Energia-uutiset

Towards carbon-neutral
production
Approximately 35 per cent of the annual
need for district heat in Helsinki is produced
from coal. Coal is used in the coldest
period, in about four winter months
every year. The development path drawn
up by Helsinki Energy suggests that its
own energy production will be completely
CO 2
neutral in 2050. In the coming years,
the use of renewable biomass fuels will be
increased in all existing coal power plants,
with these fuels to be used alongside coal.
“Within the Low2No project, we are
jointly developing a district heating product
suitable to the model applied. The heat
used in the Jätkäsaari area is produced by
the most fuel efficient CHP plants in the
world and by heat pumps which use waste
water and return water in the district heating
network as their heat sources. The fuels used
are renewable fuels, with coal replaced with
renewable biofuels,” Marko Riipinen says.
As far as electricity is concerned, the
carbon-free requirement is fulfilled more
easily, because Helsinki Energy can sell its
customers wind electricity or hydropower
electricity procured from the electricity
exchange. Helsinki Energy also has its own
hydroelectric production capacity, and it
is a co-owner in wind energy companies.
Marko Riipinen says that coal-free district
heat and electricity cost a little more than
energy generated from fossil fuels.
How will Helsinki have sufficient renewable
energy? Marko Riipinen knows
that this question puzzles people on a general
level both elsewhere in Finland and in
the neighbouring countries, because power
plants which are located on the coast and
which now fire coal can be supplied with
renewable fuels over long distances. It is
expected that competition over forest-based
fuels in Finland is going to become tougher
and the prices will rise, because large towns
increase the demand significantly.
“It is also possible to produce biogas
close to the existing natural gas network
and to transmit biogas to Helsinki using
the natural gas pipeline. It is a considerable
logistics challenge to bring pellets let alone
wood chips into Helsinki,” says Marko
Riipinen on the outlook for fuel supply. zx
Combined heat and power
production for over 50 years
H
elsinki can be regarded as a pioneer in
combined heat and power production,
district heating and district cooling. Heat
and electricity generation in the same power
plant began in the capital of Finland on the
south coast over 50 years ago. The market
share of district heating of the entire heating
demand in Helsinki is more than 90 per
cent. Moreover, the rapidly expanding ecoefficient
district cooling system in Helsinki
is the third largest cooling system in Europe.
The bulk of the district heat is produced
by four large CHP plants, two of which
use coal and the other two natural gas as
their main fuel.
“More than 90 per cent of the district
heat is produced by cogeneration. Combined
heat and power production is efficient, because
the efficiency of natural gas is 95 per
cent and that of coal 86 per cent. Approximately
60 per cent of the annual production
of district heat is based on natural gas. The
coal used by Helsinki Energy is hard black
coal, which is incinerated at a high efficiency
in cogeneration and whose flue gases are
cleaned using the best available technology,”
says Marko Riipinen, head of the district
heating business of Helsinki Energy.
“We have learned to develop well-functioning
systems with high efficiency for the
Finnish conditions, utilising imported fuels.
There are several factors which reflect the
high quality of the district heating network
and its successful maintenance: only a small
amount of water needs to be added to the
system annually, there are only a few leaks
in the district heating network, and the
annual thermal losses in the network are
very small, only 6 per cent.”
Over 14,000 customers
In 2010, Helsinki Energy acquired 7,850
gigawatt hours of district heat and roughly
the same volume of electricity, of which
73 per cent was produced in Helsinki.
The record-high heat demand was mainly
due to the weather; 2010 was 10 per cent
colder than an average year. Moreover, a
new production record of district heat in
Helsinki, 2,600 megawatts, was attained in
“Combined heat and power production is
efficient. The efficiency of natural gas is 95
per cent and the efficiency of coal 86 per
cent,” says Marko Riipinen, head of the
district heating business of Helsinki Energy.
January 2011. At minimum, in warm summer
days, district heat is only produced at
a power of a couple of hundred megawatts.
The biggest district heating company in
Finland has more than 14,000 customers
along its 1,250-kilometer-long network.
If need be, reserve power plants are
commissioned after the starting of the CHP
plants, and energy contained in heat accumulators
is exploited. Helsinki Energy
has several water reservoirs of 10,000 cubic
metres, with the energy stored in these
utilised during peak consumption. Heat is
also recovered from the waste water treated
at the effluent treatment plant. In fact,
Helsinki has the world’s largest heat pump
plant which exploits the heat of waste water.
Helsinki produces some of its electricity
in hydropower plants located elsewhere in
Finland, and partly by means of wind power.
Moreover, being a shareholder in a nuclear
power company, it obtains nuclear energy.
“Helsinki Energy produces so much
electricity itself in Helsinki that the production
would suffice the needs of two cities the
size of Helsinki,” Marko Riipinen says. zx
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