make something out of waste.

What is Biomass?

Bio-energy is basically energy derived from plants and manure. Examples are:

• Wood, wood chips, wood pellets
• Plant oils (e.g. rapeseed)
• Bio-gas from farm manure

Bio-energy can:

• provide space heating
• provide fuel for vehicles
• generate electricity

Bio-energy is considered carbon neutral. It releases carbon dioxide at the point of use but absorbs carbon dioxide when growing - a closed cycle However, to be sustainable it needs to be locally sourced.

Green Fuel for Power Plants

Fuel from Plants

In the UK, Miscanthus is recognised and supported by DEFRA, but significant areas of Miscanthus are required to supply biomass into the renewable energy market. Click here for more.

Such fuel sources in developing countries include bagasse and rice husks, but daily supply must exceed 300mt to be economical. Can result in long distribution lines to supply electricity to urban areas on the grid, so often used by sugar producers in their own mills with excess sold to the grid.

Fuel from Solid Waste

Landfill Gas (LFG) energy projects are being found to be efficient especially in developing countries with large engineered landfill sites. The methane and CO₂ can fuel a 1MW power plant from solid waste collection of at least 400mt/day; or 8MW from city collections of 5,000mt/day. Landfill emissions, however, need to be analysed to assess quality of gas and moisture.

Biomass Slurry Fuel

JGC (Japan) has successfully developed a power generation fuel from wood biomass by duplicating the hydrothermal reaction that occurs deep underground over hundreds of millions of years to produce coal using the low-grade coal up-grading technology. This "Coalified" wood has almost zero sulphur content, and has been successfully utilized in oil/coal thermal power plant boilers as a high calorific value liquid fuel that is easy to store and transport using slurry technology. More…

More on Biomass

For the Eco Centre for Wales, click here.

For a good biomass guide, click here.

Biomass Industrial Crops Ltd (BICAL), a co-operative company, exploits the many and different potential uses for Miscanthus.

Combined Heat and Power (CHP)

Combined Heat and Power (CHP) is a fuel-efficient energy technology that, unlike conventional forms of power generation, puts to use the by-product heat that is normally wasted to the environment. The principle is that a gas or oil fuelled engine produces energy much in the way of a traditional boiler. A secondary heat exchanger then absorbs the exhaust heat (which is normally wasted) from the existing engine/boiler and uses that to drive an electrical generator. Therefore, for every kilowatt of energy used to drive the generator, two kilowatts of usable heat energy is produced.

The main generator/boiler would typically be providing the space heating and hot water for a home, industry or community and the recovered energy would be used to supply electricity for lighting, cookers, refrigerators and other kitchen machines. Excess energy produced can be sold back to energy providers.

CHP can reduce the carbon emissions, from about 10% to more than 30%, depending on the amount emitted by the primary generator. Although currently being used in larger applications, Mirco Combined Heat and Power units are available for domestic use. It is expected that in the years to come Combined Heat and Power will be the main energy source for may households and business in the UK.

What on Earth is Carbon Sequestration?

Not on but under earth to be more precise.

Iceland thinks it is making the next big advance against global warming. Over 2007-2009 scientists will attempt to inject carbon dioxide-charged water into the basalt beneath the ground.

Boreholes will be drilled by a nearby geothermal energy plant and the injected CO₂ will (in theory) react with the porous rock and form a stable mineral that could remain in the rock for millions of years.

This Carbon Sequestration is one initiative that the Icelandic authorities are taking in an attempt to get most of its heat from clean renewable geothermal resources.

Will Carbon Sequestration Take-off?

It can be argued that Iceland's demographics and geology lend itself to such dramatic exercises, but they should be showcased for the initiative they are taking.

Coal is one of the dirtiest fuels around and a major source of the world's carbon dioxide emissions. It's also hard to live without. In the U.S., half the electricity generated comes from coal. What if coal-fired plants stopped spewing their carbon dioxide fumes into the air and instead sequestered them: pumped them deep into the ground for storage?

Carbon sequestration is (despite its name) a simple-sounding idea that's exciting scientists, governments and energy companies as a way to cut emissions without disrupting energy supplies. One coal-fired plant in Denmark is working to trap carbon flue gases and store them in four spots, including an unused oil field off the coast of Spain.

A Swedish utility is testing new ways to extract pure carbon dioxide from coal emissions in a lignite plant in eastern Germany. In the biggest test so far, a Norwegian energy firm is injecting 1 million tons of CO₂ a year from the Sleipner gas field into a saline aquifer under the North Sea. "All the basic technology is already here," says Howard Herzog, an energy expert at the Massachusetts Institute of Technology. A report by the International Energy Agency (IEA) in Paris says sequestration would be second only to energy-saving measures in reducing CO₂ emissions, far ahead of better-known efforts like renewable energy.

There are two major obstacles. The first is cost, which the IEA estimates to be as much as $50 for each ton of carbon captured. Those costs may drop if the technology is successful and utilities are given incentives not to spew out carbon dioxide. The other obstacle is a lack of detailed scientific knowledge.

The pilot projects are going well, and Alstom have already installed chilled-ammonia carbon capture technology at Pleasant Prairie Power Plant, USA. In the meantime, watch for sequestration to move quickly up the energy agenda.

See our page on Carbon Emissions for more on reducing your carbon footprint.