Memorandum by Solar Thermal
THE SITUATION
WITH REGARDS
TO HEAT
The Energy White Paper's targets for reductions
in the amount of carbon dioxide emitted by the UK are ambitious.
The DTI estimated that heat generation of one sort or another
accounted for 32 per cent of the UK's final energy consumption.
Despite the significance of heat as a proportion of our overall
energy usage, most of our Government's efforts to promote renewables
and reduce carbon emissions have been aimed at the electricity
generation sector. Most efforts related to heat have been aimed
at improving efficiency, through for example insulation. Whilst
the Government has recognised the contribution of renewable heating
systems there has been a lack of specific policies to promote
them. 8 per cent of the energy the UK uses is devoted to heating
water as buildings, particularly houses become more energy efficient
in heat terms, hot water will represent an even more significant
part of overall energy use. In this context, active solar heating
technology can provide even more effective and significant reductions
in our carbon emissions.
SOLAR THERMAL
TECHNOLOGY
How it works
The sun generates an enormous amount of energy.
Very large quantities of this energy reach the Earth's surface.
Solar Thermal heating systems exploit the part of this energy
that arrives in the form of heat and use it to heat up water.
A typical system would consist of a collector,
cylinder, boiler, controller and pump. Light from the sun is used
to heat up a surface within the collector. This surface is likely
to be selectively coated to maximise heat absorption and is known
as the black body or absorber. If the temperature of the hot water
cylinder is lower than that of the collectors, then the controller
will start the pump. The pump circulates a fluid, usually water
with glycol or just water depending on the design of the system,
through pipes that are in contact with the absorber. Heat is then
transferred from the absorber to the liquid in the pipes. These
pipes also pass through the cylinder. As they pass through the
cylinder, heat is transferred from the pipes to the water inside
the cylinder. Depending on the amount of thermal energy being
collected (it varies with conditions and time of year), heat from
the collectors can remove the necessity for the boiler to be active
in heating water or can effectively preheat the water reducing
the quantity of energy that needs to be used to heat the water
to the desired temperature for use.
Though it is not mandatory with every system,
many of the solar thermal water heating systems on the market
are sold in conjunction with new higher efficiency boilers often
of the condensing variety.
Condensing boilers have an extra heat exchanger
that utilises heat from the boiler's exhaust gases to pre heat
water in the boiler system. This has the result of improving their
efficiency, the National Energy Foundation suggest that condensing
boilers can achieve 95 per cent efficiency during normal operation,
this is an improvement on conventional boilers. The Energy Saving
Trust estimate that condensing boilers in combination with the
correct heating controls can reduce a household's fuel bills by
up to 40 per cent, reflecting a marked improvement in energy efficiency.
SCALE
This technology can be employed on a range of
scales. It can be fitted to residential properties to provide
a significant share of their hot water needs.
The technology can also be used for larger scale
applications in the UK there have been larger scale projects to
provide for the hot water needs on the scale of schools, homes
for the elderly, public swimming pools, town halls and office
buildings.
At the largest scale, solar thermal technology
can be employed as part of district heating projects. Often it
is used in conjunction with biomass for low carbon domestic heat
generation. This has taken place in a number of Northern European
nations such as Sweden, Denmark and Germany as well as some Southern
European nations.
THE SAVINGS
In terms of the residential scale, estimates
vary between the various systems. Depending on specific households'
usage patterns, the range across the various systems is from 40-70
per cent of the household`s hot water usage. The amount of useful
energy contributed by the solar thermal system is estimated, by
the solar trade association, to be in the region of 1,500 to 2,000
kWh annually. This assumes energy usage of about 3,000 kWh per
year for water heating being used by a family of four. In terms
of overall energy saving, this will depend on the type of system
and items installed with it.
The manufacturers' estimates of carbon saved
range from half a ton to a ton and a half of CO2 saved
a year per dwelling. The yearly savings achieved in terms of reduction
in the annual energy bill range between £50-£120 depending
on usage and system. Side by side testing of 8 different home
hot water heating units found that the active solar thermal systems
produced, between 1,000 and 1,300 kWh. Moreover, the energy usage
of pumping systems ranged from zero to approximately 108 kWh.
At the medium scale there is a much greater
variety of projects and thus bigger range of potential savings.
For example, a feasibility study for a school swimming pool project
predicted 10 tonnes of carbon savings annually. Burton on Trent
town hall has up to 70 per cent of its hot water needs supplied
by solar thermal technology.
At the very largest scale there is also significant
variation depending on the project. An example is Kungälv
in Sweden. It is one of the largest solar thermal heating plants
in Europe and generates 4,000,000 kWh of solar heat annually avoiding
the production of more than 1,000 tons of CO2. The
plant generates in combination with bio mass wood chip boilers.
BARRIERS TO
IMPLEMENTATION
Public Awareness—This was highlighted
by the findings of the ATLAS project. The report highlighted "lack
of awareness amongst the general population", which it is
not clear has been rectified as it is again mentioned in the Solar
Trade Association's recent report into the UK solar market.
Lack of Installers—The solar trade association
points to a lack of trained installers in the UK, this they claim
is leading to complaints of poor quality work that tarnish the
representation of solar thermal. Carbon Trust aims to resolve
this by providing funding for a solar thermal training course
syllabus called "SunTrain" which will allow plumbing
colleges to more easily teach solar. However, there is a general
lack of workers with plumbing and heating skills in general that
should be addressed.
Planning—The need to obtain planning permission
for some solar thermal installations is a further complication
to the process of obtaining a solar thermal installation. All
residential Solar Thermal installations should be classed as permitted
developments in planning legislation as a bare minimum.
Finance—The cost of an installed retro
fitted domestic solar thermal system ranges between about £2,500
and £4,000. Costs can be reduced in the case of new build
installations or DIY as a significant cost results from retro-fit
installation. The life cycle of solar thermal installations ranges
from 20 to in excess of 30 years in many cases.
The ATLAS project mentioned the small size of
the UK solar market and general lack of awareness as contributing
to high marketing costs and thus increasing overall costs of solar
thermal installations. Addressing both of these issues is vital
to solving the finance related problem for residential systems.
This does not seem to have been achieved yet, the solar trade
association estimates there to be around 42,000 units in operation
in the UK. Out of the potential number of properties (around 20
million), this is a poor level of proliferation. Especially considering
that the UK could be saving more than 20 million tonnes of CO2
with this technology.
Currently the main assistance that an individual
wishing to install one of these systems would receive is in the
form of a Clear Skies grant. This used to be £500, but since
July 2004 this figure has been reduced to £400. A key issue
is the lengthy pay back period of these products. In most residential
cases this is not less than 10 years.
The cost of the larger projects is clearly going
to be dependent on their size. Currently Clear Skies offers not
for profit organisations the lesser of 50 per cent of the cost
or £100,000 grants for all forms of renewable projects on
the basis of case by case applications. The Carbon Trust offers
businesses enhanced capital allowances, which allow them to write
off the whole cost of the investment in solar thermal against
taxable profits during the period during which they make the investment.
Anecdotally, there seem to have been problems with both these
schemes in terms of conflict of interest occurring at the level
of the grant awarding board for Clear Skies and whether the scheme
to encourage businesses is effective at all. Once again the issue
of the pay back period looms large at this scale too.
Solving this should be a key objective for a
government wishing to promote this mature carbon emission reducing
technology.
SOLVING THE
FINANCE PROBLEM
Given the lower cost of installing solar thermal
in new build situations, one least cost option is to alter building
regulations to require it to be installed in all new build properties.
ODPM statistics suggest that on average over the past five years
over 145,000 new dwellings were completed each year in England
and Wales, if even half of these had solar thermal installed as
a matter of course in conjunction with high efficiency condensing
boilers, in excess of 75,000 tons of CO2 could be saved
annually at a relatively low cost when spread over the life span
of the system. It would be possible to specify that all new developments
have solar thermal, the larger developments would represent an
even larger carbon saving.
A heat obligation could be established. If it
is set up along the same lines as the current renewable obligation
functions along, a system of heat obligation certificates trading
could be set up. Solar thermal installations could qualify for
this and thus the resident would receive an annual payment in
the same way that owners of micro generation equipment do now
for their ROC. This scheme would reduce carbon emissions through
encouraging greater efficiency and the installation of solar thermal,
bio mass and other forms of renewable heat generation. Renewable
district scale schemes could also qualify and therefore be encouraged.
The Government could offer interest free loans
for the installation of solar thermal units. The current problem
is related to the large initial outlay and long period over which
the returns accrue. If it was possible that individuals paid for
their solar thermal system over a period nearer to the lifetime
of the system, house holds may find it easier to see the benefit
of installing the system. One of the current problems is that
house holds pay for their current heat energy as they use it on
a monthly basis. However, those who use solar thermal have to
pay for all of the energy that they will get from the sun over
a thirty year period in one payment in advance.
If part of the reason for the long pay back
periods and apparently high start up costs is the small size of
the market. Central and local government could expand the size
of the market directly in a number of ways. There is the aforementioned
requirement to install solar thermal. The Government could encourage/require
local councils and ALMOs to install solar thermal progressively
in their housing stock through percentage of suitable housing
stock targets. Due to the large number of properties under their
control this could greatly increase the number of units being
sold and also the tonnes of carbon emissions being avoided. Moreover,
training a work force to install these systems would create jobs
and skills in the local area. In addition, the systems could go
some way to tackling fuel poverty given the sizeable reductions
they can bring about in heating bills. Public buildings should
be encouraged to install solar thermal, this would set a positive
example of functioning solar thermal to the outside community
and due to their generally larger size a larger carbon saving.
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