Second European Conference of Municipal Energy Managers Page: 1

Second European Conference of Municipal Energy Managers

Page: 1


Page: 2

Solar Power and Solar Thermal Energy

in Schools

Friedhelm Naujoks


Page: 3

For many and varied reasons, active and passive use of solar energy is an integral part of local policy in Bonn.

When the German parliament moved from Bonn to Berlin, a major policy package was adopted to secure Bonn’s future. This package comprised three main policy areas: economic, social, and environmental policy.

In this presentation, we will focus on environmental policy.


Page: 4

The Federal City of Bonn is home to twelve UN organisations, among them the Climate Change or UNFCCC Secretariat.

It also hosts many international meetings. The International Conference for Renewable Energies, Renewables2004, was held in Bonn.

Bonn is twinned with La Paz in Bolivia and Buchara in Uzbekistan, where it is involved in development work for solar energy use in projects that aim to raise environmental awareness. This work is carried out in two phases:

Phase 1: Demonstration systems

Phase 2: Fully operational systems supplying solar energy


Page: 5

Selection criteria for schools

• Aspects related to teaching and learning about the environment

• Collection of financial operating data


Page: 6

Alongside development work in twin towns, Bonn continues to promote and increase the use of solar power and solar thermal energy at home. These efforts are divided between:

• The public sector

• The private sector

In this presentation, we will look at the public sector, which in Bonn so far means the use of solar energy on school roofs and at a sports park.

In accordance with a city council decision of 17 March 2005, the city’s facility management department will add to the existing solar power installations on some of the 700 buildings in its charge.


Page: 7

Solar thermal energy is used in Bonn to supplement the water heating

systems at four public open-air swimming pools.

When heating systems are modernised, an appraisal is carried out to see if

it is economically viable to use solar thermal energy.

If their use is justified, more solar thermal systems will be installed

in future.


Page: 8

Existing and planned solar power installations

• 22 systems installed for teaching purposes

• 4 systems in 2005

• 9 systems in 2006

• More systems are planned in 2007 using the latest thin-film solar cells


Page: 9

Implementation using performance contracting

• Contractor finances

• Contractor builds

The city pays contracting fees and earns the money back by selling the generated power to the public grid.

Installed systems pay for themselves

Benefits the environment without hurting the city budget


Page: 10

The new systems built in 2006 have a total output of 123,000 kWh/a. The systems are provided on the basis of performance contracting.

Contracting fee: €57,750 per year x 20 years = €1,155,000

Added revenue: €63,714 per year x 20 years = €1,274,280

Revenue covers expenditure

Neutral impact on budget


Page: 11

Based on these figures, the use of solar energy is appraised for all new

construction and refurbishment projects.

Another option taken into consideration involves renting out school roof-

space to the private sector in order to increase the surface area used for

solar power.


Page: 12

Legal framework

Germany’s Renewable Energy Sources Act:

1. Requires energy utilities to buy power generated from renewables

2. Sets the price they must pay for solar power:

50.62 cents per kWh in 2006


Page: 13

Local industry

Under the introductory arrangement, systems are financed on a performance contracting basis. The contractor is Stadtwerke Bonn – the city services corporation – and a local firm supplies the solar power hardware. This set-up has several benefits:

Promotion of local business Promotion of the regional economy

Tax revenue for local government

Secures local employment

More training places


Page: 14

In its enforced restructuring over the last few years, Bonn has not only given greater policy emphasis to the environment, it has also promoted environmental education.

So far, solar energy has been used as a supplementary energy source rather than an alternative. The financial and performance figures are already making greater use of solar energy look more realistic as fossil fuels become scarce.

This is especially true if we remember solar energy is only one of several alternative energy sources used in Bonn. Among other things, we also generate energy from biomass in the form of woodchips.


Page: 15

Technical aspects

Conventional high-efficiency solar cells

• Efficiency of single-crystal silicon wafers 14 – 18 %

• Efficiency of polycrystalline silicon wafers 13 – 16 %

• Service life > 20 years


Page: 16

Thin-film wafers

• 100 times thinner than conventional wafers

• Lighter weight

• Cost less to make

• Service life > 20 years

• Efficiency 7 – 11 %

The future is in thin-film solar cells, despite their lower efficiency today.


Page: 17

Use of roof-integrated solar panels

• Cuts cost of modernisation work

• Panels pay for themselves with power sold to the public grid

• Thin-film cells used for structural reasons


Page: 18

Summary

• Performance contracting without impact on city budget

• Promotion of local business

• Support for globally operating firms in development of advanced technologies

• Further progress on environmental aspects

Direct effects Tax revenue and resource conservation

Indirect effects Environmental awareness

Documents

Second European Conference of Municipal Energy Managers Page: 1