Part 3 of building a carbon neutral distillery – meeting the energy challenge.

Steam from biomass – making it work

Biomass – the practicalities

Many have tried to run a distillery from a biomass boiler; some have struggled; and a few have failed, given up and gone home… but others have succeeded, and the industry has learnt from all of these examples – good and bad. 

The overriding priority when considering biomass for a distillery is to make sure it’s done safely. Distillery operators are expert in managing the hazards they are familiar with, including those associated with oil and gas fuelling, but biomass presents different hazards – often unfamiliar to distillers. Seeking expert support in the design, commissioning and operation of the boiler system is therefore essential.

The introduction of the RHI tempted lots of people into the sector – not all of them expert in the hazards or practicalities of biomass boiler systems. The flood of installations in the following years led to a significant number of installations which were not up to standard, including some dangerous examples. This resulted in some newsworthy accidents and tarnished the reputation of the sector as a whole. The cowboys who dominated the sector at its peak have mostly left town, but they left behind a legacy of poorly designed and under-performing biomass systems.

However, this shouldn’t be viewed as a failing on the part of biomass as a low carbon technology, but the result of an incentive scheme which was as poorly designed as some of the installations it triggered. Most of the companies still in the biomass sector know and understand the hazards, and how a project should be designed and implemented safely. The Combustion Engineering Association’s BG05 “Guidance on the Design and Operation of Biomass Systems” is a great place to get an appreciation of the types of hazards I refer to here.

As well as a safe boiler, distillers want a boiler that works in their application, and without applying specific knowledge, there are some well-known ways a biomass boiler can struggle in distillery service.

Offsite fabrication of a biomass steam boiler plant

Timing is everything

As anyone who’s sat round a campfire knows, there’s a delay between putting a log on the fire and feeling the benefit of it. It’s a characteristic of all solid fuels, and this delay certainly isn’t ideal in a distillery application – when the operator asks for steam to the still, he means now, not in 20 minutes. There is a similar problem when the still run is complete – the fuel on the grate continues to burn, and the heat may be wasted if the distillery doesn’t need it at that specific moment. 

In an attempt to cater for distilleries’ notoriously “peaky” steam demand, many biomass boilers have been fitted in parallel (duty/assist) with the existing fossil fired boiler. Typically, the design intent was for the biomass boiler to provide the base load, leaving the fossil fuelled boiler to pick up the peaks in demand. However, the limited turndown capacity of boilers can mean that the fossil boiler spends a lot of time on minimum fire, taking a large part of the distillery’s demand, reducing the fossil fuel displacement and actually leaving the peaks to be taken up either by the biomass system or by the fossil boiler cycling on and off. Neither is ideal.

In partnership with engineers in continental Europe who have been designing biomass systems for over 50 years, re:heat have implemented and proven a number of techniques for controlling the fire in the furnace and the boiler pressure to iron-out the mismatch between steam supply and demand. This means the peaks and troughs which are common in distillery applications can be met by a single biomass boiler – without the need for backup plant.

When foul isn’t fair

Gas boilers hardly ever need cleaning, oil boilers maybe once a year. Biomass boilers which are not properly controlled can need much more frequent cleaning due to build-up of tar or soot in the furnace or boiler, particularly when they are burning “difficult” fuels such as wet woodchip or draff.

Furred boiler tubes from running a dry wood boiler on wet fuel

If a “difficult” fuel is readily available at a low cost, then regular cleaning may be justifiable, but in a well-designed biomass boiler system, cleaning twice a year is adequate for most industrial users.

A low carbon footprint can come with a big actual footprint…

It’s an inescapable fact that a biomass store is bigger than an oil tank or a gas governor. If your site is tight, then it might be a struggle to fit a biomass system onto it, but there are usually approaches which can be adopted to manage this. For example, it may be that the fuel supply chain could be tweaked to minimise on-site storage space requirement, or it might be an application for a pellet fired boiler. Certified sustainable pellets are widely available from manufacturers in the UK, which will keep your environmental credentials intact.

It sounds obvious, but a good fuel supply is crucial to successful operation of a biomass boiler. Less obvious is that the fuel supply should be planned out well before the boiler is operational. The biomass fuel supply chain can be daunting to those unfamiliar with it, but don’t worry – there are plenty of people out there who can make it work for you. It doesn’t need to be any more difficult than buying oil, but there are some bear traps to avoid and forward planning will save stress, time and cost.

Biomass boiler plant room under construction, Brora Distillery, October 2020

Summary

There’s no getting away from the fact that distilling is an energy intensive process, and that up to 90% of all the energy used in a distillery can be in the form of steam and heat. You can certainly reduce the energy demand by implementing heat recovery strategies, but there is always going to be a need for heat input. No single heat supply solution is the right one for every application, and no single solution can provide for the whole industry. 

It’s clear, however, that biomass-fired boilers are one of the most technically and economically viable options currently available, and in many cases the only low carbon option which is likely to work for a distillery. Properly designed systems which use high quality equipment and proven technology can be the beating heart of a distillery, and with a realistic lifespan of 25 years or more on the right boiler, it’s important to get it right.

re:heat’s senior team includes forestry, biomass boiler and distillery engineering professionals, meaning we’re ideally placed to assess or implement a biomass-fired solution for your distillery, or to advise on any aspect of the project lifecycle through our consultancy arm. So, if you’re still burning dinosaurs to make whisky, then call us – we can help.

Delivering Renewable Heat – what have targets got to do with it?

Renewable Heat Targets by Steve Luker, Principal Consultant

Back in 2009 we set ourselves some very interesting renewables targets for 2020.  I never quite forgot them, but maybe others did? Theoretically of course they are binding, and you’ll certainly never hear a politician express a scintilla of doubt about this or that policy that will help us meet these targets.  But they get closer everyday.

So as we are only 4 years away, I wanted to examine where we are with the Renewable Heat Target and the role of biomass heat in delivering this.  For this blog I decided to focus on Scotland, as there is some interesting new data that allows a clear focus on this.

For some reason never made clear to me, the Scottish Renewable Heat Target for 2020 is 11%, whereas the UKs target is 12%.  If anyone knows why I’d be interested.

Beyond the obvious question of whether we will actually meet the 11% target, it’s particularly interesting as the Scottish Government is embarking on an energy review and is setting out its objectives for post-2020.  Here’s my attempt to make sense of where we are now.

What do our Renewable Heat Targets imply?

If the Scottish Renewable Heat Target is going to be met by 2020, then 6,420GWhs of annual renewable heat output are needed by that date. At present, Scotland produces 3,031GWhs of renewable heat annually.  Biomass heat contributes 1,716GWhs of that total at present, and biomass CHP contributes most of the rest.

We can roughly calculate how many heat only biomass installations 1,716GWhs is equal to, as each MW of installed capacity provides around 2,600MWhs of heat output.  On that basis, the current biomass heat output represents roughly 660MW’s of installed capacity.  If it is helpful, that’s a bit like 1½ Eon Lockerbie biomass power stations spread over several thousand schools, care homes, swimming pools, rural estates and hospitals.

In present day cash terms it represents £561 million of investment in renewable heat capacity, which I’d say has taken around 15 years to deliver.  A great achievement, if somewhat modest compared to many other northern European countries.

Now, here’s the important bit:

If we simply assume biomass heat will constitute the same proportion of our renewable heat in 2020 (57%), and that the 6,420GWhs of heat is actually provided (the 11% target); then an additional 2,000GWhs of biomass heat must be provided by 2020.  I should say to assume biomass CHP provides a bit more is perfectly reasonable, but if you ‘do the math’ on all other forms of renewable heat (heat pumps and AD), you’ll quickly see they can’t deliver anything like what is needed – never mind making up any biomass shortfall.  In other words, biomass heat may well need to be more than 57%, but lets stick with this figure for now…

192 New MW a Year

So biomass heat has a key role to play in meeting our Renewable Heat Target, and for modelling purposes this can be split into 4 years, which requires 500GWhs of biomass heat output to be added annually.

That means 192MWs of new installed capacity must be added each year for 4 years.

Having got this far, I began to sense a ‘few issues’ about the scale of that challenge…

We know that 1MW of good quality biomass heat capacity costs about £850,000 to install.  As we need 192MWs a year, that requires annual capital investment to run at £163 million for 4 years in row, and £652 million in total : more than has been achieved in the last 15 years combined.

If we assume an average installation size of 250kW, it means 768 installation contracts a year, each worth about £212,500.  Bringing that down to monthly figures it comes to 64 installs a month with a monthly spend rate of £13.6 million.

Typically, each MW of biomass heat capacity creates 2 FTE jobs, so around 1,500 new jobs would be created if 2,000GWhs of biomass heat were produced. In employment terms that would make the sector over 10 times bigger than it is now.

Each scheme will take around 4 to 6 months to plan, design and install. Biomass heat installs require a range of design and contracting skills in M&E, civils, architecture, engineering and a co-ordination expert in biomass to oversee this.

Can we achieve our targets?

There are no reliable figures on how many companies are involved in the design and installation of biomass heat just now.  My own guess is that we have around 10 to 15 specialist biomass companies based in or operating in Scotland, with fewer than 150 direct employees in total. Many others are involved in services like M&E design and civils works, and get involved biomass heat installations alongside their day to day civils contracting, heating and plumbing etc.

Total sector capacity could probably expand quite quickly, but key skills shortages in specialist areas like biomass boiler specification/commissioning and fuel handling  system design will hamper progress.  However, even if demand were to actually run at 64 x 250kW installs a month, it is hard to see how the required capacity could be mobilised sufficiently quickly (i.e. early on in the 4 years we have remaining).

I have reached the clear conclusion that unless things change, the Scottish Government will fall way short of its 2020 renewable heat target.  I do have some thoughts on what could be done to help.  More to follow next week…

re:heat expansion into Scotland

re:heat have made a key appointment to its business and opened a Scottish office as it continues to drive forward ambitious expansion plans.

Respected biomass energy expert Steve Luker has joined re:heat as principal consultant to add extra weight to its comprehensive portfolio of services, supporting client demand for green heating and leading work to drive up industry standards.