Comm: "In the earlier programmes in this series on climate change we saw how the burning of fossil fuels such as coal, oil and gas to power our factories, cars and homes has contributed to global warming and climate change. We followed the attempts of politicians to limit the use of fossil fuels, and discovered the impact a changing climate is having across the world. This week in a Hands On Special we take a look at a wide variety of new clean technologies that do not have such a serious environmental impact. Technologies that have the potential to bring power not only to small Comm: "unities in remote areas, but technologies that can run whole towns and cities. We see Electric taxis in Nepal, Wave power in Scotland, Solar power in Africa and cars driven on fuel derived from water.

"This is Europe's centre for solar energy research and development in Altimara, Southern Spain. It is pioneering technologies that could ultimately be used to power large towns or industrial complexes.

"In this system a huge array of mirrors reflect and concentrate light to a single receiver at the top of this tower, the resulting energy can turn water into superheated steam, enough to power a high output generator.

Manuel Blanco Muriel: "This mirror moves in such a way that it reflects the light from here - that goes into the mirror - to the tower - the central receiving system on top of the tower, concentrating the light from the mirrors into one receiver."

Comm: "Other systems replace water for gas."

Michael Geyer: "In this receiver we have a working gas. It's heated up here to about 650 degrees centigrade and it leaves the receiver at this temperature and here it enters the cylinder of the sterling engine where it performs the mechanical work and drives the generator."

Comm: "This is the cutting edge of solar research. But to prove its not just a theoretical technology, there is a town in Germany known as the Solar City.

"Freiburg, in the Black Forest of southern Germany. It may not have the sunniest skies, but it does have the sunniest power."

"Rolf Disch is the architect of many of Freiburg's solar buildings - including his own home."

Rolf Disch: "This is an experimental house. With this house we've tackled many problems. One of these is energy. This is the first surplus energy house that we've built, which produces five times the amount of energy that the house needs."

Comm: "Disch now builds solar-powered, low energy houses for others. These are the first of a hundred and fifty that make up Freiburg's first solar village.

"The whole city is involved in Freiburg's solar policy. There's even a solar plant on the grandstand roof of the local football stadium. Naturally, the public swimming pool is heated by solar power. And the parking meters are also powered by solar power. With Freiburg reaping major economic rewards there's a booming demand for new solar technology. At the factory where much of the hardware is made, solar power modules in the glass facade plus a power plant fuelled by vegetable oil together give enough energy for the whole building.

"There's even a Solar Cafe, it has a roof made with semi-transparent solar panels. They're not on the roof - they are the roof. They let in sunlight and give the architect greater flexibility in design. They're part of the building materials - panels of the solar future.

"But solar power needn't be about large scale projects.

"The congregation of fifteen in Kenya is lit by a single solar lantern. Enough to allow the service to go ahead. And, more important, to give Stephen enough light to read the scriptures. The lives of the lucky few who are benefiting are being transformed. Kerosene is out. Solar power is in.

"Designed by the Intermediate Technology Development Group, ITDG, Stephen's lamp is easily charged by Kenya's powerful and plentiful sunlight. A day's charge will give four hours light at night. It used to take Stephen and his wife two hours every time they had to collect their kerosene."

John Njuguna: "The lamp has many advantages. I don't have to buy kerosene and its portable. I can use it when cooking and for checking the children's rooms. We leave it on till 10 then take it to the chicken hut."

Comm: "Before the solar lantern normal life came to a standstill after dark. Now, David's family can do all sorts of things at night.

"The lamp is simple to operate but costs just over 100US$ - that's a big investment for a poor family in the countryside - but eventually the light is free. Another bonus - you can even plug a radio into it.

"When John has finished with the light for the evening, the chickens get a little more laying time."

John Njuguna: "This lantern is brighter than even a torch. The light is very bright you can see every corner of the compound."

Comm: "At the other end of the continent in South Africa, a scheme developed by Shell in partnership with ESCON, the South African national electricity company and a local manufacturer, Conlog, is showing that solar power can be cost-effective for the rural poor. It has some important supporters.

"But connecting homes to the country's electricity grid is getting very expensive, especially as we get deeper and deeper into the rural areas. Alternative methods have become important. That is why we give our full support to efforts made by Shell and ESCON to bring our people electricity through the solar home system, which is safe, affordable and friendly to the environment in which we live."

Comm: "It's the largest commercial solar rural electrification project ever undertaken. The target is to light fifty thousand homes. So far one thousand four hundred homes have seen the light. Silvina Dlamini is persuaded to invest and places an order for the system. The installation costs the equivalent of thirty US dollars and the running costs are eight US dollars a month, which goes towards the purchase of a magnetic card, which activates the unit for thirty days. When fully charged, the system provides power for TV, radio and four lights for up to four hours. Once the lid is on, Pomapi Pepu starts the system. The gauge shows how much time you have left."

Mrs Dlamini: "I got this so that when I'm dead and gone, I will leave something behind for my grandchildren which is wonderful, especially as it's something I didn't have."

Comm: "In those areas where you are more likely to be burnt from the wind than the sun, the old technologies now have a modern alternative.

"Wind power capacity in the Netherlands is already 325 megawatts. Enough power to supply a million Dutch homes with energy for one year. And in this small, overcrowded country the main problem is finding a site. At Lelystad a giant wind farm has been erected by one of the Dutch utility companies."

Henk Kouwehoven: "In fact there are two wind farms here, one wind farm with 18 wind turbines of 750 kilowatts each, and a wind farm of 28 machines with 600 kilowatts each. We always say that we generate electricity here for about 30,000 households over the year."

Comm: "It isn't only utility companies which see renewables like wind as a way to profit from green energy. Dairy farmers, like Klaas van Ittersum also see windmills as a way to earn money and provide an alternative income. Hands On asked Klaas why he wanted a windmill."

Klaas Van Ittersum: "When I was a child I always wanted to have a windmill. I built one myself and well as you grow older your plans grow bigger. I think the income of dairy cows decreases and it supports my income."

Comm: "Klaas has invested nearly 600,000 US dollars. It'll take him eight years to pay back the bank loan. So why was the windmill such a good option?"

Klaas Van Ittersum: "I have enough work with the cattle and I wanted to invest to have more income, but I didn't want to work for it. So I had to build the windmill. It's the only way to have money and not work for it."

Comm: "They needn't be that large or expensive, smaller windmills can be erected with local labour, and still provide enough power for 22 houses. Built two years ago as a pilot project, the Venivalara Village wind turbine is the only one of its kind in Sri Lanka. It's a blast away success for a Comm: "unity with no access to the national electricity grid."

Lahiru Perera: "It's incredible what they are seeing now after getting electricity and I mean some people say that children's education has gone up, and that they also feel like that they belong to the society, that some people say that they are not alone any more because they have light."

Translator: "I like it because it means I can study."

Comm: "If wind power is going to take off, local manufacture is essential."

Lahiru Perera: "If the local manufacturing capabilities and capacity is built here, the cost of building generating equipment is going to come down by fifteen times, so then the people can afford to pay for it on their own. I think the potential for wind power in everywhere around the world is so high, I mean it is an untapped resource where we should be tapping it more and more in time to come rather than using other things like coal or diesel or whatever. I think it's a real renewable energy source."

Comm: "And if the wind doesn't blow then you can take your specially adapted windmill, turn it upside down, pop it in the water, and there you have it - Hydro Power!.

"Mauricio Gnecco, an energy project coordinator with ITDG, is travelling to the village of El Paraiso on the River Napo, a tributary of the Amazon, with some important spare parts.

"With no electricity supply the villagers must use batteries for power, they have to travel miles to the local town to get them re-charged. It's hoped the river turbine will enable the village to generate enough power to recharge their batteries on site. It's the first such project in Latin America."

Mauricio Gnecco: "With this alternative it is possible to charge batteries in the same place or near.

"It's considered an appropriate technology. It's simple, it's easy to transport, it's not so expensive and the people themselves can maintain and operate it with a small training."

Comm: "There's another benefit. Villagers can now charge others for topping up batteries. It'll earn extra income to pay for installing the turbine and cover any minor repairs."

Comm: "If the Amazon is not on your doorstep, Hydro power can be obtained from even a small mountain stream.

"In Peru, only four percent of the Country's population have access to electricity.

"The system works by channelling Water from a stream or river into a tank and releasing it downhill through a pipe or penstock. When it reaches the bottom the water drives a turbine that generates power. Each kilowatt of power costs approximately US$1,500 so a plant designed to produce 10 kilowatts will cost around US$15,000. It may sound expensive but running costs are low, maintenance simple and one micro-hydro unit should last at least 20 years.

"At Atahualpa electricity has transformed the lives of people in the co-operative."

Rafael Escobar: "The micro-hydro in Atahualpa benefits approximately 120 families who are members of the co-operative. And of these 22 families have light in their homes."

Agustin Teran: "Well, now with electricity everything has changed. It's beautiful to have light in the room, in the home. The children can study. It's delightful. We're so happy. Before we had no light only a kerosene lamp. It was not enough. But now we find ourselves happy. It's a change of lifestyle."

Comm: "The sea provides an enormous untapped resource. Oceans cover 60 per cent of the planet and wave power offers a source of energy that's still virtually untapped."

Allan Thompson: "If you took 0.1% of the available energy you could power the world for five years. This is a dramatic amount of power, it's an unbelievable amount of power, its one of the biggest flywheels or storage systems of energy available to us so it's the obvious resource to harness."

Comm: "Wavegen has been trying to crack the market in Comm: "ercially viable wave power for nearly a decade. During filming foundations for the limpet - a shoreline wave power station - were being laid at Islay off the coast of Scotland. If successful, it may herald a new wave in renewable technologies.

"OK this is a model of the limpet device and if you imagine that this is the west coast of Scotland then there's several thousands of miles to America then all the way across there are winds which generates waves. The wave energy, by the time it gets to this tank, is on average 16 kilowatts per metre and we use this to extract that energy. We are doing that to get the waves to generate what is called an oscillating water column which is what is happening inside here. You can see the water going up and down, and when it goes up it squeezes the air out of the chamber through the turbine and when the column of water goes back down again it sucks air back into the chamber, back through the turbine and the turbine

"The turbine's rated at half a megawatt which is enough for, say, 300 houses.

"This is the wells turbine a device which converts the air energy into electrical energy and it takes the air from the capture chamber, the device you saw on the wave tank. That capture chamber is at the other end so I'll take you up there now.

"This is the end of the turbine that is going to be connected to the capture chamber and so if you can imagine the sea and the big concrete capture chamber over there and at the back end is the land and this is where the air rushes from the chamber into the turbine and then back out again.

"So all we need is a good wave climate, a suitable location, cliff, breakwater, harbour, a wells turbine, technical know how and we have the ability to produce renewable energy cheaply."

Allan Thomson: "The plant on Islay has an installed capacity of 500 kilowatts which is enough to produce enough power for about 300 local houses.

"The price we'll be charging the grid is just over 5p a kilowatt hour. This compares very favourably with the early wind plants in the UK which were about 11p a kilowatt hour when they were first introduced. Our subsequent plants will be about half that price.

"It's a vast, vast resource and its global. And it is more than the energy that's extracted from the oil reserves around these coasts so it's the equivalent of finding a whole North sea oil gas field every year forever. It has enough energy stored within it to provide all the power that the UK requires."

Comm: "The sun, wind and water may provide clean energy for homes and factories, but veichles are one of the greatest polluters of our atmosphere, and to power veichles, energy must be stored.

"In La Rochelle, France they are experimenting with battery powered electric cars, available on demand in a car share system."

Mollard: "We've been going since 1986, we think its successful, increasing year after year."

Chane: "There are 50 cars on 6 stations around the city etc etc."

Comm: "This assembly line produces 9 cars a day from a modified Peugeot shell....and maintence is easy, once a week top up battery!"

Mollard: "We also have an electric boat...

"We try to show its a good thing for quality of life...and also its available today, not tomorrow."

Comm: "In Nepal Diesel taxis were causing terrible pollution, the fumes were harmful to human health, and on many days would shroud the magnificent views of the Himalayas from the city. So they've developed the electric taxi.

"Local businessman Pushba Pockerel now runs a fleet of electric taxis, known as tempos. They've been so successful, both in helping clean up the air and with the passengers that the government has now passed a law banning the diesel taxis.

"Although the electric vehicles are a solution for today, they depend on batteries to store and release energy as needed. A longer term solution may well be fuel cells, far more efficient, lighter and less bulky. BMW has experimented with a working prototype in their Munich airport bus.

"This is the Munich airport bus its powered by fuel cells, which in turn is powered by hydrogen gas.

"Filing up takes 10mins and gives a range of 150 kilometers.

"The fuel tank is stored on the roof and fed to fuel cells that provide all the electricity needed to power the bus."

Burmeister: "Advantages are Resources unlimited, and no CO₂ if you make energy from this."

Comm: "In a further development BMW have produced a car that uses the Hydrogen directly, in an internal combustion engine. It's a hybrid dual system that can be either powered by hydrogen, or if there's none available, by petrol. All at the flick of a switch. Unlike the bus, these cars are powered by liquid hydrogen which requires much less storage space than gas. Hydrogen is one of the Comm: "onest elements, being derived from water, its the H from H2O. BMW have produced 15 prototypes, but there is a problem. There are only two hydrogen pumps in Germany, 11 in the world."

Wolf: "So we have a chicken and egg situation...no cars no pumps."

Comm: "To get around the distribution problem, Hydrogen can be produced on site at the filling station, but this needs lots of energy, currently energy from polluting fossil fuels - back to square one. A technical breakthrough is needed."

Wolf: "We produce the hydrogen using fossil fuel, so what we need is to use the suns energy."

Comm: "Energy reaching the earth from the sun is 10,000 times todays world energy consumption. Even in Germany the sun provides 89 times the total energy needed."

Wolf: "We looked at all the alternatives and came to the conclusion that hydrogen is the only viable sustainable fuel for the future."

Comm: "There's still some way to go, but if Hydrogen can be produced from water using the suns energy it may well be the fuel of the future."