After considerable innovation, RET have recovered ground in the
building heating services. On the one hand, new handling and heating
technology has led to a small renaissance in the environmentally benign
use of woodfuels by households and industry. On the other hand, the heat
pump technology has allowed for the use of ambient energy. In some places,
low temperature geothermal energy is tapped directly. These new
technologies receive political support in many places, mostly in the
form of financial incentives. The solar water heater (SWH) technology is
explored to become the principal energy system for heating in zero and
low energy buildings, in colder climates supported by a small
conventional boiler. In this, RE and Energy Efficiency are natural partners.
Passive solar may bring the energy supply requirements so far down,
that reasonably sized RET on their own are able to cover the low
temperature energy service..Policy is required
to define low or zero energy standards and by enforcing to create a new
relevant market for low temperature services, where different building
efficiency and heating systems compete. Systems relying on RET stand a
good chance to substitute fossil fuelled systems in many regions and
building types.
For hot
water, the solar water heater technology is a huge success in China
and beyond. In China it has become so successfull because the competing
technologies are temporarily not available ( district heating in summer), not
marketed or too expensive (electric and gas water heater). The policy supports the solar hot water
technology development and building standardization. In other countries,
financial incentives and in particular mandatory building standards have contributed to a strong
growth.
GTZ with SENER and CONAE Mexico have prepared a study on International Experiences with the Promotion of Solar Water Heaters (SWH)
at Household-level. A number of municipalities have taken
highly successful initiatives, according to
REN21
Global Status Report.
There is a promising technical development to
use solar thermal processes also for cooling
