The point that kept changing the conversation
At Industrial Heat & Power in Den Bosch in October, one point came up again and again on our stand.
An electric boiler draws its full load the moment the process asks for steam, so the grid connection behind it has to be sized for the biggest steam demand the site ever has. A Storage Boiler charges steadily ahead of time and releases the heat on demand, so the connection no longer has to follow the process.
For a lot of visitors, that was when the question shifted from whether they could electrify steam on their site to what it would take. This article sets out why that point matters.
If you'd like to check your own site first, try our steam savings estimate.
Why steam demand is peaky
Very few process sites draw steam at a steady rate. Batch processes start and stop, cleaning cycles run to a schedule, and lines often come up together at the start of a shift. In a brewhouse, the wort boil creates a large, predictable peak on every brew.
A gas boiler handles this by firing harder. Fuel arrives through a pipe, and the cost of a peak is mostly the fuel burned during it. Electricity works differently.
The first time you pay: infrastructure sized to the peak
If you replace a gas boiler with a direct electric boiler, the boiler itself isn't the expensive part. On equipment cost alone, electric boilers and Storage Boilers are comparable.
The cost is in everything around it. A direct electric boiler has to draw its full rated power whenever the process demands steam, so the grid connection, transformers, switchgear and distribution all have to be sized for peak steam demand rather than the average.
On many sites that means a grid connection upgrade. It's often the largest single item in the project, it can take years to deliver, and it's the main reason steam electrification projects stall.
The second time you pay: charges that follow peak import
Under most commercial electricity tariffs, part of your bill depends on your highest import, not just on the energy you use.
A direct electric boiler turns your steam peaks into electrical peaks. Every batch, cleaning cycle and shift start becomes a spike in import, and the charges follow it.
So a peaky load gets paid for twice: once in the infrastructure built to carry it, and again every billing period in the charges it sets.
What storage changes
A Caldera Storage Boiler is an electric boiler with thermal storage and controls built in. Because charging and discharging are decoupled, the electrical side and the steam side no longer have to move in step.
- Import sized to your average load. The Heat Cells charge steadily and the stored heat covers the peaks, so your connection, transformers and switchgear only need to be sized for average demand.
- Charging within your spare capacity. The controls only charge within the headroom your connection already has, so many sites can start without waiting for an upgrade.
- A peak you choose. Your highest import becomes a figure you set rather than one your process imposes, and the charges linked to peak import follow that figure.
- Peaks covered without oversizing. The store handles short bursts of very high steam demand, with a discharge response of under 60 seconds, so equipment upstream doesn't have to be sized for them.
The steam side stays conventional: saturated steam at up to 16 barg (204°C), over 95% dry, delivered directly into your existing steam plant. It runs alongside your existing boilers, so you can turn a gas boiler down rather than switch it off.
What a site is actually choosing between
Every route to electrified steam needs a boiler. What differs is what has to be built around it.
- Electric boiler on its own: transformer sized to peak, grid upgrade likely, and no flexibility on when you buy power.
- Electric boiler with a battery: two peak-sized transformers, grid upgrade likely, price flexibility, and a battery array to house.
- Electric boiler with a steam accumulator: transformer sized to peak, grid upgrade likely, and minutes of peak cover rather than sustained output.
- Storage Boiler: transformer sized to average, upgrade often avoided, price flexibility, and sustained peak steam without a battery.
Where peaks matter most
The argument holds in every sector, but the size of the saving depends on how peaky your load is.
- Brewing, beverage and distilling have the highest peak-to-average ratio of any sector we work with, so the infrastructure saving is largest. Their predictable batch cycles also suit scheduled charging.
- Food processing is batch and shift-patterned, and many sites belong to multi-site groups, where a design that works once can be repeated.
- Agri-food sites are often rural, where grid constraints are tightest and the connection argument is strongest.
It isn't the answer everywhere. If most of your heat demand is below 80°C and steady, a heat pump is likely to suit you better, and we'll tell you so.
Is your load peaky? Find out from your own data
Whether this works on your site depends on your load shape and your tariff, so we'll model it on your numbers. Send us twelve months of half-hourly demand data and we'll simulate a Storage Boiler across all 8,760 hours of a year against real price signals, then take you through the results.
To get a feel for your own numbers first, try our steam savings estimate. Or come and see a Storage Boiler running at our factory in Fareham.
