The figures speak for themselves: From 1990 to 2015, VEKS’ CO2 emission figure has more than halved: From 55kg CO2 per GJ to the recent years’ approx. 26kg CO2 per GJ.
VEKS’ Board of Directors has decided that VEKS must deliver CO2-neutral district heating in 2025. With the agreements which are already present today VEKS will reach 11kg per GJ before 2025. But how have the terms changed during VEKS’ first quarter of the century? What does it take to reduce the CO2 emissions even more?
Coal is being phased out in stages
During the 90s, the production conditions changed in the Greater Copenhagen Area. Apart from the initialisation of new, modern CHP units at Avedøre Holme and Amager, VEKS was among the investors that invested money in a heat accumulator plant at Avedøre Holme. The large “thermos” meant that you could store the hot water when the heat production exceeded the heat requirement. It optimised the production of power as well as heat, saved resources and thus contributed to reduction of the CO2 emission.
At the same time, the large waste plants at Amager, in Glostrup and Roskilde either rebuilt from heat to CHP production or added whole new CHP Plant units. Yet another positive gain for the environment.
In the next decade, coal stood fire. A coal-powered unit at Amager Power Plant was shut down and a new unit at Avedøre CHP Plant was put into service. This unit 2 was originally designed to firing with multi-fuels such as straw, biomass, natural gas and coal. However, the possibility of using coal was never realised.
VEKS owns – just as CTR and HOFOR – a third of a geothermal test plant at Amager – a plant which was put into operation in the beginning of the 2000s. Since then, the plant has contributed CO2-neutral district heating for 2,000-5,000 residences in the Greater Copenhagen system. So far, the three parties have postponed the decision whether to build a larger plant due to technical challenges and challenges relating to indirect tax.
From 2008 and a couple of years ahead, the global financial crisis left its marks by way of a different volume of waste. This involved an increased CHP production at the large central plants.
The biomass powers ahead
The present decade was initiated with a remarkably cold year and a far greater number of peak load boilers than usually had to be put into service to cover the heat requirement in the Greater Copenhagen area.
At the same time, the district heat was increasingly based on biomass. Unit 1 of Amager Power Plant now follows suit with Unit 2 at Avedøre CHP Plant and only uses biomass. The two units accelerated the use of biomass further in succeeding years.
All in all, conversions which contributed to yet another couple of kilos decrease in the CO2 emission to under 26kg CO2 per GJ.
At the end of 2016, Unit 1 of Avedøre CHP Plant was also reorganised to biomass which will become a reality in the present environmental declaration.
Besides the preliminary halving of the CO2 emission from 1990 to 2016, the new technologies have, moreover, reduced the emission of NOx to under a tenth and the emission of SO2 is basically gone during the 25 years in question.
Even though the figures speak for themselves, figures can be “improved”. Calculi are rarely static as they are qualified and varied on an ongoing basis. Therefore, you cannot always recognise the values for the same years e.g. in the environmental reports, as the new and improved methods are also used in relation to historical data.
When new climate objectives require another halving of the CO2 emission before 2025, new and perhaps drastic methods need to be applied. And which impact does VEKS have on the means?
Since the central works in the Greater Copenhagen area have converted to biomass a long time ago (pursuant to Heating Plan Greater Copenhagen 3), the waste will be the biggest challenge to the green conversion. In the future, a number of rather newly built waste plants will contribute with more than a third of the total district heating production. Even though the waste plants produce electricity and heat according to the latest and best technologies, there are still problems with the amount of fossil fuel in the waste. However, many municipalities have already now introduced waste sorting and more are on the way. Conversely, the heating value in waste drops when the fossil fuel is removed as plastic functions as good back-up fuel... And it requires waste combustion of large amounts of waste to obtain the same energy effect...
Many unclarified conditions force the issue. Conditions on which VEKS has no direct or indirect influence. It is a political choice – not least when it comes to taxes which determine everything!
The Danish Heat Supply Act stipulates that the heat must be produced at the lowest possible price and only include the required costs. How will the fight between economy and environment develop?
Today, Varmelast.dk only optimises the heat production according to financial parameters. At the moment, the price of biomass is competitive, however, this situation may change within a few years. DONG has stated that they will produce 100% green energy in 2023 – already helped considerably along by DONG and VEKS’ decision to convert Avedøre CHP Plant’s Unit 1 to biomass. This despite declining coal prices.
Besides converting Avedøre CHP Plant into biomass, VEKS has a direct impact on the choice of fuel at the local DHPs in Vestegnen. Usually, they are used as peak load or reserve load units. Also here, the Danish Heat Supply Act stipulates that the production should be the less expensive choice.
Most of the peak load units have combined gas/oil burners and one single boiler is fuelled with wood pellets. Instead of fossil fuels such as natural gas and gas oil, VEKS has had several test projects with biofuel. Biogas is refined/upgraded in the conventional natural gas system, however, the price of the biogas production is too high at the moment. VEKS has also tested biooil but here technical problems with a very varying quality and stratification set the project on hold for the time being. Efforts are made to find a solution to these challenges, e.g. by way of an experience group under the Danish District Heating Association where VEKS also participates. Hopefully, it will be technically and financially relevant to use biofuel at the local DHPs in the future.
Heat of the future
In the future, the district heat will to a still larger extent be part of a smart energy supply because the district heat can combine, move and store energy, e.g. excess electricity from wind turbines. Therefore, VEKS is involved in a number of cooperation projects regarding the future production types: Large heat pumps, heat storages, industrial surplus heat, a combination of remote cooling and district heating, etc. VEKS’ strategy project about this subject is called “New sustainable energy solutions”.
But what about the rest – when will VEKS become completely CO2-neutral?
Irrespective of the measures, there will still be a small amount of fossil fuels left. For instance, it is not expected at the moment that all plastic can be taken completely out of the waste and it will probably not be financially sound to remove the last part of natural gas and gasoil at the small local DHPs.
What can then be done? Will VEKS be able to enter other areas and ensure a reduction which can be ascribed to VEKS? The investment in Køge CHP Plant has for instance ensured a converted power and heat production at the same time as a large part of the heat requirement in Køge has been converted from natural gas to district heating. This is not included today – but perhaps in future environmental reportings.
“Ørsted (DONG Energy) and VEKS have had a joint well-defined objective regarding the green conversion and both parties have also been willing to make long-term investments. Therefore, the process from word to action has been brief. We can all be proud of the project of converting Avedøre CHP Plant to 100% sustainable biomass. Because we have made a difference.”
Extract of speech by VEKS’ Chairman Steen Christiansen when VEKS and DONG Energy celebrated the conversion from coal to biomass at Avedøre CHP Plant’s Unit 1.