Published on June 4th, 2014 | by Silvio Marcacci


Is The Future of Biomass District Heating In Holland? (CT Exclusive)

June 4th, 2014 by  

Most people don’t think about biomass as a direct replacement for natural gas, but then most people might not have visited Purmerend, a town located about an hour north of Amsterdam.

de Purmer biomass district heating plant

de Purmer biomass district heating plant photo via CleanTechnica

In this city of 80,000 people, an innovative approach to district heating uses wood chip biomass to provide clean and renewable heat for three-quarters of the population at grid parity prices.

CleanTechnica toured the de Purmer biomass-to-heat facility one month before it officially goes online to see how waste wood is being used to cut emissions and natural gas use – an important sustainability measure considering heating homes and offices represents 40% of all power demand in the Netherlands (Full disclosure – while my trip is being sponsored by the Dutch Government’s Ministry of Foreign Affairs, it had no involvement in the editorial process of this post).

Biomass Fixes A Good Idea’s “Bad Execution”

The District Heating Company Purmerend (SVP) was established in 1980 as a municipal service to provide heat via underground piping to the fast-growing community of Purmerend via natural gas-fired boilers.

Their initial approach turned out to be “a good idea but bad execution,” said Martijn van Lier, SVP Chief Technology Officer, never realizing full potential due to a combination of inefficient piping infrastructure and reliance on fossil fuels.

And efficiency counts for SVP – it uses 175 miles of piping to deliver heat to its customers, good for the fourth-largest managed grid in the Netherlands, behind only the three national power grid operators.

10-Inch Wood Chips Chop 50,000 Tons Of Emissions

In 2007 however, that all started to change when the utility was privatized. Its managers decided look toward biomass, and started planning a 44-megawatt capacity biomass heating plant. The new facility, scheduled to go online in August 2014, features four 11MW capacity boilers, replacing generation previously supplied by a 65MW combined cycle natural gas plant.

Wood chips from local forest maintenance by the Dutch National Forest Authority will be diverted away from low-value plywood manufacturing to feed the turbines under a 25-year supply deal, priced at the median gigajoule heating value of delivered wood.

biomass wood chips

Biomass wood chips photo via CleanTechnica

And if you think 44MW of biomass boilers use a lot of wood chips, you’d be right. When fully operational, the facility will consume 100,000 tons of 10-inch wood chips per year – roughly one-sixth of all national annual output.

By switching from natural gas to biomass, SVP will reduce emissions 50,000 tons and cut natural gas demand 30 million cubic meters, compared to individual natural gas-fired boilers, at a cost comparable to natural gas prices. For context, this one biomass plant’s output will be equivalent to one-third of Holland’s combined 2.3 million installed solar panels, or the decarbonization equivalent of adding 800,000 new solar panels, according to van Lier.

Nearly 100% Plant Efficiency

But SVP didn’t get greener, it also got much more efficient. In 2008 the utility started an efficiency benchmarking and improvement effort named SlimNet. Analysis showed system production capacity was reaching critical limits, with above average heat losses. The answer was a Euro 25 million selective renovation and redesign of system “hotspots” to reduce heat loss, and it worked.

Reducing system service area 32%, system dimensions 25%, and grid length 7%, SVP lowered heat loss from 33.6% in 2008 to 22.1% in 2014 – all without retrofitting existing customer equipment, according to van Lier.

de Purmer biomass district heating plant boilers

de Purmer biomass district heating plant boilers photo via CleanTechnica

SVP also boasts more than a 99% efficiency value by reusing nearly all the heat and water produced by burning wood chips. Heated air from the burn chamber is fed back into the system to fuel additional combustion, and water from flue gas condensation is reused on the plant’s washing tower to remove particles from emissions. Ashes are also either returned to the forest as fertilizer, or sold to concrete manufacturers.

Now Let’s Watch Some Awesome Video

All these project details are great for sustainability, but the most impressive individual aspect of the SVP plant  may be the massive chamber where wood chips are stored and fed into the boilers. Six docking doors receive wood chips from dump trucks, and three cranes scoop them up into the storage bunker into piles sufficient to supply the boilers for seven days – a process shown in the video below:




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About the Author

Silvio is Principal at Marcacci Communications, a full-service clean energy and climate policy public relations company based in Oakland, CA.

  • Hans

    Originally the wood was used for a high level application: creating plywood. This is now replaced by a low level application: heating. The plywood manufacturer must now get his wood from another source, which might be less sustainable as the left-over wood cuttings that now are burned for heat. It could well be, that overall the environmental effect of this biomass heating system is negative.

    • heinbloed

      This timber comes from landscaping, chipped bushes, tree crowns. And propably purpose grown fast rotation willows and ash trees and the like.
      There is a market for logs in the Netherlands, quite expensive home heating fuel it is.
      I don’t think the Dutch ‘mercantile soul’ would throw away this profit.

      For plywood veneer is used. ‘Peeling’ the stems demands thick straight timber without knots.

  • Imo this is not the future. The future is no heating at all, i.e. passive buildings. The future is heat pumps that use electricity from much cleaner sources like solar or wind.

    It is a waste of precious resources. Rather than burning biomass merely for low-grade heat, it would be much better to burn it in a power plant and use the on-demand electricity to provide for when solar and wind do not generate enough. The waste heat could still be used for district heating.

  • Others

    Wood for heating is an excellent idea.

    For more info on the usage of Wood and all other renewable resources, goto.

  • heinbloed

    Some strange numbers need clarifications:

    A 44 MW boiler replacing 2.3 Million ST panels?
    How that ?

    Another fact is that solar energy has not to be cut with chainsaws and being delivered with trucks.
    It would be impossible to employ solar energy to grow trees with such a hustle 🙂

    In Denmark they use ST for large district heating systems backed-up by (biomass-) boilers.

  • Jan Veselý

    I have a question: Do they use fresh wood or do they keep it for year or two to dry up?

    • heinbloed

      They use wet wood according to this video:

      Quote from 1:22

      ” De natte houtsnippers worden eerst door hete Lucht gedroogt, waarna ze ontflammen ”

      in English:

      ” The wet timber chips are dried first by warm air before they ignite ”

      Note that as shown in the video this boiler is a condensing boiler, thermal energy demanded for drying isn’t wasted due to the condensing process.
      The condensate is used further to wash the flue gases.

      There are also two more gas boilers for peak loads employed,these run on natural gas for the time being which should be replaced by biogas in the future.

      • Frozen

        So they’re not even leveraging cheap solar energy to improve the heating value of their (very limited) biomass supply by removing the moisture first.

        Wasteful, and sad.

        • heinbloed

          In this case the ST would be wasted.
          As said: it is a condensing boiler. The thermal energy to dry the timber is recovered in the (condensing) heat exchager.

          • Frozen

            Would it?  Dry wood burns at a higher temperature and produces less smoke.  Higher-temperature combustion allows greater efficiency of conversion of heat to work.

            Recovering latent heat in a humid combustion-gas stream is done at very low temperature (well under 100°C).  Such heat would be useless for anything except space heat, maybe pre-heating DHW.  Improving the heat-to-electricity conversion would add to the power available for heat pumps, producing space heat at a coefficient of performance upwards of 3.

            Maybe it really doesn’t make sense, but it’s not something to be dismissed out of hand.

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