Page 115 - A Comprehensive Guide to Solar Energy Systems

Chapter 6 • Solar Water Heaters 113

energy resources, solar thermal heating can be cost-effective under certain conditions.
The energy cost for SWHs range between £7 and £200 per GJ [3].
Financial incentives are used to encourage energy customers to utilize renewable en-
ergy sources to meet heat demands and aim to fill the cost gap between the renewable
energy sources and conventional energy technologies for use in heating. The incentive
schemes can be categorized into financial and fiscal [3,5] schemes. Financial incentives
involve direct financial support funded from government budgets, and these include
capital grants (subsidy), operating grants, and soft loans. Fiscal incentives include tax
credits, reductions, and accelerated depreciation, based on investment costs or energy
production.
Governments can intervene in the market by means of regulation, which can include
building regulations and standards, and forcing the deployment of renewable energy heat-
ing by directly requiring the implementation of SWH technologies [3,6].
Education, to promote renewable energy heating, aims at raising public awareness
through information campaigns and training programs. It may take the forms of technical
assistance, financial advice, labeling of appliances, and information distribution [3].
The concerns around saving energy and reducing carbon emission could also drive
the fast-growing solar thermal market. The manufacturing and decommissioning of solar
thermal systems requires relatively small amounts of fossil fuel, thus producing little en-
vironmental pollution, and furthermore the SWH systems involve no fossil fuel during its
operation [3].
Solar thermal markets could also be driven by local visual impact by placing SWH sys-
tems on roofs and building envelopes.

6.1.3 Existing Barriers to the Diffusion of Global Solar Thermal Market
Although the future of solar thermal systems appear to be very positive, there are still bar-
riers to its widespread rollout; these include technical, economic, legal, educational, and
behavioral barriers.
Over the past few decades of SWH development, technical problems have focused main-
ly on the availability of space for the installation of solar thermal collectors and the accom-
panying; high energy density thermal storage, the availability of appropriate materials for
mass productions of collectors, the integration of solar equipment as part of the building’s
fabric, and the protection of solar collectors from freezing in cold weather [2,7]. Another bar-
rier relating to the utilization of solar energy is that the solar radiation reaching the earth is
intermittent, weather-dependent, highly dispersed, and unequally distributed over the sur-
face of the earth in that most of the sun’s energy is experienced between 30°n and 30°S [7,8].
Several economic barriers have impacted on the desire for increased utilization of solar
thermal in developing countries. These include a lack of public awareness, a lack of energy
policies, low levels of income, a lack of subsidies, short-term investing syndrome, and a
lack of institutional support. For developed countries, the principal economic barriers are
capital cost, poor regulation of promotion, and poor public perceptions [7,9].