Even the toilets are a learning resource at a state-of-the-art environmental education centre in Worcestershire. On one wall of the gents is a huge, colourful mural, showing any visitor doing their small bit for the sewage system, its place in the water cycle.

The centre, in Crossway Green near Stourport, opened in May 1994. Since then it’s gained national and international recognition, for the quality of its environmental education work and for the pioneering green building in which it is housed, painstakingly built on environmentally sound principles.

Standing on a sub-station of the National Grid, the beautiful wood-clad building was designed and constructed in a way that ensured minimal damage to the environment, with materials coming from sustainable sources where possible.

An inviting place of warm wood, abundant light and flexible classrooms, with plenty of child-friendly nooks and alcoves, the centre is much in demand by school groups. “But a lot of the education is subliminal,” says its head, John Rhymer. “The building itself is a role model, so it’s part of the lesson. ”

One of the main lessons on offer concerns energy efficiency, of which there are any number of examples in and around the building. For example, high levels of insulation have been put into the walls, floors and ceilings (a cutaway section is on display), and all the windows are double-glazed.

In the central stairwell, the reclaimed bricks absorb heat when the building is warm, and radiate it out when it cools. Audiostats allow temperatures to fall when rooms are not occupied, while sensors in the toilets ensure lights go off five minutes after you leave.

Up on the roof, is a solar panel that warms the water tank. In summer, the glass dome at the top of the central tower draws warm air up through the open vents, replacing it with cool air drawn in from underneath the building.

But stimulating children’s interest in energy efficiency is not simply a matter of subliminal learning. Small yellow cards posing questions, such as “How can you improve the energy of light bulbs by l0 per cent?” and “How much energy is saved by recycling paper?”, are scattered around the centre. There’s even a chance to visit the National Grid substation, to learn how electricity is transmitted and transformed.

“We hope they go back armed with the knowledge and motivation to try to reduce energy consumption, both at home and school,” John Rhymer says. “In practice, the kids are enthusiastic, but teachers are often weighed down by the demands of the national curriculum.”

Despite such constraints, some school-based energy projects are getting off the ground. One such involves four teachers from Worcester primary schools being seconded to the city council on placements.

This term they’re putting together an energy pack for use at key stage 2, containing games and practical activities. Each pack includes an electrometer, donated by the Midlands Electricity Board, which will enable children to measure the efficiency of electrical appliances. The MEB has also provided low-energy light bulbs for the pack.

A different project has been launched at Cardinal Hinsley High School in Brent. Near the science block, two home-made, five-metre-high wind generators spin in the stiff November breeze, mirrored by two commercial ones fixed to the building.

Nearby stands a bright yellow temporary classroom - a refurbished building-site cabin. Soon the classroom will be self-sufficient in its energy use, and will serve as a resource for local primary schools, where pupils will be encouraged to learn about alternative energy sources, and even make their own small generators.

This “alternative energy farm” is being built, managed and staffed by students of the school. It’s already won the best partnership award in this year’s Living Earth competition “My Place, Our Place”.

Its originator is head of science, George Nagle, who was inspired to set it up after a placement at a wind-turbine manufacturers. “Wind energy is going to be the energy of the future,” he says. “We want the kids to get first-hand experience of the alternatives.”

Solar power is the next step, but for schools this is more problematic, because of the capital outlay required. The solar panel at Bishop’s Wood, for instance, costs about Pounds 3,000.

But this should change. “Panels are getting more efficient, and they’ll soon become more viable for schools,” says John Rhymer.